COMPOSITION COMPRISING A POLYMER BASED ON EPOXIDE COMPOUNDS

Abstract

The invention relates to a composition comprising components a), b) and c), to a process for the preparation thereof, and to the use thereof. In one embodiment, a composition is provided which comprises the following components a), b) and c): a) from 75 to 99.5% by weight of a polymer based on epoxide compounds, from 0.5 to 25% by weight of at least one polyhydric alcohol, and optionally additives, b) from 80 to 99% by weight of a curing agent which is suitable for curing the polymer based on epoxide compounds, from 1 to 20% by weight of a polycaprolactone-polysiloxane block copolymer, optionally an accelerator, and optionally additives, and c) optionally an accelerator.

Claims

1. A composition comprising: component a) comprising: from 75 to 99.5% by weight of a polymer based on epoxide compounds; and from 0.5 to 25% by weight of at least one polyhydric alcohol; and component b) comprising: from 80 to 99% by weight of a curing agent which is suitable for curing the polymer based on epoxide compounds; and from 1 to 20% by weight of a polycaprolactone-polysiloxane block copolymer.

2. The composition according to claim 1, wherein the ratio of components a) and b) is determined in dependence on the epoxide equivalent of the resin and the equivalent mass of the curing agent used.

3. The composition according to claim 1, wherein the polymer based on epoxide compounds is selected from the group of the polyepoxides based on cycloaliphatic or aliphatic compounds, based on bisphenol A and/or F and advancement resins produced therefrom, based on tetraglycidylmethylenedianiline (TGMDA), based on epoxidized halogenated bisphenols and/or epoxidized novolaks and/or polyepoxide esters based on phthalic acid, hexahydrophthalic acid or based on terephthalic acid, epoxidized o- or p-aminophenols, epoxidized polyaddition products of dicyclopentadiene and phenol, based on epoxidized flourenone bisphenols.

4. The composition according to claim 1, wherein the polyhydric alcohol is selected from glycolsglycerols, sugar compounds, and combinations thereof.

5. The composition according to claim 1, wherein the curing agent comprises an anhydride.

6. The composition according to claim 1, wherein the curing agent comprises an amine.

7. The composition according to claim 1, wherein the polycaprolactone-polysiloxane block copolymer has the following structure ##STR00004## n: integer between 1 and 200, R.sub.2, R.sub.3, R.sub.4, R.sub.5: identical or independently of one another selected from linear or branched alkyl, alkenyl, haloalkyl, haloalkenyl groups having up to 6 carbon atoms; aryl groups having from 5 to 7 carbon atoms or aralkyl groups having from 6 to 8 carbon atoms, R.sub.1′R.sub.1: identical or independently of one another selected from alkyl ethers or alkylamines having up to 7 carbon atoms, A″ and A′: identical or independently of one another with ##STR00005## wherein p: an integer from 1 to 6, m: an integer from 1 to 25, R.sub.6: hydrogen or linear or branched alkyl groups having up to 6 carbon atoms.

8. The composition according to claim 7, wherein the polycaprolactone-polysiloxane block copolymer has the following structure: ##STR00006## wherein n≥1 and y>3.

9. The composition according to claim 4, wherein the glycols are selected from the group consisting of ethylene glycol, propylene glycol, polypropylene glycol, and combinations thereof.

10. The composition according to claim 5, wherein the anhydride is selected from the group consisting of tetrahydrophthalic anhydride (THPA), hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA), methylhexahydrophthalic anhydride (MHHPA), methylnadic anhydride (MNA), dodecenylsuccinic anhydride (DBA), and combinations thereof.

11. The composition according to claim 6, wherein the amine is selected from the group consisting of a polyamine, polyamide, Mannich base, polyaminoimidazoline, polyetheramine, and combinations thereof.

12. A cured composition comprising the components of claim 1 for the production of casting resins, composite compositions, coatings, adhesives and molding compositions.

13. A process for the preparation of a cured composition, comprising the following steps: preparing components a) and b) according to claim 1, mixing components a) and b) according to claim 1 at temperatures up to 120° C., optionally shaping the mixture that is produced, and curing the mixture at temperatures up to 180° C.

Description

[0038] There may be mentioned here by way of example, for example, imidazoles, substituted imidazoles, imidazole adducts, imidazole complexes (e.g. Ni-imidazole complex), tertiary amines, quaternary ammonium and/or phosphonium compounds, tin(IV) chloride, dicyandiamide, salicylic acid, urea, urea derivatives, boron trifluoride complexes, boron trichloride complexes, epoxy addition reaction products, tetraphenylene-boron complexes, amine borates, amine titanates, metal acetylacetonates, naphthenic acid metal salts, octanoic acid metal salts, tin octoates, further metal salts and/or metal chelates. There can further, for example, oligomeric polyethylenepiperazines, dimethylamino-propyldipropanolamine, bis-(dimethylaminopropyl)-amino-2-propanol, N,N′-bis-(3-dimethylaminopropyl)urea, mixtures of N-(2-hydroxypropyl)imidazole, dimethyl-2-(2-aminoethoxy)ethanol and mixtures thereof, bis(2-dimethylaminoethyl) ether, pentamethyldiethylenetriamine, dimorpholinodiethyl ether, 1,8-diazabicyclo[5.4.0]undec-7-ene, N-methylimidazole, 1,2-dimethylimidazole, triethylenediamine and/or 1,1,3,3-tetra-methylguanidine.

[0039] The mentioned accelerators can be added to component b) and/or separately as component c). The addition thereof can, however, also be omitted completely.

[0040] Additives, such as processing aids, pigments and/or UV stabilizers, which are commercially available, can again likewise be added as a constituent of component b).

[0041] Dividing the individual constituents into the components, in particular into components a) and b), utilizes the solubility of the block copolymer in the curing agent, whereby the storage stability of the composition is increased. If the block copolymer was dispersed in the epoxy resin, the storage stability is lower and a tendency to crystallization was observed.

[0042] The ratio of components a) and b) is determined in dependence on the epoxide equivalent of the resin and the equivalent mass of the curing agent used. Thus, when an anhydride curing agent, for example, is used, preferably from 70 to 100 parts of component b) are added per 100 parts of component a). If an amine curing agent is used, the ratio changes to preferably from 10 to 30 parts of component b) to 100 parts of component a).

[0043] The cured composition according to the invention is prepared by the method comprising the following steps: [0044] preparing components a) and b), [0045] mixing components a) and b) and optionally c) at up to 120° C., [0046] optionally shaping the mixture that is produced, and [0047] curing the mixture at temperatures up to 180° C.

[0048] The preparation of components a) and b) is carried out in conventional mixing units, such as intimate mixers or extruders, generally at room temperature. Components a) and b) are stable to storage and can be used as required. The mixing of components a) and b) is likewise carried out in conventional units, whereby it is preferred, following the preparation of components a) and b), to blend components a) and b) with one another in the mixing unit which has already been used for the preparation of components a) or b), whereby the sequence is not important. Mixing can be carried out in a temperature range from room temperature to 120° C., optionally in vacuo. The ratio of components a) and b) is again generally determined by the epoxide equivalent of the resin and of the curing agent used. Thus, when an anhydride curing agent, for example, is used, preferably from 70 to 100 parts of component b) are added per 100 parts of component a). If an amine curing agent is used, the ratio changes to preferably from 10 to 30 parts of component b) to 100 parts of component a). Depending on the application for which the composition according to the invention is to be used, corresponding shaping of the mixture that is produced can be carried out. Curing then takes place at temperatures which, again in dependence on the curing agent used, can be between room temperature (e.g. amines) and 90-180° C. (e.g. anhydrides).

[0049] The composition according to the invention is used in the cured state preferably for the production of casting resins, composite compositions, coatings, adhesives and molding compositions.

[0050] The invention is to be explained in greater detail by means of the following implementation example.

TABLE-US-00001 TABLE 1 Prior Composition according art Invention to EP 2352793 B1 Constituent (1) (2) (3) Epikote ® 861 100 100 100 Polypropylene glycol — 1.5 — Epikure ® 871  95 95 95 Polycaprolactone-polysiloxane  6 6 6 block copolymer GENIOPERL ® W35, Wacker Polydimethoxysiloxane — — 1.5 Quartz powder 391 393 393

Preparation of Component a) of the Composition According to the Invention (2):

[0051] 1.5 parts by weight of polypropylene glycol are added at room temperature (23° C.) to 100 parts by weight of the epoxy resin Epikote® 861 and the mixture is homogenized for about 0.5 hour. The quartz powder is then added.

Preparation of Component b) of the Composition According to the Invention (2):

[0052] 6 parts by weight of Genioperl® W35 are dissolved, with stirring, in 95 parts by weight of the anhydride curing agent Epikure® 871 at about 70-80° C. for 1-2 hours. When the Genioperl® W35 has dissolved completely, the solution is cooled to room temperature (23° C.).

[0053] Components a) and b) are mixed together at room temperature and cured at 160° C. Test specimens for determining the fracture toughness were cut from this cured composition (Table 2).

[0054] Comparison compounds (1) and (3) from Table 1 were prepared in one step at room temperature and cured at 160° C. Test specimens for determining the fracture toughness were cut from the cured compositions (Table 2).

TABLE-US-00002 TABLE 2 Prior Composition according Properties of the cured art Invention to EP 2 352 793 B1 samples (1) (2) (3) T.sub.G [° C.] 115 110 110 Fracture toughness [J/m.sup.2] 640 840 770

[0055] The fracture toughness was determined using a class 1 tension/compression machine in accordance with DIN 51221. The resistance generated by the test specimen during loading over the course of the test was recorded. The test specimens used were flat sheets (80 mm×34 mm×4 mm) provided with a V-shaped notch (60° C. tapering to a point, notch radius max. 0.05 mm). The test specimens were placed on the testing device so that the notch pointed downwards on the base side. Force was applied evenly on both sides of the notch via two ball plungers at a speed of 0.05 mm/min. A determination was carried out in triplicate in a standard climate according to DIN 50-014-23/50-2. The test is terminated when the test specimen breaks into two halves or when the load drop is 99% of the maximum load. The fracture toughness was calculated accordingly.

[0056] It was possible to show that the use of a polycaprolactone-polysiloxane block copolymer (I) alone did not result in a sufficient increase in the fracture toughness. Although the fracture toughness was improved compared with the prior art (1) by using an additional siloxane compound (III), it was not increased to the desired extent. According to the invention, however, by skillfully dividing the constituents into components a) and b) and by using small amounts of polypropylene glycol in combination with the block copolymer, it was possible to bring the fracture toughness to the desired higher level without a decline in the T.sub.G,