Photocurable dielectric composition of acrylated urethane prepolymer

• US 4,740,532 A
• Filed: 12/09/1986
• Issued: 04/26/1988
• Est. Priority Date: 04/30/1985
• Status: Expired due to Fees

• Current Assignee: AMP Limited
• Original Assignee: AMP Limited
• Inventors: May, Clifton C. Jr., Wentink, Steven G.
• Primary Examiner(s): HENDERSON JR, CHRISTOPHER A
• Application Number:
  US06/940,189
• Time in Patent Office: 504 Days
• Field of Search: 525/455, 525/529, 525/350
• US Class Current: 522/34
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 1/05 Insulated conductive substrates, e.g. insulated metal substrate
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder
• CPC Class Codes: H05K 1/181 associated with surface mounted components
• CPC Class Codes: H05K 2201/09536 Buried plated through-holes, i.e. plated through-holes formed in a core before lamination
• CPC Class Codes: H05K 2201/096 Vertically aligned vias, holes or stacked vias
• CPC Class Codes: H05K 2201/09981 Metallised walls
• CPC Class Codes: H05K 2201/10636 Leadless chip, e.g. chip capacitor or resistor
• CPC Class Codes: H05K 2201/10689 Leaded Integrated Circuit [IC] package, e.g. dual-in-line [DIL]
• CPC Class Codes: H05K 2201/10977 Encapsulated connections applying non-metallic protective coatings for encapsulating mounted components H05K3/284
• CPC Class Codes: H05K 2203/1189 Pressing leads, bumps or a die through an insulating layer
• CPC Class Codes: H05K 2203/1446 Treatment after insertion of lead into hole, e.g. bending, cutting, caulking or curing of adhesive but excluding soldering
• CPC Class Codes: H05K 2203/1545 Continuous processing, i.e. involving rolls moving a band-like or solid carrier along a continuous production path
• CPC Class Codes: H05K 3/28 Applying non-metallic protective coatings H05K3/0091 takes precedence; methods for intermediate insulating layers for build-up multilayer circuits H05K3/4673
• CPC Class Codes: H05K 3/305 Affixing by adhesive
• CPC Class Codes: H05K 3/323 by applying an anisotropic conductive adhesive layer over an array of pads
• CPC Class Codes: H05K 3/4069 for via connections in organic insulating substrates
• CPC Class Codes: H05K 3/462 characterized by laminating only or mainly similar double-sided circuit boards
• CPC Class Codes: H05K 3/4623 the circuit boards having internal via connections between two or more circuit layers before lamination, e.g. double-sided circuit boards H05K3/462 takes precedence
• CPC Class Codes: H05K 3/4635 laminating flexible circuit boards using additional insulating adhesive materials between the boards
• CPC Class Codes: H05K 3/4644 : by building the multilayer layer by layer, i.e. build-up multilayer circuits making via holes in the insulating layers H05K3/0011; special circuit boards as base or core whereon the multilayer is built H05K3/4602
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

A dielectric coating composition that is screen printable and radiation curable is disclosed. The composition is composed of from about 10 percent to about 50 percent of an unsaturated thiolene prepolymer system, from about 0 percent to about 35 percent of an acrylated prepolymer system, from about 10 percent to about 40 percent of at least one crosslinking diluent monomer, from about 4 percent to about 18 percent of at least one plasticizer and from about 3 percent to about 12 percent of at least one nonshrinking monomer. The cured coating is sufficiently compliant at normal temperatures to avoid cracking upon flexure of thermal expansion of the substrate.

Claims

1. A dielectric composition capable of being polymerized for use as an insulating coating for electrical conductor members formed on a substrate, said composition being comprised of:

a. from about 10 to about 50 percent of an unsaturated thiolene prepolymer system;

b. from about 20 to about 35 percent of an acrylated urethane prepolymer system, said system being compatible with said thiolene prepolymer acrylated system;

c. from about 10 to about 40 percent of at least one crosslinking diluent monomer; and

d. from about 4 to about 18 percent of at least one plasticizer, said at least one crosslinking diluent monomer and said at least one plasticizer being compatible with said unsaturated thiolene prepolymer and acrylated prepolymer systems; and

e. catalyst means compatible with said thiolene and acrylated systems, said catalyst being activated by radiation means;

whereby

upon applying a layer of said composition over at least a portion of said electrical conductor members and polymerizing said coating by radiation means, said composition is converted to a flexible insulating coating which is sufficiently compliant at normal temperatures to avoid cracking upon flexure or thermal expansion of the substrate.

2. The dielectric composition as defined in claim 1 wherein said unsaturated thiolene prepolymer system preferably comprises from 20 to 35 percent of the composition.

3. The dielectric composition as defined in claim 1 wherein said acrylated urethane prepolymer system preferably comprises from 20 to 35 percent of the composition.

4. The dielectric composition as defined in claim 1 wherein said at least one crosslinking diluent monomer preferably comprises from 15 to 25 percent of the composition.

5. The dielectric composition as defined in claim 1 wherein said at least one plasticizer preferably comprises from 7.5 to 12 percent of the composition.

6. The dielectric composition as defined in claim 1 wherein said unsaturated thiolene prepolymer system preferably comprises from 20 to 35 percent and said acrylated urethane prepolymer system preferably comprises from 25 to 35 percent of the composition.

7. The dielectric composition as defined in claim 1 wherein said thiolene prepolymer system comprises 20 to 35 percent of said composition;

said crosslinking diluent monomer comprises 15 to 25 percent of said composition; and

said at least one plasticizer comprises 7.5 to 12 percent of said composition.

8. The dielectric composition as defined in claim 1 wherein said catalyst means comprises from about 1 to about 10 percent of said composition.

9. The dielectric composition as defined in claim 8 wherein said catalyst means comprises from 3 to 5 percent of the composition.

10. The dielectric composition as defined in claim 1 wherein said catalyst means is a photoinitiator.

11. The dielectric composition as defined in claim 1 wherein said at least one plasticizer is diallyl phthalate.

12. The dielectric composition as defined in claim 1 wherein said composition is further comprised of an adhesion promoter.

13. The dielectric composition as defined in claim 12 wherein said adhesion promoter comprises up to 0.3 percent of said composition.

14. The dielectric composition as defined in claim 13 wherein said adhesion promoter comprises 0.05 to 0.15 percent of the composition.