Abstract: A dry film for forming a solder mask includes a cover sheet, a photoimageable composition layer which is curable to form a solder mask and a top coat interposed between the cover sheet and the photoimageable composition layer which is selectively adherent to the photoimageable composition layer. The dry film is applied to a surface of a printed circuit board with a minor portion of the area of the photoimageable composition layer tacked to the printed circuit board. The cover sheet is peeled away. With heat and vacuum, the photoimageable composition layer is laminated to the irregular surface of the printed circuit board, conforming the photoimageable composition layer to the contours thereof and leaving the top coat as a protective covering over the photoimageable composition layer. The photoimageable composition layer is exposed to patterned actinic radiation, developed and cured to form a hard, permanent solder mask.

Abstract: A dry film for forming a solder mask includes a cover sheet, a photoimageable composition layer which is curable to form a solder mask and a top coat interposed between the cover sheet and the photoimageable composition layer which is selectively adherent to the photoimageable composition layer. The dry film is applied to a surface of a printed circuit board. With heat, vacuum and mechanical pressure, the photoimageable composition layer is laminated to the irregular surface of the printed circuit board, partially conforming the photoimageable composition layer to the contours thereof. Within about 60 seconds and with the photoimageable composition layer still heated, the cover sheet is peeled away, leaving the top coat as a protective covering over the photoimageable composition layer. Removal of the cover sheet allows the photoimageable composition layer to fully conform to the contours of the printed circuit board. Immediately thereafter, the circuit board is cooled to about ambient temperature or below.

Abstract: Apparatus for wet laminating a photopolymerizable film onto circuit board panels or other substrates. The apparatus is easily and quickly convertible from dry laminating to wet laminating with the rollers therefor mounted in bearing blocks which are insertable in slots in brackets at each end and removable therefrom. The lower roller thereof has a gear the teeth of which are meshable with the teeth of an idler gear for transmission of rotation power thereto. Elongate tubes for applying a fluid, which comprises between about 0.1 and about 10 wt. % of a heterocyclic metal-chelating agent, to the wet insertion rollers for application thereof to the panels are contained in a yoke which is adjustable next to wet insertion rollers for wet laminating or away from dry insertion rollers for dry laminating.

Abstract: Apparatus for wet laminating a photopolymerizable film onto circuit board panels or other substrates. The apparatus is easily and quickly convertible from dry laminating to wet laminating with the rollers therefor mounted in bearing blocks which are insertable in slots in brackets at each end and removable therefrom. The lower roller thereof has a gear the teeth of which are meshable with the teeth of an idler gear for transmission of rotation power thereto. Elongate tubes for applying a fluid, which comprises between about 0.1 and about 10 wt. % of a heterocyclic metal-chelating agent, to the wet insertion rollers for application thereof to the panels are contained in a yoke which is adjustable next to wet insertion rollers for wet laminating or away from dry insertion rollers for dry laminating.

Abstract: A dry film for forming a solder mask includes a cover sheet, a photoimageable composition layer which is curable to form a solder mask and a top coat interposed between the cover sheet and the photoimageable composition layer which is selectively adherent to the photoimageable composition layer. The dry film is applied to a surface of a printed circuit board with a minor portion of the area of the photoimageable composition layer tacked to the printed circuit board. The cover sheet is peeled away. With heat and vacuum, the photoimageable composition layer is laminated to the irregular surface of the printed circuit board, conforming the photoimageable composition layer to the contours thereof and leaving the top coat as a protective covering over the photoimageable composition layer. The photoimageable composition layer is exposed to patterned actinic radiation, developed and cured to form a hard, permanent solder mask.

Abstract: Apparatus for wet laminating a photopolymerizable film onto circuit board panels or other substrates. The apparatus is easily and quickly convertible from dry laminating to wet laminating with the rollers therefor mounted in bearing blocks which are insertable in slots in brackets at each end and removable therefrom. The lower roller thereof has a gear the teeth of which are meshable with the teeth of an idler gear for transmission of rotation power thereto. Elongate tubes for applying a fluid, which comprises between about 0.1 and about 10 wt. % of a heterocyclic metal-chelating agent, to the wet insertion rollers for application thereof to the panels are contained in a yoke which is adjustable next to wet insertion rollers for wet laminating or away from dry insertion rollers for dry laminating.

Abstract: A photoimageable composition of the negative acting type which includes a binder polymer which contains carboxyl groups is provided with a metal chelate in which the coordination number of the metal is 2 or higher. When the photoimageable composition is coated as a layer on a dry film, the metal chelate reacts with the carboxyl groups of the polymer, releasing a metal ion which bridges carboxyl groups of two or more polymer molecules. This bridging reduces cold flow of the photoimageable composition layer of the dry film.

Abstract: Photoinitiator compositions are disclosed which contain 3,3'-carbonyl bis(7-diethylaminocoumarin); an alkyl ester of a p-dialkylamino benzoic acid; and either camphorquinone or a 2,4,5-triphenylimidazolyl dimer. Photoinitiators are also provided which contain 3,3'-carbonyl bis(7-diethylaminocoumarin); an alkyl ester of a p-dialkylamino benzoic acid; camphorquinone and a 2,4,5-triphenylimidazolyl dimer. These latter photoinitiators are particularly useful in photopolymerizable compositions which are polymerized by exposure to visible laser light.

Abstract: A dry film for forming a solder mask includes a cover sheet, a photoimageable composition layer which is curable to form a solder mask and a top coat interposed between the cover sheet and the photoimageable composition layer which is selectively adherent to the photoimageable composition layer. The dry film is applied to a surface of a printed circuit board with a minor portion of the area of the photoimageable composition layer tacked to the printed circuit board. The cover sheet is peeled away. With heat and vacuum, the photoimageable composition layer is laminated to the irregular surface of the printed circuit board, conforming the photoimageable composition layer to the contours thereof and leaving the top coat as a protective covering over the photoimageable composition layer. The photoimageable composition layer is exposed to patterned actinic radiation, developed and cured to form a hard, permanent solder mask.

Abstract: Photopolymerizable compositions are described containing a polymerizable ethylenically unsaturated monomer, a photoinitiator or initiator system, and selected acidic polymeric binders. The organic binder mixture contains a compound chosen from each of two selected classes. These photopolymerizable compositions yield superior processability, i.e., on developing and stripping, in solely aqueous alkaline media devoid of organic solvents, decreased softness and/or tackiness, and improved adhesion when compared to the prior art. The compositions are particularly useful for preparing photoresists.

Abstract: Stable print-out dye systems are provided for photopolymerizable compositions, finding particular use as photoresists. The dye compositions comprise a triarylmethane leuco dye in combination with a high-boiling, relatively thermally-insensitive polyhalo alicyclic compound having at least five bromines. The print-out dye system is incorporated with an addition polymerizable composition, a light-sensitive initiator, and minor amounts of other additives.

Abstract: Photopolymerizable compositions are described containing a polymerizable ethylenically unsaturated monomer, a photoinitiator or initiator system, and selected acidic polymeric binders. The organic binder mixture contains a compound chosen from each of two selected classes. These photopolymerizable compositions yield superior processability, i.e., on developing and stripping, in solely aqueous alkaline media devoid of organic solvents, decreased softness and/or tackiness, and improved adhesion when compared to the prior art. The compositions are particularly useful for preparing photoresists.

Abstract: Photoresist compositions with improved adhesion properties are provided for use in making printed circuit boards, lithographic plates, relief image plates or cylinders and for other applications in the graphic arts. The subject invention also provides for methods and photoresist elements utilizing the photoresist compositions. The photoresist compositions include, in addition to a photopolymerizable compound, a photo initiator, a polymeric binder, and other optional additives and N-substituted benzotriazoles which serve as improved adhesion promoters.

Abstract: A composite, photohardenable element comprising in intimate surface contact (a) a resist layer, photohardenable by exposure to actinic radiation and; (b) a soluble layer comprising a macromolecular organic polymer and at least one ultraviolet absorbent dye or pigment. In the preferred elements, the layers are disposed between and adherent to a cover sheet and a support film, respectively.

Abstract: A photohardenable thermoplastic stratum containing a thermally activated blowing agent may be used to record images by imagewise exposing the stratum to actinic radiation adapted to polymerize and harden the stratum image-wise, and heating the exposed stratum to soften the unhardened areas and decompose the blowing agent, whereby a positive image of microscopic bubbles is formed in said stratum.