Process for adjusting the sensitivity to radiation of photopolymerizable compositions

• US 5,645,973 A
• Filed: 01/29/1996
• Issued: 07/08/1997
• Est. Priority Date: 10/27/1989
• Status: Expired due to Fees

• Current Assignee: Huntsman Advanced Materials Americas, Inc.
• Original Assignee: Ciba-Geigy Corporation (Novartis Ag)
• Inventors: Wiesendanger, Rolf, Bernhard, Paul, Hofmann, Manfred, Schulthess, Adrian, Hunziker, Max, Klingert, Bernd
• Primary Examiner(s): Hamilton, Cynthia
• Application Number:
  US08/592,899
• Time in Patent Office: 526 Days
• Field of Search: 430/269, 522/2, 264/401
• US Class Current: 430/269
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 70/00 Materials specially adapted for additive manufacturing
• CPC Class Codes: C08F 2/48 by ultraviolet or visible light
• CPC Class Codes: G03F 7/0037 Production of three-dimensional images
• CPC Class Codes: G03F 7/029 Inorganic compounds; Onium compounds; Organic compounds having hetero atoms other than oxygen, nitrogen or sulfur
• CPC Class Codes: G03F 7/031 Organic compounds not covered by group G03F7/029

Abstract

A process is described for the preparation of photopolymerizable compositions, wherein the photopolymerizable compositions can be photopolymerized by the irradiation of emission lines of differing wavelength from a UV/VIS laser light source, and contain a photopolymerizable compound and at least two photoinitiators, by adjusting the sensitivity to radiation. The ratio between the concentrations of the individual photoinitiators is so adjusted that the composition has virtually the same optical density for the radiation of the different emission lines at which the photoinitiators are effective.

Claims

1. A process for the production of three-dimensional objects, starting from a photopolymerizable composition which can be photopolymerized by a plurality of emission lines of different wavelength from an applied UV/VIS laser light source, which composition is prepared by

(a) providing a photopolymer formulation containing at least one photopolymerizable compound,

(b) mixing with said photopolymer formulation at least two photoinitiators to yield a final composition such that the ratio of the concentrations of the individual photoinitiators in the final composition has virtually the same optical density at a given depth for the radiation of each emission line of the applied UV/VIS laser light source which affects the photopolymerization of the composition, wherein the strength properties of said photopolymerizable composition do not suffice for the build-up of three-dimensional objects and which can be changed by irradiation so that a strength adequate for the build-up of three-dimensional objects is obtained, said process comprising the steps:

i) placing the photopolymerizable composition in a container,

ii) irradiating at the same time a predetermined fraction of the volume of the with different emission lines from a UV/VIS laser light source so that a predetermined portion of the medium solidifies in the irradiated areas.

2. A process for the production of three-dimensional objects from a photopolymerizable composition which can be photopolymerized by a plurality of emission lines of different wavelength from an applied UV/VIS laser light source, which composition is prepared by

(a) providing a photopolymer formulation containing at least one photopolymerizable compound,

(b) mixing with said photopolymer formulation at least two photoinitiators to yield a final composition such that the ratio of the concentrations of the individual photoinitiators in the final composition has virtually the same optical density at a given depth for the radiation of each emission line of the applied UV/VIS laser light source which affects the photopolymerization of the composition, wherein the strength properties of said photopolymerizable composition do not suffice for the build-up of three-dimensional objects and which can be changed by irradiation so that a strength adequate for the build-up of three-dimensional objects is obtained, said process comprising the steps:

i) placing the photopolymerizable composition in a container,

ii) irradiating at the same time a selected surface of the photopolymerizable composition over its whole area or in a predetermined pattern with different emission lines from the applied UV/VIS laser light source so that a layer solidifies in a desired layer thickness in the irradiated areas,

iii) forming a new layer of the photopolymerizable medium on the solidified layer, and

iv) repeatedly irradiating the surface in accordance with step ii) in order to build up a succession of solidified layers which adhere to one another and which together form the three-dimensional object.