Epoxide-based composition

Abstract

An epoxide based composition that can be cured at a temperature of less than about 70 C is disclosed. The composition is a liquid at ambient conditions and, therefore, can be used to rehabilitate the interior surfaces of pipelines. The epoxide-based composition comprises at least one epoxide component (component A) and at least one curing agent component (component B) wherein (A) the epoxide component comprises a phenyl glycidyl ether polyepoxide; and (B) the curing agent component comprises a mixture of two salt compounds formed, respectively, from an N-alkanol piperidine and a carboxylic acid bearing 7-12 carbon atoms, and N-cyclohexyl-N,N-dialkyl amine and a carboxylic acid bearing 7-12 carbon atoms.

Claims

1. An epoxide-based composition, comprising (A) an epoxide component comprising at least one phenyl glycidyl ether polyepoxide having at least two epoxide group of oxirane structure in the molecule; and (B) a curing agent component comprising a mixture of (i) a first salt comprising a salt of an N-alkanol piperidine and at least one carboxylic acid bearing 6-12 carbon atoms and (ii) a second salt consisting of a salt of N-cyclohexyl-N,N-dialkyl amine and a monovalent organic carboxylic acid bearing 6-12 carbon atoms; wherein the salt of N-alkanol piperidine in the mixture ranges from 20-80 wt %.

2. The composition of claim 1 wherein the amount of the curing agent of component (B) is from about 1 to about 50 wt parts per 100 wt parts of the epoxide component (A).

3. The epoxide-based composition according to claim 1, wherein the epoxide component (A) further comprises an epoxide compound other than a phenyl glycidyl ether polyepoxide.

4. The epoxide-based composition according to claim 3, wherein the epoxide compound is at least one compound selected from the group consisting of glycidyl ethers, glycidyl esters and glycidyl amines.

5. The epoxide-based composition according to claim 1, wherein the N-alkanol piperidine is selected from the group consisting of N-piperidine ethanol and N-piperidine propanol and the N-cyclohexyl-N,N-dialkyl amine is selected from the group consisting of N-cyclohexyl-N,N-dimethylamine and N-cyclohexyl-N,N-dipropylamine.

6. The epoxide-based composition according to claim 1 further comprising at least one diluent selected from the group consisting of mono glycidyl ethers.

7. The epoxide-based composition according to claim 6 wherein the diluents comprises at least one member selected from the group consisting of butyl glycidyl ether, phenyl glycidyl ether, and dodecyl glycidyl ether.

8. The epoxide-based composition according to claim 1 further comprising at least one accelerator selected from the group consisting of imidazoles.

9. The epoxide-based composition of claim 8 wherein the imidzoles comprise at least one member selected from the group consisting of 1-methylimidazole, and 2-methylimidazole.

10. The epoxide-based composition according to claim 1 further comprising at least one accelerator selected from the group consisting of phenolic tertiary amine derivatives tris(dimethylaminomethyl)phenol, and dimethylaminomethylphenol.

11. A method for treating a substrate comprising applying the epoxide-based composition of claim 1 onto a substrate, heating the substrate to a temperature of less than about 80 C. and curing the composition.

12. The method of claim 11 wherein the substrate comprises an interior surface of a conduit or pipe.

13. The method of claim 12 wherein the surface comprises a fibrous material within the conduit or pipe.

14. A treated substrate made in accordance with the method of claim 11.

15. The method of claim 12 wherein the conduit or pipe is cured in place without digging or removing the pipe.

16. The method of claim 15 wherein treatment is applied using cured in place pipe (CIPP) technology.

17. The epoxide-based composition according to claim 1, further comprising at least one hindered polyether amine selected from the group consisting of polyoxypropylenediamine having a molecular weight of about 230, polyoxypropylenediamine having a molecular weight of about 430, and polyoxypropylenetriamine having a molecular weight of about 400.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The epoxide-based composition according to the present invention can provide a flowable condition that is maintained for long period (e.g. a viscosity less than 20,000 cP at a temperature of 25 C. period up to 24 hours) after the mixing of an epoxide compound and a curing agent component, and that the viscosity within 16 hours does not exceed 20,000 cP.

(2) Further, the epoxide-based composition can be cured by using a heat medium such as hot water or hot air in a moderate temperature range (e.g., cured after exposure to a temperature of about 60 C. to about 70 C. for a period of <about 4 hrs). Therefore, the epoxide-based composition according to the present invention can be used to treat a wide range of surfaces including concrete, steel fiber glass and PVC substrates and, in particular, rehabilitation work of buried pipes as a conduit for various fluids.

(3) Further, the epoxide-based composition according to the present invention is effective for rehabilitation work performed without digging up buried pipes.

(4) Herein below, the present invention will be described in detail. In the following description, % and part(s) representing a quantitative proportion or ratio are those based on mass, unless otherwise noted specifically.

(5) The epoxide based composition according to the present invention comprises an epoxide component (component A) and a curing agent component (component B) in which the epoxide component comprises a phenyl glycidyl ether-based polyepoxide; and a curing agent component comprising a mixture of two salt compounds formed, respectively, from the tertiary amine N-alkanol piperidine and a carboxylic acid bearing 6-12 carbon atoms, and the tertiary amine N-cyclohexyl-N,N-dialkyl amine with a carboxylic acid bearing 6-12 carbon atoms. The amount of epoxide component can range from about 70 to less than 100, about 85 to about 60 and in some cases about 80 to about 90 wt. % of the epoxide based composition. The curing agent component can range from about 15 to about 30, about 40 to about 20 and in some cases about 20 to about 10 wt. % of the epoxide based composition.

(6) The epoxide component and the curing agent component can be combined by using any suitable equipment and methods such as mixing, stirring, pumping, among other equipment and methods known in this art.

(7) The salts of the curing agent can be obtained by reacting the amine with the carboxylic acid at 25 C. for 1-6 h at <80 C. The molar ratio of amine to carboxylic acid is about 1:1.

(8) The epoxide-based composition according to the present invention may have the following Properties (1)-(3).

(9) Property 1

(10) Under conditions used in the examples, the viscosity of the epoxide-based composition according to the present invention within 16 hours is <20,000 cP. Viscosity is determined by using a Brookfield viscometer (Brookfield HT-2DB). A disposable aluminum spindle (Brookfield SC4-27D) is inserted into the chamber containing curing agent mixture and the viscometer (Brookfield RVDV-II+Pro) is started to collect data points at the rate of 1 per minute in accordance with standard testing procedures.

(11) Property 2

(12) The epoxy-based compositions according to the present invention can be curedand hard to the touch without stickiness at a temperature of about <70 C. within a period of about 4 h. The curing temperature and time are inversely related in that given a longer period of time the curing temperature can be lowered. The curing temperature can range from about 60 C. to about 70 C., about 65 C. to about 70 C. and in some cases about 60 C. to about 65 C. The curing time can range from about 1 h to about 4 h, about 2 h to about 4 h and in some cases about 3 h to about 4 h. If needed, the extent of cure of the resin can be determined by DSC (differential scanning calorimetry).

(13) Property 3

(14) The epoxy-based compositions according to the present invention can be cured and hard to the touch without stickiness at <70 C. within 4 h in the presence of at least 1 wt % water. The inventive compositions can be cured in an environment containing about 2% to about 5%, about 3% to about 5% and in some cases about 4% to about 8% water. For example, heated air or a steam containing atmosphere can be used curing the inventive composition.

(15) The epoxide (component (A) of the composition of the present invention comprises a phenyl glycidyl ether epoxide having a plurality of oxirane structures in the molecule and having reactivity with an amine, and examples thereof may comprise the following: Aromatic diglycidyl ethers generated by reacting diphenols such as bisphenol A, bisphenol F, bisphenol AD, tetramethylbisphenol A, tetramethyl bisphenol F or biphenyl, with epichlorohydrin; glycidyl ether obtained by reacting a novolak such as phenol novolak, cresol novolak, ethylphenol novolak, propylphenol novolak, butylphenol novolak, pentylphenol novolak, octylphenol novolak or nonylphenol novolak, with epichlorohydrin; and glycidyl ethers obtained by reacting a polyhydric phenol such as catechol, resorcin, trihydroxybiphenyl, dihydroxybenzophenone, bisresorcinol, hydroquinone, tris (hydroxyphenyl) methane, tetrakis(hydroxyphenyl) ethane or bisphenol, with epichlorohydrin and mixtures thereof.

(16) Among the epoxy compounds above, desirable results can be achieved by using diglycidyl ethers of bisphenol A and bisphenol F.

(17) Examples of the epoxides which can be used in combination with the phenyl glycidyl ether epoxides may comprise at least one member selected from at least one of the groups of:

(18) (1) polyglycidyl ethers generated by reacting an aliphatic polyhydric alcohol such as glycol, neopentylalcohol, ethyleneglycol, propyleneglycol, tetramethyleneglycol, hexaneglycol, polyethyleneglycol or polypropylene glycol, with epichlorohydrin;

(19) (2) glycidyl ether esters generated by reacting a hydroxycarboxylic acid such as p-hydroxybenzoic acid or -hydroxynaphthoic acid, with epichlorohydrin;

(20) (3) polyglycidyl ester generated by reacting a polycarboxylic acid such as phthalic acid, methylphthalic acid, isophtalic acid, terephthalic acid, tetrahydroxyphthalic acid, hexahydoxyphthalic acid, endomethylenetetrahydrophthalic acid, endomethylenehexahydroxydrophthalic acid, trimellitic acid, a dimer acid or a polymerized fatty acid, with epichlorohydrin;

(21) (4) diglycidylamino esters generated by reacting an aminobenzoic acid with epichlorohydrin; and

(22) (5) polyglycidylamines generated by reacting aniline, toluidine, m-xylyenediamine, 1,2-diaminocyclohexane, 1,2-diaminocyclohexane, 4,4-diaminodiphenyl ether, 4,4-diaminodiphenylmethane, 4,4-diaminodiphenylsulfone, hydantoin, an alkylhydantoin or cyanuric acid, with epichlorohydrin.

(23) The curing agent component (component B) comprising the epoxide-based composition of the present invention comprises a mixture of at least two of the following salt compounds formed from: 1) the tertiary amine N-alkanol piperidine and a carboxylic acid bearing 6-12 carbon atoms; and 2) the tertiary amine N-cyclohexyl-N,N-dialkylamine with a carboxylic acid bearing 6-12 carbon atoms.

(24) While any suitable tertiary amine or amines can be employed for making the foregoing salts, examples of suitable tertiary amines comprise N-ethanolpiperidine and N-cyclohexyl-N,N-dimethylamine, N-cyclohexyl-N,N-diethylamine N-cyclohexyl-N,N-dipropylamine, and N-cyclohexyl-N,N-dibutylamine.

(25) The carboxylic acid of the tertiary amines salts as curing agent component of the present invention can comprise at least one monovalent organic carboxylic acid bearing 6-12 carbon atoms, and examples thereof may comprise the following hexanoic acid,heptanoic acid, 2-ethylhexanoic acid, octanoic acid, nonanoic acid decanoic acid, undecanoic acid, dodecanoic acid and mixtures thereof. The salts can be formed by reacting the amine with the carboxylic acid at 25 C. for about 1 to about 6 h at less than <80 C. The molar ratio of amine to carboxylic acid is about 1:1 and can range from about 0.8 mol eq to about 1.0 mol eq, about 0.9 mol eq. to about 1.0 mol eq and in some cases about 1.0 mol eq to about 1.1 mol eq.

(26) Component B of the epoxide-based composition of the present invention can comprise a carboxylic acid equivalent of the component B is from about 0.8 to about 1.2, about 1.1 to about 1.2, and in some cases about 1.0 to about 1.1 equivalents per mole of an N-alkanol piperidine and N-cyclohexyl-N,N-dimethylamine.

(27) The ratio between the epoxide component (A) and the curing agent component (B), the amount of the curing agent component (B) can range from about 1 to about 50 wt parts, or about 5 to about 20 wt parts or 10 about to about 30 parts, per 100 wt parts of the polyepoxide component (A). If the amount of the component B is less than the range above, a very long pot life after mixing of component (A) and component (B) may be expected, but the subsequent curing may take a long time, which is impracticable. On the contrary, if the curing agent component (B) is combined in excess of the range above, curing after mixing the component (A) and the component (B) may swiftly proceed, but the pot life necessary for operation may become short, which is normally impracticable.

(28) Further, in the composition of the present invention, at least one of a plasticizer, a filler, a coloring agent, an extender, pigment, organic or inorganic fibers, a silicone, titanate or aluminum coupling agent for improving adhesion to the pipe body, a thixotropic agent, and the like may be used in combination, if desired. The amount of the foregoing can range from about 10 wt % to about 20 wt %, about 10 wt % to about 12 wt % and in some cases about 18 wt % to about 20 wt % of the epoxide based composition.

(29) The composition may further comprise at least one diluent such as a mono glycidyl ethers to modify the viscosity for ease of processing as desired. Such diluents include butyl glycidylether, phenyl glycidyl ether, and dodecyl glycidyl ether. The amount of such diluent can comprise about 10 to about 20, about 10 to about 15 and in some cases about 15 to about 20 wt. % of the composition. The diluents can be included in the A and/or B component of the composition.

(30) In one aspect of the invention, the composition is free or substantially free of mercaptan, acrylonitrile, and isocyanates. By free or substantially free of the foregoing it is meant that the composition contains less than about 0.25, less than about 0.1 and in some cases about 0 wt %.

(31) In another aspect of the invention, the composition is free or substantially free of solids. By free or substantially free of solids, it is meant that the composition comprises less than about 0.25, less than about 0.1 and in some cases about 0 wt. % solids.

(32) In another aspect of the invention, the curing agent B may be combined (e.g., <50 wt %, <30 wt. % and in some cases <20 wt. % relative to B) of at least one hindered polyether amine in order to increase cross linking density and mechanical strength of the cured product. Examples of suitable hindered polyether amines include at least one member selected from the group of polyoxypropylenediamine, M. Wt. 230 (Jeffamine D230), polyoxypropylenediamine, M. Wt. 430 (Jeffamine D400) and polyoxypropylenetriamine, M. Wt. 400 (Jeffamine T403). Alternatively or in addition to an epoxy cure accelerator (e.g., <10 wt %, <5 wt. % and in some cases <2 wt. % relative to component B) may be blended into component B to further decrease cure time if needed without compromising latency. Examples of suitable cure accelerators include imidazoles such as 1-methylimidazole, 2-methylimidazole and tertiary amine substituted phenols such as tris(dimethylaminomethyl)phenol, (Ancamine K-54 available from Air Products) and dimethylaminomethyl phenol (Ancamine 1110).

(33) The following Examples are provided to illustrate certain aspects of the instant inventions and shall not limit the scope of the claims appended hereto.

EXAMPLES

Example 1: General Procedure for Preparation of Curing Agents

(34) The tertiary amine (1 mole) was charged into a 3-neck round bottom flask equipped with a overhead mechanical stirrer and nitrogen inlet and thermocouple. The acid (1 mole relative to amine) was added slowly to maintain the temperature at 25-30 C.

Example 2: Testing Procedure of Curing Agents with Epoxy Resin at 70 C.

(35) 20 g of the curing agent is mixed with 100 g of bis-phenol A diglycidyl ether (EPON 828) using a spatula in a 200 mL glass jar. Pucks are prepared from this mixture by transferring to a 2 oz. metal container, the curing agent and epoxy resin mixture (5-7 g). Two pucks are prepared, one with and one without water. In the former a small amount of water is applied to one puck 2 g. but not enough to completely cover the entire surface. The pucks are placed into 65 C. oven for 2 hrs. or until cured. The cure time and surface characteristics of the cooled pucks are noted, and tackiness, glassiness, and entrained air were determined by visual observation and hardness to touch.

Example 3: Latency of Amine Curatives

(36) 20 g of the curing agent is mixed with 100 g of bis-phenol A diglycidyl ether (EPON 828) using a spatula in a 200 mL glass jar. 15 g. of this material is transferred into a disposable aluminum chamber (Brookfield HT-2DB). A disposable aluminum spindle (Brookfield SC4-27D) is inserted into the chamber containing curing agent mixture and the Start viscometer (Brookfield RVDV-II+Pro) is stated to collect data points at the rate of 1 per minute. Pot-life is recorded as the time to reach 20,000 cP at 25 C. Complete Cure was determined by visual observation and hardness to touch.

(37) TABLE-US-00001 Pot-Life (Time Complete Cure at to 20,000 cP 70 C. in 3 h? Curing agent (20 phr) (hours) yes or no TOFA salt of 1-ethylpiperidine 38 No TOFA salt of N-ethanolpiperidine 45 No TOFA salt of 1,8- 13 No diazabicycloundecane(5.4.0)undec- 7-ene (DBU) 2-ethylhexanoic acid salt of 1,8- 1 No diazabicycloundecane(5.4.0)undec- 7-ene (DBU) 2-ethylhexanoic acid salt of N- 29 No ethanolpiperidine 2-ethylhexanoic acid salt of N- 13 h No cyclohexyl-N,N-dimethylamine Mixture of 2-ethylhexanoic acid salt 22 h yes of N-ethanolpiperidine and 2- ethylhexanoic acid salt of N- cyclohexyl-N,N-dimethylamine (40:60 w/w) Mixture of 2-ethylhexanoic acid salt 24 h yes of N-ethanolpiperidine and 2- ethylhexanoic acid salt of N- cyclohexyl-N,N-dimethylamine (50:50 w/w) Mixture of 2-ethylhexanoic acid salt 26 h yes of a N-ethanolpiperidine and 2- ethyhexanoic acid salt of N- cyclohexyl-N,N-dimethylamine (60:40) TOFA salt of 4-methylmorpholine 9 h No TOFA salt of 3 No tris(dimethylaminopropyl)amine

Example 4: Cured in Place Pipe Simulated Application

(38) To understand the applicability of the curing agent in the cured in place pipe (CIPP) application, the following experiment was conducted. The curing agent (100 g) (a mixture of the 2-ethylhexanoic acid salt of 1-piperidineethanol and the 2-ethylhexanoic acid salt of N-cyclohexyl-N,N-dimethylamine, 40/60 wt/wt) was mixed with standard DGEBA type liquid epoxy resin (500 g) having EEW=190 at ambient conditions. The mixed mass was enough to wet out a 4 diameter and a commercially available foot long cylindrical felt comprising commercially available-polyester fibers and polyethylene lining. The mixed mass was applied to the felt by manually pouring the mixed mass in the felt at one end and applying vacuum to the other end of the felt. This type of felt is commonly used for underground pipe rehabilitation.

(39) The mixed mass was evenly applied to the interior of the felt and the felt was left alone at ambient temperature overnight to evaluate the product shelf stability. After 24 h, the felt appeared to be soft and that the mixed material was still tacky and the felt was soft enough to be processed further. The felt piece was then inverted in a PVC pipe in such a way that the wet layer of the felt adheres to an interior of the PVC pipe. The interior of the PVC pipe along with the felt was then baked at 65 C for 2 hours using hot water. After it cooled down, the pipe was cut in small pieces to evaluate the adhesion of the felt and PVC pipe. Adhesion was determined by manually-pulling the liner away from the host pipe. The adhesion between the felt and the PVC pipe was excellent. The cured epoxy composite (i.e., comprising a felt reinforcement embedded by an epoxy matrix) demonstrated acceptable flexural modulus (>300,000 psi) that is required by the industry. A cured epoxy composite of the invention can have a flexural modulus from about 300,000 to about 500,000, about 300,000 to about 400,000 and in some cases about 350,000 to about 450,000 psi. Flexural modulus was determined by ASTM D-790.

(40) While the invention has been described with reference to certain aspects and embodiments, it will be understood by those skilled in the art that various combinations and changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular aspect or embodiment disclosed for carrying out this invention, but that the invention will include all aspects or embodiments falling within the scope of the appended claims.