(19) & (11) EP 1 819 763 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.: of the grant of the patent: C08K 5/00 (2006.01) 18.07.2012 Bulletin 2012/29 (86) International application number: (21) Application number: 05853524.6 PCT/US2005/044623 (22) Date of filing: 08.12.2005 (87) International publication number: WO 2006/063235 (15.06.2006 Gazette 2006/24) (54) DEFOAMER EMULSION COMPOSITIONS FOR PULP MILL APPLICATIONS ENTSCHÄUMUNGSEMULSIONSZUSAMMENSETZUNGEN FÜR ZELLSTOFFWERKANWENDUNGEN COMPOSITIONS A BASE D’EMULSION ANTI-MOUSSE POUR DES UTILISATIONS DANS LA FABRICATION DE PATE (84) Designated Contracting States: (74) Representative: HOFFMANN EITLE AT BE BG CH CY CZ DE DK EE ES FI FR GB GR Patent- und Rechtsanwälte HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI Arabellastraße 4 SK TR 81925 München (DE) (30) Priority: 10.12.2004 US 635359 P (56) References cited: EP-A- 0 523 418 EP-A- 0 559 319 (43) Date of publication of application: WO-A-00/61077 WO-A-2005/001471 22.08.2007 Bulletin 2007/34 • PATENTABSTRACTS OF JAPAN vol. 015, no.181 (73) Proprietor: HERCULES INCORPORATED (C-0830), 9 May 1991 (1991-05-09) & JP 03 044322 Wilmington, DE 19894-0001 (US) A (SHISEIDO CO LTD), 26 February 1991 (1991-02-26) (72) Inventors: • CHENG, Huai, N. Remarks: Avondale, PA 19311-1432 (US) Thefile contains technical information submitted after • FERNANDEZ, Eric, O. the application was filed and not included in this Jacksonville, FL 32256 (US) specification • SHEEPY, John, M. Burlington, Ontario L7M 3G9 (CA) Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 1 819 763 B1 Printed by Jouve, 75001 PARIS (FR) EP 1 819 763 B1 Description BACKGROUND OF THE INVENTION 5 Field of the Invention [0001] This invention relates to a method of controlling foam in pulp and paper making systems using oil-in-water emulsions as defoamers. The defoamer comprises an oil blend (of a mixture of triglyceride oils and silicone), a stabilizing agent (to make the oil blend stable in the emulsion), hydrophobic particles, surfactants, dispersants, and other compo- 10 nents. The emulsion is usable directly at low concentrations to control foam Description of Related Art [0002] Defoamers are needed in pulp and paper mills to 1) reduce unwanted foam and thereby enhance water drainage 15 from the pulp mat, 2) minimize loss of process chemicals, and 3) increase equipment capacity. Continued improvement of defoamer technology is highly desirable, particularly with respect to cost effectiveness, compliance with environmental regulations, and reduction of unwanted contaminants in pulp and paper products. [0003] Among defoaming applications, pulp and paper mill applications involving black liquors are considered the most challenging. Kraft black liquor is found at different concentrations and compositions in different Kraft mills and can 20 even be different at different stages within the same mill. For illustration, a Kraft black liquor may contain 33% lignin, 27% organic acids, 23% inorganic components, 6% extractives (such as wood resins, fatty and resin acids, di- and triglycerides, steryl esters, sterols, etc.), and 11% bound sodium Many of these components (such as fatty acids, lignin, and wood resin fractions) are natural foam stabilizers. Note that the fatty and resin acids are in saponified/ salt forms at the alkaline pH of the black liquor. In addition, chemical additives also add to the surfactant load, especially in the paper 25 mill. Particulates, such as paper fines and fillers can also stabilize foam under some conditions. Furthermore, the black liquor in the mill entails high temperatures and high pH. [0004] Additional pulp and paper applications of defoamers include their use in sulfite pulping process and in effluent and other water treatment. For many of these applications, the use of triglyceride oils may be particularly attractive because they are perceived to be less toxic and more "green" than other oils. Deformers used in pulp and paper 30 applications may also be used for other non-food industrial uses. [0005] Whereas many defoamers are known, the most effective pulp mill defoamers are oil- in-water emulsions based on silicone. In an oil-in-water emulsion, water constitutes the continuous phase. A simplified silicone defoamer for pulp mill applications consists of four components: 1) water, 2) silicone, 3) hydrophobic silica particles, and 4) one or more dispersants, surfactants, and additives. Within this general scheme, there are a variety of different defoamer formulations 35 possible, differing in the composition or functionality, number of components, nature of the materials chosen, and the process of manufacturing. [0006] Defoamer emulsions are difficult to manufacture, requiring specific compositions and processes to produce stable emulsions. If the emulsion "breaks" and phase separation occurs, the defoamer decreases in efficacy, in addition to the problem of fouling and deposit formation. Thus, a successful defoamer emulsion has to satisfy the requirement 40 of foam minimization and emulsion stability. It must also be microbiologically inert. In addition, if the defoamer emulsion can improve drainage, it has an enhanced value. [0007] WO 2005/001471 forms part of the prior art pursuant to Article 54 (3) EPC and describes a method and apparatus for determining the stability of dispersions and emulsions. [0008] WO 00/61077 relates to a liquid dispersion polymer composition comprising hydrophilic polymer microparticles 45 which are dispersed in a di- or triglyceride oil carrier phase. The compositions are used as a thickening system, in particular for use in personal care and pharmaceutical formulations. [0009] EP 0 559 319 describes an oil-in-water emulsion suitable for preparing UV-absorbing sun creams and lotions. The oil phase may comprise triglyceride esters or silicone oils and is emulsified in an aqueous phase further comprising metal oxide particles. 50 [0010] EP 0 523 418 relates to oil-in- water cream compositions which contain vesicular components such as liposomes. [0011] JP 03044322 describes an indomethacin-containing microemulsion formulation comprising an oil phase op- tionally containing triglycerides or liquid paraffin and an aqueous phase which is emulsified by a hydrophilic surfactant. SUMMARY OF THE INTENTION 55 [0012] This invention relates to a method of controlling foam in a pulp and paper making system comprising adding to said system an oil-in-water emulsion comprising: 2 EP 1 819 763 B1 1) an oil blend of a triglyceride oil and silicone oil or silicone material. The level of silicone oil or silicone material is greater than 2.5% by weight. 2) a stabilizing or compatibilizing agent for the triglyceride oil/silicone oil or silicone material blend, selected from phospolipids and modified silicone products 5 3) hydrophobic particles selected from ethylene bistearamide particles, natural and synthetic wax particles and hydrophobic silica particles 4) surfactants and /or dispersants. In addition, other ingredients, such as thickeners and biocides, can be optionally added. All functional emulsion compo- 10 nents, e.g. triglyceride oils, mixtures of triglyceride oils, silicone oils, silicone materials, stabilizing or compatibilizing agents, surfactants and dispersants, have flash points of 140°F (60°C) or higher. [0013] Optionally pH adjustment is made on the defoamer emulsion, using acid or base, to a desired pH in order to improve the emulsion stability. [0014] "Flash point" means the minimum temperature at which a liquid gives off vapor within a test vessel in sufficient 15 concentration to form an ignitable mixture with air near the surface of the liquid, and shall be determined using the appropriate test methods. For liquids which have a viscosity of less than 45 SUS at 100 °F (37.8 °C), and which do not contain suspended solids, and do not have a tendency to form a surface film while under test, the appropriate test method is specified in the Standard Method of Test for Flashpoint by Tag Closed Tester (ASTM D-56-70) and should be used to determine the Flash point. For liquids which have a viscosity of 45 SUS or more at 100 °F (37.8 °C), or which contain 20 suspended solids, or have a tendency to form a surface film while under test, the appropriate test method is specified in the Standard Method of Test for Flashpoint by Pensky-Martens Closed Tester (ASTM D-93-71) and should be used to determine the Flash point. [0015] [0009] The advantages of the defoamer compositions used in the present application include 1) decreased use of silicone oil or silicone material, 2) lower cost, and 3) more favorable environmental profiles. 25 BRIEF DESCRIPTION OF THE FIGURES [0016] Figure 1. is a graph of the surface tension of mixtures of soybean oil - castor oil at various concentrations. 30 DETAILED DESCRIPTION OF THE INVENTION [0017] All amounts are given by weight unless noted otherwise. Percentages are given as weight percentage of total weight. Ratios are given as weight ratios. [0018] The defoamers used in the present application relate to oil-in- water defoamer compositions, comprising water, 35 an oil blend, a stabilizing or compatibilizing agent for the oil blend, hydrophobic particles, surfactants and/ or dispersants, and other components in specific processes to form the oil-in-water emulsion. The oil blend comprises one or more triglyceride oilsand one or more silicones.All fimctional emulsion components,e.g. triglyceride oils, mixtures of triglyceri de oils, silicone oils, silicone materials, stabilizing or compatibilizing agents, surfactants and dispersants, have flash points of 140°F (60°C) or higher.