Desmophen - Polyester

Covestro Desmophen® T1775 SN Oil-Free Hydroxy Polyester

type	Oil Free Hydroxy Polyester
form of supply	About 75% solvent naphtha 100 solution
use	It is used as a polyol component in combination with a blocked aliphatic polyisocyanate to prepare a light-fast one-component polyurethane baking coating. The base material has been identified as meeting the requirements for food contact materials in combination with blocked aliphatic polyisocyanates* and is suitable for the preparation of can coatings for food packaging. *Instructions regarding the application of food contact materials will be provided upon customer request and only reflect current knowledge and comply with applicable food regulations in each country.

Specifications

characteristic	Numerical value	Units of measurement	method
Color value	≤80		DIN EN 1557
Acid value	≤5	mg KOH/g	DIN EN ISO 2114
Viscosity, 23 ℃	3700±600	mPa·s	DIN EN ISO 3219/A.3
Non-volatile components (2g resin/2ml toluene/1h/125℃, convection oven)	75±2	％	DIN EN ISO 3251
Hydroxyl content	2.0±0.4	％	DIN 53 240/2

other data**

characteristic	Numerical value	Units of measurement	method
equivalent	约850
Density, 20℃	约1.08	g/ml	DIN EN ISO 2811-2
Flash point	约48	℃	DIN EN ISO 1523

**The above values are general information and not part of product specifications.

Dilutable

Desmophen® T 1775 SN is typically diluted to 35% solids with the following solvents, including esters, ketones, ether esters and aliphatic hydrocarbons, including high boiling aromatic hydrocarbon mixtures such as solvent naphtha 100, 150 and 200. Aliphatic hydrocarbons and low boiling alcohols are not suitable as diluents. Diluted solutions should be tested for compatibility and storage stability.

compatibility
Desmophen® T 1775 SN is miscible with Alkydal® F251 and F300, Desmophen® T 1665, Desmophen® 680, 1200, 1300 and RD 181 in a mixing ratio of 2:1 (solids to solids). This product is miscible with the following products if equivalently crosslinked: Desmodur® BL1265, BL3175, BL3272, BL3370, BL347 and BL4265, N75, N3200, N3390 and Z4470. However, if unblocked polyisocyanates are used, the construction time will be significantly shortened.
The compatibility of the formulated solutions must be tested.
Application Desmophen® T 1775 SN has been specially developed for use with blocked isocyanates in coil coating systems. One-pack polyurethane coil coatings prepared especially with Desmodur BL4265 have a well-balanced hardness/flexibility ratio, good scratch and abrasion resistance and excellent QUV/B (ultraviolet light, 313 nm) wavelength) stability. Experiments have shown that dibutyltin dilaurate is suitable for use as a catalyst. Based on the solid base material, the added amount should be 0.1-1%.
This product can be mixed with other blocked isocyanates and hexamethoxymethyl melamine amino resins. However, such formulations are generally not as high as the surface hardness obtained with Desmodur® BL4265. Desmophen T 1775 SN can be mixed with Desmodur® BL4265 or Desmodur® VP LS 2078 to prepare autoclavable primers and varnishes for external use in cans.
Mixed with an appropriate cross-linking agent, it is certified for use in food contact materials - preparation of can lining coatings for food packaging. Baking conditions mixed with Desmodur® BL4265 and using dibutyltin dilaurate (DBTL) as catalyst were sufficient to ensure adequate crosslinking at a maximum metal plate temperature (PMT) of approximately 232°C.

store
This product is stable for at least 6 months when stored in an airtight container under appropriate conditions.

Safety
Hazardous and flammable. Irritating to the respiratory system. Repeated exposure may cause dry or cracked skin.
Vapors may cause dizziness and dizziness.
The Safety Data Sheet (309463) should be read carefully. This Safety Data Sheet includes information on labelling, transportation and storage, as well as information on product use, product safety and ecology.