Skip to Main Content
Sign In
Toggle Navigation

Open the Navigation Management window, which can be used to view the full current branch of the menu tree, and edit it.

CONNECT
  • Instagram
  • Facebook

MITRA Forum Question Details

Image Picker for Section 0

 ForumQuestion

  • vinyl as binderApproveRejectUn-ApproveSubscribeUn-Unsubscribe
    Question asked 2018-02-01 08:27:20 ... Most recent comment 2018-02-06 10:36:50
    Paint Making Acrylic Other
    Question

    ​Hi,

    At the moment I am testing Chroma Color from a Spanish factory called La Pajarita. It seems Artists like Dali have made use of their paint. I am trying to find out if it would be suitable for our Shop in School, of my Art Academy.

    The one thing I am concerned about is that it is made with vinyl in stead of acrylic. I was under the impression that acrylics are superior to vinyls. As far as I know the plastcisers in acrylics are internal and often in pva's external, am I right?

    According to them, however, when they were considering transition from vinyl to acrylic as a binder, their vinyl tested better then most of the acrylics from their competitors. And that is why they stayed with vinyl.

    My knowledge is too limited, here. So I hope you people can help me out.


    Thanks


Answers and Comments
  • EditDeleteModerator Answer

    Here are my best guesses: According to their site, the manufacturer offers both craft-grade and fine art-grade paints,​ and lists the one you mention among the latter, so they are representing it for permanent art. There are PVA products including adhesives and sizings that meet this standard, so personally I don't see any reason to be particularly suspicious of their claim of durability. Any speculation on plasticizers would be a guess without information from the source, and they might be averse to sharing something they regard as a proprietary secret. It's possible another Moderator will know more about what plasticizers are currently used with vinyl-based emulsions/dispersions. (I think it's pretty unlikely that the formula has gone unchanged since it was used by Dalí.)

    Matthew Kinsey, Utrecht Art Supplies
    2018-02-01 21:02:47
  • ApproveRejectUn-ApproveUser Comment

    ​Vinyls have somewhat notoriously low glass transition temperatures, although they can vary, from 16 C or 60 degrees F to 26 C or 79 degrees F see CAMEO http://cameo.mfa.org/wiki/Vinylite ) . A low Tg indicates that the material changes phase from a solid to a glass to a fluid at temperatures that could approach warm, summer room temperatures. Years ago conservators used to make their own inpainting pan paints using the AYA series of PVA resins and then activate them with polar solvents. They had excellent pigment dispersion characteristics as well as The almost universal problem was that the PVA's all started to "flow" at 75 degrees F, 24 degrees C and would sag and quickly absorb dust and airborne dirt. These low Tg properties may have led many manufacturers to question the durability of the media for oil painting.

    2018-02-02 12:45:44
  • EditDeleteModerator Answer

    I fear there is just not enough information to go on. What type of testing did they do? Following what standards? Can they share the results in a quantified manner? All of those things would be important to give their statement about the vinyl paints as doing better some weight and backing. At the same time, i t is good to realize that vinyls encompass a very wide field of chemistries and polymers and making generalities just isn't valuable because it glosses over precisely those fine points that can make all the difference. Just to take one example of the problem with generalizations, prior to the 1960 most vinyls were plasticized externally - meaning a separate plasticizer was added to a single, or homopolymer, binder - and these generally had issues with the plasticizer being volatile , leaving the system over time, and becoming increasingly brittle as a result. Because of that, more modern formulations have generally gone to a copolymer system where the harder vinyl is joined with a softer resin (hence "co-polymer") to allow for a more stable and flexible system without the concern around plasticizers evaporating away. And of course there are many possible combinations of copolymers, complicating all of this further. But, and here is a good illustration of the danger in just these types of generalizations, a PhD thesis I link to below concluded that the homopolymer formulations in the paints they were studying appeared more stable than the copolymer ones. So.....what can I say....its complicated.

    If interested in pursuing this further you might want to take a look at the following papers, PhD thesis, and book:

    A preliminary study of the composition of commercial oil, acrylic and vinyl paints and their behaviour after accelerated ageing conditions


    The perfect paint in Modern Art Conservation: A comparative study of 21st century vinyl emulsions


    Modern Paints Uncovered

    Unfortunately none of these will provide a definitive answer to your question. The book Modern Paints Uncovered is good to the extent that it covers several case studies involving artwork done with vinyl paints, and so gives some examples of the types of analysis and concerns conservators are involved in.

    In the end, as in so much around art materials, it comes down to the trust in the company, the testing they have done, and how much they are willing to share. Also, keep in mind, the vast majority of research around the durability of vinyls has happened in the context of commercial housepaints, where  the vulnerability of vinyls in exterior applications and UV exposure are well documented. Which is also why nearly every exterior housepaint you will find are formulated with 100% acrylic, while interior paints will use the less expensive vinyls. But these types of concerns might be moot for a work meant indoors.

    Sarah Sands, Senior Technical Specialist, Golden Artist Colors
    2018-02-03 11:14:06
  • EditDeleteModerator Answer

    Sarah

    As usual, your post is filled with dispassionate facts.

    I agree that there is just not enough info to draw any real conclusions about the performance of these paints. PVA solutions are rather simple and the Tg is a result of polymer chain length. Emulsions and dispersions of PVA can run the gamut depending on a huge variety of factors and the influence of other ingredients. Some PVAs may exhibit cold flow at room temp and others will not. As an illustration, has anyone ever seen cold flow in dried white glue like Elmer’s (a dispersion of PVA and many other proprietary ingredients)? I have not.

    Brian Baade
    2018-02-03 12:49:33
  • ApproveRejectUn-ApproveUser Comment

    What a great forum this is, thank you!​ So up front one cannot say that PVA's are not suited for art. But is it save to say that in general it is safer to go with acrylics than with PVA's?

    I understand that the La Pajarita paint might very well be a very fine paint. But knowing our students, would it be safe if they would mix this PVA-paint with the regular acrylics?

    2018-02-06 09:07:02
  • EditDeleteModerator Answer

    We do know that acrylic dispersion paints are often superior to PVA dispersion paints but there is no way to say that a particular paint is better or worse without far more info about ingredients and formulations.  

    It does seem fine to mix this paint with acrylic dispersion paints.

    Brian Baade
    2018-02-06 10:36:50
Page Settings and MetaData:
(Not Shown on the Page)
Page Settings
question
No
MetaData for Search Engine Optimization
MITRA Forum Question Details
restricted
This page cannot be accessed until you accept the Terms of Use, which can be found here.
Please note that this Terms of Use system uses cookies. If you have cookies disabled you will not be able to accept the agreement. If you delete our cookies you will need to re-accept the Terms of Use.
  • The Department of Art Conservation
  • 303 Old College
  • University of Delaware
  • Newark, DE 19716, USA
  • Phone: 302-831-3489
  • art-conservation@udel.edu