Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
  • C08J3/242—Applying crosslinking or accelerating agent onto compounding ingredients such as fillers, reinforcements

Definitions

• the present invention concerns a method for the in situ formation of a water barrier in or on at least one substrate or between at least two substrates, and a multi-pack composition suitable for use in such a method.
• SAPs Crosslinked superabsorbent polymers
• SAPs are well known and are polymers that can absorb and retain large amounts of water relative to their own mass.
• the largest use of SAPs typically derived from crosslinking of sodium and potassium salts of hydrophilic organic polymers, is in a variety of hygiene products, such as diapers, sanitary napkins and adult protective underwear.
• Such crosslinked superabsorbent polymers have also been used for blocking water penetration in underground power or communications cables, as horticultural water retention agents, in geomembranes and in the control of spill and waste aqueous fluids. Many applications utilise the SAPs in the form of dried powders.
• SAPs have often been provided as a coating on a nonwoven or woven sheet, with the coated product being used as a water blocking layer for a variety of applications.
• JP-A-11319553 discloses the manufacture of a sheet comprising a water absorbing gel binder sandwiched between two sheet-like fibre materials.
• the gel binder is prepared by coating the sheet-like fibre material with a solution comprising a polyacrylic acid and/or polyacrylate, a polyhydric alcohol and a crosslinker, before desiccation to a moisture content of 4 to 20 weight percent.
• WO2010/142568 discloses the manufacture of a swellable non-woven by a process which involves contacting a fibrous web with a polymer composition and drying the impregnated web.
• JP51-143799 discloses a liquor for textile treatment to improve oil and water repellency, wherein the liquor contains polyethyleneglycol diglycidyl ether and a copolymer of perfluoroalkyl acrylate and meth(acrylic) acid.
• WO-A-2011/121319 discloses a method of forming a crosslinked superabsorbent polymer on a non-woven or woven substrate, said method comprising (i) coating a non-woven or woven substrate with an aqueous composition comprising a dispersion of a hydrophilic organic polymer comprising carboxyl functionality, a base having a boiling point no greater than the boiling point of water, and a water soluble crosslinking agent capable of crosslinking the polymer in the absence of base; and heating the coated substrate to a temperature above the boiling point of water to volatilize the base, initiate crosslinking and remove water, so as to form the crosslinked superabsorbent polymer on a non-woven substrate.
• the present invention provides a method for the in situ formation in or on at least one substrate or between at least two substrates, of a water barrier consisting of a water-impermeable composition comprising water and a network of crosslinked organic polymer, wherein water comprises at least 50 wt% of said composition, said method comprising:
• a) providing a first composition comprising a water soluble crosslinking agent having at least two reactive groups wherein each reactive group is capable at room temperature of undergoing a condensation reaction upon contact with a carboxyl group,
• a second composition comprising a waterborne crosslinkable, hydrophilic organic polymer having a weight average molecular weight of at least 200,000 (according to ASTM D4001 - 93(2006)) wherein said polymer comprises at least 80 wt% polymerized units of an ethylenically unsaturated monomer having at least one carboxyl group, and wherein said carboxyl groups in said second composition will undergo condensation reactions with said crosslinking agent upon admixture of the first composition with the second composition at room temperature, c) forming a mixture of said first composition and said second composition, and, before all the reactive groups of the crosslinking agent have reacted with carboxyl groups on the polymer, so forming a water-impermeable composition comprising water and a network of crosslinked organic polymer,
• the amount of said first composition and said second composition in the mixture is such that the number of groups capable of undergoing a condensation reaction with a carboxyl group in the crosslinking agent to the number of carboxyl groups in said organic polymer is in the ratio of from 1:85 to 1:8.
• the substrate or at least one of the substrates is earth e.g. soil.
• the substrate or at least one of the substrates is a component of a pre- formed metal, timber, concrete, masonry or composite structure or building, such as a house, office block, store, factory, oil rig or chemical plant.
• the substrate or at least one of the substrates is at least partially located, more preferably entirely located, in a subterranean, i.e. below the surface of the Earth, and/or subaquatic environment, i.e. below the surface of an aquatic environment such as a waterway, lake, reservoir or ocean. More preferably, the substrate or at least one of the substrates is located in a subterranean environment.
• the substrate or at least one of the substrates is earth e.g. soil, or a component of a pre-formed metal, timber, concrete, masonry or composite structure or building, such as a house, office block, store, factory, oil rig or chemical plant.
• earth e.g. soil
• a component of a pre-formed metal, timber, concrete, masonry or composite structure or building such as a house, office block, store, factory, oil rig or chemical plant.
• one substrate is earth and another substrate is a component of a pre-formed metal, timber, concrete, masonry or composite structure or building, such as a house, office block, store, factory, oil rig or chemical plant.
• a pre-formed metal, timber, concrete, masonry or composite structure or building such as a house, office block, store, factory, oil rig or chemical plant.
• the water barrier is formed in situ between two substrates, each of which is a component of a pre-formed metal, timber, concrete, masonry or composite structure or building.
• the water impermeable composition used in the present invention comprises at least 50 weight percent water, based upon the total weight of the composition.
• the composition comprises at least 60 weight percent, more preferably at least 70 weight percent water.
• it is also preferred that the composition comprises no more than 95 weight percent, more preferably no more than 80 weight percent water.
• the water content of the resultant water impermeable composition can be controlled by any conventional means known to the skilled person. For example, the overall level of crosslinking and/or number of acid groups contained within the organic polymer may be modified in order to provide an end composition with the desired water absorption capacity.
• the water impermeable composition consists of a network of crosslinked organic polymer and water
• additional components for example extender particles such as aggregate materials e.g. sand, pulverised rubber, etc, may be included within the composition.
• An extender is any particulate material that may be added to the composition to increase its volume that does not react with other components in the first or second compositions or the water- impermeable composition.
• the amounts of extender that may be used will depend upon the intended application.
• the amount of extender will not be greater than 98 wt%, more preferably not greater than 90 wt%, based on the dry weight of all components in the water- impermeable composition.
• the first composition of the present invention comprises a water soluble crosslinking agent having at least two reactive groups, wherein each reactive group is capable of undergoing a condensation reaction upon contact with a carboxyl group at room temperature, i.e. at 25°C.
• the crosslinking agent can be a solid or a liquid.
• the first composition may be a solid, e.g. it may comprise a solid crosslinking agent, or the first composition may be a liquid, such as ethylene glycol diglycidyl ether.
• the first composition may be an aqueous solution comprising the crosslinking agent.
• the water soluble crosslinking agent does not comprise an ester functional group as it has been observed that the use of such crosslinking agents may lead to hydrolysis of the resultant crosslinked polymer over time.
• the water soluble crosslinking agent comprises such an ester functional group.
• a particularly preferred crosslinking agent comprising an ester functional group is pentaerythritol tris (3-(l- aziridinyl) propionate, which , when used in the method of the present invention, leads to hydrolysis of the crosslinked polymer and consequently a breakdown of the water barrier over a timescale of approximately 1 to 4 weeks.
• the water soluble crosslinking agent is a zirconium compound.
• the zirconium compound is selected from ammonium zirconium carbonate, zirconium acetate, potassium or sodium zirconyl carbonate, or a mixture thereof. Most preferably, the zirconium compound is ammonium zirconium carbonate.
• Ammonium zirconium carbonate is a stabilised alkaline solution containing anionic zirconium species with bridging hydroxyl groups with carbonate groups bonded to the zirconium. It is known that zirconium reacts strongly with carboxyl groups forming strong bonds whilst hydrogen bonding occurs weakly with hydroxyl groups. Crosslinking of linear hydrophilic organic polymers comprising carboxyl functionality causes the polymer chain to uncoil which allows water to associate with the polymer chain.
• poly(oxirane) refers to any compound comprising 2 or more oxirane moieties. Such compounds undergo surface cross-linking reactions when combined with a waterborne crosslinkable, hydrophilic organic polymer. The reactivity of the epoxy rings allows cross-linking to take place.
• the poly(oxirane) is a (poly)ethylene glycol diglycidyl ether, i.e. a compound of Formula (I): Formula (I) wherein n represents an integer from 1 to 10, preferably from 1 to 5.
• the poly(oxirane) is ethylene glycol diglycidyl ether, i.e. a compound of Formula (1), wherein n equals 1.
• the second composition of the present invention comprises a waterborne
• crosslinkable hydrophilic organic polymer having a weight average molecular weight, measured according to ASTM D4001 - 93 (2006), of at least 200,000, wherein the polymer comprises at least 80 wt%, preferably at least 90 wt%, based on the total dry weight of the polymer, of polymerized units of an ethylenically unsaturated monomer having at least one carboxyl group.
• the waterborne crosslinkable, hydrophilic organic polymer is a
• the crosslinkable, hydrophilic organic polymer has a minimum molecular weight of 300,000, more preferably 500,000 prior to the addition of a crosslinking agent.
• the crosslinkable, hydrophilic organic polymer preferably has a maximum molecular weight of 6 million, more preferably 2 million prior to the addition of a crosslinking agent.
• the water-impermeable composition and the second composition may contain small amounts of monomer and/or oligomer that are residual from the formation of the crosslinkable, hydrophilic organic polymer. However, if present, such low amounts of monomer are considered to have a negligible effect upon the performance of the water-impermeable composition.
• the first and second compositions are manufactured as two separate composition packs which, prior to their combination, are transported to the project site within which the substrate(s) is(are) located.
• the first and second compositions are then mixed (thereby initiating a condensation reaction between the crosslinking agent of the first composition and the polymer of the second composition to crosslink the polymer), conveyed and applied to said substrate(s) at the location within the site where the water barrier is required.
• the water barrier is then formed in situ by completion of the crosslinking reaction and subsequent water absorption.
• the mixture is applied to the substrate(s) where said water barrier is required before no more than 10% of the reactive groups of the crosslinker have reacted with carboxyl groups on the polymer. More preferably, the mixture is applied to the substrate(s) before no more than 5% of the reactive groups of the crosslinker have reacted with carboxyl groups on the polymer. It is preferred that the mixture is prepared and applied to the substrate(s) within a period of 4 hours, more preferably within 1 hour, following the initiation of crosslinking upon combination of the first and second compositions.
• the conveying and application process may be carried out during the early stages of crosslinking.
• the mixture is easily conveyable as subsequent water absorption and concomitant viscosity increase is minimised prior to application.
• the composition will require further time before forming the water barrier, absorbing water from the surrounding environment. Therefore, such application is preferred in dry environments such as within dry subterranean applications or within cavities between pre-formed metal, timber, concrete, masonry or composite structures.
• the conveying and application process may be carried out during the later stages of crosslinking.
• the composition possesses water-resistant properties.
• conveying and applying the resultant mixture is more difficult.
• the water-barrier is considered to have been formed once crosslinking has completed and the crosslinked polymer so formed has swollen with water.
• the method of the present invention is advantageous over the prior art methods discussed above in that it dispenses with the necessity to employ a non-woven or woven sheet or tape as a carrier for the water barrier, and the consequence that it negates the drying step required in the manufacture of such SAP coated sheets or tapes.
• the method of the present invention is further advantageous because it may address some of the difficulties associated with producing a water barrier in areas where the application of sheets or tapes may be problematic dueto their
• the water barrier formed by the present invention may act e.g. as a damp course, inhibiting or preventing absorption of environmental water into building structures; as a geomembrane, to inhibit or prevent leakage of water from a reservoir or dam; as a barrier to inhibit or prevent leaching of chemicals into the water table, streams, rivers and oceans; as a barrier to control spilt or waste fluids; or as a sealant or capping compound for tanks and pipes.
• the water-impermeable composition may also provide a barrier to liquids, including aqueous liquids and non-aqueous liquids such as hydrocarbons.
• the present invention provides a multi-pack composition suitable for use in the method of the first aspect of the present invention, said multi-pack composition comprising
• a first pack comprising a composition comprising a water soluble crosslinking agent having at least two reactive groups wherein each reactive group is capable at room temperature of undergoing a condensation reaction upon contact with a carboxyl group, and
• a second pack comprising a second composition comprising a waterborne crosslinkable, hydrophilic organic polymer having a weight average molecular weight of at least 200,000 (according to ASTM D4001 - 93(2006)) wherein said polymer comprises at least 80 wt% polymerized units of an ethylenically unsaturated monomer having at least one carboxyl group, and wherein said carboxyl groups in said second composition will undergo condensation reactions with said crosslinking agent upon admixture of the first composition with the second composition at room temperature, wherein the amount of said first composition and said second composition are such that the number of groups capable of undergoing a condensation reaction with a carboxyl group in the crosslinking agent to the number of carboxyl groups in said organic polymer is in the ratio of from 1:85 to 1:8.
• An extender if required, may be provided as an additional pack in the multi-pack composition, or the extender may be included as a component in one or both of the first and second packs.
• the multi-pack composition is a two-pack composition consisting of
• a first pack comprising a composition comprising a water soluble crosslinking agent having at least two reactive groups wherein each reactive group is capable at room temperature of undergoing a condensation reaction upon contact with a carboxyl group, and
• a second pack comprising a second composition comprising a waterborne crosslinkable, hydrophilic organic polymer having a weight average molecular weight of at least 200,000 (according to ASTM D4001 - 93(2006)) wherein said polymer comprises at least 80 wt% polymerized units of an ethylenically unsaturated monomer having at least one carboxyl group, and wherein said carboxyl groups in said second composition will undergo condensation reactions with said crosslinking agent upon admixture of the first composition with the second composition at room temperature, wherein the amount of said first composition and said second composition are such that the number of groups capable of undergoing a condensation reaction with a carboxyl group in the crosslinking agent to the number of carboxyl groups in said organic polymer is in the ratio of from 1:85 to 1:8.
• An extender if required, may be provided as a component in one or both of the first and second packs.
• Polyacrylate Aqueous dispersion comprising 25 percent by weight potassium
• Example 1 A first pack consisting of EGDE and a second pack consisting of Polyacrylate were individually prepared and delivered to the point of use.
• a polypropylene non-woven fabric substrate was installed inside a containment bund of a subterraneous storage tank.
• the first pack was combined with the second pack in a weight ratio of 1:49, and mixed for a 10 minute period by a handheld battery-powered stirrer, thereby providing a mixture wherein the ratio of oxirane groups to carboxyl groups was approximately 1:15.
• the mixture was then conveyed and applied over the polypropylene substrate.
• the coated fabric substrate was subsequently covered to prevent precipitation falling on the liquid system, and left for 24 hours to allow cross-linking to complete, thereby forming the water-impermeable composition.
• the fully crosslinked system was then uncovered and left exposed to all weather conditions. Water egression measurements were recorded at several test control points over a 3 month period during which heavy rainfall was observed.
• the crosslinked composition provided an effective water barrier, keeping all rainwater inside the containment area surrounding the storage tank.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=45929936

Family Applications (1)

Country Status (2)

Citations (6)

• 2012
  • 2012-02-12 GB GB201202332A patent/GB201202332D0/en not_active Ceased
• 2013
  • 2013-02-11 WO PCT/GB2013/050307 patent/WO2013117946A1/fr not_active Ceased

Patent Citations (6)

Also Published As

Similar Documents

Legal Events