Switchable adhesive and objects utilizing the same

Abstract

A carpet material with at least one of its components made easier for recycle by use of an adhesive which can be selectively altered to change the adhesion strength to allow component carpet layers to be separated.

1 . An object formed from a plurality of components, said object having a first form and a second form in which at least one of the components of the object are made more readily available for recycling or disposal, wherein the object includes an adhesive composition, the condition of which can be selectively altered to allow the change in condition of the object from the first to the second form to be achieved. 
     
     
         2 . An object according to  claim 1  wherein in the first form the object is for use as a floor covering or as a part thereof. 
     
     
         3 . An object according to  claim 2  wherein the object is a carpet or carpet tile. 
     
     
         4 . An object according to  claim 2  wherein the object includes a carpet face layer and a backing layer and the adhesive directly or indirectly adheres the carpet face layer to the backing layer. 
     
     
         5 . An object according to  claim 1  wherein the adhesive acts as a flame retardant. 
     
     
         6 . An object according to  claim 1  wherein a plurality of components are separable from the object following the change in condition of said adhesive composition. 
     
     
         7 . An object according to  claim 1  wherein the change in condition of the adhesive composition is achieved by performing a treatment or operation on the said object 
     
     
         8 . An object according to  claim 1  wherein the change in condition of the adhesive composition is such that the adhesion between the components with which the adhesive is in contact is reduced. 
     
     
         9 . An object according to  claim 1  wherein the adhesive composition is a hot aqueous solvent switchable adhesive comprising or essentially consisting of a plasticized esterified expanded starch. 
     
     
         10 . An object according to  claim 9  wherein said plasticized esterified expanded starch is obtained by at least expanding starch to provide an expanded starch, esterification of the expanded starch to provide an esterified expanded starch, and plasticization of the esterified expanded starch to provide a plasticized esterified expanded starch. 
     
     
         11 . A carpet or carpet tile including an adhesive composition, the condition of which can be changed to allow separation of at least one component of the carpet or carpet tile. 
     
     
         12 . A carpet or carpet tile according to  claim 11  wherein the at least one component is removed when the carpet or carpet tile, is no longer in use. 
     
     
         13 . A carpet or carpet tile according to  claim 11  wherein a plurality of components are separable from the carpet or carpet tile following the change in condition of said adhesive composition. 
     
     
         14 . A carpet or carpet tile according to any of the  claim 11  wherein the change in condition is achieved by performing a treatment or operation on the carpet or carpet tile. 
     
     
         15 . A carpet or carpet tile according to  claim 11  which is rendered recyclable by the change in condition of the adhesive composition included therein. 
     
     
         16 . A carpet or carpet tile according to  claim 11  wherein the adhesive composition whose condition is changed is that which allows the backing layer of the carpet or carpet tile to be attached to the carpet face layer. 
     
     
         17 . Hot aqueous solvent switchable adhesive comprising or essentially consisting of a plasticized esterified expanded starch characterized in that said plasticized esterified expanded starch is obtained by at least expanding starch to provide an expanded starch, esterification of the expanded starch to provide an esterified expanded starch, and plasticization of the esterified expanded starch to provide a plasticized esterified expanded starch. 
     
     
         18 . Adhesive according to  claim 17 , wherein the expanded starch has a surface area of at least 80 m 2 /gram, more preferably at least 100 m 2 /gram, even more preferably at least 150 m 2 /gram, most preferably at least 175 m 2 /gram. 
     
     
         19 . Adhesive according to  claim 17 , wherein the esterified expanded starch has a degree of substitution of at least 1.2, more preferably at least 1.5, even more preferably at least 2.0, most preferably at least 2.4. 
     
     
         20 . Adhesive according to  claim 17 , wherein the plasticized esterified expanded starch has a delamination strength of in the range of about 50 N to about 80 N, preferably in the range of about 55 N to about 75 N, more preferably in the range of about 65 N to 70 N, as determined in accordance with BS7399:1991, but with the modification that the specimens tested were 40 mm wide and 200 mm long, and the force to continue the delamination is measured by means of a tensile tester at a speed of 100+/−10 mm/min and the mean delamination force over the range 50%-75% of the total extension is measured. 
     
     
         21 . Adhesive according to  claim 17  wherein the esterified expanded starch has a density in the range of from 0.10 gr/cm 3  to 0.40 gr/cm 3 . 
     
     
         22 . Adhesive according to  claim 17  obtainable by
 a. providing starch; 
 b. subjecting the starch to hot aqueous solvent treatment in order to gelatinize the starch; 
 c. treating the gelatinized starch to induce retrogradation in said gelatinized starch to obtain expanded starch; 
 d. adding non-aqueous water-soluble solvent to precipitate the expanded starch, substantially separating the precipitated expanded starch from the solvent and further washing of the expanded starch with a non-aqueous water-soluble solvent until at least 90 vol. % of the aqueous solvent added under step b is removed. 
 e. suspending the expanded starch in inert water-free organic solvent, adding of a catalyst, adding of a fatty acid anhydride and either
 i. keeping the mixture at a temperature and for a period of time sufficient to allow the formation of an esterified expanded starch, or 
 ii. treating the mixture in a micro-wave oven at 100-1000 W and for a period of 1 to 10 minutes sufficient to allow the formation of an esterified expanded starch; 
 
 f. adding non-aqueous water-soluble solvent to precipitate the esterified expanded starch, and drying of the esterified expanded starch; 
 g. admixing a plasticizer to the esterified expanded starch, allowing the formation of a plasticized esterified expanded starch. 
 
     
     
         23 . Adhesive according to  claim 22  wherein drying of the obtained expanded starch is performed in step d. 
     
     
         24 . Adhesive according to  claim 22  wherein the starch has an amylose content (w/w) of at least 20%, preferably at least 40%, even more preferably at least 50%, most preferably at least 60%. 
     
     
         25 . Adhesive according to  claim 22  wherein the gelatinized starch is obtained by hot aqueous solvent treatment at a temperature in the range of from 50° C. to 200° C., more preferably of from 70° C. to 160° C., even more preferably of from 90° C. to 130° C. 
     
     
         26 . Adhesive according to  claim 22  wherein retrogradation is induced by storing the hot aqueous solvent treated starch at a temperature below 25° C., preferably below 10° C., more preferably below 5° C., but above −5° C., for at least 10 hours, preferably at least 24 hours, more preferably at least 100 hours, more preferably at least 500 hours. 
     
     
         27 . Adhesive according to  claim 22  wherein the non-aqueous water-soluble solvent is selected from the group consisting of ethanol, methanol, propanol, and butanol. 
     
     
         28 . Adhesive according to  claim 22  wherein the non-aqueous water-soluble solvent is added under step d) in a ratio of from 1 volumes non-aqueous watersoluble solvent to 5 volume hot aqueous solvent added in step b) to 5 volume nonaqueous water-soluble solvent to 1 volume hot aqueous solvent added in step b). 
     
     
         29 . Adhesive according to  claim 22  wherein after the further washing of the precipitated starch the precipitated starch is at least once washed with the inert water-free organic solvent of step e), and omitting the drying of the obtained expanded starch. 
     
     
         30 . Adhesive according to  claim 22  wherein the inert water-free organic solvent is selected from the group consisting of toluene, benzene, and xylene. 
     
     
         31 . Adhesive according to  claim 22  wherein the catalyst is selected from the group consisting of amines, dimethylaminopyridine (DMAP), triethylamine, and pyridine, most preferably the catalyst is DMAP. 
     
     
         32 . Adhesive according to  claim 22  wherein the fatty acid anhydride is from C2 fatty acid anhydride to C12 fatty acid anhydride, or mixtures thereof, preferably from C2 fatty acid anhydride to C6 fatty acid anhydride. 
     
     
         33 . Adhesive according to  claim 22  wherein the fatty acid anhydride is acetic anhydride. 
     
     
         34 . Adhesive according to  claim 22  wherein the plasticizer is selected from the group consisting of phthalate esters, dimethyl- and diethylsuccinate, glycerol triacetate (triacetin), glycerol mono- and diacetate, glycerol mono-, di- and tripropionate, glycerol tributanoate (tributyrin), glycerol mono- and dibutanoate, glycerol mono-, di- and tristearate, and other related glycerol esters, lactic acid esters, citric acid esters, adipic acid esters, stearic acid esters, oleic acid esters, ricinoleic acid esters, other fatty acid esters, glycerol, polycaprolactone, glyceryltrioleate, preferably the plasticizer is glycerol or glycerol triacetate, most preferably the plasticizer is glycerol triacetate. 
     
     
         35 . Adhesive according to  claim 22  wherein the plasticizer is admixed in an amount from 10 to 40%, preferably from 15 to 35%, more preferably from 20 to 30% by weight based on the esterified expanded starch. 
     
     
         36 . Adhesive according to  claim 22  wherein further flame-retardants, fillers, preservatives, binders, antimicrobial agents are admixed to the esterified expanded starch or the plasticized esterified expanded starch. 
     
     
         37 . Method for preparing an hot aqueous solvent switchable adhesive, the method comprising the steps of
 a. providing starch;   b. subjecting the starch to hot aqueous solvent treatment in order to gelatinize the starch;   c. treating the gelatinized starch to induce retrogradation in said gelatinized starch to obtain expanded starch;   d. adding non-aqueous water-soluble solvent to precipitate the expanded starch, substantially separating the precipitated expanded starch from the solvent and further washing of the expanded starch with a non-aqueous water-soluble solvent until at least 90 vol. % of the aqueous solvent added under step b is removed,   e. suspending the expanded starch in inert water-free organic solvent, adding of a catalyst, adding of a fatty acid anhydride and either
 i. keeping the mixture at a temperature and for a period of time sufficient to allow the formation of an esterified expanded starch, or 
 ii. treating the mixture in a micro-wave oven at 100-1000 W and for a period of 1 to 10 minutes sufficient to allow the formation of an esterified expanded starch; 
   f. adding non-aqueous water-soluble solvent to precipitate the esterified expanded starch, and drying of the esterified expanded starch;   g. admixing a plasticizer to the esterified expanded starch, allowing the formation of a plasticized esterified expanded starch.   
     
     
         38 . Method according to  claim 37  wherein the drying of the obtained expanded starch is performed in step d. 
     
     
         39 . Method according to  claim 37  wherein the starch has an amylose content (w/w) of at least 20%, preferably at least 40%, even more preferably at least 50%, most preferably at least 60%. 
     
     
         40 . Method according to  claim 37  wherein the gelatinized starch is obtained by hot aqueous solvent treatment at a temperature in the range of from 50° C. to 200° C., more preferably of from 70° C. to 160° C., even more preferably of from 90° C. to 130° C. 
     
     
         41 . Method according to  claim 37  wherein retrogradation is induced by storing the hot aqueous solvent treated starch at a temperature below 25° C., preferably below 10° C., more preferably below 5° C., but above −5° C., for at least 10 hours, preferably at least 24 hours, more preferably at least 100 hours, more preferably at least 500 hours. 
     
     
         42 . Method according to  claim 37  wherein the non-aqueous water-soluble solvent is selected from the group consisting of ethanol, methanol, propanol, and butanol. 
     
     
         43 . Method according to  claim 37  wherein the non-aqueous water-soluble solvent is added under step d) in a ratio of from 1 volumes non-aqueous watersoluble solvent to 5 volume hot aqueous solvent added in step b) to 5 volume nonaqueous water-soluble solvent to 1 volume hot aqueous solvent added in step b). 
     
     
         44 . Method according to  claim 37  wherein after the further washing of the precipitated starch the precipitated starch is at least once washed with the inert water-free organic solvent of step e), and omitting the drying of the obtained expanded starch. 
     
     
         45 . Method according to  claim 37  wherein the inert water-free organic solvent is selected from the group consisting of toluene, benzene, and xylene. 
     
     
         46 . Method according to  claim 37  wherein the catalyst is selected from the group consisting of amines, dimethylaminopyridine (DMAP), triethylamine, and pyridine, most preferably the catalyst is DMAP. 
     
     
         47 . Method according to  claim 37  wherein the fatty acid anhydride is from C2 fatty acid anhydride to C12 fatty acid anhydride, or mixtures thereof, preferably from C2 fatty acid anhydride to C6 fatty acid anhydride. 
     
     
         48 . Method according to  claim 47  wherein the fatty acid anhydride is acetic anhydride. 
     
     
         49 . Method according to the  claim 37  wherein the plasticizer is selected from the group consisting of phthalate esters, dimethyl- and diethylsuccinate, glycerol triacetate (triacetin), glycerol mono- and diacetate, glycerol mono-, di- and tripropionate, glycerol tributanoate (tributyrin), glycerol mono- and dibutanoate, glycerol mono-, di- and tristearate, and other related glycerol esters, lactic acid, esters, citric acid esters, adipic acid esters, stearic acid esters, oleic acid esters, ricinoleic acid esters, other fatty acid esters, glycerol, polycaprolactone, glyceryltrioleate, preferably the plasticizer is glycerol or glycerol triacetate, most preferably the plasticizer is glycerol triacetate. 
     
     
         50 . Method according to  claim 37  wherein the plasticizer is admixed in an amount from 10 to 40%, preferably from 15 to 35%, more preferably from 20 to 30% by weight based on the esterified expanded starch. 
     
     
         51 . Method according to  claim 37  wherein further flame-retardants, fillers, preservatives, binders, antimicrobial agents are admixed to the esterified expanded starch or the plasticized esterified expanded starch. 
     
     
         52 . Method of preparing a recyclable carpet or carpet tile comprising the steps of
 a. providing a carpet face layer   b. providing a backing layer of one or more layers   c. contacting a hot aqueous solvent switchable with the carpet face layer and the backing layer thereby adhering the carpet face layer to the backing layer with the adhesive.   
     
     
         53 . Method for recycling components of carpet or carpet tiles comprising the steps of
 a. providing a recyclable carpet or carpet tile obtained by the method according to  claim 52 ;   b. optionally reducing the size of the recyclable carpet or carpet tile;   c. treating the recyclable carpet or carpet tile with an hot aqueous solution and/or steam, at a temperature of at least 20° C., preferably at least 30° C., preferably at least 70° C., more preferably at least 90° C., for a period of time sufficient to allow the hot aqueous solvent switchable adhesive to detach (or de-adhere), or the adhesion of the same to reduce;   d. separating the carpet face layer from the backing layer.   
     
     
         54 . A floor covering that at least comprises a carpet face layer, a backing layer, and a hot aqueous solvent switchable adhesive and which adhesive directly or indirectly adheres the carpet face layer to the backing layer. 
     
     
         55 . Use of a hot aqueous solvent switchable adhesive as a flame retardant. 
     
     
         56 . A carpet or carpet tile including a carpet face layer and a backing layer comprising one or more layers with which the carpet face layer is adhered by an adhesive, wherein said adhesive also acts as a flame retardant. 
     
     
         57 . A carpet or carpet tile according to  claim 56  wherein the adhesive is a hot aqueous solvent switchable adhesive comprising or essentially consisting of a plasticized esterified expanded starch.