Binder Compositions and Uses Thereof

Abstract

The present disclosure provides for aqueous, curable binder compositions, as well as articles and products comprising assemblies of matter comprising mineral fibers, synthetic fibers, natural fibers, cellulosic particles and sheet materials comprising the binder compositions disclosed herein.

Claims

1. A method of manufacturing a product which comprises a bonded assembly of fibrous material or cellulosic particle or sheet material, comprising (i) the provision of (a) a polysaccharide, (ii) the provision of appropriate amounts of (b) azetidinium cross-linker, (iii) the successive or simultaneous application of (a) and (b), optionally as an aqueous composition comprising (a) and (b) and optionally (a) cross-linked by (b), onto fibrous or cellulosic particulate or sheet material to produce resinated material, and (iv) subjecting the resulting resinated material to curing conditions and allowing for evaporation of excess water.

2. The method of claim 1 comprising the successive or concomitant application onto fibrous or cellulosic particulate or sheet material of an aqueous composition comprising (a) cross-linked with (b) and (c) a cross-linker capable of undergoing radical polymerization and optionally (d) a free radical initiator, optionally as a single aqueous composition, to produce resinated material, optionally allowing for cross-linking to occur, and subjecting the resulting aqueous composition to curing conditions and allowing for evaporation of excess water.

3. The method of claim 2, wherein the cross-linking between (a) and (b) and optionally the further cross-linking with (c), optionally in the presence of (d) may be effected at a temperature ranging from ambient temperature (from 10 to 25° C.) to 200° C. during a required period of time to generate the desired cross-linked material.

4. The method of claim 1, wherein the cross-linking between (a) and (b) may be effected by radical initiation.

5. The method of claim 1, wherein the obtained resinated material is subjected to radiation followed by temperature curing.

6. The method of claim 1, wherein temperature curing may be effected at a temperature ranging from 90-200° C.

7. The method of claim 1, wherein the azetidinium cross-linker comprises a polyazetidinium comprising at least two monomeric units of general formula ##STR00002## wherein R.sup.1 comprises a C.sub.1-C.sub.25 alkanediyl group optionally substituted with a hydroxyl group, carboxyl functional group or an amino group, R.sup.2 comprises independently R.sup.1 or —R.sub.3—NH—C(O)—R.sub.4—, wherein R.sub.3 and R.sub.4 comprise independently C.sub.1-C.sub.25 alkanediyl, Y.sup.1 and Y.sup.3 comprise independently H or a C.sub.1-C.sub.5 alkyl group optionally substituted with a hydroxyl group, an amino group or a carboxyl group, Y.sup.2 comprises a hydroxyl group or independently Y.sup.1, and X.sup.− comprises a halogen counter ion.

8. The method of claim 1, wherein the polysaccharide comprises 2-5000 naturally sourced saccharide units selected from the group consisting of cellulose, partially hydrolyzed cellulose, fully hydrolyzed cellulose, chitin, crude starch, starch derivatives and mixtures thereof.

9. The method of claim 1, wherein the dry weight ratio of the polysaccharide to the azetidinium cross-linker in the product comprises a ratio of 98/2 to 70/30.

10. The method of claim 1, wherein the product further comprises one or more coupling agents, dyes, antifungal agents, antibacterial agents, hydrophobes, metal oxide nanoparticles of MgO, CaO, Al.sub.2O.sub.3 and/or CaCO.sub.4, nanoclays of montmorillonite, bentonite, kaolinite, hectorite, halloysite and/or organically modified nanoclays, and mixtures thereof.

11. The method of claim 1, wherein the product is a mineral fiber insulation article that comprises a mineral wool mat.

12. The method of claim 1, wherein the product is a composite wood board article that comprises a wood fiber board, a wood particle board, or plywood.

13. The method of claim 1, wherein the dry weight ratio of the polysaccharide to the azetidinium cross-linker in the aqueous composition comprises a ratio of 95/5 to 75/25.

14. The method of claim 2, wherein the cross-linker capable of undergoing radical polymerization is selected from the group consisting of acrylamide, methacrylamide, acrylate, acrylonitrile, bisphenol acrylics, carbohydrate monomers, fluorinated acrylics, maleimide and mixtures thereof.

15. The method of claim 2, wherein the cross-linker capable of undergoing radical polymerization comprises 1-40% by weight (wt. %) of the total dry weight of the aqueous composition.

16. The method of claim 2, wherein the free radical initiator is selected from the group consisting of inorganic peroxides, organic peroxides, reducing agents, azo compounds, redox initiators, photo-initiators, and mixtures thereof, where the cross-linker capable of undergoing radical polymerization comprises 0.05-5% by weight (wt. %) of the total dry weight of the aqueous composition.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Certain embodiments of the disclosed technology are disclosed in the drawings as filed, wherein:

[0049] FIG. 1 shows a kinetic curing profile at 160° C. for binder formulations comprising 70% Stadex® 79+20% CA1025+10% DEGDMA+1% azobis(cyclohexanecarbonitrile) (ABCN).

[0050] FIG. 2 shows a kinetic curing profile at 160° C. for binder formulations comprising 70% Stadex® 79+20% CA1025+10% HEMA+1% azobis(cyclohexanecarbonitrile) (ABCN).

[0051] FIGS. 3A and 3B show the modulus as a function of temperature measured at two different frequencies (1 Hz and 10 Hz), as determined by dynamic mechanical analysis (DMA), of two different binder compositions.

[0052] FIGS. 4A and 4B show the modulus as a function of temperature measured at two different frequencies (1 Hz and 10 Hz), as determined by dynamic mechanical analysis (DMA), of two different binder compositions.

EXAMPLES

[0053] For the production of the disclosed binder compositions, the starch polymers Stadex® 79, 125 and 201, and ETHYLEX® 2005, 2040 and 2095, were purchased from Tate & Lyle PLC (London, UK). The azetidinium crosslinker CA1025 was purchased from SOLENIS™ (Wilmington, Del., USA). Finally, hydroxyethyl methacrylate (HEMA), diethyleneglycol dimethacrylate (DEGDMA), and 1,1′-azobis (cyclohexanecarbonitrile) (ABCN) were purchased from MilliporeSigma (a division of Merck KGaA, Darmstadt, Del.).

Preparation of Binder Solution Compositions

[0054] A desired amount of saccharide was dissolved in water and stirred constantly for a sufficient period of time (for instance, 45 minutes in the case of starch) at room temperature. As necessary, the temperature was raised up to 80° C. in order to completely dissolve the saccharide in water. For crosslinking reaction, the required amount of azetidinium crosslinker was added to the saccharide solution. The saccharide was allowed to crosslink by stirring at an elevated temperature and/or by adding a small amount of free radical initiator. The resulting mixture was impregnated on a glass veil and subjected to curing. Samples were prepared from the cured glass veil and subjected to different tests as described below.

[0055] Additionally, a portion of the saccharide mixture comprising the azetidinium crosslinker was combined with HEMA or DEGDMA and free radical initiator ABCN. The resulting aqueous compositions were stirred continuously at a pre-set temperature to obtain a complex crosslinked polymer network.

[0056] In accordance with certain embodiments, the crosslinking of starch with an azetidinium crosslinker can take place between various molecules such as amylose to amylose, amylose to amylopectin, or amylopectin to amylopectin. When these linkages are formed, further crosslinking and/or copolymerization reactions can be carried out with polycarboxylic crosslinkers using a free radical initiator as described herein, with free radical initiation being promoted, in some embodiments, by an increase of temperature and/or the introduction of radiation sources such as IR, RF or UV radiation. The resulting aqueous composition was applied to a glass veil and cured. Samples were prepared from the cured veil and subjected to different tests as described below.

Kinetic Evaluation of Curing

[0057] Glass microfiber (Whatman™) GF/A filters were impregnated with binder solution as described above prior to curing at various time points at a set temperature. Samples were kept on the top shelf in an oven to avoid the potentially high moisture content inside the oven during curing. For each binder solution, samples were cured for a time period of 3 minutes to 20 minutes. After curing, each cured sample was cut into an appropriate size of defined length (150 mm) and width (20 mm), and mechanical testing was performed for stiffness and bond strength analysis on the cured samples. The results of the kinetic study or cure rate study are presented in FIGS. 1 and 2.

Bond Strength Analysis Using the Veil Method

[0058] Commercial PF (phenol formaldehyde) impregnated (A4 size) glass fiber veils were placed into a benchtop muffle furnace oven for 30 minutes at 600° C. in order to burnout the PF binder, and were then allowed to cool for 30 minutes. The resulting veil samples were then weighed.

[0059] Next, approximately 400 g binder solution samples were poured into dip trays, and the resulting veil samples were fully immersed into the binder solution samples. The impregnated veils were then cured at defined temperatures for defined periods of time. The resulting binder content was then measured and bond strength determined as described below.

[0060] The bond strength of the cured binder impregnated veils was determined by a mechanical testing instrument (M350-10CT). For each test, a cured binder-impregnated A4-type veil was cut into eight (8) equal strips. Each strip was tested separately using a 50 kg load cell (DBBMTCL-50 kg) at an automated test speed of 10 mm/min. The mechanical testing instrument was controlled using winTest™ Analysis software (Testometric Company Ltd., Rochdale, UK). The glass veil tensile plates were attached to the mechanical testing instrument, with 100 mm gaps between plates. Samples were placed vertically in the grippers, with the force measurement tarred to zero. Various parameters such as maximum load at peak, stress at peak and modulus at peak were evaluated by the software, and data presented as an average of the eight (8) samples, with the standard deviation also determined. The average maximum load at peak or stress at peak is defined as the bond strength of the sample.

Evaluation of Weathering Stability

[0061] An electronically controlled autoclave system (a steam pressure vessel) was then used to sterilize the cured binder veils samples for strength testing. Cured binder impregnated veils were placed in an autoclave (J8341, Vessel: PV02626 with associated safety valve, door interlock and integrated pipework) system. Samples were treated at 90% humidity and at a temperature ranging from 40-110° C. (full cycle), at a pressure of up to 2.62 bar, for three (3) hours. The samples were dried completely in order to ensure no moisture remained on the veils. The autoclave treated samples were then tested for bond strength using the M350-10CT testometric machine (M350-10CT), and the results were compared with those of untreated samples.

Dynamic Mechanical Analysis (DMA)

[0062] Binder impregnated Whatman™ Grade 3 Filter Papers (MilliporeSigma, a division of Merck KGaA, Darmstadt, Del.; dimensions of 35 mm×10 mm×0.36 mm) was prepared with 100 grams of pre-mixed aqueous binder solution comprising 20% solids. Binder impregnated filter strips were kept at ambient temperature (approximately 22° C.) for about one hour for initial drying. Each strip was then carefully mounted on a DMA sample holder. The DMA tests were performed on a dual cantilever mode using two frequencies (1 Hz and 10 Hz) at 1° C./min. The modulus was measured as a function of scanning temperature, and the results are presented in FIGS. 3-4.

EXAMPLE 1

[0063] The determination of binder solid weight loss upon curing at 140° C. for 2 hours is presented in Table 1. Aqueous binder compositions (solutions) as prepared above were brought to a solid content of 22.5%. About 12 g of binder solution was placed into an aluminum petri dish, which was kept in an oven at 140° C. for 2 hours. The theoretical and experimental solid concentration was measured, and the solid loss was calculated. The binder compositions comprise starch as a polysaccharide, azetidinium compound as a crosslinker, acrylates (HEMA: 2-hydroxyethyl methacrylate, or DEGDMA: di(ethylene glycol)dimethacrylate) as an additional crosslinker, and ABCN (1,1′-azobis(cyclohexanecarbonitrile) as a radical initiator.

TABLE-US-00001 TABLE 1 Binder Materials Composition Solid Loss (%) Stadex ® 79/CA1025 90:10 2.4 Stadex ® 79/CA1025/HEMA/ABCN 80:10:10:1 0.12 Stadex ® 79/CA1025 85:15 1.7 Stadex ® 79/CA1025/HEMA/ABCN 75:15:10:1 0.003 Stadex ®79/CA1025 80:20 3.49 Stadex ®79/CA1025/HEMA/ABCN 70:20:10:1 3.49 Stadex ®79/CA1025/DEGDMA/ABCN 70:20:10:1 10.04

EXAMPLE 2

[0064] The kinetic evaluation of curing was determined at 160° C. for binder formulations of Stadex® 79/CA1025/DEGDMA/ABCN, at a ratio of 70:20:10:1, as shown in FIG. 1, with a standard deviation of five replicates. The binder composition was prepared and the stiffness of corresponding sample was measured according to the procedure described in the previous section.

EXAMPLE 3

[0065] The kinetic evaluation of curing was determined at 160° C. for binder formulations of Stadex® 79/CA1025/HEMA/ABCN, at a ratio of 70:20:10:1, as presented in FIG. 2, with a standard deviation of five replicates. The binder composition was prepared according to the description given in the previous section.

[0066] In Examples 2 and 3, some samples were exposed to an additional step, i.e. UV radiation for a time period of 5 minutes, in order to enhance curing, with the results compared to a corresponding un-exposed sample. The binder compositions show good curing time in the range of 3-5 minutes. Additionally, curing may be enhanced by UV radiation treatment prior to temperature curing.

EXAMPLE 4

[0067] The bond strength of various binder formulations comprising a monosaccharide (dextrose monohydrate (DMH)), disaccharide (maltose monohydrate (maltose MH)) and polysaccharide (maltodextrin, from 3 to 19 saccharide units), and their combination with starch (Stadex® 79), CA1025, HEMA, and optionally ABCN, is presented. The mechanical tests were performed on cured (180° C. for 15 minutes) veil samples at dry conditions, for both unweathered and weather treated veils, and the results are presented with standard deviation based on eight replicates, as shown in Table 2.

TABLE-US-00002 TABLE 2 Unweathered Veil Samples Weathered Veil Samples Average Standard Average Standard Bond Deviation Bond Deviation Formulations Strength (N) (+/−) Strength (N) (+/−) DMH/CA1025: 80:20 65.64 13.61 68.61 11.13 DMH/CA1025/HEMA/ABCN: 70.17 17.09 70.45 7.23 70:20:10:1 Maltose MH/CA1025: 80:20 89.17 17.95 75.19 16.68 Maltose MH/CA1025/ 82.63 11.52 70.56 9.71 HEMA/ABCN: 70:20:10:1 Maltodextrin/CA1025: 80:20 104.31 7.62 104.67 8.39 Maltodextrin/CA1025/HEMA/ 100.40 9.70 100.75 7.45 ABCN: 70:20:10:1 Stadex ® 79/DMH/CA1025/ 109.13 14.10 102.04 14.19 HEMA/ABCN: 50:20:20:10:1 Stadex ® 79/Maltose MH/ 103.49 10.06 97.57 5.40 CA1025/HEMA/ABCN: 50:20:20:10:1 Stadex ® 79/Maltodextrin/ 112.16 5.94 99.48 8.53 CA1025/HEMA/ABCN: 50:20:20:10:1

EXAMPLE 5

[0068] Bond strength analysis of various binder formulations comprising starch, azetidinium crosslinker (CA1025), with and without acrylate (HEMA) and radical initiator ABCN or Ce.sup.4+) in the compositions, was performed. The bond strength is defined as the maximum load at which the veil impregnated cured samples breaks down. Results are shown for unweathered and weather treated veil samples. These impregnated veils were cured at a desired temperature (e.g. 180° C.) for 15 minutes and mechanical tests were performed at dry conditions. The results are presented with standard deviation based on sixteen replicates, as shown in Table 3. The invention compositions show high bond strength for all samples. It is noted that the bond strength either remained in the same range within the statistical deviation or improved after weather treatment.

TABLE-US-00003 TABLE 3 Unweathered Veils Weather Treated Samples Veils Samples Average Standard Average Standard Bond Deviation Bond Deviation Formulations Strength (N) (+/−) Strength (N) (+/−) Stadex ® 79/CA1025: 81.27 5.70 91.82 5.28 92.5:7.5 Stadex ® 79/CA1025: 84.81 7.84 95.90 9.52 90:10 Stadex ® 79/CA1025: 95.09 7.46 — — 87.5:12.5 Stadex ® 94.01 9.24 — — 79/CA1025/Ce.sup.4+: 87.5:12.5:1 Stadex ® 79/CA1025: 102.79 14.36 — — 85:15 Stadex ® 79/CA1025/ 99.84 13.08 — — Ce.sup.4+: 85:15:1 Stadex ® 79/CA1025: 92.42 9.65 95.17 7.83 80:20 Stadex ® 94.67 9.55 98.32 13.29 79/CA1025/HEMA: 70:20:10 Stadex ® 84.39 6.59 92.06 8.53 79/CA1025/HEMA/ ABCN: 82.5:7.5:10:1 Stadex ® 94.58 9.39 98.97 9.99 79/CA1025/HEMA/ ABCN: 80:10:10:1 Stadex ® 100.08 14.36 90.62 5.24 79/CA1025/HEMA/ ABCN: 70:20:10:1

EXAMPLE 6

[0069] Modulus analysis by DMA was carried out for binder formulations comprising Stadex® 79/CA1025, comprising a ratio of 85:15, and Stadex® 79/CA1025/HEMA/ABCN comprising a ratio of 75:15:10:1, as presented in FIG. 3A and FIG. 3B, respectively. A significantly higher modulus was observed for the second formulation (FIG. 3B) as compared to the first formulation (FIG. 3A). Similar results were obtained for the composition comprising Stadex® 79/CA1025/HEMA/ABCN at a ratio of 70:20:10:1 (FIG. 4B) as compared to that of Stadex® 79/CA1025 at a ratio of 80:20 (FIG. 4A).

EXAMPLE 7

[0070] The experiments of Example 5 were repeated with different starches, except that the curing temperature was 190° C. and the curing time was 10 minutes. The data obtained is shown in the tables below.

TABLE-US-00004 Veil bond strength Av. Dry Standard Av. Wet Standard Strength Deviation Strength Deviation Formulations (N) (+/−) (N) (+/−) Stadex ® 125/CA1025: 98.46 8.12 77.72 12.44 80:20 Stadex ® 125/CA1025: 95.90 10.47 85.33 6.44 75:25 Stadex ® 125/CA1025: 94.37 7.88 85.82 6.21 70:30 Stadex ® 125/CA1025: 100.38 5.96 83.69 6.45 65:25:10:1 Stadex ® 201/CA1025: 107.87 14.38 97.57 5.86 80:20 Stadex ® 201/CA1025: 109.39 12.91 104.68 7.22 75:25 Stadex ® 201/CA1025: 118.29 6.80 92.43 3.12 70:30 Stadex ® 201/CA1025: 95.22 4.23 85.63 10.44 65:25:10:1 Ethylex ® 2005 S/CA1025: 101.02 9.07 93.69 12.13 80:20 Ethylex ® 2005 S/CA1025: 98.31 5.57 83.41 9.31 75:25 Ethylex ® 2005S/CA1025: 97.85 5.26 91.19 6.94 70:30 Ethylex ® 2005 S/CA1025: 90.27 7.70 91.12 8.97 65:25:10:1 Ethylex ® 2040/CA1025: 112.27 9.55 89.37 8.97 80:20 Ethylex ® 2040/CA1025: 112.06 8.42 76.99 8.52 75:25 Ethylex ® 2040/CA1025: 102.21 8.65 85.13 8.34 70:30 Ethylex ® 2040/CA1025: 93.58 7.11 80.64 5.49 65:25:10:1 Ethylex ® 2095/CA1025: 91.62 3.99 87.38 8.07 80:20 Ethylex ® 2095/CA1025: 101.25 14.15 79.37 5.64 75:25 Ethylex ® 2095/CA1025: 109.23 7.76 82.57 9.70 70:30 Ethylex ® 2095/CA1025: 109.62 5.81 7574 6.85 65:25:10:1

[0071] The above examples make use of commercially available starches as mentioned above. As shown below by way of viscosity measurements, Stadex® starches are low molecular weight starches, Ethylex® 2040 and 2095 starches are higher molecular weight starches.

TABLE-US-00005 TABLE 6 Viscosity measurement of modified starches. Viscosity was measured using a Brookfield DV-II + Pro viscometer (AMETEK GB Ltd. Brookfield, Harlow, Essex, UK). All measurements were performed at a constant temperature. Concen- Viscosity tration Temp. Value Sample Name (wt. %) (° C.) (cps) Comments Stadex ® 79 20 35 6.67 Stadex ® 125 20 35 8.40 Stadex ® 201 20 35 4.17 Ethylex ® 2005 15 35 67 Ethylex ® 2005 20 35 275 Ethylex ® 2040 20 35 xxx The viscosity exceeded the highest detection limit of the machine. Ethylex ® 2040 15 35 9900 Highly viscous. Ethylex ® 2095 20 35 xxx The viscosity exceeded the highest detection limit of the machine. Ethylex ® 2095 15 35 xxx The viscosity exceeded the highest detection limit of the machine. Ethylex ® 2095 10 70 >101,000 Highly viscous (below 70° C. machine did not detect).