摘要:
The invention relates to a process for the preparation of low viscous, water soluble polymer dispersions on an aqueous basis with a high concentration of the active substance, containing a polymerizate A) synthesized from the monomeric components, hydrophobic monomers and optionally amphiphilic monomers, which exhibit an average molecular weight M.sub.w of at least 5.times.10.sup.5 Dalton and contain at least one polymeric dispersing agent D), where in a first step an aqueous dispersion PD) is prepared from the polymerizate A) and at least one polymeric dispersing agent D); in a second step an aqueous, highly concentrated dispersion PD') is prepared from the aqueous dispersion PD) by extracting the water; and in a third step an aqueous dispersion PD") with a high content of the active substance is prepared through the addition of an aqueous dispersion of at least one polymeric dispersing agent D) to the concentrated dispersion PD'), and where the second and third process step can be repeated in succession.
摘要:
The process of producing a stable polymer dispersion by aqueous emulsion polymerization of an ethylenically unsaturated monomer in the presence of a stabilizer selected from a polyester or polyamide containing a sulfate or sulfonate group.
摘要:
Stable water-in-oil emulsions of a hydrolyzed polymer of an N-vinylamide of the formula ##STR1## where R and R.sup.1 are each H or C.sub.1 -C.sub.6 -alkyl, are prepared by polymerizing a compound of the formula I, alone or as a mixture with other monoethylenically unsaturated monomers, in the form of a water-in-oil emulsion to give a water-in-oil polymer emulsion, and then hydrolyzing the polymer, hydrolysis of the polymer in the form of the water-in-oil polymer emulsion being carried out in the presence of an acid or base, and additives in the form of antioxidants, reducing agents or aldehyde acceptors being added for stabilization.
摘要:
Water-soluble copolymers containing copolymerized vinylamine units are prepared by copolymerizing (a) from 95 to 10 mol % of N-vinylformamide and (b) from 5 to 90 mol % of an ethylenically unsaturated monomer from the group consisting of vinyl acetate, vinyl propionate, C.sub.1 -C.sub.4 -alkyl vinyl ethers, the esters, nitriles and amines of acrylic acid and methacrylic acid and N-vinylpyrrolidone, and then eliminating from 30 to 100 mol % of the formyl groups from the copolymer. Preferred copolymers are copolymers of N-vinyl-formamide and vinyl acetate, in which from 30 to 100 mol % of the monomer units are hydrolyzed. The copolymers are used in papermaking to increase the dry strength and wet strength of the paper.
摘要:
Polymeric latexes with a relatively high T.sub.g such as: styrene, butadiene and acrylic acid; or methyl methacrylate, ethyl acrylate and fumaric acid can be used in whole or in part as a binder to produce strong composite board that will not sag substantially under conditions of high temperature and humidity.
摘要:
The invention relates to a paper sheet obtained essentially from (parts by dry weight)______________________________________ Fibers (cellulosic and 20 to 40 "basic mixture" non-cellulosic) Fillers 80 to 60 Latex 40 to 105 ______________________________________ in particular by a process of double flocculation, which has a very high resistance to delamination. The invention is applicable to floor and wall coverings.
摘要:
The invention relates to a treatment process for improving the dimensional stability of a fibrous sheet obtained by papermaking process, and of which at least part of the fibers are cellulosic fibers, said process consisting in impregnating the sheet with a chemical composition containing at least one wetting agent and one binder.
摘要:
The tearing strength of paper is improved by providing a furnish in which the fiber content is predominantly refined fiber with a minor amount, preferably 2 to 10 wt. %, of added unrefined fiber having incorporated therein a heat activatable bonding agent, particularly starch. The bonding agent adheres to and coats the added fiber without chemically reacting with the fiber. A cationic material, particularly polyethyleneimine, is premixed with the raw starch to cause it to adhere to the added fiber. During heat drying of the formed paper the starch is gelatinized to effect enhanced bonding of the added fiber.
摘要:
An antimicrobial additive is incorporated into the binding agent of a heavy-duty, kraft-type paper having the characteristics of substantial density, air impermeability, and improved printability. The antimicrobial additive migrates from within the binding agent onto the paper fibers to substantially eliminate growth of micro-organisms thereon.
摘要:
Composite fine paper suitable for offset and gravure printing at high speeds and containing over 30% filler up to 70% filler for basis weights of 30-150 lbs/3300 ft.sup.2, is produced on a high speed paper-making machine from a furnish containing large quantities of filler, preferably a mixture of clay and talc, and including 3-7% of an ionic latex which is selected to provide good retention and good strength without leaving a residue on the screen.