REINFORCING BAR, METHOD FOR THE PRODUCTION, AND USE

Abstract

The invention relates to a rebar, to a method of production and to use of a composition. In particular, the invention relates to a rebar including A) at least one fibrous carrier, and B)and a hardened composition formed from B1) at least one epoxy compound, and B2) at least one diamine and/or polyaminein a stoichiometric ratio of the epoxy compound B1) to the diamine and/or polyamine component B2) of 0.8:1 to 2:1, as matrix material, and also C) optionally further auxiliaries and additives.

Claims

1. A rebar comprising A) at least one fibrous carrier; B) a hardened composition comprising B1) at least one epoxy compound and B2) at least one diamine and/or polyamine in a stoichiometric ratio of the epoxy compound B1) to the diamine and/or polyamine component B2) of 0.8:1 to 2:1, as matrix material, and C) optionally further auxiliaries and additives.

2. The rebar according to claim 1, wherein the fibrous material selected from the group consisting of glass, carbon, polymers, natural fibers, mineral fiber materials and ceramic fibers.

3. The rebar according to claim 1, wherein epoxy compounds B1) selected from saturated, unsaturated, aliphatic, cycloaliphatic, aromatic and heterocyclic epoxy compounds are present, and these may also have hydroxyl groups.

4. The rebar according to claim 1, wherein epoxy compounds B1) selected from glycidyl ethers, glycidyl esters, aliphatic epoxides, diglycidyl ethers based on bisphenol A and/or bisphenol F, glycidyl methacrylates are present.

5. The rebar according to claim 1, wherein epoxy compounds B1) selected from the group comprising epoxy resins based on bisphenol A diglycidyl ether, epoxy resins based on bisphenol F diglycidyl ether and cycloaliphatic types are present.

6. The rebar according to claim 1, wherein amines B2) selected from primary and/or secondary di- and/or polyamines are present.

7. The rebar according to claim 1, wherein the amines B2) used are selected from the group consisting: aliphatic amines, such as the polyalkylenepolyamines, preferably selected from ethylene-1,2-diamine, propylene-1,2-diamine, propylene-1,3-diamine, butylene-1,2-diamine, butylene-1,3-diamine, butylene-1,4-diamine, 2-(ethylamino)ethylamine, 3-(methylamino)propylamine, diethylenetriamine,triethylenetetramine, pentaethylenehexamine, trimethylhexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, N-(2-aminoethyl)ethane-1,2-diamine, N-(3-aminopropyl)propane-1,3-diamine, N,N-1,2-ethanediylbis(1,3-propanediamine), dipropylenetriamine, adipic dihydrazide, hydrazine; oxyalkylenepolyamines selected from polyoxypropylenediamine and polyoxypropylenetriamine; cycloaliphatic amines selected from isophoronediamine (3,5,5-trimethyl-3-aminomethylcyclohexylamine), 4,4-diaminodicyclohexylmethane, 2,4-diaminodicyclohexylmethane and 2,2-diaminodicyclohexylmethane, alone or in mixtures of the isomers, 3,3-dimethyl-4,4-diaminodicyclohexylmethane, N-cyclohexyl-1,3-propanediamine, 1,2-diaminocyclohexane, 3-(cyclohexylamino)propylamine, piperazine, N-aminoethylpiperazine, TCD diamine (3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0.sup.2,6]decane), araliphatic amines; aromatic amines selected from phenylenediamines, phenylene-1,3-diamine, phenylene-1,4-diamine, 4,4-diaminodiphenylmethane, 2,4-diaminodiphenylmethane, 2,2-diaminodiphenylmethane, alone or in mixtures of the isomers; adduct hardeners which are the reaction products of epoxy compounds, especially glycidyl ethers of bisphenol A and F, with excess amine; polyamidoamine hardeners which are obtained by condensation of mono- and polycarboxylic acids with polyamines, especially by condensation of dimer fatty acids with polyalkylenepolyamines; Mannich base hardeners which are obtained by reaction of mono- or polyhydric phenols with aldehydes, especially formaldehyde, and polyamines; Mannich bases, formaldehyde, m-xylylenediamine, N-aminoethylpiperazine, blends of N-aminoethylpiperazine with nonylphenol and/or benzyl alcohol, phenalkamines which are obtained in a Mannich reaction from cardanols, aldehydes and amines.

8. The rebar according to claim 1, wherein amines B2) are selected from the group consisting of isophoronediamine, 4,4-diaminodicyclohexylmethane, 2,4-diaminodicyclohexylmethane, 2,2-diaminodicyclohexylmethane, alone or in mixtures of the isomers, a mixture of the isomers of 2,2,4-trimethylhexamethylenediamine and 2,4,4-trimethylhexamethylenediamine, adduct hardeners based on the reaction product of epoxy compounds and amines B2) or a combination of the aforementioned amines B2) are present.

9. The rebar according to claim 1, wherein amines B2) are selected from the group consisting of isophoronediamine and/or a combination of isophoronediamine and a mixture of the isomers of 2,2,4-trimethylhexamethylenediamine and 2,4,4-trimethylhexamethylenediamine are present.

10. The rebar according to claim 1, wherein mixtures of the di- and/or polyamines with latent hardeners are used as component B2).

11. The rebar according to claim 1, wherein latent hardeners selected from dicyandiamide, cyanoguanidines, aromatic amines, guanidines, modified polyamines, N-acylimidazoles, imidazoles, carbonyl hydrazides, triazine derivatives, melamine and derivatives thereof, N-cyanoacylamide compounds, acylthiopropylphenolsare used.

12. A method of producing rebars A) at least one fibrous carrier and B) a hardened composition formed from B1) at least one epoxy compound and B2) at least one diamine and/or polyamine in a stoichiometric ratio of the epoxy compound B1) to the diamine and/or polyamine component B2) of 0.8:1 to 2:1, as matrix material, and also C) optionally further auxiliaries and additives, by applying a mixture of B1) and B2) and optionally C) to the fibrous carrier, and then hardening the composition.

13. The method according to claim 12, wherein the rebars are produced in a pultrusion method.

14-15. (canceled)

16. A composite comprising a rebar of claim 1.

17. Composites according to claim 16, wherein the fibrous material selected from the group consisting of glass, carbon, polymers, natural fibers, mineral fiber materials and ceramic fibers.

18. A composite comprising a rebar of claim 3.

19. A composite comprising a rebar of claim 4.

20. A composite comprising a rebar of claim 5.

21. A composite comprising a rebar of claim 6.

22. A composite comprising a rebar of claim 7.

Description

EXAMPLES

[0122] In order to determine the influence of alkaline media on the stability of the matrix system, exposure tests were conducted in an alkaline environment.

[0123] For storage in 10% sodium hydroxide solution at 80 C., pure resin slabs (4 mm) were cast; for hardening conditions see Table 1. The pure resin slabs obtained were used to produce test specimens of dimensions 50504 mm and these were stored in 10% sodium hydroxide solution at 80 C. for 4 weeks. During this period, the change in weight was determined by weighing and the percentage change in weight was recorded, as shown in Table 1.

[0124] It is apparent that the sample based on the anhydride-based hardener system (Experiment 2, methyltetrahydrophthalic anhydride (MTHPA)), after initially increasing in weight, loses weight again. The samples were therefore redried after the storage had ended (1 month at RT). Under these conditions, a loss of mass of around one per cent was found in the case of the anhydride-hardened epoxy resin formulation (Experiment 2), whereas an increase in weight as a result of incorporated medium can still be detected in the case of the IPD-hardened epoxy resin formulation. All the results are compared in Table 1. This shows a substantial attack on the anhydride-hardened matrix by the alkaline medium, which is also reflected in the reduced glass transition temperature after chemical storage.

[0125] Examples and results are shown in Table 1:

TABLE-US-00001 TABLE 1 Experiment 1 according Experiment 2, to invention comparative Amount used Amount used in grams in grams Epikote 828 HEXION 441 100 1-Methylimidazole 0.5 VESTAMIN IPD Evonik Industries 100 AG (isophoronediamine) 90 MTHPA Hardening 30 min, 4 h 80 C. + 120 C. 4 h 120 C. Measurement results Tg after hardening.sup.a) and storage 144 C. 132 C. under ambient conditions (2 months, 0 sample) Tg max..sup.b) of the 0 sample 156 C. 133 C. Storage in 10% sodium hydroxide solution at 80 C. for 1 month: Change in mass after 1 d +0.56% +0.28% 3 d +0.96% +0.44% 7 d +1.26% +0.38%* 14 d +1.46% +0.18% 28 d +1.60% +0.23% Redrying under ambient conditions for 1 month: Change in mass relative to original +1.23% 0.90%* Tg after storage in 10% sodium 146 C. 123 C.*** hydroxide solution and redrying.sup.a) Tg max..sup.b) 159 C. 129 C. *the reversal of the trend in the changing mass indicates that the anhydride-based matrix (experiment 2) is being degraded **the negative change in mass demonstrates that the anhydride-based matrix dissolves ***a Tg loss of 9 C. provides additional confirmation of the degradation of the matrix system in Experiment 2 .sup.a)DSC experiment on test specimens hardened and stored under the conditions specified (pure resins). A sample was taken from the pure resin specimens and the glass transition temperature was determined in the DSC (heating rate 10 K/min up to a maximum temperature of 250 C.). .sup.b)The term Tg max refers to the result (=maximum attainable Tg of the material) of a 2nd DSC experiment on the same sample under identical conditions to those in .sup.a). All Tg measured by means of DSC in accordance with DIN EN ISO 11357-1.

[0126] DSC Mmeasurements

[0127] The DSC measurements were conducted to DIN EN ISO 11357-1 of March 2010.

[0128] A heat flux differential calorimeter from the manufacturer Mettler-Toledo, model: DSC 821 with serial number: 5116131417, was used. The samples were run twice from 30 C. to 250 C. at 10 K/min. The cooling ramp between the two measurements is 20 K/min.

[0129] Detailed description of the test method: [0130] 1. Type (heat flux differential calorimeter or performance-compensated calorimeter), model and manufacturer of the DSC unit used; [0131] 2. Material, form and type and, if required, mass of the crucible used; [0132] 3. Type, purity and flow rate of the purge gas used; [0133] 4. Type of calibration method and details of the calibration substances used, including source, mass and further properties of significance for the calibration; [0134] 5. Details of sampling, sample preparation and conditioning [0135] 1: Heat flux differential calorimeter [0136] Manufacturer: Mettler-Toledo [0137] Model: DSC 821 [0138] Serial no.: 5116131417 [0139] 2: Crucible material: ultrapure aluminium [0140] Size: 40 l, no pin, [0141] Mettler cat. no.: ME-26763 [0142] Mass including lid: about 48 mg [0143] 3: Purge gas: nitrogen [0144] Purity: 5.0 (>99.999% by vol.) [0145] Flow rate: 40 ml/min [0146] 4: Calibration method: simple [0147] Material 1: indium [0148] Mettler calibration set ME-51119991 [0149] Mass: about 6 mg per weighing [0150] Calibration of temperature (onset) and heat flow [0151] Material 2: demineralized water [0152] Taken from the in-house system [0153] Mass: about 1 mg per weighing [0154] Calibration of temperature (onset) [0155] 5: Sampling: from specimen supplied [0156] Sample weight: 8 to 10 mg [0157] Sample preparation: none [0158] Crucible lid: perforated

[0159] Measurement program: 30 to 250 C., 10 K/min, 2