Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-01-04
2002-02-19
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S245000, C524S247000, C524S249000, C524S250000, C524S251000, C524S460000, C526S203000, C526S209000, C526S211000, C526S217000, C526S220000
Reexamination Certificate
active
06348530
ABSTRACT:
The present invention relates to heat-curable aqueous compositions comprising a carboxyl-containing polymer component and a hydroxyalkylated amine and to their use as binders for shaped articles.
The solidification or consolidation of sheetlike fiber structures such as fiber nonwovens, shaped articles such as fiberboard or chipboard panels, etc., is frequently done chemically using a polymeric binder. To increase the strength, especially the wet strength and heat stability, it is common to employ binders whose crosslinkers give off formaldehyde. However, this brings with it the risk of formaldehyde emissions.
In order to avoid formaldehyde emissions numerous alternatives have already been proposed to the binders known to date. For instance, U.S. Pat. No. 4,076,917 discloses binders whose crosslinkers comprise &bgr;-hydroxyalkylamides and polymers which contain carboxylic acid or carboxylic anhydride. The molar ratio of carboxyls to hydroxyls is preferably 1:1. A disadvantage is the relatively complex preparation of the &bgr;-hydroxyalkylamide.
EP-A-445 578 discloses sheets made of finely divided materials, such as glass fibers, in which mixtures of high molecular mass polycarboxylic acids and polyhydric alcohols, alkanolamines or polyfunctional amines act as binders. High molecular mass polycarboxylic acids described are polyacrylic acid and methyl methacrylate-n-butylacrylate-methacrylic acid and methyl methacrylate-methacrylic acid copolymers. Polyhydric alcohols or alkanolamines employed are 2-hydroxymethyl-1,4-butanediol, trimethylolpropane, glycerol, poly(methyl methacrylate-co-hydroxypropyl acrylate), diethanolamine and triethanolamine. However, the water resistance of the resulting sheets is unsatisfactory.
EP-A-583 086 discloses formaldehyde-free aqueous binders for producing fiber webs, especially glass fiber webs. The binders comprise a polycarboxylic acid having at least two carboxyl groups with or without anhydride groups. Polyacrylic acid, in particular, is used. The binder also comprises a polyol, for example glycerol, bis[N,N-di(&bgr;-hydroxyethyl)adipamide, pentaerythritol, diethylene glycol, ethylene glycol, gluconic acid, &bgr;-D-lactose, sucrose, polyvinyl alcohol, diisopropanolamine, 2-(2-aminoethylamino)ethanol, triethanolamine, tris(hydroxymethylamino)methane and diethanolamine. These binders require a phosphorus-containing reaction accelerator in order to achieve sufficient strengths of the glass fiber nonwovens. It is mentioned that a reaction accelerator of this kind can only be absent if a high reactive polyol is employed. &bgr;-Hydroxyalkylamides are mentioned as highly reactive polyols.
EP-A-651 088 describes corresponding binders for cellulose fiber substrates. These binders necessarily include a phosphorus-containing reaction accelerator.
EP-A-672 920 describes formaldehyde-free binders, impregnating compositions or coating compositions which comprise at least one polyol and a polymer of which from 2 to 100% by weight is accounted for by an ethylenically unsaturated acid or an acid anhydride comonomer. The polyols are substituted triazine, triazinetrione, benzene or cyclohexyl derivatives, the polyol radicals always being in position 1, 3 and 5 of these rings. Despite a high drying temperature, the wet tear strengths achieved with these binders on glass fiber nonwovens are low. In comparative experiments, amine-containing crosslinkers and predominantly linear polyols were tested as well. It is mentioned that amine-containing crosslinkers have a flocculating effect and that the predominantly linear polyols lead to weaker crosslinking than the cyclic polyols.
DE-A-22 14 450 describes a copolymer composed of from 80 to 99% by weight of ethylene and from 1 to 20% by weight of maleic anhydride. Together with a crosslinker, the copolymer is used, in powder form or in dispersion in an aqueous medium, for surface coating. The crosslinker used is an amino-containing polyalcohol. However, in order to bring about crosslinking it is necessary to heat the system at up to 300° C.
EP-A-257 567 describes a polymer composition obtainable by emulsion polymerization of ethylenically unsaturated monomers, such as olefins, vinylaromatic compounds, &agr;,&bgr;-ethylenically unsaturated carboxylic acids and their esters, ethylenically unsaturated dicarboxylic anhydrides and vinyl halides. During polymerization a water- or alkali-soluble or -dispersible resin having a number-average molecular weight of from about 500 to about 20,000 is added in order to influence the flow properties of the polymer composition. The resin is composed of olefins, vinylaromatic compounds, &agr;,&bgr;-ethylenically unsaturated carboxylic acids and the esters thereof or ethylenically unsaturated dicarboxylic anhydrides. Ammonium hydroxide is indicated as the alkaline medium in which said resin is to be soluble or dispersible. The composition can be used to produce formaldehyde-free coatings on wooden substrates.
EP-A-576 128 describes repulpable adhesive compositions comprising an acid-rich polymer component and a low-acid polymer component. The acid-rich polymer component is based on a monomer mixture of from 40 to 95% of an alkyl acrylate or methacrylate and from 5 to 60% of an ethylenically unsaturated acid, such as acrylic or methacrylic acid. The low-acid polymer component is based on a monomer mixture of from 90 to 100% of an alkyl acrylate or methacrylate and from 0 to 10% of an ethylenically unsaturated acid. The compositions are prepared by aqueous emulsion polymerization, with the acid-rich polymer component being polymerized in the presence of the low-acid polymer component or vice versa. The pH of the composition is set at the desired level by adding ammonium hydroxide or sodium hydroxide. The composition can be used as a pressure-sensitive adhesive, laminating adhesive, adhesive for textile wovens, tiles and packaging, and as wood glue.
U.S. Pat. No. 5,314,943 describes a quick-curing formaldehyde-free binder composition of low viscosity for textile materials. The composition comprises a latex, which is a copolymer based on a vinylaromatic compound and a conjugated diene, and a water-soluble copolymer, which is obtained by copolymerizing a mixture of at least one ethylenically unsaturated polycarboxylic acid and at least one olefinically unsaturated monocarboxylic acid. The pH of the composition is set at from 5 to 9 by means of ammonium hydroxide or sodium hydroxide. The composition is employed as a binder for textile substrates.
U.S. Pat. No. 4,868,016 describes a composition based on at least one thermoplastic latex polymer which is insoluble in an aqueous alkaline medium and on at least one alkali-soluble polymer which is incompatible with the latex polymer. The latex polymer is a water-dispersed polymer which can be composed of acrylic or methacrylic esters, vinylaromatic compounds and vinyl esters and of from 0.5 to 3% by weight of an ethylenically unsaturated carboxylic acid as additional copolymer. The alkali-soluble polymer is also composed of these monomers, but contains from 10 to 60% by weight of an ethylenically unsaturated carboxylic acid. To establish the pH at >7 the composition can include ammonia, triethylamine, ethylamine or dimethylhydroxyethylamine. It can be used to provide substrates with a coating.
It is known that stable aqueous (meth)acrylate dispersions formed by emulsion polymerization in the presence of protective colloids can only be obtained if at least 50% of vinyl acetate, based on overall monomers, is incorporated by copolymerization. If the amount of vinyl acetate is less than 50%, agglomeration occurs. U.S. Pat. No. 4,670,505 describes as a solution to this problem a polyacrylate dispersion which is prepared by emulsion polymerization in the presence of from 0.1 to 5% by weight of at least one water soluble amino alcohol having 2 to 36 carbon atoms and from 0.04 to 5% by weight of a protective colloid, based in each case on overall monomers. The resulting latices are of low viscosity and improved pigment binding capacity, and are essent
Beckerle Wilhelm Friedrich
Dreher Stefan
Reck Bernd
Roser Joachim
Seufert Michael
BASF - Aktiengesellschaft
Egwim Kelechi C.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Wu David W.
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