UV at InChem

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UV at InChem

• Presented by
• InChem Corporation
• R. David Zopf

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Overview

• UV Terminology
• UV Chemistry Review
• InChem Coatings Evaluation Review
• Phenoxy in Cationic UV

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UV TerminologyFormula Components

• Conventional
• Resin
• Solvent
• Pigment
• Additives

• UV
• Oligomer
• Monomer
• Pigment
• Additives
• Photoinitiator

Unique to UV formulas
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UV TerminologyEquipment

• UV Lamp
• Sometimes called UV oven
• UV Radiometer
• Measures energy output
• UV Bulb
• MPMV bulb (old standard)
• H, D, V bulbs (metal doped bulbs)

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UV TerminologyEquipment

• Lamp Power
• Watts per Inch
• Old systems 300 WPI
• New systems 500 WPI

UV Dose Amount of UV that the substrate
sees Measured by Radiometer
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UV Chemistry

• Free Radical Cationic
• gt90 Market Share lt10 M.S.
• Epoxy Acrylates Phenoxy
• Phenoxy Acrylate Epoxy Resins
• Urethane Acrylates Polyols

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UV ChemistryFree Radical

• Acrylate Chemistry makes it Work!
• Photoinitiators
• H Abstraction (benzophenone)
• Photocleavage (BDK)
• Oxygen Inhibited Mechanism
• Reaction Stops when Light is Gone
• Full Conversion Issue

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UV ChemistryCationic

• Epoxies and Polyols
• Photoinitiators
• Break open with UV to make super-acids
• Aryl sulfonium and iodonium salts
• Super-acid opens Epoxy rings
• Reaction continues after Light is removed
• Sensitive to moisture, alkalines

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UV Chemistry Free Radical

• Amine Synergists
• Used with H-abstraction PIs
• MDEA most common
• Interaction with UV-91, 93, 95
• Increased viscosity
• Recommend reduced amine content
• Best quantity Zero
• Or up to 50 of original content

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UV ChemistryFree Radical

• Oxygen Inhibition
• O2 is a great free radical scavenger
• Can make surface cure an issue
• Best Solution A powerful lamp
• 2nd Best Solution More PI
• 3rd Best Solution Abstractable Hydrogen
• 4th Best Solution Nitrogen Blanketing

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UV ChemistryFree Radical

• Inhibitor Content
• HQMME to minimize risk of gelation
• Free Radical Scavenger
• Needs Oxygen to work properly
• Variation can impact some applications
• HPLC monitoring

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UV ChemistryPigment Effects

• Acrylate Systems
• Biggest problem is blocking UV light
• Cationic Systems
• Biggest problem is alkaline surface treatments
• Slows cure by neutralizing super acid

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UV Coatings Evaluation

• Crosshatch Adhesion
• Taber Abrasion H-18
• Taber CS-17
• 60 Gloss
• Shore A Hardness (plastic coatings)
• Simple Crease Test (plastic coatings)

• Barcol Hardness
• Glass Transition Temperature
• UV-91 CAB Compatibility
• Stain Testing
• Mandrel Bend Test (metal coatings)

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Crosshatch Adhesion
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H-18 Taber Abrasion
H-18 Taber Abrasion
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CS-17 Taber Abrasion
CS-17 Taber Abrasion
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60 Degree Gloss
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Shore A Hardness
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Simple Crease Test(plastic coatings)
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UV-91 CAB Compatibility
For a 50/50 blend of UV-91 and monomer
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Mandrel Bend Test (metal coatings)
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UV Epoxy AcrylateStain Testing

• (see Chemical Resistance Table - attached Adobe
  Acrobat Reader file titled Chem. Resist. Of UV
  Ctgs)
• UV-93 on metal and UV-95 on Valox are standouts
• UV-91 modified with UV-11TP70 on metal shows
  slight negative effect of non-reactive material.

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Barcol Hardness
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Glass Transition Temperature
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UV-11XX Products

• PKHB as is dissolved in an acrylated monomer
• Imparts non-reactive flexibility to formula
• Doesnt block UV light
• Has its own chemical integrity
• Works for hybrid systems (cationic/free rad)

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Forced Dry UV

• Lacquer Dry implied Room Temperature. A room
  temperature dry is not viable with n-butyl
  acetate alone.
• Some faster drying co-solvent is needed (MEK,
  acetone)
• Low temperature oven (45 C) dry cycles possible
• 15-20 minutes for 3 mil WFT

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Phenoxy in Cationic UV

• Improved Glass Transition Temp.
• The DOW Chemical Co. Paper
• Dr. Antoine Carroy (RadTech 1991 Proceedings)