3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexane carboxylate

from Wikipedia, the free encyclopedia
Structural formula
Structure of 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexane carboxylate
Complex mixture of stereoisomers - structural formula without stereochemistry
General
Surname 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexane carboxylate
other names
  • 7-oxabicyclo [4.1.0] hept-3-ylmethyl-7-oxabicyclo [4.1.0] heptane-3-carboxylate
  • ECC
Molecular formula C 14 H 20 O 4
Brief description

colorless and odorless, viscous liquid

External identifiers / databases
CAS number 2386-87-0
EC number 219-207-4
ECHA InfoCard 100.017.463
PubChem 16949
Wikidata Q19694494
properties
Molar mass 252.306 g mol −1
Physical state

liquid

density

1.17 g cm −3

Melting point

−37 ° C

solubility

slightly soluble in water (13.85 g l −1 at 20 ° C)

Refractive index

1.498 (20 ° C)

safety instructions
GHS labeling of hazardous substances
07 - Warning

Caution

H and P phrases H: 317
P: 280
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

3,4-Epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexane carboxylate (ECC) is a cycloaliphatic epoxy resin that has numerous industrial uses. It is converted into crosslinked, insoluble thermosets through cationic polymerization with the aid of thermolatent photoinitiators . Formulations based on cycloaliphatic epoxy resins such as ECC are known to convert to thermosets with high heat and chemical resistance and good adhesion through hardening .

history

The homopolymerization of 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate is based on cationic radiation curing , which proceeds via a photochemical formation of a super acid and subsequent cationic polymerization. This was first recognized in the 1970s.

Manufacturing

3,4-Epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate can be produced via a Claisen-Tiščenko reaction with subsequent epoxidation using a peracid .

properties

3,4-Epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate has a dynamic viscosity of 400 mPas at 25 ° C.

Reactivity

For homopolymerization, 1.5 to 3 wt.% Of an initiator are added to the monomer 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate  . No more acceleration was found above 3 wt% initiator, but increasing proportions of initiators increase the brittleness of the thermoset. After photopolymerization, post-curing is usually necessary for complete curing.

It is known that the reactivity of the monomer is less than it could be, since the ester group it contains reacts with the reactive chain end and thus stabilizes it. It therefore reacts much more slowly than other molecules without an ester group. The rate of polymerization of ECC is also significantly slower than that of radical monomers. It is therefore the aim of research to invent cationic systems with higher polymerization rates but the same performance.

Networked ECC

Cationically crosslinked 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate is used in a variety of industrial applications because of its low viscosity, excellent electrical properties and high reliability as an electrical insulator, coating and adhesive or printing ink. However, homopolymerized ECC is extremely brittle , which is disadvantageous. This problem can be countered by integrating elastomer particles into the epoxy matrix, such as rubber or silicone, by integrating inorganic fillers or by plasticizing due to the polymerization in the presence of polyester polyols. The latter are also covalently integrated into the polymer network via the activated monomer mechanism .

safety instructions

3,4-Epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate was included in the EU's ongoing action plan ( CoRAP ) in 2013 in accordance with Regulation (EC) No. 1907/2006 (REACH) as part of substance evaluation . The effects of the substance on human health and the environment are re-evaluated and, if necessary, follow-up measures are initiated. The reasons for the uptake of 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate were concerns regarding exposure of workers and the high risk characterization ratio (RCR) as well as the dangers arising from a possible assignment to the group of CMR substances and the suspected dangers due to sensitizing properties. The reassessment started in 2013 and was carried out by Ireland . A final report was then published.

literature

Individual evidence

  1. ↑ a b c d e f Entry on 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate in the GESTIS substance database of the IFA , accessed on January 1, 2015(JavaScript required) .
  2. ↑ Data sheet 3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate from Sigma-Aldrich , accessed on March 24, 2015 ( PDF ).
  3. ↑ a b c d Hiroshi Sasaki: Curing properties of cycloaliphatic epoxy derivatives . In: Progress in Organic Coatings . 58, No. 2-3, February 2007, pp. 227-230. doi : 10.1016 / j.porgcoat.2006.09.030 .
  4. ^ JV Crivello, JHW ​​Lam: Dye-sensitized photoinitiated cationic polymerization . In: Journal of Polymer Science: Polymer Chemistry Edition . 16, No. 10, October 1978, pp. 2441-2451. doi : 10.1002 / pol . 1978.170161004 .
  5. ^ Brian Dillman, Julie LP Jessop: Chain transfer agents in cationic photopolymerization of a bis-cycloaliphatic epoxide monomer: Kinetic and physical property effects . In: Journal of Polymer Science Part A: Polymer Chemistry . 51, No. 9, May 1, 2013, pp. 2058-2067. doi : 10.1002 / pola.26595 .
  6. ↑ a b Atsushi Udagawa, Yasuhiko Yamamoto, Yoshio Inoue, Riichirô Chûjô: Dynamic mechanical properties of cycloaliphatic epoxy resins cured by ultra-violet and heat-initiated cationic polymerizations . In: polymer . 32, No. 15, January 1991, pp. 2779-2784. doi : 10.1016 / 0032-3861 (91) 90108-U .
  7. ↑ James V. Crivello, Ulrike Varlemann: Mechanistic study of the reactivity of 3,4-epoxycyclohexylmethyl 3 ′, 4′-epoxycyclohexanecarboxylate in photoinitiated cationic polymerizations . In: Journal of Polymer Science Part A: Polymer Chemistry . 33, No. 14, October 1995, pp. 2473-2486. doi : 10.1002 / pola.1995.080331421 .
  8. ↑ Cristina Mas, Ana Mantecón, Angels Serra, Xavier Ramis and Josep Maria Salla: Improved thermosets obtained from cycloaliphatic epoxy resins and γ-butyrolactone with lanthanide triflates as initiators. I. Study of curing by differential scanning calorimetry and Fourier transform infrared . In: Journal of Polymer Science Part A: Polymer Chemistry . 43, No. 11, June 1, 2005, pp. 2337-2347. doi : 10.1002 / pola.20711 .
  9. ↑ Hendrik Lützen, Peter Bitomsky, Kurosch Rezwan, Andreas Hartwig: Partially crystalline polyols lead to morphology changes and improved mechanical properties of cationically polymerized epoxy resins . In: European Polymer Journal . 49, No. 1, January 2013, pp. 167-176. doi : 10.1016 / j.eurpolymj.2012.10.015 .
  10. ^ Emmanouil Spyrou: Radiation initiated cationic polymerization with tailor-made polyesters . In: Progress in Organic Coatings . 43, No. 1-3, November 2001, pp. 25-31. doi : 10.1016 / S0300-9440 (01) 00240-5 .
  11. ^ Yusuf Yagci, Wolfram Schnabel: On the mechanism of photoinitiated cationic polymerization in the presence of polyols . In: Applied Macromolecular Chemistry . 270, No. 1, September 1, 1999, pp. 38-41. doi : 10.1002 / (SICI) 1522-9505 (19990901) 270: 1 <38 :: AID-APMC38> 3.0.CO; 2-S .
  12. ↑ European Chemicals Agency (ECHA): Substance Evaluation Conclusion and Evaluation Report .
  13. ↑ Community rolling action plan ( CoRAP ) of the European Chemicals Agency (ECHA): 7-oxabicyclo [4.1.0] hept-3-ylmethyl 7-oxabicyclo [4.1.0] heptane-3-carboxylate , accessed on March 26, 2019.