Showing papers on "Vinyl acetate published in 1980"

Liquid emulsion polymers useful as pH responsive thickeners for aqueous systems

Abstract: Novel aqueous liquid emulsion polymers are prepared by the copolymerization of (A) about 15-60 weight percent of a C 3 -C 8 α,β-ethylenically unsaturated carboxylic acid monomer, preferably acrylic or methacrylic acid or a mixture thereof with itaconic or fumaric acid, (B) about 15-80 weight percent of a nonionic copolymerizable C 2 -C 12 α,β-ethylenically unsaturated monomer, preferably a monovinyl ester such as ethyl acrylate or a mixture thereof with styrene, acrylonitrile, vinyl chloride or vinyl acetate, and (C) about 1-30 weight percent of certain nonionic vinyl surfactant esters, such as nonylphenoxypoly(ethyleneoxy) 9 ethyl acrylate, to give an emulsion copolymer stable as an aqueous colloidal dispersion at an acid pH lower than about 5.0 but responsive to pH adjustment with base. These emulsion polymers adjusted to a pH of about 5.5 or higher are effective thickeners for a wide variety of aqueous systems including cosmetic products, drilling muds, and particularly aqueous coating compositions such as latex paint.

The Temperature Dependence of the Viscoelastic Behavior of Poly(vinyl acetate)

Abstract: The torsional creep and creep recovery behavior of a high molecular weight (Mw=6.5×105) poly(vinyl acetate) is reported for the temperature range, 37.5°C to 154°C. The results for the recoverable compliance, Jr(t), reveal the usual two dispersions seen between glassy and steady state behavior. The intermediate rubbery plateau compliance, JN, has a value of 2.8×10−7 cm2 dyn−1, reflecting a molecular weight per entangled unit of 8,500. Though the specimen studied was a fraction, the terminal dispersion was extensive. The steady-state recoverable compliance, Je°, was approximately 80 times larger than JN. Because there was considerable information on the terminal dispersion, it was possible to independently determine its temperature dependence, which was found to be indistinguishable from that of the viscous deformation. However, this temperature dependence is significantly different from that of the softening dispersion. The differences observed are in the same sense as that found previously for the softening dispersion and viscous flow dependences of polystyrene.

Piezoelectricity Revealed in the Copolymer of Vinylidene Cyanide and Vinyl Acetate

Abstract: The piezoelectric properties of an alternative copolymer of vinylidene cyanide and vinyl acetate were investigated in connection with the results of dynamic modulus, X-ray diffraction, and electrostriction effect. The rolled and polarized copolymer showed piezoelectricity strong enough to be comparable to that in poly(vinylidene fluoride) films treated by the same poling conditions, but the piezoelectric activity prevailed at high temperature exceeding 100°C. This strong piezoelectricity is considered due to the introduction of large dipole moments such as C–CN groups in the molecule and to the orientation of this large dipole moment in the film.

Polymer blend composition for stretch wrap film

Abstract: A composition adapted for processing into stretch wrap film. The composition comprises between about 40 and about 90% by weight of a high molecular weight copolymer of ethylene and vinyl acetate containing between about 4 and about 25% by weight of repeating units derived from vinyl acetate and having a melt index of between about 0.1 and about 4.0. The composition further comprises between about 8 and about 55% by weight of a linear copolymer of ethylene and a higher alkene. Such linear copolymer has a specific gravity of between about 0.917 and about 0.945. The invention further includes stretch wrap film, a method of producing stretch wrap film of differential cling properties, and a composite film constituted of a layer of the aforesaid ethylene vinyl acetate copolymer and a layer of the linear copolymer of ethylene and a higher alkene.

Additive combinations and fuels containing them

Abstract: An additive combination for improving the cold flow properties of distillate fuels comprises a combination of: (A) a distillate flow improver which is an ethylene containing polymer, preferably a copolymer of ethylene with unsaturated esters, e.g. vinyl acetate; (B) a hydrocarbon polymer of C2 to C30 olefin of number average molecular weight of 103 to 106 or derivatized version thereof, for example copolymers of ethylene and propylene, or polyisobutylene, which are used as lubricating oil V.I. improvers; and (C) a polar oil soluble compound which includes amides, salts, carboxylates, sulfonates, sulfates, phosphates, phenates and borates, having hydrocarbon solubilizing groups, for example salts and amides of polycarboxylic acid such as phthalic anhydride reacted with hydrogenated secondary tallow amine.

Rheology of molten blends of polyoxymethylene and ethylene‐vinyl acetate copolymer and the microstructure of extrudates as a function of their melt viscosities

Abstract: Blends of polyoxymethylene (POM) with a copolymer of ethylene and vinyl acetate (CEVAc) have been studied. The effect of viscosity ratio for melts of the components on the processes of fiber formation in extrudates and on the rheological properties of the molten blend has been tested. The viscosity ratio of the fiber-forming POM and the matrix varied in the range 0.35-27.7. POM ultrathin fibers of unlimited length can be formed in the CEVAc only at a viscosity ratio close to unity. For ratios much greater than unity, the extrudate is found to contain short fibers and a finely dispersed powder or no fibers at all. If the viscosity of the POM melt is lower than that of the matrix, films are formed in addition to fibers. The second factor that governs fiber formation is the extrusion shear stress. An optimum shear stress exists at which the amount of ultrathin fibers is a maximum.

Heat-adhesive composite fibers

Abstract: The heat-adhesive fine composite fibers of the present invention have a denier within the range of 1-20, and consist of as a first component, a crystalline polypropylene and as a second component, an ethylene-vinyl acetate copolymer, a saponification product thereof or a mixture of any of these materials with polyethylene, the content in said second component, of vinyl alcohol and/or vinyl acetate units based upon the total of vinyl acetate, vinyl alcohol and ethylene units being 0.5-18 mol %, and said second component forming at least one part of the fiber surface of said fibers. These fine composite fibers are superior in low temperature heat-adhesiveness, in adhesiveness with foreign raw materials, and in low crimpability. Further the fine composite fibers in which the second component has a specific density of 0.93 or less show almost no crimpability and are useful for wet-type non-woven fabrics. When a polypropylene having a Q value of 3.5 or less is used as the first component, the composite fiber can be obtained by spinning process alone with sufficient fiber strength, and the composite fibers having almost no sensible and latent crimping are very suitable for wet type non-woven fabrics.

Heat-sealable packaging film producing a peelable seal

Abstract: Heat-sealable packaging film producing a peelable seal, process for the preparation thereof and packages made therefrom or comprising such a film. This film produces such a seal on a wide range of packaging films, including polyester, polyvinyl chloride, polyamide and polyacrylonitrile films owing to: 1. its chemical composition which comprises: (a) 55 to 95% by weight of at least one ethylene polymer selected from polyethylene having a density of from 0.91 to 0.93 g/cm 3 and an ethylene-vinyl acetate copolymer containing at most 10% by weight of vinyl acetate, (b) 5 to 30% by weight of polystyrene, and (c) 0 to 20% by weight of a thermoplastic, elastomeric styrene-butadiene-styrene or styrene-isoprene-styrene block copolymer, and 2. the fact that that face of the film which is intended to form the peelable seal, has a surface tension of from 35 to 50, preferably of 37 to 45 millinewtons per meter. The film is prepared by extrusion followed by a corona discharge pretreatment of said face.

Copolymers for pressure-sensitive adhesives based on acrylic esters, (meth)acrylamide vinyl acetate and ethylene

Abstract: A copolymer having good properties for use as a pressure-sensitive adhesive from an aqueous dispersion comprising: (a) from 10% to 30% by weight of ethylene units, (b) from 29% to 69% by weight of acrylic ester units, (c) from 20% to 55% by weight of vinyl acetate units, (d) from 0.2% to 8% by weight of (meth)acrylamide units, and (e) from 0 to 12% of other olefinically-unsaturated monomer units copolymerizable with the above, said copolymer having a glass transition temperature of from -20° C. to -60° C. and a K-value according to Fikentscher, measured in tetrahydrofuran, of from 50 to 180; as well as processes to make the same and aqueous dispersions of the same for use as pressure-sensitive adhesives.

Laminated multilayer structure

Abstract: The multilayer structure is composed of a grafted high-density polyethylene resin layer directly attached to a resin layer of polyamide resin, polyester resin or a saponified copolymer of ethylene and vinyl acetate, or to a metal layer. In such structures it has been difficult to provide adequate bond strength between the iayers, and delamination has previously tended to occur under severe operating conditions. The grafted high-density polyethylene resin layer composed of (a) 97 to 50 parts by weight of a high-density polyethylene resin having a density of 0.945 to 0.970 g/cm3 and being grafted with an aliphatic dicarboxylic acid or functional derivative thereof, with or without a high-density polyethylene resin having a density of 0.945 to 0.970 g/cm3, (b) 3 to 50 parts by weight of an ethylene/4-methyl-1-pentene copolymer having an ethylene content of 93 to 99.5 moie% and a melt index at 190°C of 0.1 to 10 g/10 min., and (c) 0 to 20 parts by weight of a rubbery synthetic polymer or copolymer, the parts by weight of (a), (b) and (c) being per 100 parts by weight of resins (a) and (b) combined. The structures of the invention find use as, for example, packaging materials and building panels.

Continuous emulsion polymerization of vinyl acetate. Part I: Experimental studies

Abstract: An interesting feature of commercial continuous emulsion polymerization reactors is the important phenomenon of sustained oscillations. Laboratory investigations of emulsion polymerization in a continuous stirred tank reactor (CSTR) have shown that the conversion, number of polymer particles and other related properties often oscillate widely with time. These oscillations can lead to emulsifier levels too small to adequately cover polymer particles resulting in excessive agglomeration and reactor fouling. Herein is reported an extensive experimental study of vinyl acetate emulsion polymerization in a CSTR. The effects of initiator and emulsifier concentrations, mean residence time and rate of agitation on the production rate and size distribution of polyvinyl acetate latices were investigated. Domains of reactor operation which give rise to sustained oscillations and massive agglomeration of the latex are mapped which give rise to sustained oscillations and massive agglomeration of the latex are mapped out. The effect of different start-up policies on reactor transients were also investigated.

Adhesive compositions comprising ethylene/polar monomer copolymer and an elastomer

Abstract: Compositions comprising a mixture of an adhesive copolymer of ethylene and a monoolefinically unsaturated polar comonomer, for example, vinyl acetate, in combination with an olefin rubber, preferably a rubbery copolymer of ethylene and propylene, exhibit excellent adhesive properties, particularly when applied to non-porous surfaces such as metals. Creep resistance can be improved by lightly crosslinking the composition with radiation. Typically thermoplastic in nature, these compositions can be made thermosetting by including in the composition a heat activated crosslinking system. The compositions also exhibit resistance to blocking and flexibility at low temperatures.

Semiconducting resin compositions

Abstract: A semiconducting resin composition comprises: (A) 100 to 40 parts of a modified ethylene-vinyl acetate copolymer prepared by graft processing of 100 parts of an ethylene-vinyl acetate copolymer of a vinyl acetate content of less than 35 percent with 25 to 200 parts of an aromatic vinyl monomer; (B) 0 to 60 parts of a rubber; and (C) 3 to 150 parts of a carbon black with respect to 100 parts of the above described components (A) and (B), all quantities in "parts" and "percent" being by weight. A composition of this character has excellent characteristics for its use in forming the outer semiconducting layer of polyethylene-insulated cables.

Package for compounding rubber and compounded rubber

Abstract: A package comprised of (A) an article selected from unvulcanized rubber or compounding ingredients therefor and (B) a protective film of a thermoplastic ethylene/vinyl acetate copolymer containing anti-block agent and having a vinyl acetate content in the range of 11 to 22 percent. The invention further relates to a compounded rubber comprised of a mixture of unsaturated rubber and a package of compounding ingredients contained in the ethylene/vinyl acetate copolymer film.

Cling film composition of olefin polymer blend

Abstract: A film forming composition was prepared which comprises a homogeneous mixture of (a) from 2% to 10% by weight of polyisobutylene having a Staudinger molecular weight of from 3,000 to 50,000; (b) from 3% to 20% by weight of an ethylene-propylene copolymer rubber having a melt index of from 0.2 to 2.0 dg/min. and an ethylene/propylene copolymerization ratio of from 30/70 to 70/30 and (c) the remainder of the mixture being an olefin polymer selected from polyethylene having a density of from 0.915 to 0.930 gm/cc and a melt index of from 0.3 to 5.0 dg/min. and an ethylene-vinyl acetate copolymer wherein vinyl acetate comprises up to 20% of the copolymer. Film prepared from the composition exhibited improved cling properties down to at least -40° C.

Copolymers of acryl esters, vinyl acetate and ethylene, process for their preparation and their use as adhesives

Abstract: Die Erfindung betrifft Copolymerisate aus 30 bis 69 Gew.-% Acrylestern, 20 bis 55 Gew.-% Vinylacetat, 10 bis 30 Gew.-% Athylen, 0,5 bis 8 Gew.-% Amide athylenisch ungesattigter Carbonsauren mit Glasubergangstemperaturen von -20 bis -60° C und K-Werten von 50 bis 180, ein Verfahren zu ihrer Herstellung und Haftkleber, die diese Copolymerisate enthalten. The invention relates to copolymers of 30-69 wt .-% of acrylic esters, 20 to 55 wt .-% vinyl acetate, 10 to 30 wt .-% ethylene, 0.5 to 8 wt .-% of ethylenically unsaturated amides carboxylic acids having glass transition temperatures from -20 to -60 ° C and a K value of from 50 to 180, a method for their preparation and pressure-sensitive adhesive containing these copolymers.

Cocrystallization and polymer miscibility

Abstract: Low-density polyethylene was blended in various proportions with an ethylene/propylene/1,4-hexadiene copolymer having an ethylene/propylene mole ratio of 4.5 and a low level of crystallinity. The DSC melting peak of polyethylene was decreased, the unit cell was expanded, and the spherulitic development was disturbed. The temperature of a dynamic mechanical loss peak varied smoothly with composition between the Tg of the copolymer and the β-relaxation of the polyethylene, but the glass temperature of the copolymer measured by DSC was unchanged. These effects were all diminished when the ethylene/propylene ratio of the copolymer was reduced. Blends with highdensity polyethylene showed little depression of the melting point or change in crystal structure and much less effect on the dynamic mechanical behavior. However, the behavior of copolymers of ethylene with low levels of vinyl acetate or methyl methacrylate was similar to that of low-density polyethylene. Therefore, the ability to cocrystallize is an important factor for limiting the tendency of nonpolar polymers to separate, thereby facilitating the preparation of blends with desirable combinations of properties.

Infrared and microcalorimetric studies of the adsorption of polymers with ester groups, in the main or side chain, at the silica/carbon tetrachloride interface

Abstract: The adsorption of poly(vinyl acetate), poly(methacrylic acid n -butyl ester), and poly(caprolactone) at the silica/carbon tetrachloride interface has been investigated. In these cases, the adsorption occurs largely via hydrogen bonding between the unperturbed surface silanol (SiOH) groups and the carbonyl groups of the polymer. The ratio, Q , between the measured concentrations of interacting SiOH and carbonyl groups was not, however, stoichiometric (i.e., 1:1). Depending on the nature of the polymer and the coverage, the values of Q range above or below 1. Values Q p , of poly(caprolactone) is strongly dependent on the surface coverage, as opposed to the behavior of poly(methacrylic acid n -butyl ester) where no such dependency is indicated. There is a small effect on p with changing coverage in the case of poly(vinyl acetate). By correlating p values with the measured integral adsorption enthalpies, molar net binding (adsorption) enthalpies per polymer segment were determined. These results facilitate a correlation of the binding enthalpy with the spectral shift of the maximum of the SiOH band, in the IR spectrum.

Process for producing antithrombogenic vinyl acetate polymer or hydrolyzate thereof

Abstract: A process for producing an antithrombogenic vinyl acetate polymer or a hydrolyzate thereof which comprises treating the vinyl acetate polymer or hydrolyzate with a solution of a fibrinolytic enzyme so as to fix the fibrinolytic enzyme to the polymer. The resulting antithrombogenic vinyl acetate polymer or hydrolyzate is advantageously used in a material which comes into contact with the blood in use and is especially useful in a surgical tube.

Grafting onto wool. VII. Ceric ion‐initiated graft copolymerization of vinyl monomers. Comparison of monomer reactivities

Abstract: In an attempt to compare relative reactivities of vinyl monomers toward grafting, methyl methacrylate (MMA) and acrylic acid (AAc) were grafted separately to Himachali wool in aqueous medium by using ceric ammonium nitrate (CAN) as redox initiator. Nitric acid was found to catalyze the reaction. Percent grafting was determined as a function of concentration of nitric acid, concentration of CAN, concentration of monomer, time, and temperature. Optimum conditions for maximum grafting were evaluated for each monomer and were found to depend upon the nature of the monomer. Reactivities of MMA and AAc toward grafting were compared with those of methyl acrylate (MA), ethyl acrylate (EA), and vinyl acetate (VAc) reported earlier from this laboratory and were found to follow the order MA > EA > MMA > VAc > AAc. An explanation for the observed order of reactivity of different vinyl monomers is presented.

Thermoplastic molding compositions and process

Abstract: Flame-retardant thermoplastic molding compositions having improved physical and electrical arc track resistant properties are provided, the compositions comprising an intimate admixture of (a) a high molecular weight poly(1,4-butylene terephthalate) homo- or co-polyester, (b)(i) a copolymer of ethylene and vinyl acetate in combination with an aromatic polycarbonate; (ii) poly(ethylene terephthalate); or (iii) reinforcing glass; (c) a flame retardant agent; and (d) a mineral filler.

Flame retarding resin composition

Abstract: A flame-retarding resin composition comprising (1) polybutylene terephthalate, (2) an organohalogen compound as a flame-retarding agent, (3) a flame-retarding supplementary agent, (4) calcium sulfate, and (5) an inorganic fibrous reinforcing agent, and optionally (6) at least one polymer selected from a saponified polyvinyl acetate having a saponification degree of greater than 50 mole %, an ethylene/vinyl acetate copolymer, and a saponified ethylene/vinyl acetate copolymer.

Preparation of vinyl acetate from ethylene, acetic acid and oxygen in the gaseous phase

Abstract: The carriers contain common active components, namely noble metals of the 8th sub-group or compounds thereof, and as activators alkali metal compounds, alkaline earth metal compounds or cadmium compounds. The carriers, too, consist of common materials, such as silicic acid. A novel feature is to be seen in the shape of the carrier particles which are designed as rod sections having a star-shaped cross section (FIGS. 1 to 7) or as ribbed rods (FIG. 8). In relation to the apparent density and thus in relation to the amount of noble metal employed, a considerably higher space-time yield is reached than with carrier particles of a conventional shape.

Ethylenic polymer foams having improved dimensional stability

Abstract: The dimensional stability of relatively unstable substantially closed-cell low density foams of non-ionic ethylenic polymers (e.g., polyethylene, ethylene/vinyl acetate copolymers, etc.) can be notably improved by the incorporation therein (during the preparation thereof) of from about 5 to about 95 weight percent (based on total polymer weight) of a copolymer of ethylene with from about 3 to about 45 weight percent of a monoethylenically unsaturated carboxylic acid.

Method for preparing a water-containing vinyl acetate polymer dispersion, dispersion thus prepared and protective colloid used thereby

Abstract: For preparing a water-containing vinyl acetate polymer dispersion, vinyl acetate monomer and initiator are added to a water solution from an emulsifier and hydroxypropyl starch and/or hydroxyethyl starch. The emulsifier amount is equal to 0,5 to 5 weight % from the monomer amount. The degree of substitution of the starch is higher than 0,8 substituted glucose hydroxyl groups per anhydroglucose unit and lies more specially between 0,8 and 1,8 substituted glucose hydroxyl groups per anhydroglucose unit, when the starch is hydroxypropyl starch or between 0,8 and 2,75 substituted glucose hydroxyl groups per anhydroglucose unit, when the starch is hydroxyethyl starch.

Copolymers of substituted piperidines, their manufacture and use

Abstract: The invention relates to copolymers of polyalkyl piperidines which are substituted by a polymerizable group and which have the formula ##STR1## with olefinic comonomers such as ethylene, styrene, vinyl acetate, acrylates or methacrylates. The copolymers which have a molecular weight of from 1,000 to 10,000 are used as light stabilizers for synthetic polymers which do not migrate to the surface of the polymers.