Curing agents for cationically curable compositions

a technology of cationically curable compositions and curing agents, which is applied in the field of curing agents for cationically curable compositions, can solve the problems of system imparting significantly reduced thermal stability to the cured material, high level of unreacted epoxy monomer present, and high level of unreacted epoxy monomer, so as to improve the dark stability, prolong the dark stability, and improve the effect of dark stability

Inactive Publication Date: 2005-01-06
3M INNOVATIVE PROPERTIES CO
View PDF18 Cites 11 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

Catalysts for cationic addition photopolymerization reactions that produce compositions with long dark stability (before light exposure) and result in highly cured, colorless or low color, thermally stable products can be very useful in optically colorless coatings, adhesives, encapsulants, and sealants for optical and electronic applications. Improved dark stability can allow greater latitude in thermal processing of curable/thermoplastic blends, allowing the use of higher temperature thermoplastics or higher processing temperatures for lower viscosity extrusion

Problems solved by technology

Measurement of the degree of cure of these two systems, however reveals that while the sulfonium PF6− catalyst produces a colorless product there is a high level of unreacted epoxy monomer present in it, producing thermal instability in the cured product.
Although met

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Curing agents for cationically curable compositions

Examples

Experimental program
Comparison scheme
Effect test

example 1

Properties of Comparative Formulations (No Added Salts)

Curable compositions were prepared using the general sample preparation method described above. DMA molds were used and the samples were given a total of 4 J / cm2 dose using the 600 W Fusion D system and a post cure as described in the sample preparation section. The amounts of material used and the results of the DMA, IR and visual color evaluation tests are shown in Comparative formulations Table 2, below.

TABLE 2Properties of Comparative Formulations (no added salts) Exposed to 4 J / cm2ComparativeUVI-UVI-ToneERL-Tg,Cure EstimateSample6990697402014221Color° C.from IRA0.4091 gNone4 g16 gcolorless 51 68%B0.3119 g0.1020 g4 g16 glight136100%brownC0.2562 g0.1531 g4 g16 glight124100%brownD0.2014 g0.2183 g4 g16 glight120100%brownE0.1528 g0.2622 g4 g16 glight119100%brownF0.1059 g0.3210 g4 g16 glight122100%brownG0.0497 g0.3608 g4 g16 glight125100%brownHnone0.4214 g4 g16 glight120100%brown

The Comparative Samples of Table 2 show that i...

example 2

Evaluation of Properties of Comparative Formulations (No Added Salts) vs UV Exposure

A stock solution of 36 g Tone 0201, 144 g ERL-4221 was mixed in a glass jar and placed in the oven at 100° C. for about 30 minutes to mix thoroughly before using. Individual curable composition samples were prepared by weighing out the desired amount of stock solution, UVI-6990 and UVI-6974 (Table 3) into a brown jar, heating the jars in an oven at 100° C. and mixing thoroughly. The compositions were allowed to cool to room temperature before proceeding. The amount used are described in Table 3, below.

TABLE 3Comparative Formulations (no addedsalts) For UV Intensity TestingComparativeStock Solution,SampleUVI-6990 UVI-697420% Tone 0201 / 80% ERL-4221I0.41 gNone20 gJ0.31 g0.10 g20 gK0.25 g0.18 g20 gL0.20 g0.22 g20 gM0.15 g0.25 g20 gN0.11 g0.31 g20 gO0.05 g0.35 g20 gPNone0.40 g20 g

The compositions in Table 3, above, were cured using the 600 W Fusion D (at 12.6 m / min) (548 J / pass) using the small sampl...

example 3

Addition of a Non-Photochemically Active Salt Containing an Inhibiting Anion to a Formulation with a Photochemically Active Salt Containing an Accelerating Anion

Individual curable composition samples were prepared by weighing out the amounts of TBA+ PF6−, ERL-4221E and UVI-6990 or UVI-6974 into a brown jar as shown in Table 6 below, heating the jars in an oven at 100° C. and mixing thoroughly. The compositions were allowed to cool to room temperature before proceeding.

TABLE 6Formulations With a Photochemically Active SaltContaining an Accelerating Anion with a Non-photochemically Active Salt Containing an Inhibiting Anion(Photocurative A)SampleAdditiveCatalystEpoxyQNone0.4 g UVI-699020.0 g ERL-4221E10.12 g TBA+ PF6−0.4 g UVI-697420.0 g ERL-4221E20.10 g TBA+ PF6−0.4 g UVI-697420.0 g ERL-4221E30.08 g TBA+ PF6−0.4 g UVI-697420.0 g ERL-4221E40.06 g TBA+ PF6−0.4 g UVI-697420.0 g ERL-4221E50.04 g TBA+ PF6−0.4 g UVI-697420.0 g ERL-4221ERNone0.4 g UVI-697420.0 g ERL-4221E

DMA molds were...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
Temperatureaaaaaaaaaa
Fractionaaaaaaaaaa
Fractionaaaaaaaaaa
Login to view more

Abstract

Novel catalyst systems in cationically curable compositions provide colorless cationically cured compositions with improved degree of cure and thermal stability. The curable composition comprises at least one cationically curable monomer and a curing agent comprising Photocurative A or Photocurative B. Photocurative A comprises an effective amount of an accelerating photochemically active salt comprising a photochemically active cation and an accelerating anion, and an effective amount of an inhibiting non-photochemically active salt comprising a non-photochemically active cation and an inhibiting anion. Photocurative B comprises an effective amount of an inhibiting photochemically active salt comprising a photochemically active cation and an inhibiting anion, and an effective amount of an accelerating non-photochemically active salt comprising a non-photochemically active cation and an accelerating anion. The inhibiting and accelerating salts in photocuratives A and B are defined by photo differential scanning calorimetry (pDSC) and thermal differential scanning calorimetry (tDSC). The compositions are useful, for example, as optically colorless or low color coatings, adhesives, encapsulants, and sealants for optical and electronic applications.

Description

FIELD OF THE INVENTION Novel catalyst systems provide cationically photocured compositions with reduced color, improved degree of cure, and increased thermal stability. Such compositions are useful as optically colorless or low color coatings, adhesives, encapsulants, sealants and abrasives for optical and electronic applications. BACKGROUND OF THE INVENTION Salts that have an organic, inorganic or organometallic cation and a nonnucleophilic counteranion are widely used in industry as initiators, particularly photoinitiators, for cationic addition polymerization reactions. Common initiator salts include onium salts such as diaryliodonium, triarylsulfonium, and (cyclopentadienyl)(arene)iron+ salts of the anions PF6−, AsF6−, or SbF6−. It has been well documented that the identity of the anion associated with the onium cation can significantly affect the rate of polymerization as well as the color and thermal stability of the resulting cured polymer. For example when a sulfonium SbF6...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): C08G59/62C08G59/68
CPCC08G59/687C08G59/62C08J3/28C08F2/46C08L63/00C08G59/685C08G59/56C08G59/40
Inventor PALAZZOTTO, MICHAEL C.GRYSKA, STEFAN H.
Owner 3M INNOVATIVE PROPERTIES CO
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap