UV/EB Chemistry to Improve Package Durability. James E. Goodrich

Transcription

1 UV/EB Chemistry to Improve Package Durability James E. Goodrich May 24, 2010

2 Introduction UV/EB chemistry has many environmental and processing advantages that are useful Still more advantages being researched and proven Technology becomes even more powerful when coupled with the improvements in final products Replacement of current technologies Enhancement of packaging Protection of packaging Protection of goods in packaging Weatherability Chemical Resistance Variance of properties MVTR Scratch and abrasion resistance Protection from physical destruction Dielectric

3 Weatherability UV/EB chemistry can be tailored to improve outdoor weathering resistance and increase package lifetimes Benefits are gained by moving to weatherable packaging Better resistance of inks / coatings to yellowing and embrittlement Protection of substrates No deterioration of the substrate Reduction or elimination of yellowing Protection of pigmented layers Base acrylate chemistry used in most packaging inks / coatings will not stand up to outdoor conditions Epoxy acrylate, tertiary amine, and EO monomer based To realize improvements in outdoor weathering performance a change in acrylate chemistry is needed

4 Yellowness Index Oligomer Backbone QUV testing is a good tool to narrow down chemistry selection Yellowness index is used to determine degradation Epoxy Acrylate Polyester Acrylate Aliphatic Urethane Acrylate 40 Comparison of three different oligomer backbones Epoxy Acrylate Polyester Acrylate (Some aromatic character) Aliphatic Urethane Acrylate Study backs up what is intuitive Aromatic character in epoxy acrylate and polyester acrylate lead to degradation Oxidation and development of conjugated species Aliphatic urethane acrylate has a polycarbonate backbone that offers good weathering resistance Used as the baseline in many studies Time (Hours)

5 60 Gloss Monomers Structure FL outdoor exposure comparison of different acrylate functional monomers 60 gloss measured Looks at surface defects like erosion 50:50 blend of aliphatic urethane acrylate with the various monomers The non-alkoxylated monomers hold up better to weathering testing Aliphatic Urethane Acrylate IBOA HDDA PO HDDA TMPTA EO TMPTA O 60 O O 50 O 40 O O O O O O TUVR (MJ/m2)

6 Chemical Resistance Chemical exposure can quickly degrade a package Decreases aesthetic appeal, not necessarily the functionality UV/EB chemistry can improve the resistance Acids and bases Solvents and oils Detergents and cleaners Water Foodstuffs Dyes and colorants Resistance due to three main factors Backbone chemistry resistance to chemical of interest Crosslinking Surface cure

7 Ability to Match Package Properties A wide range of cured properties are achievable from UV/EB chemistry Able to match or enhance the package properties Elongation Achieve % in cured systems Needed elongation depends on film thickness Tensile strength plays a part in the ability to achieve ultimate elongation Glass transition T g of -40 to 180 C Backbone, crosslinking, and cure conditions all affect Leads to adjustable heat resistance of cured system Useful for thermoforming, shrinking, or resisting high temperatures Refractive index 1.45 to 1.61 cured RI UV/EB chemistry applied to a package can match the packaging material RI Reduces visual imperfections and allows for control of light Tensile strength and modulus Tensile strength of < psi 1% Modulus of < psi Chemistry can be used to reinforce or increase package strength

8 Scratch and Abrasion Resistance The scratch and abrasion resistance of UV/EB coatings has long been used to improve products In packaging, epoxy acrylate formulations offer a good balance of low cost and scratch resistance Enhanced by incorporation of higher functional oligomers and monomers Too much crosslinking increases brittleness and can actually decrease abrasion resistance Changes in chemistry can lead to improvements in performance Polyester acrylates are less brittle and exhibit better wear resistance High functional urethane acrylates Increase scratch resistance but can increase brittleness Useful at small amounts Way to remove BPA and PETA from formulas

9 Barrier Properties of UV/EB Systems Increasing in interest in UV/EB cured barriers Moisture barrier Gas (O 2, N 2, etc.) barrier Electrical barrier Liquid coating and curing process vs. lamination of films Improved speed Decreased thickness Increased functionality of each layer Mocon Permatran-W 3/33 WVTR testing platform Single film at a time 100% relative humidity Measure the transmission rate in (g*mil)/(m 2 *day) Test the same formulation in two cells

10 Water Vapor Transmission Rate (WVTR) More Permeable Better Barrier

11 Barrier Applications by Performance Current range of UV cured polymers alone

12 Barrier Applications by Performance UV polymers can be used as a component

13 Oligomer Permeation Permeation with 25% SR506 Permeation with 20% SR238 Permeation with 20% SR833S Permeation with 50% SR833S Current Status 100% RH, 100 F g/(m 2 *day) for 1 mil Typical Values Important to keep in mind physical properties Need for flexibility or hardness will affect materials needed Continue to get better results New experimental New technologies upcoming CN972 >> CN9800 >> CN9023 >> CN816 >> CN CN CN CN CN PRO CN CN CN Blend CN9014 and CN NTX SR833S + 10% Clay SR833S CN CN Solar EVA PET Tedlar PEN 6.67 Dupont Teijin Q45FA 5 Frito Lay 0.47

14 WVTR Backbone Comparison Studies have been conducted to understand the effect of backbone, surface cure and cross link density Polyester backbone ALUA Polyether backbone ALUA Polycarbonate backbone ALUA Polybutadiene backbone ALUA Formula: 70% Oligomer 25% HDDA 4% Esacure KIP150 1% Esacure TZT

15 WVTR Crosslinking Comparison CN309 - aliphatic oligomer Good WVTR results by itself WVTR decreases as the crosslink density increases SR833S > SR238B 25% CN % CN % SR833S 50% CN % SR833S Compatible with polybutadiene backbone oligomers like CN9014 Combination gives lowest WVTR to date 80% CN % SR833S 69 80% CN % SR238B 89 CN Formula: 96% Oligomer / Monomer 4% Esacure KTO (g*mil)/(m2/day)

16 Tide Box WVTR A Tide detergent box was tested for its WVTR properties No PE liner Package permeation of 201 (g*mil)/(m 2 *day) Package WVTR of 8.1 g/(m 2 *day) Takes into account the entire thickness of the package (24.8 mil) Cardboard probably does not increase the water vapor resistance If the cardboard thickness is ignored Ink and coating layers only (~15µm) WVTR of 335 g/(m 2 *day) Well within what acrylate chemistry has been proven to do

17 Protection from Physical Destruction Traditionally acrylic and PVC plastisol coatings were used to impart impact resistance to glass To decrease space and gas-fired oven usage, UV chemistry is now being incorporated UV coating performs several functions Addition of color or aesthetics Improved resistance to breaking during drops If bottle breaks, coating able to hold contents until cleanup Particularly useful when dealing with pharmaceutical or expensive liquids

18 Dielectric Properties UV/EB chemistry had good dielectric properties Able to increase dielectric properties of packaging materials Protect contents from electrical current ASTM D149 (Dielectric Withstand Voltage) was tested of eight different monomer / oligomer blends Looked at various backbones of urethane acrylate oligomers with monomers PRO10085 is CN996 made with an organic, not Sn, catalyst ASTM D150 (Dielectric Constant) was tested on the same eight blends

19 ASTM D149 Results Dielectric withstand voltage A higher withstand voltage is desired All oligomers were tested with 25% monomer Allows for higher film integrity Most thermoplastics have withstand voltages in the range of VAC/mill Brown block on graph PTFE is around VAC / mill

20 ASTM D150 Results Dielectric constant A lower dielectric constant is desired Tested at 1 khz At 1 khz most non-polar plastics, such as PP and PE have a ĸ of less than 3 The ĸ of polar plastics will decrease as the frequency increases

21 Conductivity Some conductivity is possible with UV/EB chemistry Current Technology Capability Need additional, non-reactive fillers to achieve properties Acrylates are insulators and will resist electron flow Possible use in anti-static protective coatings Resistant to magnetic and electrical fields Protects sensitive instruments during shipping and storage

22 Thank You Questions? James E. Goodrich Manager, UV/EB Technology Sartomer USA, LLC 502 Thomas Jones Way Exton, PA Phone: Fax: