Before working with this product, you must read and become familiar with the available information on its risks, proper use, and handling. Information is available in several forms, e.g., in particular in the currently valid safety data sheets and product labels. For further information contact your Covestro representative.
Product description
Desmophen 650A-65 PMA is a saturated polyester resin.
Applications
Desmophen 650A-65 PMA polyester is used as a coreactant for Desmodur N polyisocyanate two-component polyurethane coatings. Finishes based on Desmophen 650A-65 PMA polyester and Desmodur N polyisocyanates are well-suited for uses requiring light stability and weatherability as well as good chemical and abrasion resistance. Suitable substrates include metal, concrete, wood, plastics and paper. Adequate substrate preparation is advisable before using coatings containing Desmophen 650A-65 PMA polyester.The drying times of coatings based on Desmodur N polyisocyanate and Desmophen 650A-65 PMA polyester can be reduced by the addition of catalysts. Suitable catalysts include Desmorapid PP (0.2-0.5% based on solid resin) and dibutyl tin dilaurate (.003-.005% based on solid resin). Such additions reduce the potlife of the formulation and should be evaluated prior to use.The flow of systems containing Desmodur N polyisocyanate and Desmophen 650A-65 PMA polyester can be inmproved by additions of cellulose acetate butyrate resins such as CAB 381-0.1 (0.2% based on resin solids) or certain types of silicone fluids such as Baysilone Paint Additive OL-17 (0.05-0.2% based on resin solids). As with any product, use of Desmophen 650A-65 PMA in a given application must be tested (including but not limited to field testing) in advance by the user to determine suitability.
Form supplied
It is supplied in propylene glycol monomethyl ether acetate and xylene (6:1).
Specification
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Solids | 65 ± 3 | % | ||
| Water content | ≤ 0,1 | % | ||
| Viscosity | at 25°C | 10,000 - 20,000 | mPa∙s | |
| Acid number | ≤ 3,0 | |||
| Color | (Gardner) | ≤ 2,0 | ||
| Hydroxyl number | 155 - 190 |
Typical Values
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Appearance | Light yellow liquid | |||
| Specific gravity | at 25°C | 1,14 | ||
| Equivalent weight | avg. (as supplied) | 325 | ||
| OH content | 5,2 | % | ||
| Flash point | (Setaflash) | 42 | °C | |
| Weight per Gallon | at 25°C | 9,5 | lb. |
Solubility / thinnability
Desmophen 650A-65 PMA polyester is soluble in esters such as ethyl acetate, in ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol, and in glycol ethers such as PM Acetate. Butyl acetate is unsuitable for use as the sole solvent. Desmophen 650A-65 PMA polyester is insoluble in aromatic and aliphatic hydrocarbons. However, it is possible to incorporate aromatic hydrocarbons such as tolune and xylene as diluents.
Compatibility
Desmophen 650A-65 PMA polyester is compatible with Desmodur® N 75A BA/X, N 100A, and N 3200A aliphatic polyisocyanates. It is incompatible with Desmodur N 3300A and 3390A BA/SN polyisocyanates, yielding hazy films and low gloss. Desmophen 650A-65 PMA polyester has only borderline compatibility with most polyester and acrylic resins. Desmophen R-221-75 polyester can be used at levels up to 10% of the Desmophen 650A-65 PMA resin solids as a pigment dispersing resin.
Storage
Desmophen 650A-65 PMA should be stored in tightly sealed containers and protected from moisture, heat, and foreign materials. The product is hygroscopic. Recommended storage temperature is at maximum 30°C.
Storage time
Desmophen 650A-65 PMA has a shelf life of six months after receipt of material by customer, provided the material is stored in sealed original containers.
Health and Safety Information
Disclaimer
General
The manner in which you use our products, technical assistance and information (whether verbal, written or by way of production evaluations), including any suggested formulations and recommendations, are beyond our control. Therefore, it is imperative that you test our products to determine suitability for your processing and intended uses. Your analysis must at least include testing to determine suitability from a technical, health, safety, and environmental and regulatory standpoint. Such testing has not necessarily been done by Covestro, and Covestro has not obtained any approvals or licenses for a particular use or application of the product.
Unless we otherwise agree in writing, all products are sold strictly pursuant to the terms of our standard conditions of sale which are available upon request.
All information and including technical assistance is given without warranty or guarantee and is subject to change without notice. It is expressly understood and agreed by you that you assume and hereby expressly release indemnify us and hold us harmless from all liability, in tort, contract or otherwise, incurred in connection with the use of our products, technical assistance, and information. Any statement or recommendation not contained herein is unauthorized and shall not bind us. Nothing herein shall be construed as a recommendation to use any product in conflict with any claim of any patent relative to any material or its use. No license is implied or in fact granted under the claims of any patent.
Non Medical and non Food Contact
This product is not designated for the manufacture of a medical device or of intermediate products for medical devices (1). This product is also not designated for other specifically regulated applications (e.g. including cosmetics, plant protection, fertilisers, plant strengtheners, food processing, food contact and others). If the intended use of the product is for the manufacture of a medical device or of intermediate products for medical devices or for other specifically regulated applications Covestro must be contacted in advance to provide its agreement to sell such product for such purpose. Nonetheless, any determination as to whether a product is appropriate for use in a medical device or intermediate products for medical devices, for Food Contact products or cosmetic applications must be made solely by the purchaser of the product without relying upon any representations by Covestro.
1) Please see the Guidance on Use of Covestro Products in a Medical Application document.
Sample
Any samples provided by Covestro are for testing purposes only and not for commercial use.
Typical value
These values are typical values only. Unless explicitly agreed in written form, they do not constitute a binding material specification or warranted values
Contact
Please use our contact form or contact us directly by sending an e-mail to technical-datasheets@cx.covestro.com .
