Method of duplicating plastics information carriers

• US 4,275,091 A
• Filed: 11/16/1979
• Issued: 06/23/1981
• Est. Priority Date: 10/15/1976
• Status: Expired due to Term

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Lippits, Gerardus J. M., De Jonge, Jelis, Op Het Veld, Adriaan J. G., Dijkstra, Rinse, Van Den Broek, Arnoldus J. M.
• Primary Examiner(s): Newsome, John H.
• Application Number:
  US06/095,130
• Time in Patent Office: 585 Days
• Field of Search: 427/44, 427/54.1, 427/355, 427/359, 427/362, 156/242, 156/245, 156/246, 156/272
• US Class Current: 427/510
• CPC Class Codes: G03F 7/00 Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor using photoresist structures for special production processes, see the relevant places, e.g. B44C, H01L, e.g. H01L21/00, H05K
• CPC Class Codes: G11B 23/0057 Intermediate mediums, i.e. mediums provided with an information structure not specific to the method of reproducing or duplication such as matrixes for mechanical pressing of an information structure for record carriers with directly readable mechanical information G11B3/685; record carriers having a relief information structure provided with or included in layers not specific for a single reproducing method; apparatus or processes specially adapted for their manufacture
• CPC Class Codes: Y02P 20/582 Recycling of unreacted starting or intermediate materials
• CPC Class Codes: Y10S 156/922 Specified electronic component delaminating in preparation for recycling
• CPC Class Codes: Y10T 156/11 Methods of delaminating, per se; i.e. , separating at bonding face
• CPC Class Codes: Y10T 428/21 Circular sheet or circular blank

Abstract

The invention relates to a method of reproducing plastics record carriers, in particular duplicating video records. According to the invention, a metal die is used which is provided with a thin-liquid molding resin of a particular composition which can be polymerized by radiation. A radiation-pervious substrate which is manufactured from synthetic material, for example polymethylmethacrylate, is provided on the molding resin. The molding resin is exposed to light via the substrate after which the cured molding resin together with the substrate connected thereto is removed from the die. The molding resin used in the process comprises low-molecular monomers or oligomers which contain on an average 25-70% by weight of hydrocarbon groups and/or phenyl groups. The molding resin is aprotic and has a functionality as regards unsaturatedness which is between the values 2 and 6. A suitable molding resin contains mono-, tri- or tetra esters of acylic acid. The molding resin preferably has a swelling capacity with respect to the substrate and for that purpose preferably comprises a vinylmonomer. The metal die used in the method preferably is a quite flat die which is obtained by providing the master disk which is a flat glass plate with information track with a nickel layer, gluing hereon a flat stiffening plate and then removing the master disk. The resulting father disk may be used as a die. Alternatively, further metal copies may be made herefrom which are provided in a simpler manner with a flat stiffening plate. The invention also extends to the molding resin, substrate and die used in the method, as well as to the resulting plastics record carriers.

Claims

1. The method of manufacturing a plastic information carrier containing an information track having detail of such fineness as to be suitable for reading by an optical beam or similar reading means, said fineness being as small as in the order of a micron or less, comprising:

(a) directly applying to a metal surface of a rigid, substantially flat die, which surface contains the negative of the desired information track, a thin layer of a thickness of 0.2-300 microns of a light-curable polymerizable liquid having a viscosity of from 1 to 100 cP and comprising low molecular weight acrylic monomers or a mixture of low molecular weight acrylic monomers and acrylic oligomers, which liquid contains 25-70% by weight of saturated hydrocarbon and/or phenyl groups, has an average functionality in regard to unsaturatedness of between 2.1 and 6, is at least substantially aprotic and consists for at least 95% of monomers having a maximum average molecular weight of about 400;

(b) applying to the exposed surface of said thin layer of polymerizable liquid a thin light-pervious plastic substrate;

(c) exposing said thin layer of polymerizable liquid to light radiation through said substrate for a time sufficient to cause said thin layer of polymerizable liquid to cure to a solid state adhering to said substrate thereby producing a laminate of said substrate and said cured layer containing the desired optically readable information track readily removable from said die without effect on said laminate or said die; and

(d) removing said laminate from said die.

2. The method of claim 1 wherein the average content of saturated hydrocarbon groups and/or phenyl groups in the polymerizable liquid lies between about 40 and 65% by weight.

3. The method of claim 2 wherein the polymerizable liquid contains a liquid mixture of low molecular weight mono-, di-, tri- or tetraesters of acrylic acid.

4. The method of claim 3 wherein the polymerizable liquid contains esters of acrylic acid selected from the group consisting of alkylacrylates, phenylacrylates, alkoxyalkylacrylates, alkanedioldiacrylates, akyleneglycoldiacrylates, trimethylolpropanetriacrylate, pentaerythritoltriacrylate, polyethyleneglycoldiacrylate, polypropyleneglycoldiacrylate, polyesteracrylate, urethane acrylate, epoxy acrylate and ethoxylated bisphenol A-diacrylate.

5. The method of claim 4 wherein the polymerizable liquid contains in addition as a component having a swelling capacity with respect to the substrate material a vinyl monomer.

6. The method of claim 5 wherein polymethylmethacrylate is employed as the substrate and the component having the swelling capacity is an alkyl acrylate wherein the alkyl contains 2 or 3 carbon atoms or an alkoxylalkyl acrylate wherein both the alkoxy and alkyl moieties contain 1 to 2 carbon atoms.

7. The method of claim 1 wherein the substrate has a thickness of 200 microns to 1.5 millimeters, is foil, plate or disk shaped and consists essentially of polyvinylchloride acetate copolymer, polyvinylchloride, polycarbonate, polyester, polystyrene, cellulose triacetate, cellulose acetobutyrate or mixtures thereof.

8. The method of claim 1 wherein the substrate is a disk, plate or foil shaped member having a thickness of 200 microns to 1.5 millimeters and consists essentially of polymethylmethacrylate.

9. The method of claim 1 wherein the die and the resultant information carrier are both disk shaped.

10. The method of claim 1 wherein after separation from the die a thin light-reflective metal layer is applied over the exposed surface of the cured layer.

11. The method of claim 10 wherein the metal layer is an aluminum layer.

12. A plastic information carrier produced by the method of claim 1.

13. A method of manufacturing a plastic information carrier containing on a major surface an information track optically readable through the carrier, comprising the steps:

(a) bringing into contact relationship with a metal surface of a rigid substantially flat die, a thin layer of a thickness of 0.2-300 microns of a light radiation-curable polymerizable liquid having a viscosity of from 1 to 100 cP and comprising low molecular weight acrylic monomers and/or acrylic oligomers which on an average contains 25-70% by weight of saturated hydrocarbon radicals and/or phenyl groups, and which liquid has an average molecular weight of approximately 400 or less, and which liquid has an average functionality as regards unsaturatedness in the range of 2.1 to 6, and which liquid is substantially aprotic, said polymerizable liquid containing less than 5% by weight of polymers, having the properties that will cause it, when cured, to be substantially stress-free and to adhere to a contacting plastic substrate but to be removable without damage from the die metal surface, and also having the property that it will fill when liquid and stably retain when cured any fine surface structure present on the die surface;

(b) said die metal surface to which the polymerizable liquid is contacted is substantially flat and contains a fine surface structure pattern having surface level differences less than 1 micron in size and constituting the negative of the said information track to be replicated on the information carrier;

(c) providing in contact relationship with the exposed surface of said thin layer of polymerizable liquid while still in the liquid state, which exposed surface is remote from the surface in contact with the die, a thin light radiation-pervious plastic substrate to whose contacting surface said polymerizable liquid adheres when cured;

(d) exposing said thin layer of polymerizable liquid while in contact with the die to curing light radiation through said contacted substrate for a time sufficient to cause said thin layer of polymerizable liquid to cure to a solid layer adhering to said substrate but removable without damage from said die metal surface thereby producing a laminate of said substrate and said cured layer whose major surface contacting the die contains a replica of the fine surface structure pattern present on the die metal surface;

(e) removing said laminate from said die; and

(f) applying over the exposed cured layer surface containing the fine surface pattern a thin light-reflective layer thereby to form the plastic information carrier containing the optically-readable information track.

14. A method as claimed in claim 13 wherein the polymerizable liquid incorporates a component which has a swellable effect on the contacting substrate surface.

15. A method as claimed in claim 13 wherein the substrate contacting surface is subjected to a pretreatment for improving its adhesion to the polymerizable liquid before it is contacted to the latter.