Utilization of phenylglyoxalic acid esters as photoinitiators

• US 6,562,464 B1
• Filed: 09/21/2001
• Issued: 05/13/2003
• Est. Priority Date: 03/24/1999
• Status: Expired due to Term

• Current Assignee: IGM Group B.V.
• Original Assignee: BASF AG (BASF SE)
• Inventors: Schwalm, Reinhold, Königer, Rainer
• Primary Examiner(s): PIANALTO, BERNARD D
• Application Number:
  US09/926,194
• Time in Patent Office: 599 Days
• Field of Search: 427/553, 427/487, 427/508, 427/517, 427/519, 427/521, 427/558, 427/372.2, 427/375, 427/384, 430/56, 430/270.1, 430/581.1, 522/1, 522/6, 522/8, 522/9, 522/37, 549/465, 428/411.1
• US Class Current: 428/411.1
• CPC Class Codes: C07C 69/738 Esters of keto-carboxylic acids or aldehydo-carboxylic acids
• CPC Class Codes: C08K 5/103 with polyalcohols
• CPC Class Codes: G03F 7/031 Organic compounds not covered by group G03F7/029
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]

Abstract

The use of phenylglyoxalic esters of the formula I

in which the two radicals R¹ and A are as defined in the description

as photoinitiators in powder coating materials for exterior applications. The compounds of the formula I show little propensity toward yellowing.

Claims

1. A phenylglyoxalic ester of the formula I

wherein R², R³ and R⁴ independently of one another H, C₁-C₆-alkyl, which is unsubstituted or substituted by OH, OC₁-C₆-alkyl or OCOC₁-C₆-alkyl, or are OH or OC₁-C₆-alkyl;

2. A phenylglyoxalic ester as claimed in claim 1 of the formula I in which R², R³ and R⁴ independently of one another are H or C₁-C₆-alkyl.

3. A radiation-curable composition comprising as photoinitiator at least one phenylglyoxalic ester as claimed in claim 1.

4. A composition as claimed in claim 3 in the form of a powder coating material.

5. A method of coating a substrate comprising:

applying to said substrate a composition as claimed in claim 4;

heat treating the coated substrate to melt the applied composition; and

irradiating the coated substrate with light having a wavelength in the range from 200 to 600 nm.

6. A coated substrate prepared by the method as claimed in claim 5.

7. A coated substrate coated at least partly with a composition as claimed in claim 4.

8. A method of coating a substrate, which comprises applying to said substrate a composition as claimed in claim 3 and irradiating the coated substrate with light having a wavelength in the range from 200 to 600 nm.

9. A coated substrate prepared by the method as claimed in claim 8.

10. A coated substrate coated at least partly with a composition as claimed in claim 3.

11. A method of coating a substrate for exterior applications which comprises applying to said substrate a radiation-curable powder coating material comprising as photoinitiator a phenylglyoxalic ester of formula I

in which the two radicals R¹ independently of one another are a radical of the formula

R², R³ and R⁴ independently of one another H, C₁-C₆-alkyl, which is unsubstituted or substituted by OH, OC₁-C₆-alkyl or OCOC₁-C₆-alkyl, or are OH or OC₁-C₆-alkyl;

A is a radical of the formulae

thereby preparing a coated substrate useful in exterior applications.

12. The method as claimed in claim 11 the exterior coating of buildings or parts of buildings and for coating vehicles or aircraft.