EP1877458A1

EP1877458A1 - Resorcinol-based mannich base

Info

Publication number: EP1877458A1
Application number: EP06754919A
Authority: EP
Inventors: Ulrich Gerber
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2005-04-29
Filing date: 2006-04-28
Publication date: 2008-01-16
Also published as: EP1717253A1; JP2008539207A; CA2605523A1; RU2007144210A; AU2006243839A1; US20090118457A1; WO2006117339A1; KR20080007484A; MX2007012959A; CN101166772A

Abstract

The invention relates to Mannich bases that can be produced from resorcinol, formaldehyde, and triethylenetetramine and/or tetraethylenepentamine. Also disclosed are a method for the production thereof and the use thereof as hardeners for amine-reactive compounds. The inventive Mannich bases are particularly suitable as hardener components in adhesives.

Description

MANNICHBASE ON RESORCIN BASIS

Technical area

The present invention relates to the field of preparation and use of Mannich bases.

State of the art

The class of Mannich bases has been known for a long time and has already been used in hardener components of reactive systems. For the preparation of phenols are used. However, phenol (hydroxybenzene) as starting material has the great disadvantage that the Mannich bases prepared therefrom still contain portions of unreacted phenol. Due to the toxicity of phenol, phenol-based Mannich bases can not be used in many market sectors. Therefore, great efforts have been made to produce phenol-free Mannich bases. For example, Mannich bases based on nonylphenol or p-tert-butylphenol or cardanol have been developed and commercialized.

Mannich bases are mainly used as accelerators for epoxy resins or as hardeners for epoxy resins and polyurethanes. WO 00/15687, for example, describes a Mannich base accelerator which is prepared by transamination of a Mannich base with an amine.

The processes for preparing known Mannich bases are very complicated and difficult to perform, especially if the formation of high molecular weight condensation products should be prevented as much as possible. For example, EP-A-1 475 411 discloses a two-stage preparation process for the preparation of Mannich bases based on m-cresol or 3,5-xylenol and polyamines, in which a tertiary amine is preferably used. Likewise a two-stage production process of Mannich bases is disclosed in EP-A-1 475 412, which are obtained from phenols such as m-cresol, 3,5-xylenol or resorcinol with polyamines, preferably using tertiary amines. However, such two-stage processes are associated with additional expense and increase the production of Mannich bases.

Presentation of the invention

The object of the present invention is therefore to provide novel Mannich bases and the process for their preparation which are free of phenol and can be prepared by a simplified process.

Surprisingly, it has been found that Mannich bases according to claim 1 can be prepared by a specific selection of known in the art polyamine and phenolic compounds, which can solve this problem. These Mannich bases can be made from cheap, easily accessible raw materials through simple production. They are characterized by an excellent curing behavior, especially at low temperatures, with amine-reactive compounds.

Further aspects of the invention are described in the further main claims. Further advantageous embodiments of the invention will become apparent from the dependent claims.

The present invention relates to Mannich bases which can be prepared from resorcinol, formaldehyde and / or triethylenetetramine and / or tetraethylenepentamine.

Resorcinol (CAS No. [108-46-3]) is commercially available in a wide range of purities. Resorcinol is distinguished from the other dihydroxybenzene isomers catechol and hydroquinone, among other things by a lower toxicity (German water hazard class WGK 1 compared to 2 or 3 or Swiss poison class 3 compared to 2). It has particularly shown that resorcinol over these, as well as others Phenols such as phenol, the various isomers of cresol or xylenol surprisingly very well suited for the preparation of Mannich bases.

Formaldehyde can be used in forms commonly known to those skilled in the art directly or from formaldehyde-releasing compounds. Preferred is formaldehyde in the form of para-formaldehyde or as a formalin solution. Particularly preferred is formalin solution.

Furthermore, triethylenetetramine and / or tetraethylenepentamine is used for the preparation of the novel Mannich bases. Both triethylenetetramine (TETA) (CAS No. [112-24-3]) (3,6-diazaoctan-1,8-diamine) and tetraethylenepentamine (TEPA) (CAS No. [112-57-2]) (3 , 6,9-triazaun-decane-1,11-diamine) are commercially widely available and are very inexpensive. They are offered and used in particular in technical quality. Such technical quality is preferred. It is known to the person skilled in the art that TETA and TEPA in such technical quality are not a pure, uniform chemical substance. In particular, they contain further substances and isomers due to the process for their preparation. In the case of TETA, the predominantly formed substances and isomers are: N, N'-bis (2-aminoethyl) piperazine (BisAEP or DiAEP) (CAS No. [6531-38-0])

- Piperazinoethylethylenediamine (PEEDA) (CAS No [24028-46-4])

Tris (2-aminoethyl) amine (NTEA or NTE) (CAS No. [4097-89-6]) or, in the case of TEPA:

- 4-Aminoethyltriethylenetetramine (AETETA) (CAS No [31295-46-2]) - Aminoethyl piperazinoethylethylenediamine (AEPEEDA) (CAS No [31295-54-2])

Piperazinoethyldiethylenetriamine (PEDETA) (CAS No [31295-49-5]).

Other compounds and isomers can be formed to a low mass, but the sum thereof in addition to the above explicitly mentioned compounds in terms of quantity below 3 wt .-% based on the weight of the technical TETA or TEPA. A mixture of TETA and TEPA can be used or only TETA or only TEPA. Both polyamines TETA and TEPA have a high N / C ratio, and accordingly, a lot of amino groups can be introduced by means of a small molecule, and hence a small amount.

Those made from resorcinol, formaldehyde and TETA and / or TEPA

Mannich base preferably has an amine number of between 800 and 1100 mg / g KOH, in particular in the range between 900 and 1000 mg / g KOH, preferably in the range between 950 and 1000 mg / g KOH. Mannich bases can be prepared which no longer have measurable amounts of unreacted resorcinol, the amine number.

Another aspect of the present invention relates to the preparation of the described Mannich base. For this purpose, resorcin, triethylenetetramine and / or tetraethylenepentamine with formaldehyde at a temperature below 25 ⁰ C is reacted. Specifically, to a premix of resorcinol and triethylenetetramine and / or tetraethylenepentamine formaldehyde under stirring and cooling to a temperature below 25 ⁰ C, especially below 15 ⁰ C, is added. The addition is preferably carried out in portions, in particular as a drop of. The resorcinol / [TETA and / or TEPA] premix is preferably previously heated to a temperature of about 8O ⁰ C to dissolve the resorcinol and cooled again before the formaldehyde is added. It has been shown that it is advantageous if the premix further comprises a solvent, in particular an alcohol, preferably methanol, in order to better dissolve the resorcinol and lower the viscosity, and which is added before the reaction with formaldehyde. Particularly advantageously, the solvent is already used at the very beginning, ie in the preparation of the premix. After the formaldehyde has been added dropwise, the reaction mixture is preferably raised to a temperature and in particular to about 95 ⁰ C and at the same time a slight vacuum of typically 0.6 to 0.9 bar set. Here, the possibly introduced by the formaldehyde water, and the water formed and the distilled off any solvents used. The solvent used is therefore advantageous to select so that it is easy to distill off at this temperature and pressure.

It has been found to be particularly advantageous that the Mannich bases can also be prepared without the presence of additional tertiary amines which are not already present in technical triethylenetetramine and / or technical tetraethylenepentamine.

The molar ratios of resorcinol to formaldehyde to the sum of TETA and TEPA are in particular 1: 1.5-2.5: 2.5-3.5. Such a ratio of 1 to about 2 to about 3 has proven particularly suitable.

The Mannich base so formed is preferably free of unreacted resorcinol, i. that no measurable amounts of resorcinol are present in the Mannich base, and in particular has an amine number of between 800 and 1100 mg / g KOH, in particular in the range between 900 and 1000 mg / g KOH, preferably in the range between 950 and 1000 mg / g KOH , on.

The Mannich base can be used as such or in a composition.

The Mannich bases are particularly suitable as hardeners for an amine-reactive substance which has at least two amine-reactive functional groups. Suitable amine-reactive functional groups are, in particular, glycidyl ether and / or isocyanate groups. In one embodiment, the amine-reactive substance having at least two amine-reactive functional groups is a diglycidyl ether. In particular, it is a diglycidyl ether of bisphenol-A, bisphenol-F or bisphenol-A / F. More preferably, such a diglycidyl ether is a so-called liquid resin, especially as available on the market under the trade name Araldite® GY 250, Araldite® PY 304, Araldite® GY 282 (Huntsman) or D.E. R 331 (Dow).

In another embodiment, the amine-reactive substance having at least two amine-reactive functional groups, a Polyisocyanate or a prepolymer having at least two isocyanate groups. As polyisocyanate are in particular 1, 6-hexamethylene diisocyanate (HDI), 2,2,4- and 2,4,4-trimethyl-1,6-hexamethylene diisocyanate (TMDI), 1-isocyanato-3,3,5-trimethyl -5-isocyanatomethylcyclohexane (= isophorone diisocyanate or IPDI), 2,4- and 2,6-tolylene diisocyanate (TDI) and also 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate (MDI) suitable. As prepolymers having at least two isocyanate groups are, in particular, those prepolymers which are obtainable from at least one of the abovementioned polyisocyanates and at least one polyol. Particularly suitable polyols are polyoxyalkylene polyols or polyester polyols having at least two OH groups, in particular 2 or 3 OH groups.

By mixing the amine-reactive substance, which has at least two amine-reactive functional groups, with the novel Mannich base, a reaction of the amine groups of the Mannich bases with the amine-reactive functional groups of the amine-reactive substance occurs and curing takes place.

Thus, the present invention also includes a two-component composition consisting of a first component K1 and a second component K2. The first component K1 comprises at least one amine-reactive compound having at least two functional groups which can react with amines. The second component K2 comprises at least one Mannich base, as previously described. The compounds which are suitable as amine-reactive compounds which have at least two functional groups which can react with amines have already been described above.

The first component K1 advantageously comprises several amine-reactive compounds. In particular, the use of a more viscous and a lower viscosity amine-reactive compound is recommended. As the low-viscosity amine-reactive compound, special so-called reactive diluents are preferred.

The second component K2 may contain, in addition to the Mannich base, further amines. In particular, this is an aliphatic or cycloaliphatic amine, preferably isophoronediamine (IPDA). Further preferably, the component K2 may contain TETA or TEPA. This additional amine can be added already at the end of Mannich base or only when formulating component K2. Both components K1 and K2 can be added to the

Those skilled in the art include known ingredients. Such further ingredients are in particular fillers, plasticizers, solvents, catalysts and / or additives.

Particularly suitable fillers are Russian, chalks, in particular coated chalks, sands, silicates, light fillers, such as ceramic or glass spheres, in particular ceramic or glass hollow spheres, pyrogenic silicic acids, fly ash.

Particularly preferred solvents are solvents which are not classified as VOC "volatile organic compounds." Particularly preferred are higher-boiling hydrocarbons.

As plasticizers are in particular phthalates and adipates, in particular diisodecyl phthalate (DIDP) and dioctyl adipate (DOA).

Such two component compositions can be widely used. Particularly preferred is their use as an adhesive or

Sealant, especially as a structural adhesive. It has been shown that the achievable by means of the novel Mannich bases

Properties are particularly desirable, especially in the adhesive sector.

In particular, it has been found that high cure rates, especially at low temperatures, can be achieved and that high glass transition temperatures (Tg) can be achieved even if the cure is cold, i. at room temperatures. This is particularly important for epoxy resin compositions, since so far for the

Achieving high Tgs-substituted Mannich base free amine hardeners, for example, isophoronediamine-based hardeners, either at high levels

Temperatures, ie above 6O ⁰ C, had to be implemented or for which after the room temperature curing a post-annealing, ie subsequent

Heating to temperatures above 6O ⁰ C, had to be used. In addition, with Mannichbasen-free amine hardened epoxy resins often occurs the problem that the curing in the so-called beta-stage stops and the final strength is only possible through a subsequent heating. In addition, Hesse is such Mannich base-free or not harden Aminhärtem at temperatures below 1O ⁰ C and especially below 5 ⁰ C very bad. These disadvantages of the prior art can be remedied by Mannich bases according to the invention. In particular, after curing at room temperature glass transition temperatures of over 8O ⁰ C can be achieved without a post-annealing is necessary. In addition, DER-like composition of cure even at low temperatures, particularly below 10 ° C, preferably of between -10 ° C and 5 ⁰ C.

For all applications, it is important, in particular from ecotoxicological and working-physiological aspects, that hardener components can be made available with the novel Mannich bases which are free of phenols but also free of other phenolic compounds, and preferably also free, i. no longer containing measurable amounts of unreacted resorcinol.

After mixing the components K1 and K2 of the described two-component composition, the adhesive is applied to a substrate surface and joined to another surface of the substrate. The cured composition acts as an adhesive layer capable of transferring forces between the two substrate surfaces of the formed composite. The two-component composition is suitable because of their

Properties especially good as a structural adhesive in civil engineering, as well as in industry.

For example, such a two-component composition, especially a two-part epoxy resin composition, ie where component K1 comprises a diglycidyl ether, can be used as an adhesive for the bonding of fiber-reinforced composites. An illustrative example of this is the bonding of carbon fiber fins in reinforcing structures such as bridges. Furthermore, inventive two-component compositions, in particular a two-component epoxy resin composition, can be used as a plastic matrix for the production of fiber-reinforced composites. For example, carbon or glass fibers can be embedded in a two-component composition and can be used in the cured state as a fiber composite, for example in the form of a lamella.

Likewise, for example, fiber fabric or scrim can be applied by means of a two-component composition, in particular by means of a two-component epoxy resin composition, to a building, and together with the building together form a fiber-reinforced composite.

Examples

Preparation Mannich bases a) with solvent dilution

1 mol of the phenolic compound shown in Table 1 was initially charged with 3 mol of the specified in Table 1 polyamine with 90 g of methanol in a reaction vessel under nitrogen and heated to a maximum of 8O ⁰ C until the phenol went into solution. Subsequently, it was cooled by means of ice bath to a temperature between 2 and 13 ⁰ C. With stirring, 2 moles of formaldehyde (used as 37% formalin solution) were then added dropwise with vigorous stirring and ice bath cooling. After the formaldehyde was completely added dropwise at a pressure of 400 mbar, the temperature slowly increased to 90 ⁰ C. Finally, the vacuum was increased to 50 mbar. The amount of distillates obtained corresponds to the amount of the theoretical amount of methanol and water which has been used and formed.

TABLE 1 Properties of Mannich bases (variation of the phenolic compound). 'Average of a triple determination' detection limit below 0.05%

The viscosity was measured by means of Rheomat at 2O ⁰ C cone / plate (40 mm cone, 300 revolutions / sec or 20mm cone, 50 revolutions / s). The residual content of the polyamine was determined by GC / FID (Optima-5MS, 60 mg dissolved in 10 ml ethyl acetate, carrier gas He, external 3 point calibration in the concentration range 2-6 mg / ml) and the residual content of the phenolic compound by HPLC / PDA (Varian , LiChrosphere 100 RP-18, eluent water, acetonitrile, UV 273 nm). The amine number was determined titrimetrically on a Memotritator DL-55 from Mettler, Switzerland.

b) without Lösunqsmittelverdünnunq

1 mol of resorcinol was initially charged with 1.7 mol of the specified in Table 2 polyamine in a reaction vessel under nitrogen and heated to 14O ⁰ C until no solid resorcinol was present. Subsequently, it was cooled by means of an ice bath to a temperature between 9O ⁰ C and 8O ⁰ C, again 1.7 mol of the polyamine indicated in Table 2 added in technical grade and cooled to a temperature between 5 ⁰ C and 1O ⁰ C. With stirring, 2 moles of formaldehyde (used as 37% formalin solution) were then added dropwise with vigorous stirring and ice bath cooling. After the formaldehyde was completely added dropwise at a pressure of 400 mbar, the temperature slowly increased to 15O ⁰ C. Finally, the vacuum was increased to 50 mbar. The amount of distillates obtained corresponds to the amount of theoretical amount of water used and formed. In each case a stable Mannich base resulted in M2 and M3, while the reference examples gel with IPDA (Ref. MS), diethylenetriamine (DETA) (Ref. M4) as polyamine.

Table 2 Mannich bases Variation of the polyamine.

Use as hardener

The Mannich bases were used as hardener component K2 for an epoxy resin component K1. The epoxy resin component consisted of either 80% by weight of diglycidyl ether of bisphenol A (Araldite® GY 250, Huntsman) and 20% by weight of hexanediol diglycidyl ether (Araldite® DY-H, Huntsman, Epoxy Number 6.25-6.65) (K1-1) or from 85% by weight of diglycidyl ether of bisphenol-A (Araldite® GY 250, Huntsman) and 15% by weight of trimethylolpropane triglycidyl ether (Araldite® DY-T / CH, Huntsman) (K1-2).

Table 3. Properties of cured compositions. n.b. = not determined.

The pot life was determined by stirring 100 g of the mixed components at room temperature in a beaker by means of a spatula. The pot life was the time at which the batch gelled. The tensile strength (ZF (1d)) and the elongation at break (BD (ID)) were measured after 1 day of curing at room temperature according to ISO 527 at a measuring speed of 5 mm / min on a Zwick tensile machine. The glass transition temperature was measured as peak maximum by means of DSC (0-25O ⁰ C 107 min).

Use as an adhesive

With the compositions Z1 and Z2 were aluminum plates as well

Glued steel plates. The adhesives showed good adhesion and good

Bond strengths.

Furthermore, the Mannich base M1 as hardener component K2 with the A component of Sikadur®-30 (commercially available from Sika Schweiz AG), which is based on bisphenol A diglycidyl ether and an epoxy reactive diluent, was prepared as component K1 in a mixing ratio of 1: 10 mixed and glued a concrete slab with a concrete ceiling. The bond had a good adhesion and a good bond strength.

Claims

claims

1. Mannich base, which can be produced from resorcinol, formaldehyde and triethylenetetramine and / or tetraethylenepentamine.

2. Mannich base according to claim 1, characterized in that the molar ratios of resorcinol: formaldehyde: (triethylenetetramine + tetraethylenepentamine) = 1: 1.5-2.5: 2.5-3.5, in particular 1: about 2: about 3, be.

3. Mannich base according to claim 1 or 2, characterized in that the triethylenetetramine and / or tetraethylenepentamine is a triethylenetetramine and / or tetraethylenepentamine in technical grade.

4. Mannich base according to one of the preceding claims, characterized in that the amine number is between 800 and 1100 mg / g KOH, in particular in the range between 900 and 1000 mg / g KOH, preferably in the range between 950 and 1000 mg / g KOH.

5. Mannich base according to one of the preceding claims, characterized in that the Mannich base has no measurable amounts of unreacted resorcinol.

6. A process for preparing a Mannich base according to any one of claims 1 to 5, characterized in that resorcinol, triethylenetetramine and / or tetraethylenepentamine are reacted with formaldehyde at a temperature of below 25 ⁰ C.

7. The method according to claim 6, characterized in that the reaction without the presence of additional tertiary amines, which are not already in technical triethylenetetramine and / or technical

Tetraethylenepentamine are present takes place.

8. The method according to claim 6 or 7, characterized in that formaldehyde is added to a premix comprising resorcinol and triethylenetetramine and / or tetraethylenepentamine with stirring.

9. The method according to any one of claims 6 to 8, characterized in that a solvent, in particular an alcohol, preferably methanol, is added before the reaction with formaldehyde.

10. The method according to any one of claims 6 to 9, characterized in that after the reaction with formaldehyde, water and optionally solvent is distilled off.

11. Two-component composition consisting of a first component K1 which comprises at least one amine-reactive compound having at least two functional groups which can react with amines, and a second component K2 which comprises at least one Mannich base according to one of claims 1 to 5 includes.

12. Two-component composition according to claim 11, characterized in that the first component K1 in addition to the Mannich base according to one of claims 1 to 5, a further amine, in particular an aliphatic or cycloaliphatic amine, preferably isophorone diamine.

13. Two-component composition according to claim 11 or 12, characterized in that the amine-reactive compound having at least two functional groups which can react with amines, in the component K1 a diglycidyl ether, in particular a diglycidyl ether of bisphenol-A, bisphenol-F or bisphenol A / F.

14. Two-component composition according to claim 11 or 12, characterized in that the amine-reactive compound having at least two functional groups which can react with amines in the component K1 is a polyisocyanate or a prepolymer having at least two isocyanate groups.

15. Use of the two-component composition according to one of claims 11 to 14 as an adhesive or sealant, in particular as a structural adhesive.

16. Cured composition, characterized in that it is obtained by mixing and curing the two components K1 and K2 of a two-component composition according to one of claims 11 to 14.

17. A composite body which has a cured composition according to claim 16 as an adhesive layer.

18. Use of a Mannich base according to one of claims 1 to 5 as a curing agent for an amine-reactive substance which has at least two amine-reactive functional groups.

19. Use according to claim 18, characterized in that the amine-reactive substance which has at least two amine-reactive functional groups, a diglycidyl ether, in particular a

Diglycidyl ether of bisphenol-A, bisphenol-F or bisphenol-A / F.

20. Use according to claim 18, characterized in that the amine-reactive substance which has at least two amine-reactive functional groups is a polyisocyanate or a prepolymer having at least two isocyanate groups.