Durable thermosets from reducing sugars and primary polyamines

Abstract

The present invention provides thermosetting aqueous binder compositions of one or more diprimary diamine, e.g. lysine, or poly(primary amine), e.g. polyethylenimine, and one or more reducing sugar in which the number of equivalents of primary amine relative to the number of equivalents of carbonyl groups in the reducing sugar ranges from 0.4:1 to 2:1, the binders being suitable for use on fiber, nonwoven, woven web and finely divided substrates. The binders are at least substantially formaldehyde free, need no polycarboxylic or polycarboxylate component, and yet provide excellent hot wet tensile strength when cured for as little time as a minute or less in use.

Claims

1. An aqueous binder composition comprising one or more diprimary diamine, and one or more reducing sugar chosen from a reducing monosaccharide, a reducing disaccharide, a stereoisomer thereof, an optical isomer thereof, a hydroxy, halo, alkyl, alkoxy or carbonyl substituted reducing monosaccharide, a hydroxy, halo, alkyl, alkoxy or carbonyl substituted reducing disaccharide, a dehydrated reducing monosaccharide, and a dehydrated reducing disaccharide, wherein the number of equivalents of primary amine relative to the number of equivalents of carbonyl groups in the reducing sugar ranges from 0.4:1 to 2:1, wherein the one or more diprimary diamine is chosen from aliphatic primary diamines, aminoguanidine, aminoguanidine salts, alkylene diamines; cycloaliphatic primary diamines, and aromatic di-primary amines.

Description

EXAMPLES

(1) The following examples serve to better illustrate the invention, which is not intended to be limited by the examples.

Example 1

Treated Glass Microfiber Filter Paper and Tensile Testing Thereof

(2) Curable compositions were prepared by admixing components of each formulation to provide approximately 150 g of an aqueous binder at 15 wt. % solids.

(3) A binder impregnated microfiber filter (Whatman International Inc., Maidstone, England, GF/A, catalog No. 1820 866), in 20.3 cm25.4 cm sheets was prepared by mechanically drawing a filter sheet through a trough filled with 120 grams of a 15 wt. % pre-mixed aqueous binder that has been further mixed by agitation, then sandwiching the soaked sample between two cardboard sheets to absorb excess binder, and pressing between the two cardboard sheets in a Birch Bros. Padder (Waxham, N.C.), set at a pressure of 68.9476 kPa, and a speed 5 m/min. The resulting samples are dried @ 90 C. for 90 seconds in a Mathis Oven (Niederhasli/Zurich, Switzerland) that is vented or equipped with a devolatilizer.

(4) The dried sheets were then cured at 190 C. for 60 seconds and 180 seconds in the same type of Mathis oven used to dry the samples. Post curing weight was determined to calculate binder add-on. Add on is the wt. % based on filter sheet weight of binder solids retained on the filter sheet after curing. All sheets had about 20 wt. % of binder add-on.

(5) The cured sheets were cut into 2.56 cm (1 inch) (cross machine direction) by 10.24 cm (4 inch) (machine direction) test strips and tested for tensile strength in the machine direction in a Thwing-Albert Intelect 500 tensile tester (Phila., PA) The fixture gap was 5.12 cm (2 inches) and the pull rate was 2.56 cm (1 inches)/minute. Strips were tested either as is (dry tensile) or immediately after a 10 minutes soak in water at 85 C. (10 min wet tensile.) Tensile strengths were recorded as the peak force measured during parting. Data reported are averages of seven test strips.

(6) TABLE-US-00001 TABLE 1 Aqueous Binder Formulations A B NH.sub.3 Water Example (g) (g) (g) (g) Add-on 1 Dextrose 20.0 Lysine 4.43 1.84 124.87 21.3/19.8 2 Dextrose 20.0 Lysine 8.87 3.68 146.76 20.4/20.9 3 Comp Dextrose 20.0 Glycine 2.28 1.84 115.60 23.0/19.8 4 Comp Dextrose 20.0 Ethanolamine 0 115.6 19.0/14.4 1.85 5 Comp Dextrose 20.0 Arginine 1.84 133.96 20.4/18.3 5.28 6 Dextrose 20.0 bisAMC 1.84 127.26 20.2/17.6 4.31 7 Comp Sucrose 18.2 Lysine 9.33 3.87 152.12 20.7/18.5 8 Dihydroxy- Lysine 8.86 3.68 148.99 20.4/18.8 acetone 18.2 9 Comp Fructose 18.2 Piperazine 5.23 0.0 132.65 15/8.0 10 Dextrose 20.0 MXD 8.23 0.0 147.83 18.9/20.8 11 Comp Dextrose 20.0 Cysteine 7.65 0.0 144.66 19.5/17.1 12.sup.1 Dextrose 20.0 Lysine 8.86 0.0 167.64 17.4/17.4 13 Dextrose 20.0 poly (ethylenimine).sup.5 0.0 185.16 20.4/19.3 10.00 14.sup.2 Dextrose 20.0 Lysine 8.87 0.0 186.22 20.8/19.9 15.sup.3 Dextrose 20.0 Lysine 8.86 0.0 185.20 20.3/20.3 16.sup.4 Comp Dextrose 20.0 Fish Gelatin 10.09 0.0 214.28 21.1/19.5 17.sup.2 Dextrose 20.0 Lysine 8.87 0.0 180.07 19.3/20.8 .sup.1Tyzor LA (DuPont) 50% solution (DuPont, Wilmington, DE) titanium complex of lactic acid .sup.23-aminopropyl-trimethoxysilane, 1.44 g .sup.3Aluminum I-lactate 1.44 g. .sup.4Norland Dried Fish Gelatin (lot# 8098), mix 30 minutes. .sup.5Poly(ethylenimine): MW.sub.w ~1800; amine equivalent weight is ~175.

(7) The following ingredients were used in the aqueous Binder Formulations:

(8) Dextrose was obtained from Fisher Scientific (Pittsburgh, Pa.) as dextrose hydrate.

(9) Sucrose was obtained from Aldrich Chemical (Milwaukee, Wis.) as an anhydrous solid.

(10) bisAMC: 1,3-bis(aminomethyl)cyclohexane (CAS#2579-20-6)

(11) MXD: m-xylenediamine (CAS#1477-50-0)

(12) PEI: polyethylenimine as a 50% wt. aq. sol'n of a polymer with a Mn ca. 1,800 (GPC) having roughly 25 wt. % of groups as primary ethylenamine (Aldrich catalog no. 408700-250 ml.)

(13) Fish gelatin protein has a content of >1000 amino acids and roughly 3.5 wt. % of primany amine groups (1.3% methionine; and 3.5% lysine).

(14) Lysine and other amino acids were added dry to the formulation.

(15) Ammonia is used as a 28 wt. % aqueous solution.

(16) TABLE-US-00002 TABLE 2 Test Results-Tensile Strength Dry Hot Wet Dry Hot Wet Example 60 sec 60 sec 180 sec 180 sec 1 12.4 3.0 13.0 7.1 2 14.7 5.9 14.2 7.3 3 Comp 10.4 0.0 10.0 0.7 4 Comp 2.4 0.0 7.9 0.0 5 Comp 8.5 0.0 10.4 0.6 6 12.7 7.0 13.3 7.9 7 Comp 10.0 0.0 11.0 0.0 8 12.9 4.9 13.3 5.9 9 Comp 1.3 0.0 6.8 0.0 10 10.8 10.1 13.0 11.8 11 Comp 9.0 0.0 9.0 0.0 12 10.9 7.4 10.2 7.5 13 14.7 9.0 14.0 9.4 14 14.7 11.2 14.2 11.3 15 14.7 8.3 14.8 9.0 16 Comp 13.0 2.5 15.9 4.0 17 14.2 9.3 14.8 12.3

(17) As shown in Table 2, above, aqueous binders of reducing sugars with roughly the same (50) mol. % of diprimary diamines, such as lysine in Examples 2 and 8, a 1,3-bis(aminomethyl)cyclohexane (bisAMC) in Example 6, and an m-xylenediamine (MXD) in Example 10 provided treated filter paper nonwovens having especially good hot wet tensile strength with or without NH.sub.3. As shown in Example 12, the hot wet tensile strength can be further improved by addition of a capping agent, such as a titanium, for example, lactate complex. In addition, Table 2 shows that the inventive aqueous binders successfully provided for a rapid, 60 second cure at 190 C. In contrast, the amino acids glycine, arginine and cysteine which have only one free primary amine and as shown, respectively, in Examples 3, 5, and 11 provided binders exhibiting zero or little hot wet tensile strength. As shown in Example 9, above, a disecondary diamine, piperazine, provided no hot wet tensile strength. In addition, as shown in Example 4, the primary monoamine ethanolamine provided a binder with no hot wet tensile strength. As shown in Example 7 a binder of lysine and a non-reducing sugar, sucrose, gave no hot wet tensile strength.

(18) Also, shown in Table 2, above, a binder of polyethylenimine with dextrose gave very good tensile strength results in Example 13. Binders of Examples 14, 15, and 17 all gave very good tensile strength results with reducing sugars, lysine and capping agents (Example 15) or silanes (Examples 14 and 17) and showed further improvement over the same binder without the capping agent or silane. Meanwhile, fish gelatin in Example 16 gave poor hot wet tensile strength results and did not contain the desired amount of primary amine.