Are there any good cheap epoxy resins?

[Jimbo1490]

Back on topic, most sellers mentioned so far are in fact re-sellers of epoxy. US Composites, West and most others simply buy large quantities and decant and re-badge. Oh, and need I mention: they mark the stuff up a bit

It follows that if you want to get epoxy very cheap, as cheap as the re-badgers, you have to buy from a manufacturer of epoxy, not a re-seller. Alas, most manufacturers of epoxy resins like to make and sell lots of the stuff, with minimum orders of say 55 gallons (railcar purchases are always welcome ) Try to buy less than that and you will either be a) turned down or b) hit with a very high 'less than minimums' premium. With Epon, it was like $2.50/lb over the drum price for purchases less than a drum which came to like an extra $70 per 5 gal pail(Ouch!)

That's most manufacturers, but not all. Back when I was in a composites business of my own, I found a small epoxy manufacturer that was willing to sell small quantities (5 gallon pail minimums) at very reasonable prices.

That company is CVC Cpecialty CHemicals Their resins are of consistently better quality than comparable products made by the 'big three' resin manufacturers. They are also generous with both samples and tech/formulation data. They make some pretty cool odball curing agents, too. A couple of these are of special interest to anyone interested in resin infusion using an epoxy system.

Jimbo

[kengrome]

Their resins are of consistently better quality than comparable products made by the 'big three' resin manufacturers.

Jimbo, can you please explain why you characterize their resins as 'better'?

[Jimbo1490]

Originally Posted by kengrome

Jimbo, can you please explain why you characterize their resins as 'better'?

OK, here goes. In general terms, we can rank epoxies by certain properties, like viscosity. Less viscosity is always better. Another parameter is 'weight per epoxide' or its brother 'epoxide equivalent weight' or EEW. These are measures of the reactivity of the resin. More reactive sites on the molecule means stronger cured resin. Generally, the more reactive, the more viscosity. EEW is an inverse of WPE, so lower EEW means more reactivity.


There are several different 'classes' of epoxy resin. Bisphenol-A and bisphenol-F are two examples of these classes. BPF is more reactive than BPA and lower viscosity so better all around.

Now if you compare the specific numbers, like EEW and viscosity, you will find that when comparing apples to apples, like say the standard EEW 190 BPA resin from Shell (now Hexion) compared to the analogous one from CVC, the one from CVC always has lower viscosity.

If you cross apples and oranges by comparing cross class, say BPF and BPA, the standard BPA resin from CVC is nearly as low in viscosity as the more sophisticated (and costlier) BPF resin from Epon, without adding any modifiers.

CVC says this is because the CVC resins are higher in purity. Whatever the reason, I have used their resins in side by side comparison against Epon and there is a notable difference in viscosity. This means you can get the handling properties you need with less (or maybe no) reactive modifiers, which always degrade the cured-state properties somewhat.

A quick example: Hexion's BPF resin is their Epon 862. They advertise an EEW of 165-174 with a viscosity of between 2500 and 4500 centipoise at ISO Std. Water is 1 cP BTW.

The equivalent resin from CVC is their Epalloy 8220 with an EEW of 164-176 and a viscosity of 1800-2800 cP at ISO standard.

So the CVC resin starts out with substantially lower viscosity for the same reactivity.

And it like this across the board with their products; better resins for less money.


Jimbo

[kengrome]

Hi Jimbo,

Thanks for the good basic explanation. If you don't mind I have some follow up questions and comments:

My shop is located in the Philippines and CVC manufactures only in the USA. I've asked them about making me a distributor in this country but for the sake of argument let's say they cannot or will not. Let's also assume that because of the higher shipping costs I will be better off going with Hexion since they not only manufacture in Asia but they already have two distributors in the Philippines that I can buy from. I've been considering EPON 862 precisely for these reasons ...

You specifically mentioned EPON 862 in your comparison with a CVC equivalent but you never mentioned any curing agents, and curing agents are the components responsible for the overall performance of the cured material. Naturally this brings up some questions which you may be able to answer since you're apparently familiar with Hexion products ...

Which curing agent might you suggest for use with EPON 862 in a shop that does hand layup of glass over plywood in typically 80-90 degree F temperatures and 80% relative humidity? Should I go with EPIKURE 3387 or another Cycloaliphatic Amine? Or should I go with a Polyamide or a typical Aliphatic Amine or maybe some other type of curing agent?

Would you suggest the use of a HELOXY modifier to produce a lower viscosity mix or better wet out characteristics? How about the flexibility issue ... should I use a flexibilizer to toughen the end product or will this resin/curing agent combo flex enough to avoid chipping and cracking as-is?

[Boston]

I would recommend you actually read the literature on the toxicity of epoxy before you scoff at the hundreds of scientists who have worked so hard to protect what is ( less and less thank God ) an occasionally unappreciative public

I will again recommend that these chemicals be used with an informed caution
and point out that ignorant disregard is what has led to plastic outweighing plankton in our oceans 10/1 (check the references this time if you question the veracity of the claim)

Bysphenol
in all its toxic glory
even the epoxy producers recommend a little more caution than would be used in handling table salt
and suggesting a comparison to sodium chloride
please
and in order to enjoy the toxic effects of salt you need to heat it to 1474 deg F
a temperature seldom ever achieved even in a serious fire
to realize the toxic efects of Byshenol you need only be
mixing it
( something the rest of us often do )
breathing it
( maybe trolls dont breath )
exposing it to sunlight
( some of us may be living in the dark )
and then let the out-gassing begin
although the industry has at least
( if not some others )
recognized the problem of out gassing
and has begun producing low out gassing resins

I again include the following abstracts for your reading pleasure
If you wish to question there veracity
well
your not only scoffing at a reasonable warning given in an effort to help this gentleman make a good decision
but your embarrassing yourself in the face of overwhelming scientific evidence
and feel free to insult my spelling
its what some people digress to rather than admit they should reevaluate an antiquated argument

(1) Microbiology and Biotoxins Area, ANFACO-CECOPESCA, Campus Univ de Vigo, 36310 Vigo (Pontevedra), Spain
Received: 21 March 2006 Accepted: 17 May 2006 Published online: 17 June 2006

Abstract Bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE) are used as starting substances for the manufacturing of epoxy resins used in internal can coatings. They are obtained by a condensation reaction between epichlorohydrin with bisphenol A and bisphenol F, respectively. These potential endocrine disrupting chemicals are able to enter the food chain and to reach the intestinal epithelium, causing structural and functional damages. The human colorectal adenocarcinoma cell line Caco-2 is a widely used in vitro model of the intestinal cells. The aim of this study was to characterize BADGE and BFDGE toxicity in Caco-2 cells, in particular, at the cellular and molecular level. Using several approaches, we characterized BADGE- and BFDGE-induced cell toxicity in Caco-2 cells. The treatment was done using different concentrations up to cytotoxic doses and different times of exposure to the agents. We evaluated the effect of these compounds on cell morphology, cell detachment, cell proliferation, F-actin disruption and plasma membrane integrity. Both compounds are able to induce morphological changes, cell detachment from the substratum and to inhibit cell proliferation, being these effects time and dose-dependent. Moreover, BADGE and BFDGE induce F-actin depolymerization, this effect is very potent at 24 h of incubation with the agents and a complete F-actin disruption can be observed at 200 μM BADGE or BFDGE. In addition, cell integrity is not damaged, since neither propidium iodide uptake nor LDH release takes place in Caco-2 cells exposed to high doses of these agents for 24 h.

also

http://schizophreniabulletin.oxfordj...sc/terms.shtml


In recent years, numerous substances have been identified as so-called "endocrine disruptors" because exposure to them results in disruption of normal endocrine function with possible adverse health outcomes. The pathologic and behavioral abnormalities attributed to exposure to endocrine disruptors like bisphenol-A (BPA) have been studied in animals. Mental conditions ranging from cognitive impairment to autism have been linked to BPA exposure by more than one investigation. Concurrent with these developments in BPA research, schizophrenia research has continued to find evidence of possible endocrine or neuroendocrine involvement in the disease. Sufficient information now exists for a comparison of the neurotoxicological and behavioral pathology associated with exposure to BPA and other endocrine disruptors to the abnormalities observed in schizophrenia. This review summarizes these findings and proposes a theory of endocrine disruption, like that observed from BPA exposure, as a pathway of schizophrenia pathogenesis. The review shows similarities exist between the effects of exposure to BPA and other related chemicals with schizophrenia. These similarities can be observed in 11 broad categories of abnormality: physical development, brain anatomy, cellular anatomy, hormone function, neurotransmitters and receptors, proteins and factors, processes and substances, immunology, sexual development, social behaviors or physiological responses, and other behaviors. Some of these similarities are sexually dimorphic and support theories that sexual dimorphisms may be important to schizophrenia pathogenesis. Research recommendations for further elaboration of the theory are proposed.

I would also cite

The estrogenicity of bisphenol A-related diphenylalkanes with various substituents at the central carbon and the hydroxy groups.
P Perez, R Pulgar, F Olea-Serrano, M Villalobos, A Rivas, M Metzler, V Pedraza, and N Olea
Laboratory of Medical Investigation, Department of Radiology, School of Medicine, HUSC-University of Granada, Granada, Spain.
See letter "Bisphenol A diglycidyl ether as a potential metabolic source of bisphenol A." on page A472b.
This article has been cited by other articles in PMC.
Abstract
The chemical structure of hydroxylated diphenylalkanes or bisphenols consists of two phenolic rings joined together through a bridging carbon. This class of endocrine disruptors that mimic estrogens is widely used in industry, particularly in plastics. Bisphenol F, bisphenol A, fluorine-containing bisphenol A (bisphenol AF), and other diphenylalkanes were found to be estrogenic in a bioassay with MCF7 human breast cancer cells in culture (E-SCREEN assay). Bisphenols promoted cell proliferation and increased the synthesis and secretion of cell type-specific proteins. When ranked by proliferative potency, the longer the alkyl substituent at the bridging carbon, the lower the concentration needed for maximal cell yield; the most active compound contained two propyl chains at the bridging carbon. Bisphenols with two hydroxyl groups in the para position and an angular configuration are suitable for appropriate hydrogen bonding to the acceptor site of the estrogen receptor. Our data suggest that estrogenicity is influenced not only by the length of the substituents at the bridging carbon but also by their nature. Because diphenylalkane derivatives are widespread and their production and use are increasing, potential exposure of humans to estrogenic bisphenols is becoming a significant issue. The hazardous effects of inadvertent exposure to bisphenol-releasing chemicals in professional workers and the general populations therefore deserve investigation.
Edit/Delete Message

I will also include the following links and papers being used by me to write my next paper on the comparison between glass and plastic

1 ) Materials, geometry, and net energy ratio of tubular ...
2 ) http://www.mindfully.org/Berkeley/Be...Task-Force.htm
3 ) www.mindfully.org/Plastic/
4 ) measure of sustainability embodied energy
5 ) http://www.mindfully.org/Plastic/Bes...le-Plastic.htm
6 ) http://www.lotuslive.org/products/fi...ontainer01.pdf
7 ) http://www.fakeplasticfish.com/synth...ranscript.html
8 ) www.ecologycenter.org
9 ) Metro: Waste reduction fast facts: Glass
10 ) Metro: Waste reduction fast facts: Plastic
11 ) www.acfnewsource.org/environment/
12 ) www.fragmentsfromfloyd.com/ 2007/06/
13 ) NRC: Radioactive Waste
14 ) BBC NEWS | Science/Nature | Warning on plastic's toxic threat
15 ) Keeping our ocean clean : Bradley Beach Today
16 ) Untitled Document
17 ) http://www.mountainfilm.org/download...lastic_Sea.pdf
18 ) http://www.visiongroup.co.uk/go.jsp?...oup_uk.compare comparison of glass and plastic
19 )http://www.firsttankguide.net/tanktype.php comparison of glass and acrylic
20 )www.stii.dost.gov.ph/pjsweb/data/decomposer.htm - 7k
21 ) http://archive.greenpeace.org/toxics...abase/bad.html
22 ) http://www.epa.gov/chemfact/f_acrlac.txt
23 ) http://en.wikipedia.org/wiki/Polymethyl_methacrylate
24 ) http://www.freepatentsonline.com/5998554.html
25 ) http://www.npi.gov.au/database/subst...rofiles/6.html
26 ) http://goalgreen.com/2007/06/25/plas...eps-on-giving/
27 ) http://www.chemsoc.org/exemplarchem/...head/facts.htm
28 ) http://www.wasteonline.org.uk/resour...s/Plastics.htm
29 ) www.level.org.nz
30 ) www.grisb.org/publications/pub33.htm - 24k -
31 ) http://www.environment.gov.au/settlements/publications/
32 ) GLASS vs. PLASTIC
33 ) RADIOACTIVE WASTE MANAGEMENT PROCEDURES FOR DUKE UNIVERSITY ...
34)http://www.devicelink.com/mpb/archive/96/01/001.html
http://www.environmentwriter.org/res...crylicacid.htm
35 ) Fact Sheets - Glass
36 ) ftp://ftp.dot.state.tx.us/pub/txdot-...df/yrr_feb.pdf
37 ) Cullet Preheating: The Realistic Solution for All Glass Furnaces ...
38 ) Professional Environmental Solutions - Atlanta, Georgia
39 ) Patagonia Under Siege: The Plastic Killing Fields - Pacific Ocean ...
40 ) Composition and process for the encapsulation and stabilization of ...
41 ) APPENDIX D - Key Federal Laws and Regulations
42 ) Mixed-Waste Shipping & Transportation | Radiation Protection | US EPA
43 ) Low Level Radioactive Waste Information Page
44 ) DEP: Atlantic Green Sea Turtle Fact Sheet
45 ) Ulrich Reifenhäuser: Plastics and rubber have changed the world ...
46 ) Plastic Debris Washed Ashore
47 ) Bizarre Properties of Glass Revealed | LiveScience
48 ) Canada Likely to Label Plastic Ingredient ‘Toxic’ - New York Times


http://www.epa.gov/epaoswer/non-hw/muncpl/
http://www.americanplasticscouncil.o...ID=1110&VID=86
http://www.mindfully.org/Berkeley-Pl...Task-Force.htm
http://www.designboom.com/eng/educat...recycling.html
http://americanplasticscouncil.org/s_apc/sec.asp
http://www.epa.gov/epaoswer/non-hw/muncpl/glass.htm
http://www.epa.gov/grtlakes/seahome/.../src/glass.htm
http://www.cityofmadison.com/streets/plastic.html

White, R; Jobling, S; Hoare, SA; Sumpter, JP; Parker, MG. Environmentally persistent alkylphenolic compounds are estrogenic. Endocrinology, 135, 175-182 (1994).
Tyler, CR; Jobling, S; Sumpter, JP. Endocrine disruption in wildlife: a critical review of the evidence. Critical Reviews in Toxicology, 28, 319-361 (1998).
Soto, A.M., Justica, H. Wray, J.W., Sonnenschein, C. p-Nonyl-phenol: an estrogenic xenobiotic released from "modified" polystyrene. Environ. Health Perspect. 92, 167-173 (1991).
Sonnenschein, C; Soto, AM. An updated review of environmental estrogen and androgen mimics and antagonists. J. Steroid Biochem. & Molec. Biol. 65, 143-150 (1998).
Mato, Y., Isoibe, T., Takada, H., Kanehiro, H., Ohtake, C, Kaminuma, T. Plastic resin pellets as a transport medium for toxic chemicals in the marine environment. Environ. Sci. Technol. 35, 318-324 (2001).
Kelce, WR; Stone, CR; Laws, SC; Gray, LE; Kemppainen, JA; Wilson, EM. Persistent DDT metabolite p,p'-DDE is a potent androgen receptor antagonist. Nature 375, 581-585 (1995).
Sumpter, JP; Jobling, S. Vitellogenesis as a biomarker for estrogenic contamination of the aquatic environment. Environmental Health Perspectives 103, Suppl 7, 173-184 (1995).
Kuiper GGJM, Carlsson B, Grandien K, Enmark E, Haggblad J, Nilsson S, Gustafsson J-A. Comparison of the ligand binding specificity and transcript tissue distribution of estrogen receptors ? and ?. Endocrinology 138, 863-870 (1997).
Kuiper, GGJM., Lemmen, J.G., Carlsson, B., Corton, J.C., Safe, S.H., van der Saag, P.T.,van der Burg, B., Gustafsson, J-A. Interaction of estrogenic chemicals and phytoestrogens with estrogen receptor ?. Endocrinology 139, 4252-4263 (1998).
Baker ME, Sklar DH, Terry LS, Hedges MR. Diethyl Pyrocarbonate, a histidine selective reagent, inhibits estrogen binding to receptor protein in rat uterus cytosol. Biochem. Int. 11, 233-238 (1985).
Baker ME, Terry LS. Diethylpyrocarbonate, a histidine selective reagent, inhibits progestin binding to chick oviduct cytosol. Steroids 42, 593-60 (1983).
Nagel, SC; vom Saal, FS; Welshons, WV. Developmental effects of estrogenic chemicals are predicted by an in vitro assay incorporating modification of cell uptake by serum. J. Steroid Biochem. & Molec. Biol. 69, 343-357 (1999).
Baker, M.E. Adrenal and sex steroid receptor evolution: environmental implications. J. Molec. Endocrinol. 26, 119-225 (2001).

[kengrome]

Bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE) are used as starting substances for the manufacturing of epoxy resins ...

That's right, they are "starting substances" -- they no longer exist in the resin you buy from an epoxy manufacturer.

Lye is a starting substance that makes soap too -- but it no longer exists in the soap you buy from a retailer because the saponification reaction consumes it.

[mastcolin]

Less politics, less high school chemistry gentlemen please.

Read the health and safety labels. It tells you all you need to know. (and can be randomly overly cautious or under cautious depending on the state of knowledge and "fashion" at the time). Contrary to some belief, they are trying protect you/the world.

I once visited Shell where they told us/me (as representative of the world's largest purchaser of epoxy resins) that if they were discovered now, they probably wouldn't be allowed for any sort of "wet" or open process. This has as much to do with the curing agents as well however. The fact that they exist and have a very important role in painting and now construction means there is no going back. Just an increase in health and safety concerns and warnings.

Nothing is "safe". You read the warnings and make a risk assessment. This applies to crossing a road as much to using chemicals.

On topic - dopn't just judge on price. It also useful to have a supplier who has good service, good stocks and is reliable. "Cheap" normally means something is missing from the true definition of quality.

[Boston]

I apologize for the ignorance and sarcasm of my protagonist and the terse
nature of my response

I wish only to interject the consideration of toxicity
some products being less than others

Ild recommend
Oak & Teak Epoxy Glue
http://www.smithandcompany.org/OT/UsingOT.html

it adheres to the difficult to stick to woods and is less out gassing
the less it out gas's the more stable it is and the longer it lasts
and the less of it ends up inside of you
cant remember what it costs but it does stick well
although it may be a bit much if your only gluing ply and mat

being new here myself I was completely shocked any one would scoff at the consideration of environmental factors in choosing something like glue
the more I think about it
the more surprised I get
its been about thirty years since anyone seriously argued that plastics which contain bysphinol-a do not for instance photo degrade and release that chemical
or release it through other means
like food or skin contact

one of those articles notes that byshenol was found in 100% of samples taken from workers in factories were its use was common
100%
what more need be said
100%
thats pretty compelling
it deserves a mention
and it deserves a consideration

an environmental endocrinologist friend at cu recently received $1,500,000 to find an effective expiration date for bottled water
( I coulda used it to improve my grammar )
as the plastic leaches contaminants into fluids at an alarming rate

this same scientist also worked with others bringing a case to the Canadian
government which instigated the proceedings leading to the ban on all polycarbonate's for food contact
that one is still coming down the pipes but the offending ingredient is bysphenol-a

no one is arguing this
Ive just never heard it before
and hours after reading that response I am just in awe
Ive got to save that and send it to some of the guys at the university

Ill leave it at that and hope you have a great time on your new boat
best wishes
B

[Boston]

do more home work people

[Boston]

my bad
I just got an urge to go look up what Ild paid for that stuff
it was an arm and a leg
keep looking friend
and best of luck
B

[Jimbo1490]

Originally Posted by Boston

I apologize for the ignorance and sarcasm of my protagonist and the terse
nature of my response

B

Terse???!!! You've gotta be kidding!!! You're about the most VERBOSE poster I've ever seen on this board!



Go look up terse in a dictionary; terse you are not!

Jimbo

[Jimbo1490]

Kengrome,

Your application is pretty straightforward as far as the handling properties you need for hand layup. But you haven't stated what kind of working time or pot life you expect. Is it a big layup that needs to be completed and cured up together in one shot? Or is the layup small, or one that you expect to be able to break up into smaller layups with peel-ply between?

If you need anything special WRT cured state properties is another question. High temperature service? Extra hardness? Fracture toughness? How about worker safety? Some of the amines are very toxic.

The expected batch size counts, too since epoxy does exotherm in big batches. So if you are dispensing from a metering system, especially one with static mixing, you could get away with a higher reactivity systems without running into pot life problems than you could if workers are expected to measure and mix or even pump then mix, beacause you can dispense and mix a squirt at a time so that pot life is maximized.

There are so many different amine curing agents out there that if you are looking for the *perfect* choice, there's probably no substitute for careful study of data sheets as well as doing some sample layups.

Polyamides might be good choices IF you do not need the highest cured state performance in the resin. They offer the advantage of being very low toxicity compared to just about any amine agent. But they are typically viscous, degrading the handling properties somewhat. The more so since their AHEW numbers mean you typically need more for stoichiometry, thus adding significant viscosity. But the BPF resin starts out with higher reactivity and low viscosity so this is just the sort of trade-off in properties that you might welcome. Polyamides improve flexibility and toughness, but typically have poor HDT performance.

A couple of the modifiers work exceptionally well in Epon 862. Heloxy 68 and 61 come to mind. Both of these not only improve viscosity but also make the cured resin tougher with higher elongation and flexibility. This is especially useful with certain amines since they tend to produce a rather brittle cured state (albeit with high UTS) especially with elevated temperature cure.

I seem to recall there were a couple of Shell Resin's "Starting Formulations" that used 862, a Heloxy modifier and an amine blend for high performance hand layup. Maybe you could get the boys at Hexion to look them up for you. They took them off of their website a few years back

Don't forget to consider the curing agents from other manufacturers like Air Products and Chemicals. The also make a very wide range and are very helpful with both samples and formulation info.

The manufacturer's rep can most likely help you make an informed choice since he will be (should be ) familiar with the numbers for his product line. Be as detailed as you can when making an inquiry as each little detail of your process can affect the selection of that 'goldilocks' curing agent.

Jimbo