Patent Application
20080221236
The present invention provides binder materials for use in applications such as acid-cured furanic grouts, polymer cements and underwater applications.
Briefly, there is a need to replace petrochemically-derived materials with bio-derived materials due to the gradual decrease in the world supply of petrochemical base materials and the rising costs associated with this decline or manufacture. There is also a need to reduce harmful emissions in the workplace and into the environment. Current technology grouts often incorporate petrochemical materials (phenol, formaldehyde, urea-formaldehyde resins, epoxies, etc.) and a variety of solvents as well as some bio-derived materials (furan, furfuryl alcohol, furanic-based composite pre-blends).
This text focuses on grouts, but the use of the invention in polymer cements will be obvious to those skilled in the art. There is a further example of the utility of this invention in underwater applications.
Formaldehyde and urea-formaldehyde resins in particular are added for strength, chemical resistance and improving the speed of cure with specific catalysts in grouts. If these qualities can be obtained in the grout formulation without the use of formaldehyde or urea-formaldehyde resins, the formulation would be much more acceptable both environmentally and from a safety standpoint.
There is a particular need for chemical resistance in the case of grouts used in food service and/or medical service facilities. In these situations very thorough cleaning, is required. The solutions used for cleaning tend to be very corrosive and tend to degrade typical grouts. Chemically resistant grouts include epoxy and, preferably, furanic grouts (Walters).
Although the furanic grouts are the most chemically resistant, they are also rather dark in color and permeate the tiles, leaving a dark stain to tiles adjacent to the furanic grout when utilized immediately after mixing. Furanic resins darken from a deep-green or deep-blue to a dark-green or black as they cure. To avoid staining, it is necessary to seal the tiles, which can be done during the application of the tiles or at the factory before the tile is shipped by using a wax or paraffin. Either way, this represents extra steps in the application of the furanic grout and therefore an extra expense.
The use of a wax or paraffin tile coating during the furanic grout application also involves an additional step after the furanic grout hardens by requiring the installer to use a high-pressure water or steam rinse to remove the wax or paraffin coating from the tiles. This represents an additional cost in application.
The present invention relates to the use of furanic materials as components of binders for grouts and related materials while reducing or, preferably, eliminating petrochemically derived materials such as formaldehyde, urea-formaldehyde resins, phenol, and epoxy materials as binder components. In one aspect of the invention, the invention relates to the use of materials derived from agricultural waste streams which have been converted into a form suitable for their use in organic binders. Complicating the situation is the increased pressure on agricultural feedstocks by the recent increase in the use of such raw materials for industrial applications such as discussed herein. Furfuryl alcohol, for example, has recently been increasing in cost. Consequently, a formulation balancing inexpensive raw materials from both bio-based and the petrochemically based feedstocks would be best situated to provide a balance of cost, safety, environmental responsibility, and performance.
Such formulation could ideally be utilized to reduce the need for or, preferably, replace phenol-formaldehyde resins, furan-formaldehyde resins, furan-acetone resins, urea-formaldehyde resins, resorcinol, bisphenol-A, bisphenol-A Tars, and/or a portion of FA in a variety of acid-cured furanic grouts.
Examples of bio-derived materials that could be utilized include:
A broad embodiment of the invention includes a furanic grout consisting of a furfuryl alcohol, between about 1 wt-% and 90 wt-% of said furfuryl alcohol being replaced with HMF, FMD or a blend of HMF and FMD; an aromatic polyol between about 15 wt-% and about 50 wt % or between 25 wt-% and about 50 wt %; and optionally glycerol, optionally, silane, and optionally water. Typically the blends of HMF and FDM are at weight ratios between the two components of about 1 to about 99 HMF to FDM, to about 99 to about 1 HMF to FDM.
In some embodiments of the furanic grout the proportion of HMF or FMD ranges from between about 1% and 40% by weight and with organic fillers such as aromatic polyols between about 1 wt-% and 50 wt-%. Also included in the formulations are the appropriate glycerol, silane, and water levels to balance performance.
The present invention provides for formulations which function as chemically resistant grouts. In one aspect of the invention these materials can be the result of acid catalyzed digestion of hexoses, such as fructose, and include furfuryl alcohol (FA, Formula 1) and HMF (Formula 2) as a major component (for examples of HMF synthesis, see U.S. Pat. No. 4,740,605 or the Roman-Leshkov article).
HMF is a primary product of the acid digestion of carbohydrate materials and, as such, is of great interest in the discovery of new applications as it requires relatively few steps to produce.
FDM (Formula 3) can be obtained from HMF by a simple reduction of the aldehyde group.
FDM is known as an accelerator for furanic acid-cured foundry binder processes (WO 9605925) in the metal casting industry where a formaldehyde-containing material is also included in the formulation. FDM in prior furanic binder art is typically synthesized in-situ by the treatment of FA or furan with formaldehyde (See EP 1531018 and U.S. Pat. No. 6,479,567). Thus FDM, oligomers of FDM, and varying amounts of free formaldehyde are present in typical furanic acid-cured binder formulation. Even in a case where FDM was used without added formaldehyde in its formation (EP 0698432), the binder formulation included both FDM and formaldehyde-containing resins. It is commonly believed among those practiced in the aggregate binding art that some formaldehyde, or a urea-formaldehyde resin is needed for rapid through-cure and deep-set properties. It is an intent of this invention to achieve acceptable grout properties without added or in-situ formaldehyde, urea-formaldehyde, or phenol.
In contrast to the reaction of formaldehyde with furan or FA, the FDM in this invention is typically derived from the reduction of HMF. The elimination of formaldehyde improves process safety of these formulations by decreasing potential worker or end-user exposure to formaldehyde.
Surprisingly, the rate of cure with the FDM thus derived is at least as fast as the commercial control containing furanic-formaldehyde resins. This enables either higher productivity with high loadings of FDM, or typical productivity using lower loadings of FDM and/or higher loadings of inexpensive fillers reducing the amount of acid catalyst needed to achieve a similar pot life of the mixed ingredients. This may also allow for the use of less chemically-active catalysts.
A key commercial disadvantage of furanic grouts in chemically resistant applications is the tendency of these rather dark materials to permeate, or “wick” into and stain light colored tiles while the grouts are in a non-cured state. This is especially true if the tiles are lightly fired and/or not sealed. Some embodiments of the furanic grouts of the present invention appear to show less staining, owing in large part to their higher reactivity. The decreased tendency to stain can eliminate or reduce the need to apply protective coatings to the tiles before and during grout applications, which would save time and cost.
Advantages of the various aspects of the present invention include one or more of the following: the replacement or reduction of petrochemical materials used in grouting formulations, replacement or reduction of FA in furanic acid-cured type binders, replacement or reduction of reacted base resins, very fast cure response, reduction in the amount of acid catalyst (as part of the filler) required, decrease in tile staining, reduction in amount of catalyst required, allowance for a less reactive catalyst, and reduction or elimination of formaldehyde from the process and the formulations of making metal casting binders.
In the foundry core and mold making industry, other materials, such as aromatic polyols and various tars have been used as “fillers” in furan based formulation for performance and cost reasons. Such materials have not generally been used in grout formulations as past practice has been to keep the viscosity very low. Using tars and polymers tends to thicken formulation and therefore were thought to impede flow and harm adhesion and/or sealing properties. These materials are largely to entirely petrochemically derived, but they are inexpensive and, in some cases, would be disposed of in land fill. Decreasing the cost of grout type products and finding good use for materials that would otherwise be wasted makes good economic and environmental sense. The materials use in the present invention did not result in reduction of desirable properties such as adhesion, hardness by their inclusion.
Acid-cured furan binders are generally recognized as attractive alternatives to phenolic-based acid-cured binders because grouts made from them, preferably, do not contain free phenol, free formaldehyde, or high levels of volatile organic compounds (VOCs). These grout formulations have excellent chemical resistance and will withstand highly corrosive cleaning conditions such as exist in the food and medical industries except for nitric acid and chlorine compounds.
Inorganic fillers, typically minerals, used at 0-75 wt %, are used to enhance mechanical properties, cover or hide the darkening color from reaction, reduce the reactivity during application between the furfuryl alcohol and the acid catalyst(s), and decrease cost. Typical fillers include clays, graphites, silicates, silica, carbon fibers, polyester or glass fibers, and aluminates or composites thereof. The inorganic fillers are typically introduced to the mix as part of the Part-2 or Part-3 component, which typically includes the acid catalyst component as well. Care must be taken that the surface pH does not compromise the cure of the grout.
Examples of some commercially available silanes are γ-aminopropyl-methyldiethoxy silane (Aldrich); 3-(diethoxymethylsilyl) propylamine (Aldrich); γ-glycidoxy propyltrimethoxy silane (Dow Corning Z6040 and Union Carbide A-187); γ-aminopropyltriethoxy silane (Union Carbide A-1100); N-beta(aminoethyl)-γ-amino-propyltrimethoxy silane (Union Carbide A 1120); γ-ureidopropyltriethoxy silane (Union Carbide A-1160); and many others.
The HMF can be utilized as a partial or full replacement for either FA or a reacted base resin in accordance with the teachings of the present invention. The amount of HMF can range up to about 75 wt % and advantageously it ranges from about 1 to 40 wt %.
The FDM can be utilized as a partial or full replacement for either FA or a reacted base resin in accordance with the teachings of the present invention. The FDM can also enhance the reactivity of formulations in which it is utilized. The amount of FDM can range up to about 90 wt % and advantageously it ranges from about 1 to 50 wt %.
Caution needs to be exercised above 30 percent FDM or HMF, however, as the typical sulfonic or sulfamic catalyzed reaction becomes extremely violent and some ingredients may affect the solubility of the FDM in the binder solution.
Aromatic polyols that may be used as organic fillers include products named Phenrez®, Terol®, and others. These are derived from the reactions of polyethylene oxide polyols and maleic, phthalic and other aromatic acids.
Unexpectedly, it was determined that the use of FDM in a furanic acid-catalyzed grout that is further modified by aromatic polyols and glycerol (an inexpensive bio-derived raw material) greatly increased the rate of reaction as determined by the exotherm temperature. Thus, a less active catalyst can be used and still result in fast cure at a similar pot life compared to a standard furanic grout. This may allow the use of less reactive, lower costing acid catalyst.
HMF and FDM were also tested together along with typical furanic grout binder components to demonstrate their compatibility in various combinations with current state of the art ingredients. These formulations were subjected to a wide variety of tests and were at least comparable to conventional controls in terms of overall reactivity and curing performance.
HMF and glycerol were also tested together along with aromatic polyol fillers and other typical binder components to demonstrate their compatibility in various combinations with current state of the art ingredients. These formulations were subjected to a wide variety of tests and were at least comparable to conventional controls in terms of overall performance.
FDM and glycerol were also tested together and with typical binder components to demonstrate their compatibility in various combinations with current state of the art ingredients. These formulations were subjected to a wide variety of tests and were at least comparable to conventional controls in terms of overall performance.
The faster setting time and early strength development in several inventive formulations could translate into lower overall cost savings owing to higher productivity and a reduction in catalyst percentage, or lower cost alternative catalysts. The higher productivity comes from the faster cure rate and from the fact that these lower-staining formulations may not require the extra step of coating the tiles for stain prevention or it the removal of the wax or paraffin coating after tile and grout application.
All apparatus developed and used for the furanic grout studies were based on ASTM specifications. One apparatus was fabricated to produce the 1-inch×1-inch (25.4 mm×25.4 mm) cylindrical “plugs” used for compressive strength studies (Table 2, C579-01). An apparatus was also compiled to simulate a tile grid with ¼-inch (6.35 mm) wide channels between the cut tiles 19. These channels were filled with the grout formulation under study.
For evaluating the furanic grout formulations, a set of tiles were set and placed into a mortar bed in compliance with the testing methods outlined in the various ASTM methods.
Referring now to
Samples of standard 4-inch×4-inch (101.5 mm×101.5 mm) non-glazed, lightly-fired tiles produced by Dal-Tile Corporation were obtained. These tiles have a small outcropping on each edge measuring 0.25-inch (6.35 mm) used to align the tiles. The tiles are cut down to a 2-inch×2-inch (50.8 mm×50.8 mm) size (shown as length “d” in “
Samples of a mortar material were produced by Superior Adhesives & Chemicals were obtained, as the underlayment material or “mortar bed” 12 used prior to the setting of the tiles. The composition of the mortar is shown on Table 1.
The following examples illustrate various aspects of the invention and are not meant to limit the scope of the invention in any way. All percentages and proportions herein unless otherwise specified are by wt % and all citations are expressly incorporated herein by reference.
The formulations illustrated in Examples 1 through 5 were used to evaluate HMF and FDM as reactive components in furanic grout formulations as partial or complete replacements of FA. For the evaluations, the Part-1, or resin component contained the formulation changes, while the Part-2 or Part-3 remained constant. Chosen as the lab standards was a commercially available furanic grout resin and catalyst component. These standards, designated FURATHANE Part-1, FURATHANE Part-2 and FURATHANE Part-3 are available from Atlas Minerals & Chemicals, Inc., 1227 Valley Road, Mertztown, Pa., 19539-0038.
FURATHANE Part-1 (hereafter Industry Standard Part-1) is a furanic resin containing approximately 35-45 wt % monomeric furfuryl alcohol, 50-60 wt % furfuryl-alcohol-formaldehyde polymer, 3-5 wt % water, and less than 2 wt % each of ethanol, xylene and urea.
FURATHANE Part-2 is a grout powder containing 80-95 wt % petroleum coke, 3-10 wt % sulfamic acid and 1-8 wt % sulfuric acid, with the active acids at the lower ranges per the MSDS.
FURATHANE Part-3 is a grout powder containing the same wt % of ingredients as the FURATHANE Part-2, but with the active acids at the higher ranges per the MSDS.
Lab standards are mixed in a specific ratio of Part-1 to Part-2. This is “typically” a 1:1.3 ratio to maintain a given amount of active catalyst to the resin component. The Part-3 is added in specific ratio's to the Part-1 and Part-2 as required for specific ambient temperature conditions to maintain a given “work time” of the mixed ingredients. Examples of these ratio's are as follows.
Table 2 shows the standard ratio of Part-1 to Part-2 and Part-3 to maintain a given “work time” of the mixed ingredients based on selected ambient temperatures.
1Pph = Parts per hundred (weight)
As Table 2 shows, more part 3 catalyst is needed when the ambient temperature is lower.
This example illustrates the use of HMF in furanic grout formulations.
1Pph = Parts per hundred (weight)
23-(diethoxymethylsilyl) propylamine
The ingredients in each Table 3 formulations were added to an 8 oz jar and shaken for 1 minute at 120° F. (48.9° C.) until dissolved to a clear amber solution. The test methods include:
Measuring exotherms from mixing 28.25-grams of the Industry Standard Part-1 formulation shown in Table 2 with 21.75-grams of the FURATHANE Part-2 grout powder in a small FlackTek® 160 ml mixing cup. The ingredients were mixed using a standard laboratory tongue depressor for 1-minute at 68° F. (20° C.), then placing a pocket thermometer into the mixed grout material and taking temperature readings over the course of several minutes. This gives a relative measurement of the “working time” or “open time” that a person may have to apply the furanic grout mixture between tiles.
Secondly, 43.5 grams of the grout formulations 1, 2, and 3 in Table 3 were mixed additionally for 1-minute at ambient conditions with 56.5-grams of the FURATHANE Part-2 Grout Powder.
Once mixed, the furanic grout mixture was placed in a 60 cc Luer-Lok Syringe having a short ¼-inch (6.35 mm) polyethylene extension nozzle approximately 2-inch (50.8 mm) long attached over the output hole to allow the grout mix to flow evenly to the ¼-inch grout channels between the cut tiles.
An alternative method of applying the mixed grout in the channels between the cut tiles was using a Plas-Pak Industries, 1 Norwich Avenue, Norwich, Conn., 06360, single-chamber 50 cc dispensing tube (item # 060B24×013) attached to a Plas-Pak Industries hand-held ratchet gun (item # TRU30/60 Gun). Using the Plas-Pak Industries ratchet gun provided more control in application of the grout formulations.
ASTM Test C 308-00 Standard test method for working, initial settings, and service strength setting times of chemical-resistant resin mortars was followed as much as possible.
Physical testing of the furanic grout mixtures were based on a known industry standard (FURATHANE) having the following properties according to the relevant test methods indicated and referenced to the ASTM methods shown in Table 4.
Test results for the formulations on Table 3 were as follows; All three resin formulations were observed to “crust over” within 30-minutes of application to the channels. The control did not crust over until 60-minutes. Although crusting over, each mix was observed to be free-flowing under light pressure from the syringe to the grout channel. After 1-hour, the grout channels were observed to have light-colored staining adjacent to the grout channel. The lightly colored initial staining of the cut tiles is attributed to the “wicking” effects of the monomeric furfuryl alcohol, followed by the gradual and typical blacked staining of the petroleum coke as it is drawn into the pre-softened tiles. As the furanic resin is catalyzed and hardens, the furanic resin also darkens to approximately the same coloration as the petroleum coke, giving the typical blackened effect of standard furanic grouts and resins upon complete catalysis.
The end-result being that each HMF containing formulation reacted with the standard Part-2 faster than the control. After being allowed to set overnight, the completed and hardened grout lines were about identical in set and in staining to that obtained with the industry standard grout mix.
This example illustrates the use of FDM in furanic grout formulations.
Additional studies were conducted replacing a portion of the furfuryl alcohol with 2,5 Furan Dimethanol (FDM).
Test results indicated that the reactivity of FDM within a furanic formulation had a considerably higher rate of reactivity with known acid catalysts compared to standard furanic resins.
Table 5 shows selected furanic resin formulations having various levels of FDM and several aromatic polyester polyols.
1Pph = Parts per hundred (weight)
23-(diethoxymethylsilyl) propylamine
The control 3 material of Table 5 was mixed with FURATHANE Part-2 as before.
Then 43.5 grams of the grout formulations 4, 5, and 6 in Table 5 were mixed additionally for 1-minute at ambient conditions with 56.5-grams of the FURATHANE Part-2 Grout Powder.
The Table 6 data based on Table 5 formulations show that the exotherm created by mixing Table 5 resin formulations with the standard Part-2 increases as the wt % of FDM in the formulation increases.
Data in Table 6 shows the exotherms over time. As the weight % of FDM increased, so did the exotherm from the time of mixing. Once the exotherm stopped increasing over two to three minutes, the measurements were stopped.
Each mixture was applied to the grout channels as previously outlined. Over the course of 24 hours, the applied grout mixtures in this example showed slightly more staining than the standard, despite the cure speed. These formulations are good for speed of cure, but obviously need additional help for reduction of staining. The example shows, however, that the use of FDM as a replacement for the reacted base resin of a standard furanic grout formulation is possible. It is possible, then, to eliminate all formaldehyde from this type of formulation.
This Example illustrates the use of HMF and FDM blends in furanic grout formulations.
Given the reactivity of the HMF and the FDM when added separately to a furanic Part 1 formulation, this test used a blend of the FDM and HMF. This was done to determine if any synergistic or adverse effects occurred.
Formulations were made as shown in Table 7. In this example, glycerol was added to determine if this bio-derived ingredient would retard the wicking of FA into the tiles.
1Pph = Parts per hundred (weight)
23-(diethoxymethylsilyl) propylamine
3Water added to slow the exotherm down
The control 3 material of Table 7 was mixed with FURATHANE Part-2 as before.
Secondly, 43.5 grams of the grout formulations 7, 8, and 9 in Table 7 were mixed additionally for 1-minute at ambient conditions with 56.5-grams of the FURATHANE Part-2 Grout Powder.
The three test grout formulations were mixed and applied to grout channels as previously outlined. After 1-hour, the light furfuryl alcohol staining was again observed. In all cases, the experimental grout formulations formed a fully hardened grout channel when checked after 24-hours, as did the standard.
This example demonstrates that blends of HMF and FDM may be added to furanic formulations in the presence of aromatic polyols, water and glycerol to deliver a high degree of reactivity. This may allow the use of lower reactivity/lower cost catalysts.
This example illustrates the use of HMF blends in furanic grout formulations with glycerol.
Another series of formulations (Table 8) were made using HMF from two lots, as a replacement for a reacted base resin, and also containing Glycerol, but no HMF. This test was performed to determine lot-to-lot reproducibility.
1Pph = Parts per hundred (weight)
23-(diethoxymethylsilyl) propylamine
Once again, the formulations were mixed and applied as previously outlined. That is the control 4 material of Table 8 was mixed with FURATHANE Part-2 as before. Secondly, 43.5 grams of the grout formulations 10, 11, and 12 in Table 8 were mixed additionally for 1-minute at ambient conditions with 56.5-grams of the FURATHANE Part-2 Grout Powder.
As with the previous tests, all the experimental formulations had noticeably higher exotherms.
All grout channels appeared to fully cure over 24-hours, as did the lab standard. With the increased reactivity of the experimental formulations, a reduced concentration of acid catalyst could be possible, or alternate methods of application used for placing the grout between tiles (as with a static mixer). Staining was not improved in these tests.
This example illustrates catalyzing the HMF containing furanic grout with phosphoric acid.
Because of the increased reactivity of the HMF and FDM in a cold-blended furanic grout resin, it was desirable to learn if such a formulation would fully harden using inexpensive, relatively weak phosphoric acid in place of the standard sulfamic/sulfuric acid combination.
A simple formulation of was made as show in Table 9.
1Pph = Parts per hundred (weight)
23-(diethoxymethylsilyl) propylamine
To evaluate this concept, a Part-2 had to be formulated containing the phosphoric acid, with a “filler” to replace the petroleum coke. Since the source of petroleum coke used for the standard Part-2 was not available, it was decided to use finely screened Wedron 540 silica sand.
A blend of 85% phosphoric acid, from Sigma-Aldrich (10 wt %); was mixed into the screened Wedron silica sand (90 wt %) to create a blended Wedron-P Part-2 that could be used with the Formulation 13 Part-1 as shown in Table 8.
The Formulation 13 Part-1 resin was mixed with the Wedron-P Part-2 catalyst blend using the same procedures as before. Approximately 28-grams of the Wedron-P Part-2 catalyst blend was mixed with 22-grams of the experimental furanic resin from Table 9 for 1-minute. The exotherm was measured at 95° F. (35° C.) after 1.5 minutes and completely set up within 4-minutes from mix. Since the HMF appears to be less reactive than FDM in these formulations, it can be assumed that an experimental resin made with FDM in place of the HMF and catalyzed with a phosphoric acid mixture would be even more reactive.
The use of the phosphoric acid by itself (e.g. without a filler such as silica sand) in a Part-2 formulation with a HMF or FDM containing Part-1 Resin provides a formulation suited for high-speed applications, or applications of a furanic grout at lower ambient temperatures.
Those skilled in the art will also be able to use other weaker acid (i.e. lower pKa) catalysts, such as sulfonic acid, in place of either sulfamic acid, sulfuric acid or phosphoric acid in a Part-2 formulation if the Part-1 formulation incorporates the HMF or FDM raw materials, preferably using an aromatic polyol, glycerin and water to adjust cost, flow, and cure rates as taught in the examples above.
This example illustrates the catalyzing of a HMF and FDM furanic grout mix under water.
The Examples above have shown that the HMF and/or FDM containing furanic grout formulations show extreme reactivity, as evidenced by high exotherms compared to the industry standard Part-1 Formulation. It seemed possible that such a formulation would be amenable to underwater curing if the reactivity rate is much higher that the rate of water incursion and dispersion of the components.
A resin Formulation 14 made from a composite blend (Table 10) was mixed with the standard catalyst containing Part-2 grout material. The use of glycerol was chosen as a replacement for a portion of the water and to aid in “waterproofing” some of the bonding that would take place between the ingredients.
1Pph = Parts per hundred (weight)
23-(diethoxymethylsilyl) propylamine
Using standard aquarium stones procured from a local aquarium shop with stone size varying from ⅛″ (3.1 mm) to ⅞″ (22.2 mm) in size and shape as the aggregate, a mixture was made of the Table 10 formulation 14 with the standard FURATHANE Part-2 powder as follows.
To 200-grams of the dried, but used, aquarium stones was mixed 56.5-grams of the FURATHANE Part-2 grout powder. Then 43.5-grams of the Formulation 14 furanic resin composite was added to the blend of stones and FURATHANE Part-2. This was mixed by hand using a tongue depressor. As soon as a 1-minute mixing cycle was completed, the mixed Part-1, Part-2 and aquarium stones was poured into a 500 ml beaker filled halfway with tap water, using as 1.5-inch diameter tube to simulate placing the aggregate mix under the water's surface through a large hose or similar apparatus. The poured mixture was then allowed to remain over night.
The mixture that was poured under the surface of the water showed no sign of any residual resin or petroleum coke migrating to the surface. There was a trace of particulate, probably from the mixed aggregate that floated to the surface.
After 24 hours, the mixture was evaluated by decanting the water from the beaker, then removing the furanic grout mix from the bottom. The mix came out as a solid mass. The solid mass was slightly soft and was allowed to dry hard on paper towels for approximately 1-hour.
The performance verifies the concept of under water cure using the FDM and HMF modified furanic formulations. Such as composite should have many uses for those skilled in the use of furanic resins. As in previous examples, it should be possible to achieve cure with a wide range of catalyst acids.
While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all of the possible equivalent forms or ramifications of the invention. It is to be understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit of the scope of the invention.
The present application claims the benefits of U.S. Provisional Application Ser. No. 60/903,794, filed Feb. 27, 2007. The complete disclosure of the above provisional application is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 60903794 | Feb 2007 | US |
