Dual-curing isocyanurate polymers

Abstract

The present invention relates to polymerizable compositions which contain components that can be crosslinked both via isocyanurate bonds and by a radical reaction mechanism. The invention further relates to methods by way of which polymers can be produced from said compositions.

Claims

1. A process for preparing a polymer, comprising the steps of a) providing a polymerizable composition having a ratio of isocyanate groups to isocyanate-reactive groups of at least 3.0:1.0, comprising: a) an isocyanate component A; b) at least one trimerization catalyst C; and c) at least one component B and at least one component D and/or E, where component B is an acrylate, a methacrylate, an ester of an acrylate or an ester of a methacrylate; component D has at least one isocyanate-reactive group and at least one ethylenic double bond in one molecule; and component E has both at least one isocyanate group and at least one ethylenic double bond in one molecule; b) crosslinking the ethylenic double bonds present in said polymerizable composition; and c) crosslinking the isocyanate groups present in said polymerizable composition; wherein process steps b) and c) are conducted simultaneously or in any desired sequence.

2. The process as claimed in claim 1, wherein the polymerizable composition comprises at least one component E and the process comprises a further process step d) in which the isocyanate-reactive group of component E is crosslinked with an isocyanate group of the isocyanate component A or of a reaction product of the isocyanate component A.

3. The process as claimed in claim 1, wherein process step b) is conducted before process step c) and the polymerizable composition contains a radiation- activated initiator F1.

4. The process as claimed in claim 1, wherein, in process step b), at least 50% of the free isocyanate groups present in isocyanate component A are converted to isocyanurate structural units.

5. The process as claimed in claim 1, wherein process step b) is conducted with actinic radiation of wavelength 200 nm to 500 nm and process step c) is effected at a temperature between 50° C. and 250° C.

Description

EXAMPLES

(1) General Details:

(2) All percentages, unless stated otherwise, are based on percent by weight (% by weight).

(3) The ambient temperature of 23° C. at the time of conduct of the experiments is referred to as RT (room temperature).

(4) The methods detailed hereinafter for determination of the appropriate parameters were employed for conduction and evaluation of the examples and are also the methods for determination of the parameters of relevance in accordance with the invention in general.

(5) Determination of Phase Transitions by DSC

(6) The phase transitions were determined by means of DSC (differential scanning calorimetry) with a Mettler DSC 12E (Mettler Toledo GmbH, Giessen, Germany) in accordance with DIN EN 61006. Calibration was effected via the melt onset temperature of indium and lead. 10 mg of substance were weighed out in standard capsules. The measurement was effected by three heating runs from −50° C. to +200° C. at a heating rate of 20 K/min with subsequent cooling at a cooling rate of 320 K/min, Cooling was effected by means of liquid nitrogen. The purge gas used was nitrogen. The values reported are each based on the evaluation of the 2nd heating curve. The glass transition temperature T.sub.g was obtained from the temperature at half the height of a glass transition step.

(7) Determination of Infrared Spectra

(8) The infrared spectra were measured on a Bruker FT-IR spectrometer equipped with an ATR unit.

(9) Starting Compounds

(10) Polyisocyanate A1: HDI trimer (NCO functionality >3) with an NCO content of 23.0% by weight from Covestro AG. The viscosity is about 1200 mPa.Math.s at 23° C. (DIN EN ISO 3219/A.3).

(11) Polyisocyanate A2: PDI trimer (NCO functionality >3) with an NCO content of 21.5% by weight from Covestro AG. The viscosity is about 9500 mPa.Math.s at 23° C. (DIN EN ISO 3219/A.3).

(12) Acrylate 1: hexanediol diacrylate (HDDA) was sourced with a purity of >99% by weight from Sigma-Aldrich.

(13) Acrylate 2: hydroxypropyl methacrylate (HPMA) was sourced with a purity of 98% by weight from abcr GmbH.

(14) Acrylate 3: isobornyl methacrylate (IBOMA) was sourced with a purity of >99% by weight from Sigma-Aldrich.

(15) Initiator I1: Trigonox® C. (cert-butyl peroxybenzoate) was sourced with a purity of >98% by weight from Akzo Nobel.

(16) Potassium acetate was sourced with a purity of >99% by weight from ACROS.

(17) Lucirin TPO-L is an ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate from BASF, sourced from Sigma Aldrich.

(18) Polyethylene glycol (PEG) 400 was sourced with a purity of >99% by weight from ACROS.

(19) All raw materials except for the catalyst were degassed under reduced pressure prior to use, and the polyethylene glycol was additionally dried over 0.5 nm molecular sieve sourced from Merck for >24 h.

(20) Preparation of Catalyst K1:

(21) Potassium acetate (5.0 g) was stirred in the PEG 400 (95.0 g) at RT until all of it had dissolved. In this way, a 5% by weight solution of potassium acetate in PEG 400 was obtained and was used as catalyst without further treatment.

(22) Preparation of the Reaction Mixture

(23) Unless stated otherwise, the reaction mixture was produced by mixing polyisocyanate (A1-A2) and the acrylate(s) with an appropriate amount of catalyst (K1-2), initiator and any additive at 23° C. in a Speedmixer DAC 150.1 FVZ from Hauschild at 2750 min.sup.−1 and mixing for 2 min. This was then either poured into a suitable mold without further treatment for crosslinking or knife-coated onto a glass plate.

Working Examples 1-20

(24) The amounts of polyisocyanate, acrylate, catalyst solution, initiator and any additive that are specified in table 1 were treated according to the abovementioned production method for reaction mixtures. The curing in the oven was conducted with the times and temperatures likewise listed in table 1.

(25) The T.sub.g of the cured reaction mixtures was 70-128° C. The viscosities of the inventive reaction mixtures comprising polyisocyanate A1 (examples 3, 4, 6-9) directly after the production of the mixture were 0.5-0.7 Pa.Math.s and rose to 1.0-2.1 Pa.Math.s over the course of 4 h at RT. The viscosity of the inventive reaction mixture comprising polyisocyanate A2 (example 11) directly after the production of the mixture was 3.0 Pa.Math.s and rose to 5.6 Pa.Math.s over the course of 4 h at RT.

(26) TABLE-US-00001 TABLE 1 Compositions, production conditions and material properties of working examples 1-20. Catalyst + Resin composition initiator Amount Amount Amount Amount of of of Amount of Processing Material Iso- polyisocyanate acrylate acrylate Amount of of cat. initiator Reaction Reaction Pot life properties Ex. cyanate [g] 1 [g] 2 [g] acrylate 3 [g] K[g] I[g] temperature [° C.] time [min] at RT T.sub.G  1 (inv.) A2 20.00 2.00 2.00 / 0.84 0.08 200 4 n.d. 124.0° C.   2 (inv.) A1 20.00 2.00 2.00 / 0.84 0.08 200 4 n.d. 97.5° C.  3 (inv.) A1 20.00 / 2.00 2.00 0.84 0.08 200 4  50 min   90° C.  4 (inv.) A1 20.00 1.33 1.33 1.33 0.84 0.08 200 4  56 min 93.5° C.  5 (inv.) A1 20.00 3.80 0.19 / 0.80 0.08 200 4 n.d. 87.0° C.  6 (inv.) A1 20.00 1.90 0.19 1.90 0.80 0.08 200 4 >240 min 106.0° C.   7 (inv.) A1 20.00 3.80 0.19 / 0.80 0.08 200 10 >240 min 102.5° C.   8 (inv.) A1 20.00 3.80 0.19 / 0.80 0.08 200 7 >240 min 102.0° C.   9 (inv.) A1 20.00 3.80 0.19 / 0.80 0.08 220 5 >240 min 102.0° C.  10 (inv.) A1 20.00 1.90 0.19 1.90 0.80 0.08 200 10 n.d.  134° C. 11 (inv.) A2 20.00 1.90 0.19 1.90 0.80 0.08 200 4 >240 min 128.5° C.  12 (inv.) A1 20.00 / 2.00 / 0.74 0.08 200 3 n.d.   87° C. 13 (inv.) A1 20.00 2.00 2.00 / 0.80 0.10 200 4 n.d.   86° C. 14 (inv.) A1 20.00 2.00 2.00 / 0.80 0.12 200 4 n.d. 90.5° C. 15 (inv.) A1 20.00 2.00 2.00 / 0.80 0.14 200 5 n.d.   92° C. 16 (inv.) A1 20.00 / 2.00 / 0.74 0.007 200 3 n.d. 71.5° C. 17 (inv.) A1 20.00 / 2.00 / 0.74 0.02 200 3 n.d. 83.0° C. 18 (inv.) A1 20.00 / 2.00 / 0.74 0.04 200 3 n.d. 82.5° C. 19 (inv.) A1 20.00 3.00 3.00 / 0.84 0.12 200 4 n.d. 77.5° C. 20 (inv.) A1 20.00 2.00 2.00 2.00 0.84 0.12 200 4 n.d. 93.5° C. n.d.: not determined

Working Examples 21-24

(27) The amounts of polyisocyanate, acrylate, catalyst solution specified in table 2 were treated according to the abovementioned production method for reaction mixtures.

(28) The reaction mixture was knife-coated onto the tin-free side of a glass plate in a thickness of 250 μm and then UV-treated with a gallium-doped mercury lamp and an undoped mercury lamp. Subsequently, the samples were cured at 180° C. for 15 min.

(29) TABLE-US-00002 TABLE 2 Compositions and material properties of working examples 21-24. Resin composition Amount Amount Catalyst + initiator Amount of of of Mode of Amount Amount of Material properties Isocyanate acrylate 1 acrylate 2 cross- of cat. Lucirin TPO-L Appearance Appearance Ex. A1 [g] [g] [g] linking K1 [g] [g] after exposure after curing 21 50.0 9.5 0.5 PUR, PIR, 2.0 0.3 Transparent, Solid, pale PAC rubber-like yellowish solid lacquer. lacquer. No run-off. Cannot be pulled off. 22 50.0 7.13 0.38 PUR, PIR, 2.0 0.3 Transparent, Solid, pale PAC rubber-like yellowish solid lacquer. lacquer. No run-off. Cannot be pulled off. 23 50.0 1.19 0.06 PUR, PIR, 2.0 0.3 Partly dried Solid, pale PAC material, yellowish slight run-off lacquer. apparent after Cannot be 10 min. pulled off. 24 50 9.5 / PIR, PAC 2.0 0.3 Partly dried Solid, pale material, yellowish, slight run-off slightly cloudy apparent after lacquer. 5 min. Cannot be pulled off.

Comparative Example 25

(30) 93.5 g of polyisocyanate A1 and 4.0 g of catalyst solution K1 were treated according to the abovementioned production method for reaction mixtures. The curing in the oven was conducted at 220° C. for 3 min.

(31) The T.sub.g of the cured reaction mixture was 101° C. The viscosity of the comparative reaction mixtures with polyisocyanate A1 directly after the production of the mixture was more than 2 Pa.Math.s and rose to 3.5 Pa.Math.s within 4 h.

(32) By comparison, the starting viscosity in the case of a mixture with acrylate (see inventive examples) was much lower (0.5-0.7 Pa.Math.s) and even after 4 h at RT had lower values (1.0-2.0 Pa.Math.s) than the starting viscosity of the comparative experiment. At the same time, the material properties (e.g. Tg) of the materials made of the inventive examples were also within a comparable order of magnitude.

Comparative Example 26

(33) 93.5 g of polyisocyanate A2 and 4.0 g of catalyst solution K1 were treated according to the abovementioned production method for reaction mixtures. The curing in the oven was conducted at 220° C. for 3 min.

(34) The T.sub.g of the cured reaction mixture was 137° C. The viscosity of the comparative reaction mixtures with polyisocyanate A2 directly after the production of the mixture was >10 Pa.Math.s, which distinctly complicates processing.

Comparative Example 27

(35) 93.5 g of polyisocyanate A1 and 4.0 g of catalyst solution K1 were treated according to the abovementioned production method for reaction mixtures.

(36) The reaction mixture is applied to the tin-free side of a glass plate in a thickness of 250 μm and then UV-treated with a gallium-doped mercury lamp and an undoped mercury lamp, with no change in the reaction mixture and detectable run-off.