Up to now, the solvents most currently used for cleaning were :

• chlorinated solvents
• CFC

For whatever cleaning process :

• cold cleaning
• vapour cleaning

Today the most used products are :

• methylene chloride : CH₂ Cl₂
• trichlorethylene : CHCl = C Cl₂
• perchlorethylene : C Cl₂ = C Cl₂
• 111-trichlorethane : C Cl₃ - CH₃
• CFC 113 : C F Cl₂ - C F₃ Cl
• CFC 111
• CFC 141 b : CH₃ - C Cl₂ F

LIMITATIONS AND PROBLEMS LINKED
TO THE USE OF CHLORINATED SOLVENTS

Legislations

---

Interdiction of use and production	Montreal Protocol 87 Review London 90 +Copenhagen 92	CE Agreement 29.12.1992
111-trichloroethane CFC 113 CFC 111 HCFC 141 b	01/01/1996 01/01/1996 01/01/1996 01/01/2030	01/01/96 01/01/1995 01/01/2015 + limits of use (article V)

Other legislations:

Germany : the Netherlands : England : U.S.A. :

2 Blm Sch. V KWS 2000 Environmental Protection Act BT N EEC Clean Air Act

} } very severe }

EuropeanDirectiveunder

vote in

negotiation { 1998 ? { { 1999 ?

Toxicity

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TL V	Methylene chloride2	Trichloro ethylene	Perchlor- ethylene	111-trichloro- ethane
ppm V	50	50	25	350
mg/m3	174	264	170	1920
methylal 1000 PPM

Environment

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A. Ozone

• Stratosphere
  
  Useful ozone :
  • filters the UV-B rays
  • ozone transformed in oxygen by long life chlorinated derivatives
    ozone depletion
    holes in the ozone layer
    
    
• Troposphere
  
  Harmful ozone :
  • pneumological problems
  • all volatile solvents are concerned, but those miscible in water in smaller proportion
  • P.O.C.P.

B. Greenhouse effect

Solvents characterized by their GWP.

C. Acid rain

Chlorinated solvents are concerned in the phenomenon of acid rain.

D. Wastes

Waste containing more than 0,1 % of chlorinated solvent is TOXIC.

treatment by specialized center or authorized destruction

administrative problems


• balance of incoming / outgoing waste
• authorization
  
  high cost

E. Water pollution

Advantage of the biodegradability of acetals.


REPLACEMENT OF CHLORINATED SOLVENTS

There is no ideal solvent to replace 111-trichlorethane.
A series of 10 to 20 different solvent mixtures is suggested to meet the specific requirements.

Possibilities :

A. Halogenated hydrocarbons

Problems :

• toxicity
  weak TLV
  
• use authorized until 2015
  (141 b)
  
• recycling / stabilization

B. Non-halogenated hydrocarbons

Inconveniences :

• flammability
  the flash point of HC evolves parallel to the boiling temperature
  
  

  high flash point	= low solvent power = slow drying
  toxicity : OEL ~ 300 / 500 ppm (TLV methylal = 1000 ppm)

C. Other

lactic acid esters : DBE modified alcohols : N.M.P.

costs mell low rate drying cost low rate drying low rate drying cost

CONCLUSION

None of the suggested solvents comprises all the qualities expected of a cleaning solvent.:

• solvent power
  
• non-flammability
  
• high drying rate
  
• absence of toxicity

And more particularly, none of them can reach a high drying rate.

The answer to this matter :
the acetals : Methylal - Dioxolane
used in pure or in blended form.

METHYLAL, even used in small proportion mixed with hydrocarbons, can improve

• the drying process
• the solvent and cleaning power
  
  in relation to
  • greases
  • silicones
  • waxes

FORMULATION GUIDELINES

Cleaning products

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SR 7	SPOT REMOVER FOR TEXTILES
BACL 1	BATHROOM CLEANER
CLD 1	CLEANER DEGREASER
CLD 2	CLEANER DEGREASER

Automotive

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BC 1	BRAKE CLEANER CO2 PROPELLED
CCL 1	DASH BOARD CLEANER
DCL 1	DASH BOARD CLEANER
DCL 2	DASH BOARD CLEANER
DCL3	DASH BOARD CLEANER
DCL4	DASH BOARD CLEANER
DCL5	DASH BOARD CLEANER

Cosmetic cleaning products

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HCL1	HAND CLEANING GEL
CC 1	NAIL VARNISH REMOVER
CC 2	LIQUID COSMETIC CLEANER