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. A resin composition comprising a) 30 to 70% by weight of a reaction product of a1) one or more epoxy compounds having at least two epoxy groups, and a2) sorbic acid as component A; b) 30 to 70% by weight of a solvent containing vinyl groups as component B; wherein a bisphenol F diglycidyl ether or an epoxy novolac is used as epoxy compound component a1) in component A, wherein the sum of components A and B adds up to 100% by weight, and wherein the resin composition excludes unsaturated polyester resin.

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

3. A resin composition according to claim 1, wherein 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. A 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 initiator.

Description

EXAMPLES

Example 1

(1) 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

(2) 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

(3) 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

(4) 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

(5) 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.

(6) The gel time is determined to DIN 16945.

Examples 6 and 7

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

(8) 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 mPa .Math. s 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

(9) The resin from Example 7 has a bond strength of 400 N at 23 C. and 130 N at 155 C.

(10) The bond strength is determined to IEC 61033.

Example 8

(11) 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.

(12) 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.

(13) The resin from Example 8 has a bond strength of 190 N at 23 C. and 50 N at 155 C.

Example 9

(14) 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.

(15) The resin from Example 9 has a bond strength of 470 N at 23 C. and 57 N at 155 C.

Example 10

(16) 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.

(17) The resin from Example 10 has a bond strength of 450 N at 23 C. and 170 N at 155 C.

Example 11

(18) 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.

(19) The resin from Example 11 has a bond strength of 300 N at 23 C. and 95 N at 155 C.

(20) 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.

(21) Subsequently, the stators were sawn open. All stators showed bubble-free through-impregnation of the copper windings.