Improved Binder Compositions and Uses Thereof

Abstract

The present invention relates to an assembly of matter comprising mineral fibers, synthetic fibers or natural fibers, cellulosic particle or sheet material, bonded together by a curable binder composition comprising a monosaccharide and/or polysaccharide and an azetidinium crosslinker and possibly reaction product resulting from the cross-linking between polysaccharide and azetidinium crosslinker, or by a binder obtained by subjecting to curing conditions an aqueous curable binder composition comprising a monosaccharide and/or polysaccharide and an azetidinium crosslinker and possibly reaction product resulting from the cross-linking between polysaccharide and azetidinium crosslinker. The binder composition may further comprise a crosslinker capable of undergoing radical polymerization. Binder compositions and a process for manufacturing said assembly of matter are also disclosed.

Claims

1. An assembly of matter selected from insulation products comprising mineral fibers, and composite wood boards comprising cellulosic particle or sheet material, bonded together by a curable binder composition comprising a polysaccharide and an azetidinium crosslinker and possibly reaction product resulting from the cross-linking between polysaccharide and azetidinium crosslinker, or by a binder obtained by subjecting to curing conditions an aqueous curable binder composition comprising a polysaccharide and an azetidinium crosslinker and possibly reaction product resulting from the cross-linking between polysaccharide and azetidinium crosslinker wherein the weight ratio on a dry basis of polysaccharide to azetidinium cross-linker is comprised between 99/1 to 60/40.

2. The assembly of matter of claim 1 wherein the polysaccharide comprises at least two, preferably at least 4 saccharide units and up to 106 saccharide units, preferably up to 10000 saccharide units, more preferably up to 5000 or even 3000 saccharide units and may be selected from natural sources including but not limited to partially hydrolysed or fully hydrolysed cellulose, derivatives thereof, chitin, crude starch and starch derivatives.

3. The assembly of matter of claim 1 wherein the azetidinium cross-linker is made up of at least two monomeric units, preferably a polyazetidinium of formula ##STR00002## wherein R.sup.1 may be C.sub.1-C.sub.25 alkanediyl, preferably C.sub.1-C.sub.10 alkanediyl or C.sub.1-C.sub.5 alkanediyl, possibly substituted with a hydroxyl group, carboxyl functional group or an amine, R.sup.2 may be independently R.sup.1 or R.sub.3NHC(O)R.sub.4, with R.sub.3 and R.sub.4 being independently C.sub.1-C.sub.25 alkanediyl, preferably C.sub.1-C.sub.10 alkanediyl or C.sub.1-C.sub.5 alkanediyl, Y.sup.1 and Y.sup.3 being H or a C.sub.1-C.sub.5 alkyl group, possibly substituted with a hydroxyl group, an amine or a carboxyl group, Y.sup.2 being OH or independently Y.sup.1, X.sup. being a halogen counter ion; more particularly the product coded CA1025.

4. The assembly of matter of claim 1 wherein the weight ratio on a dry basis of polysaccharide to azetidinium cross-linker is comprised between 98/2 to 70/30, preferably between 95/5 to 75/25.

5. The assembly of matter of claim 1 characterized by one or more of the following features: wherein the binder composition comprises polysaccharide cross-linked with azetidinium cross-linker and further comprises a crosslinker capable of undergoing radical polymerization and possibly a free radical initiator; wherein the binder composition comprises polysaccharide cross-linked with azetidinium cross-linker and further comprises a crosslinker capable of undergoing radical polymerization and possibly a free radical initiator, and the crosslinker capable of undergoing radical polymerization is selected from polycarboxylic acid, acrylamide, methacrylamide, acrylate, acrylic acids and their salts, acrylonitrile, bisphenil acrylics, carbohydrate monomers, fluorinated acrylics, maleimide and mixtures thereof, for initiation of further cross-linking reactions between saccharide residues and the crosslinker; wherein the binder composition comprises polysaccharide cross-linked with azetidinium cross-linker and further comprises a crosslinker capable of undergoing radical polymerization and the further cross-linker is present in the range between 1-40 wt. % of total dry weight of the binder composition; wherein the binder composition comprises polysaccharide cross-linked with azetidinium cross-linker and further comprises a crosslinker capable of undergoing radical polymerization and possibly a free radical initiator selected from inorganic peroxides, organic peroxides, reducing agents, azo compounds, redox initiators, photo-initiators, and mixtures thereof, and is contained in the binder composition in the range of 0.05-5% by weight, preferably higher than 1%, preferably lower than 2% by weight, based on dry weight of the binder composition.

6.-8. (canceled)

9. The assembly of matter of claim 1 further comprising coupling agents, dyes, antifungal agents, antibacterial agents, hydrophobes and other additives known in the art for such binder applications, such as nano-particles derived from inorganic materials such as metal-oxides, preferably MgO, CaO, Al2O3 and CaCO4 or nanoclays, such as montmorillonite, bentonite, kaolinite, hectorite, and halloysite and other organically-modified nanoclays, and mixtures thereof.

10. 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), possibly as an aqueous composition comprising (a) and (b) and possibly (a) cross-linked by (b), onto fibrous or cellulosic particulate or sheet material to produce resinated material, and (v) subjecting the resulting resinated material to curing conditions and allowing for evaporation of excess water.

11. The method of claim 10 comprising the successive or concomitant application onto fibrous or cellulosic particulate or sheet material of an aqueous composition comprising (a) crosslinked with (b) and (c) a cross-linker capable of undergoing radical polymerization and possibly (d) free radical initiator, possibly as a single aqueous composition, to produce resinated material, possibly allowing for cross-linking to occur, and subjecting the resulting aqueous composition to curing conditions and allowing for evaporation of excess water.

12. The method of claim 10 wherein the cross-linking between (a) and (b) and possibly the further crosslinking with (c), possibly in the presence of (d) may be effected at a temperature ranging from ambient temperature (from 10 to 25 C.) to 200 C., preferably from 40-95 C., during a required period of time to generate the desired cross-linked material.

13. The method of claim 10, wherein the cross-linking between (a) and (b) may be effected by radical initiation.

14. The method of claim 10, wherein the obtained resinated material is subjected to radiation followed by temperature curing.

15. The method of claim 10 wherein temperature curing may be effected at a temperature ranging from 90-200 C., preferably higher than 140 C., more preferably lower than 190 C., typically between 160 and 180 C.

16. An aqueous binder composition comprising polysaccharide cross-linked with azetidinium cross-linker, and a crosslinker capable of undergoing radical polymerization, and possibly a free radical initiator.

17. The aqueous binder composition of claim 16 wherein the crosslinker capable of undergoing radical polymerization is selected from polycarboxylic acid, acrylamide, methacrylamide, acrylate, acrylic acids and their salts, acrylonitrile, bisphenil acrylics, carbohydrate monomers, fluorinated acrylics, maleimide and mixtures thereof,

18. The aqueous binder composition of claim 16 wherein the polysaccharide comprises at least two, preferably at least 4 saccharide units and up to 106 saccharide units, preferably up to 10000 saccharide units, more preferably up to 5000 or even 3000 saccharide units and may be selected from natural sources including but not limited to partially hydrolysed or fully hydrolysed cellulose, derivatives thereof, chitin, crude starch and starch derivatives.

19. The aqueous binder composition of claim 16 wherein the azetidinium cross-linker is made up of at least two monomeric units, preferably a polyazetidinium of formula ##STR00003## wherein R.sup.1 may be C.sub.1-C.sub.25 alkanediyl, preferably C.sub.1-C.sub.10 alkanediyl or C.sub.1-C.sub.5 alkanediyl, possibly substituted with a hydroxyl group, carboxyl functional group or an amine, R.sup.2 may be independently R.sup.1 or R.sub.3NHC(O)R.sub.4, with R.sub.3 and R.sub.4 being independently C.sub.1-C.sub.25 alkanediyl, preferably C.sub.1-C.sub.10 alkanediyl or C.sub.1-C.sub.5 alkanediyl, Y.sup.1 and Y.sup.3 being H or a C.sub.1-C.sub.5 alkyl group, possibly substituted with a hydroxyl group, an amine or a carboxyl group, Y.sup.2 being OH or independently Y.sup.1, X.sup. being a halogen counter ion; more particularly the product coded CA1025.

20. The aqueous binder composition of claim 16 wherein the initiator is selected from inorganic peroxides, organic peroxides, reducing agents, azo compounds, redox initiators, photo-initiators, and mixtures thereof, and is contained in the binder composition in the range of 0.05-5% by weight, preferably higher than 1%, preferably lower than 2% by weight, based on dry weight of the binder composition.

21. The assembly of fibrous material according to claim 1 being a mineral wool mat.

22. The assembly of particles according to claim 1 being a wood fiber board, a wood particle board, or plywood.

Description

[0046] The invention will be explained in more details in the examples below with reference to the attached Figures, in which:

[0047] FIG. 1 shows the kinetic evaluation of curing determined at 160 C. for binder formulations of 70% T&L Stadex79+20% CA1025+10% DEGDMA+1% Azobis(cyclohexanecarbonitrile) (ABCN); and.

[0048] FIG. 2 shows the kinetic evaluation of curing determined at 160 C. for binder formulations of 70% T&L Stadex79+20% CA1025+10% HEMA+1% azobis(cyclohexanecarbonitrile).

[0049] FIGS. 3A and 3B show the modulus as a function of temperature measured at two different frequencies (1 Hz and 10 Hz), according to the DMA method, of two different binder compositions.

[0050] FIGS. 4A and 4B show the modulus as a function of temperature measured at two different frequencies (1 Hz and 10 Hz), according to the DMA method, of two other binder compositions.

MATERIALS FOR BINDER FORMULATION

[0051] Starch polymerStadex 79 was purchased from Tate & Lyle. Azetidinium cross-linker CA1025 was obtained from SOLENIS. Hydroxyethyl methacrylate (HEMA), diethyleneglycol dimethacrylate (DEGDMA), and 1,1-Azobis (cyclohexanecarbonitrile) (ABCN) were purchased from Aldrich.

Preparation of Binder Solution Compositions

[0052] A desired amount of saccharide was dissolved in water and stirred constantly for a sufficient period of time (45 minutes in the case of starch) at room temperature. If required, temperature may be raised up to 80 C. in order to dissolve the saccharide in water. For crosslinking reaction, the required amount of azetidinium cross-linker was added to the saccharide solution. The saccharide was allowed to cross-link by stirring at elevated temperature and/or by adding a small amount of free radical initiator. The obtained mixture was then impregnated on a glass veil which was subjected to curing. Samples were prepared from the cured veil and subjected to different tests as described below.

[0053] Part of the saccharide mixture comprising azetidinium cross-linker, obtained above was retained and then combined with HEMA or DEGDMA and free radical initiator ABCN. The obtained aqueous compositions were further stirred continuously at a pre-set temperature to obtain a complex crosslinked polymer network.

[0054] The crosslinking of starch with azetidinium cross-linker can take place between various molecules such as amylose to amylose, amylose to amylopectin, or amylopectin to amylopectin. When these linkages are formed, a further crosslinking and/or copolymer reaction can be carried out with polycarboxylic cross-linkers using radical initiator. The Energy required for radical initiation may be adduced by increase of temperature. Other means are available too, like IR, RF or UV radiation. The obtained aqueous composition was applied to a glass veil which was then subjected to curing. Samples were prepared from the cured veil and subjected to different tests as described below.

Kinetic Evaluation of Curing

[0055] Glass microfiber (Whatman) GF/A filters were impregnated with binder solution as prepared above prior to curing at various time points at a set temperature. Samples were kept on the top shelf in the oven to avoid high moisture content inside the oven during curing. For each binder solution, samples were cured from 3 minutes to 20 minutes. After curing, each cured sample was cut into an appropriate size with a length (150 mm) and width (20 mm), and then mechanical testing was performed for stiffness and bond strength analysis. Results of the kinetic study or cure rate study are presented in FIGS. 1 and 2.

Bond Strength Analysis Using the Veil Method

[0056] Commercial PF (phenol formaldehyde) impregnated (A4 size) glass fiber veils were placed into a 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 obtained veil samples were weighted.

[0057] Approx. 400 g binder solution samples were poured into dip trays, and the obtained veil samples carefully fully immersed into the relevant binder solutions. The impregnated veils were cured at desired temperature for desired periods of time. Binder content was then measured and bond strength determined as follows.

[0058] The bond strength of the relevant cured binder impregnated veils was determined by means of mechanical testing instrument (M350-10CT). For each test a cured binder impregnated A4 veil was cut into 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 controlled by winTest Analysis software. Glass veil tensile plates were attached to the testometric machine in order to ensure a 100 mm gap between plates. Samples were placed vertically in the grippers; and the force was 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 8 samples with standard deviation. The average maximum load at peak or stress at peak defined as the bond strength.

Evaluation of Weathering Stability

[0059] An electronically controlled autoclave system (a steam pressure vessel) was used to sterilise the cured binder veils samples for subsequent 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 C. to 110 C. (full cycle), at a pressure of up to 2.62 bar, for 3 hours. The samples were dried completely in order to ensure no moisture remains onto the veils. The autoclave treated samples were tested for bond strength by means of testometric machine (M350-10CT) described here above, and the results were compared with those of untreated samples.

Dynamic Mechanical Analysis (DMA)

[0060] Binder impregnated Whatman Filter Papers 3 (Catalog No. 1003-150) with a dimension of 35 mm10 mm0.36 mm was prepared with 100 grams of 20% solids pre-mixed aqueous binder solution. Binder impregnated filter strips were kept at ambient temperature (22 C.) for about one hour for initial drying. Each strip was then carefully mounted on DMA sample holder. The DMA tests were performed on a dual cantilever mode using two frequencies (e.g. 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

[0061] Determination of binder solid weight loss upon curing at 140 C. for 2 hours, as presented in Table 1. Aqueous binder compositions (solutions) as prepared above were brought to a solid content of 22.5%. About 12 g of solution was placed into aluminium petri dish, which was kept in an oven at 140 C. for 2 hours. Theoretical and experimental solid was measured and solid loss calculated. The binder compositions comprise starch as a polysaccharide, azetidinium compound as a cross-linker, acrylates (HEMA: 2-hydroxyethyl methacrylate, or DEGDMA: di(ethylene glycol)dimethacrylate) as further cross-linker, and ABCN (1,1-azobis(cyclohexanecarbonitrile) as a radical initiator.

TABLE-US-00001 TABLE 1 Binder Materials Composition Solid Loss (%) Stadex79/CA1025 90/10 2.4 Stadex79/CA1025/HEMA/ABCN 80/10/10/1 0.12 Stadex79/CA1025 85/15 1.7 Stadex79/CA1025/HEMA/ABCN 75/15/10/1 0.003 Stadex79/CA1025 80/20 3.49 Stadex79/CA1025/HEMA/ABCN 70/20/10/1 3.49 Stadex79/CA1025/DEGDMA/ABCN 70/20/10/1 10.04

Example 2

[0062] The kinetic evaluation of curing was determined at 160 C. for binder formulations of Stadex79/CA1025/DEGDMA/ABCN: 70/20/10/1, as presented 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

[0063] The kinetic evaluation of curing determined at 160 C. for binder formulations of Stadex79/CA1025/HEMA/ABCN: 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.

[0064] In examples 2 and 3, some samples are exposed to an additional step, e.g. UV radiation for 5 minutes, in order to enhance curing and the results are compared with corresponding un-exposed sample. It appears that the binder compositions show good curing time in the range of 3-5 minutes. Further, curing may be enhanced by UV radiation prior to temperature curing.

Example 4

[0065] Bond strength analysis of various binder formulations of monosaccharide (e.g. 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, with or without 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 Weathered Veil Samples Samples Average Average Bond Bond Strength STDEV Strength STDEV Formulations (N) (+/) (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 MaltoseMH/CA1025: 80/20 89.17 17.95 75.19 16.68 Maltose MH/CA1025/HEMA/ 82.63 11.52 70.56 9.71 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 Stadex79/DMH/CA1025/HEMA/ 109.13 14.10 102.04 14.19 ABCN: 50/20/20/10/1 Stadex79/MaltoseMH/CA1025/ 103.49 10.06 97.57 5.40 HEMA/ABCN: 50/20/20/10/1 Stadex79/Maltodextrin/CA1025/ 112.16 5.94 99.48 8.53 HEMA/ABCN: 50/20/20/10/1

Example 5

[0066] Bond strength analysis of various binder formulations comprising starch, azetidinium cross linker (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 Veils Samples Samples Average Average Bond Bond Strength STDEV Strength STDEV Formulations (N) (+/) (N) (+/) Stadex79/CA1025: 92.5/7.5 81.27 5.70 91.82 5.28 Stadex79/CA1025: 90/10 84.81 7.84 95.90 9.52 Stadex79/CA1025: 95.09 7.46 87.5/12.5 Stadex79/CA1025/Ce.sup.4+: 94.01 9.24 87.5/12.5/1 Stadex79/CA1025: 102.79 14.36 85/15 Stadex79/CA1025/Ce.sup.4+: 99.84 13.08 85/15/1 Stadex79/CA1025: 92.42 9.65 95.17 7.83 80/20 Stadex79/CA1025/HEMA: 94.67 9.55 98.32 13.29 70/20/10 Stadex79/CA1025/HEMA/ 84.39 6.59 92.06 8.53 ABCN: 82.5/7.5/10/1 Stadex79/CA1025/HEMA/ 94.58 9.39 98.97 9.99 ABCN: 80/10/10/1 Stadex79/CA1025/HEMA/ 100.08 14.36 90.62 5.24 ABCN: 70/20/10/1

Example 6

[0067] Modulus analysis by DMA was carried out for binder formulations comprising Stadex79/CA1025:85/15, Stadex79/CA1025/HEMA/ABCN: 75/15/10/1, as presented in FIG. 3A and FIG. 3B, respectively. Results show a significantly higher modulus in the case of the second formulation (FIG. 3B) as compared to that of the first formulation (FIG. 3A). Similar results were obtained for the composition comprising Stadex79/CA1025/HEMA/ABCN in the ratio of 70/20/10/1 (FIG. 4B) as compared to that of Stadex79/CA1025 in the ratio 80/20 (see FIG. 4A).

Example 7

[0068] The experiment of Example 5 was 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 StDev Av. Wet StDev Formulations (N) +/ (N) +/ Stadex125/CA1025: 98.46 8.12 77.72 12.44 80/20 Stadex125/CA1025: 95.90 10.47 85.33 6.44 75/25 Stadex125/CA1025: 94.37 7.88 85.82 6.21 70/30 Stadex125/CA1025: 100.38 5.96 83.69 6.45 65/25/10/1

TABLE-US-00005 Veil bond strength Av. Dry StDev Av. Wet StDev Formulations (N) +/ (N) +/ Stadex201/CA1025: 107.87 14.38 97.57 5.86 80/20 Stadex201/CA1025: 109.39 12.91 104.68 7.22 75/25 Stadex201/CA1025: 118.29 6.80 92.43 3.12 70/30 Stadex201/CA1025: 95.22 4.23 85.63 10.44 65/25/10/1

TABLE-US-00006 Veil bond strength Av. Dry StDev Av. Wet StDev Formulations (N) +/ (N) +/ Ethylex2005S/CA1025: 101.02 9.07 93.69 12.13 80/20 Ethyles2005S/CA1025: 98.31 5.57 83.41 9.31 75/25 Ethyles2005S/CA1025: 97.85 5.26 91.19 6.94 70/30 Ethyles2005S/CA1025: 90.27 7.70 91.12 8.97 65/25/10/1

TABLE-US-00007 Veil bond strength Av. Dry StDev Av. Wet StDev Formulations (N) +/ (N) +/ Ethylex2040/CA1025: 112.27 9.55 89.37 8.97 80/20 Ethyles2040/CA1025: 112.06 8.42 76.99 8.52 75/25 Ethyles2040/CA1025: 102.21 8.65 85.13 8.34 70/30 Ethyles2040/CA1025: 93.58 7.11 80.64 5.49 65/25/10/1

TABLE-US-00008 Veil bond strength Av. Dry StDev Av. Wet StDev Formulations (N) +/ (N) +/ Ethylex2095/CA1025: 91.62 3.99 87.38 8.07 80/20 Ethyles2095/CA1025: 101.25 14.15 79.37 5.64 75/25 Ethyles2095/CA1025: 109.23 7.76 82.57 9.70 70/30 Ethyles2095/CA1025: 109.62 5.81 7574 6.85 65/25/10/1

[0069] 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 starch are higher molecular weight starches.

TABLE-US-00009 TABLE 6 Viscosity measurement of modified starches. Viscosity was measured using DV-II + Pro Viscometer Brookfield LV. All measurements were done at a constant temperature. Viscosity Sample Concentration Temp. Value Name (wt. %) ( C.) (cps) Comments Stadex 20 35 6.67 79 Stadex 20 35 8.40 125 Stadex 20 35 4.17 201 Starch 15 35 67 Ethylex 2005S Starch 20 35 275 Ethylex 2005S Starch 20 35 xxx The viscosity above Ethylex the highest detection 2040 limit of the machine. Starch 15 35 9900 Highly viscose. Ethylex 2040 Starch 20 35 xxx The viscosity above Ethylex the highest detection 2095 limit of the machine. Starch 15 35 xxx The viscosity above Ethylex the highest detection 2095 limit of the machine. Starch 10 70 >101,000 Highly viscose (below Ethylex 70 C. machine did 2095 not detect).