RESIN COMPOSITIONS COMPRISING SORBIC ESTERS

Abstract

Resin composition comprising a) the reaction product of a1) one or more epoxy compounds having at least 2 epoxy groups, and a2) sorbic acid as component A; b) a solvent containing vinyl groups as component B; characterized in that a bisphenol F diglycidyl ether or an epoxy novolac is used as epoxy compound a1) in component A.

Claims

1. Resin composition comprising a) the reaction product of a1) one or more epoxy compounds having at least 2 epoxy groups, and a2) sorbic acid as component A; b) a solvent containing vinyl groups as component B; characterized in that a bisphenol F diglycidyl ether or an epoxy novolac is used as epoxy compound a1) in component A.

2. Resin composition according to claim 1, characterized in that the epoxy groups in component A are reacted fully with sorbic acid.

3. Resin composition according to claim 1, characterized in that the solvent containing vinyl groups in component B is selected from the group consisting of acrylates of monoalcohols, diols and polyols, and of methacrylates of monoalcohols, diols and polyols.

4. Coating composition comprising i) 100 parts by weight of a resin composition according to claim 1, and ii) 1 to 3 parts by weight of a free-radical-forming polymerization.

Description

EXAMPLES

Example 1

[0059] A three-neck flask with thermometer, stirrer and reflux condenser is charged with 600 g of a bisphenol A diglycidyl ether (of low molecular weight compared to Example 2) (epoxy equivalent of 184-190 g), 350 g of sorbic acid, 14.6 g of dimethylbenzylamine and 2 g of hydroquinone. The mixture is heated at 100 C. under nitrogen until the mixture has an acid number below 1 mg KOH/g.

Example 2

[0060] A three-neck flask with thermometer, stirrer and reflux condenser is charged with 900 g of a bisphenol A diglycidyl ether (of higher molecular weight compared to Example 1) (epoxy equivalent of 806-909 g), 125 g of sorbic acid, 21 g of dimethylbenzylamine, 3 g of hydroquinone and 270 g of toluene. The mixture is heated at 100 C. under nitrogen until the mixture has an acid number below 5 mg KOH/g. The toluene solvent is removed by distillation under reduced pressure.

Example 3

[0061] A three-neck flask with thermometer, stirrer and reflux condenser is charged with 600 g of bisphenol F diglycidyl ether, 396 g of sorbic acid, 14.6 g of dimethylbenzylamine and 2 g of hydroquinone. The mixture is heated at 100 C. under nitrogen until the mixture has an acid number below 1 mg KOH/g.

Example 4

[0062] A three-neck flask with thermometer, stirrer and reflux condenser is charged with 480 g of a phenol novolac glycidyl ether (epoxy equivalent 174.3 g), 307.8 g of sorbic acid, 14.6 g of dimethylbenzylamine, 1.6 g of hydroquinone and 200 g of toluene. The mixture is heated at 110 C. under nitrogen until the mixture has an acid number below 1 mg KOH/g.

Example 5

[0063] 500 g of resin from Example 1, 500 g of hydroxyethyl methacrylate and 0.001 g of p-benzoquinone are mixed with one another. The corresponding impregnation resin exhibits a viscosity of 290 mPa.Math.s at 23 C. With 2% by weight of tert-butyl perbenzoate at 120 C., the gel time is 3 min.

[0064] The gel time is determined to DIN 16945.

Examples 6 and 7

[0065] The resins from Examples 6 and 7 are, as described in Example 5, prepared with the methacrylates listed in Table 1.

TABLE-US-00001 TABLE 1 Example 5 6 7 Resin from Example 1 in g 500 500 500 Hydroxyethyl methacrylate in g 500 Hydroxypropyl methacrylate in g 500 Triethylene glycol dimethacrylate in g 500 Viscosity in mPas at 23 C. 290 600 700 Gel time with 2% by weight of tert-butyl 3.0 3.4 2.5 perbenzoate at 120 C. in min

[0066] The resin from Example 7 has a bond strength of 400 N at 23 C. and 130 N at 155 C.

[0067] The bond strength is determined to IEC 61033.

Example 8

[0068] 308 g of maleic anhydride, 114 g of adipic acid, 92 g of hexanediol, 72 g of glycerol, 409 g of hexanol and 0.3 g of hydroquinone are used to prepare an unsaturated polyester having an acid number below 20 mg KOH/g.

[0069] This unsaturated polyester is mixed in a ratio of 1:1 with the resin from Example 1. The corresponding impregnation resin is stabilized with 0.001% p-benzoquinone and exhibits a viscosity of 17 800 mPa.Math.s at 23 C. With 2% by weight of tert-butyl perbenzoate at 120 C., the gel time is 7.5 min.

[0070] The resin from Example 8 has a bond strength of 190 N at 23 C. and 50 N at 155 C.

Example 9

[0071] 500 g of resin from Example 2, 500 g of triethylene glycol dimethacrylate and 0.001 g of p-benzoquinone are mixed with one another. The corresponding impregnation resin shows a viscosity of 12 800 mPa.Math.s at 23 C. With 2% by weight of tert-butyl perbenzoate at 120 C., the gel time is 2.5 min.

[0072] The resin from Example 9 has a bond strength of 470 N at 23 C. and 57 N at 155 C.

Example 10

[0073] 500 g of resin from Example 4, 500 g of triethylene glycol dimethacrylate and 0.001 g of p-benzoquinone are mixed with one another. The corresponding impregnation resin shows a viscosity of 980 mPa.Math.s at 23 C. With 2% by weight of tert-butyl perbenzoate at 120 C., the gel time is 2.5 min.

[0074] The resin from Example 10 has a bond strength of 450 N at 23 C. and 170 N at 155 C.

Example 11

[0075] 450 g of resin from Example 1, 50 g of resin from Example 4, 500 g of hydroxypropyl methacrylate and 0.001 g of p-benzoquinone are mixed with one another. The corresponding impregnation resin shows a viscosity of 480 mPa.Math.s at 23 C. With 2% by weight of tert-butyl perbenzoate at 120 C., the gel time is 3.75 min.

[0076] The resin from Example 11 has a bond strength of 300 N at 23 C. and 95 N at 155 C.

[0077] The resins from Examples 5 to 11 are used to impregnate size 90 stators containing copper windings. In the case of the resins from Examples 8 and 9, the resin was preheated to 40 C., and this was then used to impregnate the stators. After a dripping phase of 20 min, the resins were hardened at 160 C. for two hours.

[0078] Subsequently, the stators were sawn open. All stators showed bubble-free through-impregnation of the copper windings.