Photopolymer or making polymer light sensitive

[Mustafa Umut Sarac]

Do you know Any reasonable cost transparent or semi transparent photopolymer which could be used as reliefed gelatin or lithophane or woodburytype master without pressing the metal?
I am thinking silicon or polyurethane is widely available but I did not read any light sensitive one. Vinyl and epoxy and acrylic are used at rapid prototyping but they come in large containers and expensive. And I am searching for make a widely available polymer light sensitive.

 

[Nicholas Lindan]

Printed circuit board resist

 

[Whiteymorange]

For photo polymer printing plates, try Boxcar press. The KM73 plates are what I use for plastic photogravure. They require high actinic light in exposure, for which I use a facial tanning lamp, set up at 4" above the plate glass that holds my photo positive to the emulsion. I researched sourcing of the emulsion a bit, but the plates were actually what I wanted, so I gave up the search rather early and found little that would help.

 

[Mustafa Umut Sarac]

I searched for photopolymers on printed circuit boards and I found they are epoxy or acrylic based. But how a liquid epoxy got polymerised on the plastic plate before it is directed to uv and it is than deeper polymerised to form an other shape ?

I think I have to ask about photopolymer plates for gravure . Do you wash them after uv exposure to remove remaining traces or does it form a complete shape to do your print ? Do they come soft and scratchable and do they very hard after the uv exposure ?

 

[Mustafa Umut Sarac]

I thought when I was thinking about reading an old article about screen printing photopolymers. I dived in to patents and need time to find a cheap photopolymer.

 

[Hexavalent]

Novolacs are cheap and commonly used for DIY circuit board fabrication.

 

[Mustafa Umut Sarac]

Thank you Ian , let me search for its maximum applicable thickness. Circuitboard photopolymers coat for 1/5 mm or so.

 

[Mustafa Umut Sarac]

Cresol Novolacs for Offset Photolithography Photoresist

Precise Viscosity Control and Narrow Dissolution Rate
Momentive's Durite® novolac resins bring both of these desired advantages to the exacting process of etching ultrafine line patterns into the photoresist surface coating of an annealed aluminum plate.

Printing plate manufacturers demand precise viscosity control of Durite® resins, available in low- to high-viscosity products, each having a tight max/min specification range. Our customers can formulate photoresist solutions (by addition of photoactive compounds) that offer chip makers an ability to continuously focus on finer line resolution and better aspect ratios. It allows them to optimally match the viscosity of their photoresist solution to the characteristics and conditions of their own processing system. That’s critical to operating with just the right post-imaging dissolution rate to get peak performance from in-place equipment.

Momentive Specialty Chemicals offers Durite® cresol novolac resins for use in positive photoresist formulations with the focus on the right combination of meta-, para- and ortho- cresol monomers, which then provide the following benefits:

The required bulk dissolution rates (BDR) for the customer's developer
Features such as narrow molecular weight and low polydispersity
Optimum hardness for longer service life
Low free-monomer
Novel monomers are also incorporated to fine-tune or customize the final properties of the resin to meet the customer's needs.

Durite PD-140A, for example, is a medium molecular weight resin that can be used for optimizing the BDR as well as improving the hardness of the coating, whereas Durite D_PD-1640 is a special high molecular resin that exhibits a very high rate of dissolution but is lower in hardness compared to PD-140A. These resins are also available in solutions such as ethyl lactate and glycol ether at 30% solids.

View technical data sheet for Durite PD-140A

It’s easy to see why more and more formulators are turning to Momentive Specialty Chemicals to supply the main ingredient of the photoresists in order to meet the demanding requirements of chip makers.

Recommended Products

Product B/ADR (A/S) Solution Viscosity¹, cSt Typical Mw
PD-427A 1000 - 2500 28 - 44 4000 - 6000
PD-140A 750 ± 100 41 - 49 6000 - 9000
PD-646A 300 - 500 48 - 73 10000 - 14000
PD-422A 1500 - 3000 18 - 30 3000 - 5000
PD-494A 50 to 125 40 - 75 12000 - 1700
D_PD-1632 15 to 55 68 - 82 17000 - 22000
D_PD-1634 170 ± 40 72 - 92 16000 - 23000
D_PD-1622 10 to 80 35 - 45 5500 - 9000
D_PD-1623 50 to 150 30 - 35 4500 - 5500
D_PD-1615 550 ± 125 35 - 45 5000 - 7500
PD-6564 LB 1450 - 2000 36 - 46 6000 - 8000
D_PD-1640 700 ± 100 72 - 86 16000 - 23000
D_PD-1642 275 - 375 31 - 38 6000 - 8500
PD-126A 4000 ± 1000 17 - 29 1400 - 5000
¹Solution viscosity is for 30% PMA solution @ 25ºC.
We are also capable of supplying in 30% or 40% solids resin solutions (after micro-filtration).

 

[Mustafa Umut Sarac]

How can we determine the maximum thickness of epoxy and maximum relief depth from above numbers ?

 

[Mustafa Umut Sarac]

I wrote to Hexion about sourcing of 2 and 5 mm thick relief polymer. They answer in 24 hours. Tomorrow night , everything will be more open.

Umut

 

[Mustafa Umut Sarac]

I learned that TOYOBO Solar plates are major seller. I looked in to google patents and there were two patents about similar plates. I dont know these plates in use but patents frequently talks about heat sensitive layer. Is there such a thing at solar plate ?

Umut

 

[Fast14riot]

When I worked in the MEMS field using LIGA process, we used SU-8 photoresist for high aspect microstructures. The biggest issue concerning the thickness you want to use is maintaining columnar structure. We often did multiple layerings to get thicker build up, but run a higher exposure to error in alignment.

If you have access to a synchrotron you could have LIGA moulds made in the thickness you want, though costs could be prohibitive.


-Xander