MXPA05009510A - Method of consolidating sand or gravel into a solid mass - Google Patents

Abstract

A composition and method for consolidating aggregate material is disclosed. The method includes introducing a reaction composition into the aggregate material and allowing it to reach on form a polymer which binds the aggregate together. The composition includes polyol, isocyanate, and ester.

Description

METHOD TO CONSOLIDATE SAND OR GRAVEL IN A SOLID MASS The invention relates to a composition and method for consolidating aggregate (gravel, rocks, earth, sand, iron ore, wood chips, or other solid particulate material). More particularly, the invention relates to a composition including polyol, isocyanate and ether, and to a method for reacting the composition to form a polymer that consolidates the aggregate together. As a result of the hydrocarbon reserves in Alaska, there is a significant amount of activities related to the fuel fields that occur in the tundra of Alaska. Alaska tundra typically contains the following materials: salt water ice, fresh water ice, partially melted water or ice, sand, gravel, bedrock, and pebbles. The tundra presents a number of problems to build or to install buildings, well heads, oil pipelines, drilling equipment, etc. As the freeze freezes and thaws with changes in atmospheric conditions, the frozen tundra rises, sinks and sags. As a consequence, it is impractical to employ ordinary methods for building buildings, either by erecting the building in empty concrete foundation walls, or in an empty concrete floor fill.

Additionally, as hydrocarbons flow into the well pipe to a hydrocarbon wellhead, the hot hydrocarbons often melt the tundra ice near the pipeline. When the ice melts, the remaining gravel, rock, etc., simply falls to the nearest solid mass, resulting in large caverns or sunken holes around the hydrocarbon wells. Additional gravel can be added to fill the holes, but continuous melting can result in a continuous problem of sunken hole. A known method has been to inject a reaction composition into the soil below conventional slabs or floors. As discussed above, conventional earthenware construction can not be used under environmental conditions such as the tundra of Alaska. U.S. Patent No. 4,567,708 discloses a method wherein the components of an expanded polymeric foam, such as a closed cell polyurethane foam, is injected below the sunken or broken portion of a floor or tile held on the ground. The space between the floor or earthenware and the earth is reached by drilling at least one hole through the ground or the earthenware and injecting the components of the foam through the hole. As the foam expands between the earth and the floor or tile, a pressure is created, which pushes the part that is sunken or broken upwards. The hardened foam serves as a support for the previously sunken part of the slab or floor. Another frequent construction problem that occurs in Many areas (not limited to the tundra of Alaska) are that temporary construction platforms, foundations, or roads, etc. are often needed. (collectively, surface bases). Surface bases are often prepared by cementing with piles and compacting aggregate. A problem with the use of aggregate for surface bases is that there is little or no cohesiveness, and the aggregate can become dispersed, decreasing the effectiveness of the base. To minimize this problem, some have applied heavy hydrocarbon products, etc., to surface bases, but this can create numerous environmental problems. The present invention includes a reaction composition and a method for reacting the composition to form a polymer that solidifies or solidifies aggregate. The preferred composition of the present invention includes polyol, isocyanate, and ester. The ester acts as a slimming agent in addition to excluding water foreign to the reaction product. More preferably, the composition includes a component on the A side that includes polymeric MDI and a component on the B side that includes a polyol, catalyst, water and 1,4-trimethyl-1,2-pentanediol diisobutyrate (marketed by Eastman Chemical Company under the trade name of TXIB). This preferred composition forms a foam that will strengthen the aggregate. An alternative embodiment includes the same components, but the water is substantially reduced or eliminated. By reacting this composition of alternative reaction, a solid or semi-solid polymer is produced that consolidates the aggregate. Compared with the heavy hydrocarbon products of the prior art, the TXIB with the polyurethanes provides a non-hazardous, environmentally compatible binder. The preferred method of the present invention includes injecting the reaction composition into an aggregate either above or below the ground. The reaction composition ltrates the aggregate and reacts to form a polymer that binds the aggregate particles together when the composition of reaction includes an expanding agent, the reaction composition expands through the aggregate, creating a foam that binds the earth together. When the reaction composition does not include an expanding agent, the reaction composition flows into the aggregate, creating a more dense or solid polymer, which binds the aggregate together, without displacing the aggregate. The present invention includes an improved composition and method for reacting the composition to form a foam or other polymer that consolidates or solidifies the aggregate. Generally, the composition comprises a polyol component ((side B), an isocyanate component (side A), and an ester component.The ester may be present on either side A, side B, or both. The ester acts as a slimming agent in addition to excluding water foreign to the product of the reaction.

The ester is preferably a diester, and is more preferably exemplified by 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (sold by Eastman Chemical Company under the tradename TXIB), but is not limited thereto. A particular advantage that a system using TXIB has over prior art systems is that it is not dangerous and is not harmful to the environment. The ester is preferably present in a range from about 5 weight percent to about 60 weight percent of the total composition. The ester more preferably is present in the range from about 10 weight percent to about 25 weight percent. The isocyanate component of the composition can include isocyanates, polyisocyanates, or isocyanate prepolymers. Preferably, the isocyanate component is a polyisocyanate. As used in the present application, the term "polyisocyanate" refers to any isocyanate having an average functionality greater than or equal to about 2.0. Preferably the polyisocyanate is based on diphenylmethane diisocyanates, such as those obtainable by condensation of aniline / formaldehyde followed by phosgenation ("polymeric MDI") or as derivatives of these polyisocyanates which may contain carbodiimide, biuret, urethane, isocyanurate groups, allophanate, and mixtures of compounds that have these groups, and are liquid at room temperature. The preferred polyisocyanates are exemplified by polymeric MDI sold by Bayer under the trademark MONDUR MR, by BASF under the trademark LUPRANATE M20S, by The Dow Chemical Company under the tradename PAPI 27 or by Huntsman Chemical under the trademark RUBINATE M., but are not limited to them. Alternatively, an isocyanate homopolymer may be used in the composition if it is desired to produce an elastomeric polymer. The elastomeric polymers may be desired to provide some flexibility. A preferred polyisocyanate homopolymer for the preparation of a producing elastomer composition is exemplified by a 4,4-diphenylmethane diisocyanate of equivalent weight 143 modified, such as MM 103, marketed by Basf, MONDUR CD, marketed by Bayer, ISONATE 143L, marketed by The Dow Chemical Company or R 1680, marketed by Huntsman Chemical. Alternatively, an isocyanate prepolymer may be used in the composition, if it is desired to produce an elastomeric polymer. Preferred prepolymers include MONDUR PF, marketed by Bayer, ISONATE 181, marketed by The Dow Chemical Company, or R 1209, marketed by Huntsman Chemical, but are not limited thereto. The polyol component of the composition can include a variety of polyols including polyether polyols, polyester polyols, or combinations thereof. In the preferred embodiment, the polyol is a polyether polyol or a combination of polyols of polyether More preferably, the polyol component includes a fast-reacting amine-based polyol. Preferred polyether polyols are exemplified by 40-770 (a tetrol, with an average hydroxyl number of 770), marketed by Arch Performance Urethanes and Organics, or another equivalent, such as QUADROL®, marketed by BASF. A similar polyol, VORANOL® 800, marketed by The Dow Chemical Company can also be used. Additional polyols that can be used in the composition include Mannich® 466X, marketed by Huntsman or other equivalents, such as Carpol® MX-470, marketed by Carpenter Chemical or Voranol® 470X, marketed by The Dow Chemical Company. Additionally, polyglycols such as E-600, marketed by The Dow Chemical Company and others, can be used in the composition, but are not limited thereto. In addition to the polyol component, the isocyanate component, and the ester, other components may be desired in various embodiments of the composition of the present invention. Catalysts, surfactants, water, and other blowing agents are non-limiting examples of additional components. Preferably, a catalyst is used in the present invention. Preferred catalysts for use in the composition include organic tin compounds, such as tin octoate (II), dibutyltin dilaurate, UL-22 (marketed by Witco Chemical Organics Division under the trademark WITCO FOMREZ UL-22), or Lead naphthenate (PbN), or tertiary amines such as N, N-dimethylcyclohexylamine (DMCHA), marketed as PolyCat 8 by Air Products & Chemicals, 1,4-diazabicyclo [2.2.2] octane (TEDA), marketed under the trademark DABCO by Air Products & Chemicals, and 70% of bis (dimethylaminoethyl) ether in DPG (marketed as BL-11 by Air Products &Chemicals), or amine polyol catalysts such as or 33% TEDA in glycol or dimethylethanolamine (DMEA), amine catalysts, such as pentamethyl diethylenetriamine (PMDETA), marketed as PolyCat 5 by Air Products & Chemicals, but are not limited to them. Other conventional amine and organometallic catalysts known for use in polyurethane forming reactions can be used. Surfactants such as the polyether polysiloxanes known to be useful in polyurethane foam formation reactions can be used in the composition. Surfactants other than silicone can also be used. Surfactants that are not silicone include, but are not limited to, LK443 (sold by Air Products). Suitable surfactants can be obtained from Goldschmidt Chemical, Air Products & Chemicals, Inc., Witco or others. Preferred surfactants for use in the composition include Y-10762, marketed by OSI, B8423, and B8935, marketed by Goldschmidt Chemical. Preferably, the composition will include water. The water can be added in an amount of up to about 5 per percent by weight, preferably up to about 4 percent by weight, and more preferably up to about 2 percent by weight based on the weight of the polyisocyanate. Alternatively, other blowing agents may be used in combination with or as a replacement for water. Organic expanders include non-ozone-containing hydrofluorocarbons, ozone-depleting hydrochlorofluorocarbons, and aliphatic hydrocarbons. Known conventional blowing agents can be used to prepare water-expanded polyurethanes and expanded polyurethanes without water. The expanding agents can be used alone or in mixtures. U.S. Patent No. 6,521,673 describes many of the components that are suitable for use in the present composition. U.S. Patent No. 6,521,673, is incorporated into the present application by reference in its entirety for all purposes. Preferably, the composition is reacted to form a closed cell foam. However, the composition can be reacted to form an open cell foam when better flow characteristics are desired. As described above, an elastomeric polymer can also be formed. An example of a preferred composition includes an A side containing mainly polymeric MDI. Side B of this preferred composition contains about 35 percent by weight up to about 45 weight percent of an amine-based polyether polyol, about 15 weight percent up to about 35 weight percent polyglycol, about 20 weight percent up to about 45 weight percent TXIB, about 0.25 percent by weight up to about 2.00 percent by weight of surfactant, about .75 percent by weight to about 1.5 percent by weight of water, and a combination of amine catalyst and tin catalyst of less than about 1.0 percent by weight. cent by weight. In this preferred embodiment, side A contains about 50 weight percent to about 60 weight percent of the total composition, and side B contains about 40 weight percent to about 50 weight percent. Preferably, the components of this preferred composition are reacted to produce a foam having a free lift density of between about 32.02 and about 128.08 grams per liter. An example of an alternative preferred embodiment includes a composition that uses the same components and scales of the previous paragraph, minus the water component. Preferably, the components of this alternative preferred embodiment react to form a dense polymer in preference to a foam. The following non-limiting examples demonstrate the preferred compositions for reacting and forming a polymer that consolidates or solidifies the porous soil.

EXAMPLE 1 An experimental composition for soil consolidation was prepared using the following components: The B-side components were reacted with an A side containing polymeric MDl. The composition contained 55.2 percent by weight of side A and 44.8 percent by weight of side B, giving an isocyanate index of about 1.08. The composition of the reaction was injected into a container with very small diameter rocks. The product resulting from the reaction was a foam with a free elevation density of about 80.05 grams per liter. The foam did not join rocks with each other.

EXAMPLE 2 When the liquid reaction composition of Example 1 was injected into the reocas, there was a tremendous effect on the reaction, due to the internal heat inherent in the rock mass. A second experimental composition for soil consolidation was prepared using the following components: The amount of TXIB was decreased in the second example and the E-600 replaced a part of the TXIB to give more polymer bonds to the mixture. The composition of the reaction was injected into a container with very small diameter rocks. The product resulting from the reaction was a foam with a free elevation density of approximately 64.04 grams per liter. The Foam did not join the stones together.

EXAMPLE 3 The above experiments were repeated using the water expanding agent. The finished rock / polymer mass was a solid, but the injection and reaction resulted in very little movement of the rock. That is, the reactant composition did not expand in place and pushed the rocks, but instead oozed around and infiltrated the space between the rocks. The preferred method of the present invention generally includes introducing, by injection or otherwise, the composition of the reaction into aggregate, and allowing the composition to react and form a polymer that binds to the soil. The polymer formed by the reaction composition can be a foam or a solid polymer, depending on the specific components used, as described above. The A-side and B-side components of the composition are first added to the aggregate. The A-side components and the B-side components can be premixed, injected by a reaction head, or combined and inserted using other techniques, as a person skilled in the art would know. Once the composition has been injected into the aggregate, the components are allowed to react to form a polymer. Preferably, the reaction process is rapid, and the Training becomes substantially complete within a time of a few minutes. The foregoing discussion and description of the invention are illustrative and explanatory thereof, but to the extent foreseeable, the spirit and scope of the invention are defined by the appended claims.

Claims (21)

1. CLAIMS 1 A method for consolidating aggregate material, comprising: introducing a reaction composition into aggregate material; and allowing the composition to react and form a polymer; characterized in that the reaction contains: polymeric MDl, and a B-side component containing between about 35 percent by weight and about 45 percent by weight of an amine-based polyether polyol, about 15 percent by weight up to about 35 percent by weight polyol, and about 20 weight percent up to about 45 weight percent diisobutyrate of 2,2,4-trimethyl-1,2-pentanediol.
2. 2. The method of claim 1, further characterized in that the composition contains an organic tin catalyst.
3. 3. The method of claim 1, further characterized in that the composition additionally contains an amine catalyst.
4. 4. The method of claim 1, further characterized in that the composition additionally contains water.
5. 5. The method of claim 1, further characterized in that the composition additionally contains a hydrocarbon expanding agent.
6. 6. The method of claim 1, further characterized because the composition additionally contains a hydrocarbon expanding agent.
7. The method of claim 1, further characterized in that the composition additionally contains a surfactant based on a silica.
8. 8. The method of claim 1, further characterized in that the polymer includes a polyurethane foam.
9. The method of claim 1, further characterized in that the polymer includes a polyurethane foam having a density between about 32.02 and about 192.12 grams per liter.
10. The method of claim 1, further characterized in that the polymer includes an elastomeric polymer.
11. The method of claim 1, further characterized in that the isocyanate includes an isocyanate prepolymer.
12. 12. The method of claim 1, further characterized in that the composition is introduced below the earth.
13. 13. A method for consolidating aggregate material, comprising: introducing a reaction composition containing polyol, isocyanate, and an ester, into aggregate material; and allowing the composition to react and form a polymer.
14. The method of claim 13, further characterized in that the composition additionally contains polyglycol.
15. 15. The method of claim 13, characterized in addition because the polyol includes an amine-based polyether polyol.
16. 16. The method of claim 13, further characterized in that the isocyanate comprises polymeric MDl.
17. 17. The method of claim 13, further characterized in that the ester includes 2,2,4-trimethyl-1,2-pentanediol diisobutyrate.
18. 18. The method of claim 13, further characterized in that the polymer includes a polyurethane foam.
19. 19. The method of claim 13, further characterized in that the polymer includes an elastomeric polymer.
20. 20. The method of claim 13, further characterized in that the composition is introduced below the earth.
21. 21. A reaction composition for aggregate consolidation, containing: a side A component containing polymeric MDl; and a B-side component containing polymeric MDl, and a B-side component containing between about 35 weight percent up to about 45 weight percent of an amine-based polyether polyol, about 15 weight percent up to about 35 weight percent. percent by weight of polyglycol, and about 20 weight percent up to about 45 weight percent of 2,2,4-tri-methyl-1,2-pentane diisobutyrate.