Multi-component epoxy resin compound with leakage indicator, and curing component for the epoxy resin compound
11499003 · 2022-11-15
Assignee
Inventors
Cpc classification
International classification
C04B40/06
CHEMISTRY; METALLURGY
Abstract
A curing composition is useful for a multi-component epoxy resin compound and includes at least one first polyamine, at least one second polyamine, and at least one polyphenol from the group of bisphenols and novolac resins as an accelerator. Upon contact with atmospheric oxygen, the curing composition discolors within a few days and therefore leakages can be visually identified.
Claims
1. A curing composition for a multi-component epoxy resin compound, comprising: 5 to 20 wt. % of at least one first polyamine, 15 to 50 wt. % of at least one second polyamine, and from 1 to 40 wt. % of at least one polyphenol selected from the group consisting of bisphenols, wt. % being based on the weight of organic parts of the curing composition, wherein the at least one first polyamine corresponds to the following general formula (I): ##STR00005## in which R.sub.1 and R.sub.2 denote, independently of one another, —H or —CH.sub.3, or together denote an optionally substituted C.sub.3 to C.sub.8 hydrocarbon chain which is connected to form a cycle, and R.sub.3 denotes —H, —CH.sub.3, —CH.sub.2—CH.sub.2—NH.sub.2 or —CH.sub.2—CH.sub.2—NH—CH.sub.2—CH.sub.2—NH.sub.2, and wherein the at least one second polyamine corresponds to the following general formula (II) or (HI): ##STR00006## in which R.sub.1 and R.sub.2 denote, independently of one another, H or —CH.sub.3, and X denotes NH, O or S.
2. The curing composition according to claim 1, wherein the at least one first polyamine is selected from the group consisting of 1,2-diaminocyclohexane, 1,2-diaminocyclohexene, diethylenetriamine, triethylenetetramine, and mixtures thereof.
3. The curing composition according to claim 1, wherein the at least one second polyamine is selected from the group consisting of 1,3-bis(aminomethyl)cyclohexane, aminoethylpiperazine, and mixtures thereof.
4. The curing composition according to claim 1, wherein the at least one polyphenol further comprises a novolac resin which corresponds to the following formula (IV): ##STR00007## in which R.sub.1 and R.sub.2 each denotes, independently of one another, H or —CH.sub.3; R.sub.3, R.sub.4, R.sub.5 and R.sub.6 each denotes, independently of one another, H, —CH.sub.3 or an aliphatic functional group; and n is 0 to 20.
5. The curing composition according to claim 1, wherein the at least one polyphenol further comprises a novolac resin which corresponds to the following formula (V): ##STR00008## in which R.sub.1 denotes H, R.sub.2 denotes C.sub.1 to C.sub.10 alkyl, m is 0, 1 or 2, and n is 0 to 20.
6. The curing composition according to claim 1, wherein the at least one polyphenol comprises a bisphenol from the group consisting of bisphenol A, bisphenol F, and mixtures thereof.
7. The curing composition according to claim 1, wherein the curing composition further comprises: additional monoamines and/or polyamines, and/or a curing agent for epoxy resins selected from the group consisting of Mannich bases, polyamidoamines, phenalkamines, and mixtures thereof.
8. The curing composition according to claim 1, wherein the curing composition further comprises: an additive selected from the group consisting of diluents, solvents, accelerants, silanes, thickeners, inorganic tillers, and mixtures thereof.
9. A multi-component epoxy resin compound comprising: an epoxy resin component (A) containing at least one curable epoxy resin and optionally a reactive diluent, at least one curing component (B) comprising the curing composition according to claim 1, wherein the epoxy resin component and the at least one curing component are separate from one another.
10. The multi-component epoxy resin compound according to claim 9, further comprising: an additive selected from the group consisting of co-accelerants, adhesion promoters, reactive diluents, thickeners, fillers, and mixtures thereof.
11. A method for detecting leaks, comprising: detecting discoloration of a mixture of a polyphenol and a first and a second polyamine in the curing composition according to claim 1, wherein the curing composition visibly discolors within 10 days upon contact with atmospheric oxygen.
12. The curing composition according to claim 1, wherein said polyphenol further comprises a novolac resin as an accelerator.
Description
DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF PRACTICAL EXAMPLES OF THE INVENTION
(12) Further advantages of the invention can be found in the following examples, which are, however, not understood to be in any way limiting.
EXAMPLES
(13) In the examples, the abbreviations denote the following:
(14) TABLE-US-00001 1,3-BAC 1,3-bis(aminomethyl)cyclohexane, CAS number 2579-20-6, available from Mitsubishi Gas Chemicals DCH 1,2-Diaminocyclohexane, CAS number 694-83-7, available from INVISTA under the name Dytek DCH-99 mXDA m-Xylenediamine, CAS number 1477-55-0, available from Mitsubishi Gas Chemicals IPDA Isophorone diamine, CAS number 2855-13-2, available from Evonik AEP Aminoethyl piperazine, CAS number 140-31-8, available from DOW Chemicals TETA Triethylenetetramine, CAS number 112-24-3, available from DOW Chemicals TEPA Tetraethylene pentamine, CAS number 112-57-2, available from DOW Chemicals SP Styrenized phenol, CAS number 61788-44-1, available from Ruetgers under the name LS500 SA Salicylic acid, CAS number 69-72-7, available from Sigma-Aldrich DMP 2,4,6-tri-(dimethylamino-methyl)phenol, CAS number 90-72-2, available from AirProducts under the name DMP-30 or Ancamine K54 EK Epikure 132, a Mannich base curing composition, available from Hexion/Momentive
(15) A. Preparation of the Curing Compositions
(16) All liquid components of the curing composition are mixed apart from the polyphenol component. The solid additives are then optionally added to the mixture. Finally, the polyphenol component is dissolved in the mixture with stirring.
(17) After the polyphenol component had completely dissolved, the mixture thus obtained was poured into 10 ml rolled-rim glasses (diameter: 2.2 cm, height: 4.4 cm) and sealed with a lid so as to be airtight. Storage took place in a storage room heated to 23° C.
(18) The formulations of the curing compositions tested in each case are summarized in Table 1 below. The measurement setup used for the color measurements described below is also indicated.
(19) TABLE-US-00002 TABLE 1 Formulations of the curing compositions in wt. % Measurement Example Novolac mXDA 1,3-BAC DCH AEP SP SA DMP EK BPA total setup E1 20 80 100 1 E2 20 80 100 1 E3 20 80 100 1 E4 20 24 56 100 1 E5 20 52 28 100 1 E6 20 56 24 100 1 E7 20 20 49 11 100 1 E8 20 24 56 100 2 E9 20 40 40 100 2 E10 20 61 14 5 100 2 E11 20 61 14 5 100 2 E12 20 61 14 5 100 2 E13 20 61 14 5 100 2 E14 20* 70 10 100 2 E18 50 10 40 100 2 E15 80 10 10 100 2 E16 90 10 100 2 E19 50 50 100 2 E17 82 18 100 2
(20) B. Color Measurements
(21) Measurement Setup
(22) The ColorCatcher® system from Techkon GmbH was used for the color measurements. This system allows color-binding measurements to be carried out using the camera of a commercially available smartphone and suitable software in conjunction with a calibration color chart (ColorChart). The calibration color chart contains different color ranges as a reference and a cut-out that allows a view of a portion of the object placed under the chart.
(23) To carry out a measurement, the chart is placed on the object to be measured and a photo is taken using the software (“app”) installed on the smartphone, which photo covers at least the entire region of the calibration color chart. The measured values in the desired color system are then shown on the display of the mobile device. An iPhone 6 was used for the measurements.
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(26) In
(27) An HFB RB500 DL lighting device (Kaiser Fototechnik GmbH & Co. KG; item number 5556) is used as the light source (5), which device is equipped with two Dulux L 36 W/12-950 daylight fluorescent tubes (Osram).
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(29) The soft boxes (9) fastened to the two tripod arms (8) are aligned with the centrally positioned measuring setup (10). The tripod arms provided with clamp holders are attached and positioned at the rear end of a base plate measuring 50 cm×45 cm in such a way that the two soft boxes are at a height h of 35 cm and a distance d of 22 cm.
(30) Measurement Method and Color Space
(31) As part of the color measurement, the colors of the respective curing compositions are determined and displayed in the CIELAB color space. The CIELAB color model is based on the normal spectral value functions that were determined by reference experiments with a large number of normal-sighted test subjects.
(32) The CIELAB color space thus takes the color perception of the human eye into account and is therefore particularly suitable for drawing conclusions regarding the perceptibility of a change in color. It is also a widely used method in the graphics industry (for the normal spectral function see E. Lübbe: Farbempfindung, Farbbeschreibung und Farbmessung (Color perception, color description and color measurement), Springer Vieweg 2013, p. 22ff; for the CIELAB color space, see E. Lübbe: Farbempfindung, Farbbeschreibung und Farbmessung, Springer Vieweg 2013, p. 86ff).
(33) The CIELAB color space is spanned by the three axes L*, a* and b*, where L* represents the luminance axis a* represents the green-red axis b* represents the blue-yellow axis.
(34) These three coordinates can be used to describe a color location in the CIELAB color space.
(35) The color difference ΔE of two colors in the CIELAB color space can be calculated using the following formula:
ΔE=√{square root over (ΔL*.sup.2+Δa*.sup.2+Δb.sup.−2)}Δ
where ΔL* represents the difference between the luminance values of the two colors, Δa* represents the difference between the two green-red values and Δb* represents the difference between the two blue-yellow values (cf. E. Lübbe: Farbempfindung, Farbbeschreibung und Farbmessung, Springer Vieweg 2013, p. 131).
(36) The greater the value of ΔE, the greater the perceived color difference, which is why the ΔE value is used in the following tests as a measure of the visible change in color.
(37) Practical Implementation of Color Measurements
(38) The rolled-rim glass with the curing composition to be measured is brought into the measuring position in the relevant measuring setup. After switching on the illumination, the ColorCatcher application installed on the smartphone is started and a color measurement is carried out according to the instructions.
(39) For each rolled-rim glass, three color measurements are carried out in succession and then the arithmetic mean of the values obtained for L*, a* and b* is calculated.
(40) Color Measurement Results
(41) Measurement Series 1: Discoloration Upon Contact with Atmospheric Oxygen
(42) Two curing compositions according to the invention according to Examples E6 and E7 were each poured into two 10 mL rolled-rim glasses (diameter: 2.2 cm, height 4.4: cm), closed with a lid and stored in a room illuminated with daylight at 23° C., The glasses were each only approximately 70% filled to ensure an excess of air.
(43) A rolled-rim glass filled with a curing composition was shaken manually once a day and then opened for 20 seconds to allow atmospheric oxygen to enter. The comparative samples remained closed and were only shaken once a day during this time.
(44) On the day of production and after 1, 4, 8, 13 and 15 days, color measurements were carried out on all four samples using measurement setup 1.
(45) The results of measurement series 1 shown in
(46) Since the discoloration of the curing compositions according to the invention occurs only upon contact with (atmospheric) oxygen, it is ensured that the discoloration in curing compositions packaged in the customary manner only occurs at defect sites, such as cracks in the packaging.
(47) Measurement Series 2: Discoloration Compared to Reference Compositions
(48) Curing compositions according to Examples E1 to E5 (reference) and E6 and E7 (according to the invention) were poured into 10 mL rolled-rim glasses (diameter: 2.2 cm, height: 4.4 cm), closed with a lid and stored in a room illuminated with daylight at 23° C. The glasses were each only approximately 70% filled to ensure an excess of air.
(49) The rolled-rim glasses were shaken manually once a day and then opened for 20 seconds to allow atmospheric oxygen to enter.
(50) On the day of production and after 1, 4 and 11 days, color measurements were carried out on all samples using measurement setup 1.
(51) The results of measurement series 2 are shown in a diagram in
(52) Measurement Series 3: Replacement of 1,3-BAC with AEP
(53) Curing compositions according to Examples E8 (reference) and E9 (according to the invention) were poured into 10 mL rolled-rim glasses (diameter: 2.2 cm, height: 4.4 cm), closed with a lid and stored in a room illuminated with daylight at 23° C. The glasses were each only approximately 70% filled to ensure an excess of air. The rolled-rim glasses were shaken manually once a day and then opened for 20 seconds to allow atmospheric oxygen to enter.
(54) On the day of production and then again after 2, 8 and 8 days, color measurements were carried out on all samples using measurement setup 2.
(55) The results of measurement series 3 are shown in a diagram in
(56) Even a curing composition in which DCH is used as the first polyamine and AEP as the second polyamine thus shows the desired clear change in color, while the reference composition E8 does not achieve an unusually significant change in color in the same period. The measurement series 3 shown in
(57) Measurement Series 4: Change in Color when Additives are Added
(58) Curing compositions according to Examples E8 (reference) and E10 to E13 (according to the invention) were each poured into 10 ml rolled-rim glasses (diameter: 2.2 cm, height: 4.4 cm), closed with a lid and stored in a room illuminated with daylight at 23° C. The glasses were each only approximately 70% filled to ensure an excess of air. The rolled-rim glasses were shaken manually once a day and then opened for 20 seconds to allow atmospheric oxygen to enter.
(59) On the day of production and then again after 2, 6 and 8 days, color measurements were carried out on all samples using measurement setup 2. The results of measurement series 4 are shown in a diagram in
(60) The results of the color measurements show that the curing compositions E10 to E13 according to the invention also exhibit a clear change in color when a combination of 1,3-BAC and AEP is used as the second polyamine (Example E10) and/or when further additives are added, which are typically used in curing compositions for epoxy compounds. Such additives are, for example, a combination of phenol with tertiary amines (DMP-30, Example E11), salicylic acid (Example E12) and styrenized phenol (Example E13). The ΔE value of the reference composition hardly changes after 2 days and is only about 20% of the ΔE value of the compositions according to the invention after 6 days at the latest.
(61) Measurement Series 5: Use of Further Polyphenols
(62) Curing compositions according to Examples E14 and E15 (according to the invention) and compositions according to Examples E16 and E17 (reference) were poured into 10 ml rolled-rim glasses (diameter: 2.2 cm, height: 4.4 cm), closed with a lid and stored in a room illuminated with daylight at 23° C. The glasses were each only approximately 70% filled to ensure an excess of air. The rolled-rim glasses were shaken manually once a day and then opened for 20 seconds to allow atmospheric oxygen to enter.
(63) On the day of production and then again after 1, 2, 4 and 8 days, color measurements were carried out on all samples using measurement setup 2. The results of measurement series 5 are shown in a diagram in
(64) The composition according to Example E14 contains the Novolac Supraplast 3616 from SWC and the composition according to Example E15 contains bisphenol A as a polyphenol. After only a few days, the two compositions demonstrate a significantly greater discoloration than the two reference compositions E16 and E17. The ΔE value of the reference compositions is below 5 even after 8 days, while the ΔE values of the compositions according to the invention are already above 10 after 2 days and well above 20-30 after 8 days.
(65) The reference composition E16 that is not according to the invention contains a mixture of a polyphenol (bisphenol A) according to the invention and the polyamine mXDA that is not according to the invention. The reference composition E17 that is not according to the invention contains the combination of polyamines 1 and 2 used according to the invention, but not polyphenol. It can be seen from measurement series 5 that a clear color change can also be achieved in the curing compositions according to the invention with polyphenols other than novolac upon contact with atmospheric oxygen.
(66) Measurement Series 6: Use of Further Polyphenols
(67) Curing compositions according to Example E18 (according to the invention) and Examples E16 and E19 (reference) were poured into 10 mL rolled-rim glasses (diameter: 2.2 cm, height: 4.4 cm), closed with a lid and stored in a room illuminated with daylight at 23° C., The glasses are each only approximately 70% filled to ensure an excess of air. The rolled-rim glasses were shaken manually once a day and then opened for 20 seconds to allow atmospheric oxygen to enter.
(68) On the day of production and then again after 1, 2 and 4 days, color measurements were carried out on all samples using measurement setup 2. The results of measurement series 6 are shown in a diagram in
(69) The curing composition according to Example E18 contains a mixture of Epikure 132 and the two polyamines 1,3-BAC and DCH used according to the invention. Epikure 132 is a Mannich base from the amine mXDA and bisphenol A that is dissolved in excess mXDA, The Mannich base has another two phenolic groups and is therefore a polyphenol according to the invention. In addition, there is still a residual content of free bisphenol A in the commercially available product Epikure 132, The reference composition according to Example 16 contains the Mannich base Epikure 132 and the amine mXDA. The reference composition according to Example 19 contains the Mannich base Epikure 132 and the polyamine 1,3-BAC, but no compound from the group of the first polyamines.
(70) As expected, the curing composition according to Example 18 shows a clear change in color when atmospheric oxygen is admitted, while the two reference compositions E16 and E19 do not show the desired clear change in color. The ΔE values of the reference compositions E16 and E19 do not rise above the value 2 even after 8 days, while the ΔE value of the composition E18 according to the invention is already approximately 7 after 4 days.
(71) The measurement series 6 confirms that polyphenols other than novolac can also be used in the curing compositions according to the invention.
(72) C. Production of Epoxy Mortar Compounds and Measurement of Bond Strength
(73) The curing compositions according to Examples E1, E2, E4, E6, E11 and E18 were filled with inorganic additives in accordance with Table 2 below and mixed as curing component B in a stoichiometrically correct ratio with an epoxy resin mixture (component A) likewise containing fillers. The composition of the epoxy resin compound prepared in this way is given in Table 3 below.
(74) The thus produced components of the mortar compound were stirred in a dissolver (PC laboratory system, volume 1 L) for 10 minutes under a vacuum at 3500 rpm.
(75) In Examples 1 to 3, the bisphenol A-based and bisphenol F-based epoxy resins commercially available under the names DER 330 and DER 354 (Dow Europe), respectively, were used as the epoxy resins.
(76) The adhesion promoter was 3-glycidyloxypropyl-trimethoxysysilane, available under the name Dynalsylan GLYMO™ (Evonik Industries).
(77) 1,4-Butanediol-diglycidyl ether and trimethyolpropane-triglycidyl ether, commercially available under the names Epilox P 13-21 (Leunaharze) and Araldite™ DY-T (Huntsman), respectively, were used as reactive diluents.
(78) A mixture available under the trade name Millisil™ W12 from the Quarzwerke Frechen was used as filler, which mixture contains quartz powder and optionally aluminate cement. The fumed silica used as a thickener is commercially available from Cabot Rheinfelden under the name Cab-O-Sil™ TS-720.
(79) The bond strength or failure load was determined by centric pull-out tests of three anchor rods per mortar compound. Anchor rods M12 with a seating depth of 72 mm and a borehole diameter of 14 mm were used. The boreholes were drilled using a Hilti TE-40 combihammer, A TE-CX 14 mm drill was used as the drill. The boreholes were cleaned with a wire brush and compressed-air lance (8 bar). The concrete used had strength class C20/25. The curing time was 24 hours at 23° C. The bond strength of the mortar compounds determined by the pull-out tests is shown in Table 4 below.
(80) The pull-out tests were carried out in the same way as in the “European Organization for Technical Approvals” (EOTA) (2001): ETAG No 001, November 2008 edition: European Technical Approval Guidelines for metal anchors for anchoring in concrete, Part 5: bonded anchors, February 2008, conditions described under 5.1.2.1 (b), where the concrete compressive strength of the concrete used for the pull-out tests is 30.9 MPa.
(81) TABLE-US-00003 TABLE 2 Composition of the curing component B Curing composition Wt. % Amines/polyphenol 61.5 Fillers 35 Fumed silica (hydrophobic) 3.5
(82) TABLE-US-00004 TABLE 3 Composition of the epoxy resin component A Resin component composition Wt. % 3-Glycidyloxypropyltrimethoxysilane 2.5 Bisphenol A-based epoxy resin 30 Bisphenol F-based epoxy resin 17 1,4-butanediol diglycidyl ether 6 Trimethylolpropane triglycidyl ether 6 Quartz powder 36 Fumed silica (hydrophobic) 2.5
(83) TABLE-US-00005 TABLE 4 Average failure load of the mortar compounds according to the invention Curing component Bond strength [N/mm.sup.2] E1 36.9 E2 37.8 E4 38.0 E6 36.8 E11 37.6 E18 37.8
(84) The results show that the bond strength of the mortar compounds produced with the curing compositions E6, E11 and E18 according to the invention are comparable to those using the reference compositions E1, E2 and E4 that are not according to the invention. All values are in the bond strength level to be expected for mortar compounds based on epoxy resins. The curing compositions according to the invention are therefore suitable for use in mortar compounds for chemical fasteners.