Polycarboxylate ethers used as dispersing agents for epoxy resins

Abstract

The invention relates to curable epoxy resin compositions containing at least one epoxy resin having on average more than one epoxide group per molecule, at least one inorganic filler and at least one polycarboxylate ether, wherein the inorganic filler is coated with the polycarboxylate ether. The invention also relates to multi-component systems for producing said epoxy resin compositions, cured epoxy resins, a powder component K3 for the multi-component system, uses and methods.

Claims

1. A curable epoxy resin composition containing at least one epoxy resin having on average more than one epoxide group per molecule, at least one inorganic filler and at least one polycarboxylate ether, wherein the inorganic filler is coated with the polycarboxylate ether, wherein the polycarboxylate ether has side chains linked to a main chain via ester, amide and/or ether groups, wherein the main chain has at least one acrylic acid moiety or a salt thereof, and/or at least one methacrylic acid moiety or a salt thereof, and/or a maleic anhydride moiety or a salt thereof, and/or a maleic acid moiety or a salt thereof, and/or an itaconic acid moeity or a salt thereof, and/or a crotonic acid moiety or a salt thereof, and/or a fumaric acid moiety or a salt thereof.

2. The epoxy resin composition according to claim 1, wherein the coated inorganic filler was obtained by impregnating with a solution or suspension containing the polycarboxylate ether and a solvent.

3. The epoxy resin composition according to claim 2, wherein the solvent is a polar organic solvent.

4. The epoxy resin composition according to claim 1, wherein the inorganic filler has a proportion of finely divided fillers of at least 5 wt. % based on the total weight of the inorganics filler.

5. The epoxy resin composition according to claim 1, additionally containing at least one curing agent and/or at least one reactive diluent.

6. The epoxy resin composition according to claim 5, wherein the epoxy resin comprises at least one glycidyl ether, and/or the curing agent contains at least one polyamine, which is selected from the group consisting of aliphatic, cycloaliphatic or arylaliphatic primary diamines, triamines, tetramines, polyamines with more than four amine groups per molecule, secondary amine group-containing polyamines, amine/polyepoxide adducts, poly(ethylene imines), polyamidoamines, Mannich bases and amino-terminated butadiene/acrylonitrile copolymers, and/or the inorganic filler has at least one filler selected from silicon compounds of at least one of silica, silicates and precipitated and pyrogenic silicas, metal oxides of at least one of titanium dioxide, iron oxide, alumina, zinc oxide and magnesium oxide; metal carbonates of at least one calcium carbonate and dolomite; metal sulfates of at least one of calcium sulfate and barium sulfate; metal hydroxides of at least one of aluminum hydroxide, nitrides and carbides, clay minerals of at least one of kaolin, fly ash, cement, glass and ceramic materials.

7. A multi-component system for producing a curable epoxy resin composition according to claim 1, comprising at least one component K1 containing said at least one epoxy resin, and optionally a curing agent component K2 containing said at least one curing agent, wherein at least one curing agent is contained in said component K1 or K2, wherein said at least one inorganic filler coated with the polycarboxylate ether is contained in said component K1, K2, and/or a further component K3.

8. The multi-component system according to claim 7, comprising at least one component K1 containing at least one epoxy resin, one component K2 containing at least one curing agent, and one solid component K3 containing (a) 93 to 99.7 wt. % inorganic fillers, (b) 0.01 to 2 wt. % polycarboxylate ether, and (c) 0.02 to 5 wt. % solvent.

9. A cured epoxy resin obtainable by mixing the components and curing a multi-component system according to claim 7.

10. A method comprising applying the multi-component system according to claim 7 to a substrate to bond, coat or seal the substrate, or to a mold to produce a molding therein.

11. A cured epoxy resin obtainable by curing an epoxy resin composition according to claim 1.

12. A curable epoxy resin composition containing at least one epoxy resin having on average more than one epoxide group per molecule, at least one inorganic filler and at least one polycarboxylate ether, wherein the inorganic filler is coated with the polycarboxylate ether, wherein the polycarboxylate ether comprises: a) at least one acid moiety A of formula (I): ##STR00006## wherein in formula (I): each R.sup.1, R.sup.2 and R.sup.3 independently of one another represents H, COOM, CH.sub.2COOM or an alkyl group having 1 to 5 carbon atoms, each R.sup.4 independently of one another represents COOM, CH.sub.2COOM, SO.sub.2OM, OPO(OM).sub.2 and/or PO(OM).sub.2, or wherein R.sup.3 together with R.sup.4 forms a COOCO-ring; wherein M represents H, an alkali metal, an alkaline earth metal, ammonium, an ammonium cation, an organic ammonium compound, or mixtures thereof; with the proviso that overall one or two of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is/are acid groups; b) at least one structural moiety B of formula (II); ##STR00007## wherein in formula (II): R.sup.1 independently of one another represents H or CH.sub.3; R.sup.2 independently of one another represents an ester group COO or an amide group CONH; R.sup.3 independently of one another represents a C.sub.2-C.sub.6 alkylene group, R.sup.4 independently of one another represents H, a C.sub.1-C.sub.12 alkyl or cycloalkyl radical, a C.sub.7-C.sub.20 alkylaryl or aralkyl radical, or a substituted or unsubstituted aryl radical, or a monovalent organic radical having 1 to 30 carbon atoms, which optionally comprises heteroatoms, and x independently of one another represents a value between 3 and 250, wherein the main chain of the polycarboxylate ether is a linear copolymer which was obtained by polymerization using said at least one acid moiety or a salt or anhydride thereof, wherein said structural moiety B is a component of this linear copolymer.

13. The epoxy resin composition according to claim 12, wherein the polycarboxylate ether has at least one further structural moiety C, which is different from the structural moieties A and B, and which is selected from an ether, ester, amide or imide moiety, an acid moiety selected from carboxylic acid, sulfonic acid, phosphonic acid, phosphoric acid ester, carbonylamidomethylpropanesulfonic acid and salts thereof, or a polyoxyalkyleneoxycarbonyl, polyoxyalkyleneaminocarbonyl, polyoxyalkyleneoxyalkyl, polyoxyalkyleneoxy, hydroxyethyloxycarbonyl, acetoxy, phenyl or N-pyrrolidonyl group.

14. A method comprising dispersing an an inorganic filler in a curable epoxy resin composition with a polycarboxylate ether as a dispersing agent, wherein the polycarboxylate ether has side chains linked to a main chain via ester, amide and/or ether groups wherein the main chain has at least one acrylic acid moiety or a salt thereof, and/or at least one methacrylic acid moiety or a salt thereof, and/or a maleic anhydride moiety or a salt thereof, and/or a maleic acid moiety or a salt thereof, and/or an itaconic acid moiety or a salt thereof, and/or a crotonic acid moiety or a salt thereof, and/or a fumaric acid moiety or a salt thereof.

15. A solid filler which is coated with a polycarboxylate ether, containing (a) 93 to 99.97 wt. % inorganic fillers, (b) 0.01 to 2 wt. % polycarboxylate, and (c) 0.02 to 5 wt. % organic solvent, wherein the polycarboxylate ether has side chains linked to a main chain via ester, amide and/or ether groups, wherein the main chain has at least one acrylic acid moiety or a salt thereof, and/or at least one methacrylic acid moiety or a salt thereof, and/or a maleic anhydride moiety or a salt thereof, and/or a maleic acid moiety or a salt thereof, and/or an itaconic acid moiety or a salt thereof and/or a crotonic acid moiety or a salt thereof, and/or a fumaric acid moiety or a salt thereof.

Description

FIGURES

(1) FIG. 1 shows the particle size distribution of the component K3 as described in exemplary embodiment 1. The screen residue in weight percent is plotted against the screen size in millimeters.

(2) FIG. 2 shows the flowability of compositions E3 and V3 from exemplary embodiment 4 in a flow channel as described in Example 5. The flow distance in millimeters is plotted against the flow time in minutes (from 0 to 60 minutes). The lower curve (squares) shows the flowability of composition V3 without PCE, while the upper curve (triangles) shows the flowability of composition E3 with PCE. In addition, the flowability of composition E4 with PCE with a higher filler content is shown (middle curve, diamonds).

EXEMPLARY EMBODIMENTS

Example 1

Production of a Three-Component System

(3) A three-component system was produced as the basis for an epoxy grout with a filler content of about 82 wt. %.

(4) Component K1: Epoxy Resin

(5) TABLE-US-00001 Component wt. % Bisphenol A-epichlorohydrin resins with 74.7 average molecular weight >700 Mixture of silicone-free defoamer, 0.3 solvent naphtha and 2-methoxy-l- methylethylacetate 1,6-Hexanediol diglycidyl ether 25 Total 100

(6) The epoxy resin was charged first. All other materials were added and homogenized for about 5 minutes.

(7) Component K2: Curing Agent

(8) TABLE-US-00002 Component wt. % Triethylenetetramine 100

(9) Component K3: Filler:

(10) TABLE-US-00003 Component wt. % Quartz sand mixture 79.5 TiO.sub.2 white pigment 0.45 Cement, particle size <0.06 mm 20 Iron oxide black 0.05 Polycarboxylate ether solution (20% PCE 1 dissolved in 80% benzyl alcohol) Total 101

(11) Component K3 is composed of a mixture of different quartz sands with particle sizes in the range of 0.06 mm to 3.2 mm. The particle size distribution of the quartz sand mixture is shown in FIG. 1. In addition, component K3 contains cement as inorganic finely divided filler and a low proportion of titanium dioxide and iron oxide as pigments.

(12) The polycarboxylate is first dissolved in benzyl alcohol. The fillers are successively weighed and placed in a stirred tank (the coarse fillers first, the finely divided fillers last). Then, the polycarboxylate ether/benzyl alcohol mixture is added and mixed for about 5 minutes at RT. A Hobart planetary mixer N50 CE at level 1 was used as the stirring unit.

Example 2

Production of Curable Epoxy Resin Compositions E1 and V1

(13) An epoxy composition E1 according to the invention was prepared by mixing components K1 to 3. The mixing ratio of component K1:K2:K3 was 6:1:35 parts by weight.

(14) For comparison, an epoxy composition V1 was produced whose component K3 did not contain any polycarboxylate ether/benzyl alcohol mixture and which, otherwise, was identical to the composition E1.

Example 3

Determination of the Flowability of Epoxy Resin Compositions E1 and V1

(15) The flowability of epoxy compositions E1 and V1 was determined using a brass cone (about 500 g epoxy resin mortar) in accordance with DIN EN 13395-1 or EN 1015-3 and the flow spread (diameter) was determined after curing. The flow spread without polycarboxylate ether/benzyl alcohol mixture was 265 mm. With a proportion of about 0.85% polycarboxylate ether/benzyl alcohol mixture the flow spread was 310 mm, which is an improvement of about 17%.

Example 4

Production and Evaluation of Curable Epoxy Resin Compositions E2 and V2 with Commercially Available Filler

(16) Another three-component system was produced, in which components K1 and K2 corresponded to those described in Example 1 above. The filler component of a commercially available epoxy cement (brand name Masterflow 410 PCT BASF Construction Chemicals) is used as component K3. 0.3 wt. % of a solution of 95 wt. % benzyl alcohol and 5 wt. % polycarboxylate ether were added to this filler component and stirred for 5 min at RT in a planetary mixer.

(17) Components K1 and K2 were mixed in the mixing ratio 6:1 (parts by weight), component K3 was added (mixing ratio K1:K2:K3=6:1:60.9 or (K1+K2):K3=1:8.7) and homogenized for 3 minutes using a spiral mixer or basket mixer, resulting in epoxy resin composition E2. For comparison, an epoxy composition V2 was produced whose component K3 did not contain any polycarboxylate ether/benzyl alcohol mixture and which, otherwise, was identical to composition E2.

(18) In each case, in accordance with DIN EN 13395-1 or EN 1015-3, the material was filled into a brass ring standing on a flat plastic surface. The brass ring was lifted and the spreading of the grout was observed. After curing, the diameter/the flow spread was determined. Composition E2 with polycarboxylate ether/benzyl alcohol flows better and exhibits a flow spread that is increased by about 13% compared to composition V2 without polycarboxylate ether/benzyl alcohol.

(19) The flow spread without polycarboxylate ether/benzyl alcohol mixture was 228 mm. With about 0.3% polycarboxylate ether/benzyl alcohol mixture the flow spread was 258 mm, which is an improvement of about 13%.

Example 5

Production and Evaluation of Curable Epoxy Resin Compositions E3 and V3 with Commercially Available Filler

(20) 0.3 wt. % of a solution of 95 wt. % benzyl alcohol and 5 wt. % polycarboxylate ether were added to the filler component of a commercially available epoxy grout (trade name Sikadur-42 LE; Sika Canada) and stirred for 5 minutes at RT in a planetary mixer, resulting in component K3.

(21) Components K1 and K2 were mixed in the mixing ratio 6:1 (parts by weight), component K3 was added (mixing ratio K1:K2:K3=6:1:45.5 or (K1+K2):K3=1:6.5) and homogenized for 3 minutes using a spiral mixer or basket mixer, resulting in epoxy resin composition E3. For comparison, an epoxy composition V3 was produced whose component K3 did not contain any polycarboxylate ether/benzyl alcohol mixture and which, otherwise, was identical to composition E3.

(22) The material is filled into a flow channel according to EN 13395-2 and the flow path is determined as a function of time.

(23) The course of the flow curve over a period of time of about 35 minutes is shown in FIG. 2. Epoxy resin composition E3 flows much faster (steeper rise at the beginning of the curve) and in a comparable time, even further than composition V3. The flow path covered by epoxy resin E3 after 25 minutes is already about 60% greater. Even with an increase in the filler content to a mixing ratio of the liquid components to filler component to (K1+K2):K3=1:8.5 in an epoxy resin composition E4, the grout with PCE is still flowing further than the same grout without PCE at a ratio of the components (K1+K2):K3 of 1:6.5.

(24) In further experiments it was found that for epoxy resin grouts the mixing ratio between liquid binder and filler K3, depending on the desired flowability, can vary, for example, from 1:4 to 1:9 ((K1+K2):K3, gravimetrically) (about 78-90 wt. % filler content). Here, it is advantageous to adapt the concentration of the polycarboxylate ethers in each case.

Example 6

Impact of the Solvent

(25) To exclude the possibility that the solvent causes the improvement of the flowability of compositions according to the invention, comparative experiments were performed with similar quantities of solvent but without polycarboxylate. For this purpose, the flowability of epoxy resin composition with components K1 and K2 in accordance with Example 1 and various filler components N3 (base composition comparable to Example 1, however, without PCE and solvent) was compared. The quantitative ratio was (K1+K2):K3=1:6.5. The differences in the epoxy resin compositions and the results are summarized in the following table. The results show that the polycarboxylate ether significantly improves flowability.

(26) TABLE-US-00004 Flow spread * Components [approx. in mm] K1+ K2 + N3 252 mm K1+ K2 + N3 + 0.3% benzyl alcohol 260 mm K1+ K2 + N3 + 0.03% 281 mm polycarboxylate ether (Sika Viscocrete-125) + 0.27% benzyl alcohol) * Approx. 500 g, measured by cone at 23 C. (DIN EN 13395-1 and EN 1015-3)

Example 7

Epoxy Resin Composition E4

(27) Another epoxy resin composition E4 based on a three-component system was produced and tested. The production of the components, processing and determination of the flow spread were carried out as described for Examples 1 to 3 above, unless described differently hereinafter. A three-component system was produced as a basis for an epoxy resin coating having a filler content of about 63 wt. %.

(28) Component K1: Epoxy Resin

(29) TABLE-US-00005 Component wt. % Bisphenol A-epichlorohydrin resin with an 85 average molecular weight >700 C12/C14-alkyl glycidyl ether 10 Heavy aromatic solvent naphtha 4.9 (petroleum) Mixture of solvent naphtha and 2-methoxy- 0.1 1-methylethylacetate Total 100

(30) Component K2: Curing Agent

(31) TABLE-US-00006 Component wt. % Benzyl alcohol 40 Isophorone diamine 25 Triethylenetetramine 20 Heavy aromatic solvent naphtha 15 (petroleum) Total 100

(32) Component K3: Filler:

(33) TABLE-US-00007 Component wt. % Natural CaCO.sub.3, <0.06 mm particle size 60 Quartz powder <0.06 mm particle size 38.4 TiO.sub.2 white pigment 1.2 Iron oxide black 0.1 PCE solution (20% PCE dissolved in 80% 0.3 benzyl alcohol) Total 100

(34) Component K3 was produced by first dissolving Sika ViscoCrete-125 (Sika, CH) in benzyl alcohol (20 wt. % Sika ViscoCrete-125 and 80 wt. % benzyl alcohol). Quartz powder is charged into the stirred tank and the solution Sika ViscoCrete/benzyl alcohol is added and mixed for 3 minutes using planetary mixer N50 CE (level 1) at RT. After addition of the remaining filler components it is mixed for further three minutes in the planetary mixer at RT. Component K3 contains calcium carbonate and quartz powder as finely divided fillers.

(35) The mixing ratio (gravimetrically) of the individual components in the epoxy resin composition is K1:K2:K3 component=3:1:7; or liquid to filler component (K1+K2):K3=1:1.75 (parts by weight).

(36) Flowability was determined using 150 g samples and the flow spread (diameter) was determined after curing. The flow spread without polycarboxylate ether/benzyl alcohol mixture was 212 mm.

(37) The flow spread with 0.2% polycarboxylate ether/benzyl alcohol mixture was 250 mm. Thus, with the addition of polycarboxylate ether the flow spread could be increased by more than 18%.

Example 8

Impact of the Solvent

(38) Three-component systems and epoxy resin compositions E5 and E6 were produced according to Example 7 with the following modification. Components K3 were produced in a three-component system according to Example 7, wherein one component K3 was coated with 0.3 wt. % benzyl alcohol, another one was coated with a solution of 0.06 wt. % polycarboxylate ether and 0.24 wt. % benzyl alcohol. Flowability was determined using 150 g samples and the flow spread (diameter) was determined after curing. The flow spread of E5 without polycarboxylate ether, only with 0.3% benzyl alcohol, was about 210 mm. The flow spread of E6 with 0.06 wt. % polycarboxylate ether and 0.24 wt. % benzyl alcohol was about 250-260 ram. The increase of the flow spread by approx. 20% shows it is caused by the polycarboxylate ether.