Which plastic is used for PCB connectors and plastic parts. - Page 1
Forum section: electronics / general

author: hisense999
author_rank: Contributor
timestamp: December 19, 2011, 10:42:11 pm
content: I have question about plastic parts as PCB connectors, buttons etc. is it ABS or something other and maybe some data about this cuz I found is resistive for industrial grade isopropyl alcohol when standard ABS, PLA and other common used just nice looking plastic react with it as with acid so I'm just curious which material must be used for PCB connectors and buttons for make it so resistive.Regards

author: IanB
author_rank: Super Contributor
timestamp: December 19, 2011, 11:54:13 pm
content: I don't know, but I would guess it might be high density polyethylene, HDPE. (Or not. I forgot that HDPE melts at reflow temperatures...)Also I'm surprised when you say isopropyl alcohol damages plastics. Most plastics are quite safe to use with IPA suffering no damage at all. Are you sure your IPA is pure and not mixed with something else?

author: Unknown
author_rank: Unknown
timestamp: December 20, 2011, 12:07:59 am
content: Check the data sheets for connectors from manufacturers like Molex and Hirose, they will often state the materials.If IPA would dissolve standard ABS, there would be lots of damaged equipment out there, since IPA is a very common solvent for cleaning electronics and equipment. Not sure what you mean by 'industrial grade IPA', is this even worse than reagent grade (only suitable for dish washing as far as some chemists are concerned)? Does it mean it contains other crap which may dissolve plastics?

author: Short Circuit
author_rank: Frequent Contributor
timestamp: December 20, 2011, 12:31:29 am
content: Never seen plastics damaged by IPA, perhaps you used something like acetone accidentaly?Anyway, many connectors from HST are made from Nylon 66, or Nylon 46 for higher temperatures (SMD/reflow soldering).Some I/O connectors (like DVI, USB) use Glass-filled Polybutylene terephthalate (PBT).Yet another datasheet mentions Liquid Crystal Polyester (LCP)

author: hisense999
author_rank: Contributor
timestamp: December 20, 2011, 02:36:01 am
content: Quote from: alm on December 20, 2011, 12:07:59 amIn attachement is what this done with ABS-757 which is commonly used as shiny plastic usually for some kitchen equipement and is common in China, other ABS which I tested is some pure natural color (white) ABS this also my "super IPA" melted, test with PLA is - desintegration in 10minutesI also used a lot of IPA in my life but first time I bought some special HK brand and I must say is really good - PCB is so clean without white dust which make me crazy many times with IPA on the market, so I think this 'animal' with which I deal now is a real IPA for use in fully metalic ultrasonic cleaner not with this crappy shiny plastic one from China.Attached picture is a damage which is done for ultrasonic cleaner after use this IPA, I can blame my IPA but PCB even with the most cheap connectors can stay in it even 2h without any damage, but housing of ultrasonic cleaner is melted now.

author: IanB
author_rank: Super Contributor
timestamp: December 20, 2011, 02:58:34 am
content: Quote from: hisense999 on December 20, 2011, 02:36:01 amI can't see from your picture whether what you have is really IPA or maybe some other solvent. The damage you show is not typical of IPA, but it is likely with more aggressive solvents.IPA is not a generic term for cleaning solvent, it refers specifically to isopropyl alchohol, (CH3)2CHOH. When you buy it, you need to make sure this is exactly what is in the container. There are many circuit board cleaning solvents out there that contain mixtures of other things.Here is an example of something that is not IPA and that might damage some plastics:http://www.mgchemicals.com/products/4140.html

author: hisense999
author_rank: Contributor
timestamp: December 20, 2011, 11:29:12 am
content: Quote from: IanB on December 20, 2011, 02:58:34 amYes my label after translation say clean 99.9% isopropyl cwithout water etc. and IPA is just IPA - in old days when I use IPA a lot I know is depend even on the batch how much water and other things they put inside to drop price down which as result was always white dust.I found good info:"1. Most people don't know that pure IPA alcohol leaves almost no residues. By itself, high-quality IPA is a very clean material and if properly packaged, handled and used it can be expected to produce no more than 200-400 ppm of residues, and almost all of those residues are actually from the packaging. The bad news is that very, very few people buy high quality IPA. IPA is considered a commodity, so everybody wants a low price, so they buy the cheapest IPA on the market. These materials often are highly diluted (usually with water of uncertain origins) to lower the selling price. Products like these will not deliver high quality, reliable cleaning. "So according to this my IPA is real pure IPA with which I never have contact before - even package is made from steel not typical plastic bootle and as result no residues on the PCB after cleaning but this working as acid when contact with ABS unfortunelly my ultrasonic cleaner is from ABS-757 so just now I must put it into trash and buy some which is made only from staineless steel. Anyway ABS is never used as PCB parts cuz now I remember melting point is ~100C for ABS.

author: Short Circuit
author_rank: Frequent Contributor
timestamp: December 21, 2011, 12:51:36 am
content: Reading the label (and your symptoms) I don't believe this is IPA at all.Chemical properties of IPA can be found on wikipedia;http://en.wikipedia.org/wiki/Isopropyl_alcoholand none of the numbers correspond with your label. Also, the wide boiling point temperature range indicatessome mixture of various chemicals.

author: Unknown
author_rank: Unknown
timestamp: December 21, 2011, 01:52:06 am
content: I second this. Based on the label, I don't think it's IPA either. The presence of a boiling range indeed means that it's a mixture, not a pure substance. The boiling range and melting don't match the data for IPA at 1 bar. Not sure what the 1.34/1.39 figures refer to, but if it's density they're way off for IPA, which is lighter than water.

author: ejeffrey
author_rank: Super Contributor
timestamp: December 21, 2011, 06:08:57 pm
content: Isoproponol is a mediocre solvent and cleaning agent. It is good at cleaning light oils, thinning other organic solutions, and displacing water along with any contaminants dissolved in the water, but it doesn't dissolve any common plastics. If what you have dissolves plastics it is not IPA. Just that the fact that you say it works so well makes me reasonably confident that it isn't IPA. It must either be something else entirely or isoproponol mixed with other chemicals to improve its cleaning properties.

author: vk6zgo
author_rank: Super Contributor
timestamp: December 22, 2011, 03:10:43 am
content: Yeah,the main advantage of Isoproponol is that it is fairly mild,but does a good job of removing most of the gunk from circuit boards,etc.Even the stuff we call "Methylated Spirits" in Oz is good ,although some people are a bit namby-pamby about the "white residue" it leaves.Neither of these affect normal plastics in any way,though they might remove spirit based markings on the PCB.The only solvents I know of that damage plastics are acetone based stuff like Nail Polish Remover,Lacquer Thinners,etc.VK6ZGO

author: ron
author_rank: Regular Contributor
timestamp: December 22, 2011, 06:11:01 am
content: I suspect that the ultrasonic cleaner housing is not ABS. IPA will damage styrene plastic. I learned this the hard way "cleaning" the focusing screen on a Leica R3.

author: baljemmett
author_rank: Unknown
timestamp: December 22, 2011, 03:19:08 pm
content: Quote from: ron on December 22, 2011, 06:11:01 amYeeeeouch! Yes, cleaning solvents and focusing screens in general are a really bad combination, as the mess found inside one of my eBay acquisitions will tell you. Even real glass ones can be a bit of a bugger to clean properly and safely :-/

author: amyk
author_rank: Super Contributor
timestamp: December 26, 2011, 11:40:00 am
content: The properties listed sound like it's a mix of solvents that contains things like dichloroethane:http://en.wikipedia.org/wiki/1,2-Dichloroethaneand trichloroethane:http://en.wikipedia.org/wiki/1,1,1-TrichloroethaneI also found this, indicating it can dissolve ABS:http://nerfhaven.com/forums/index.php?showtopic=18527Especially if it has a "sweet" smell, it is likely to be a chlorinated hydrocarbon solvent. IPA has a very different strong alcohol smell. (It's very noticeable, don't deliberately inhale!)Be careful, it is much more dangerous than IPA.