Cleaning compositions and methods for cleaning resin and polymeric materials used in manufacture

Compositions and methods for cleaning, solvating, and/or removing plastic resins and polymers or other contaminants from manufactured articles or manufacturing equipment, particularly in the production of optical lenses. The compositions contain at least one nitrogen containing compound as well as other optional solvents and additives. The compositions can be contacted with a surface to be cleaned in a number of ways and under a number of conditions depending on the manufacturing or processing variables present.

BACKGROUND OF THE INVENTION 
This invention relates to compositions useful in and methods for cleaning, 
solvating and/or removing plastic resins and polymers from manufactured 
articles or manufacturing equipment, such as in the production of optical 
lenses. More particularly, the invention relates to solvent and solvent 
mixtures used to remove residues and methods of removing residues of 
plastic lens resins and polymers from materials that come in contact with 
the polymers, such as, but not limited to, lenses, molds, holders, racks, 
tools, and equipment used in the process of manufacturing organic lenses. 
In recent years, plastic lenses have seen greater utility in eyeglass and 
camera lenses as well as in optical devices since they are lighter, 
dyeable, and more durable than lenses made from inorganic components. 
Original work focused on developing transparent plastic resins and 
polymers that possessed these better characteristics and had a refractive 
index similar to optical glass, which was approximately 1.52. A popular 
resin discovered for this use, and widely used commercially today, was a 
material obtained by subjecting diethylene glycol bisallyl carbonate 
(DEGBAC) (PPG Industries, Inc. Trademark "CR-39") to radical 
polymerization. This resin had various positive attributes of impact 
resistance, light weight, dyeability, and good machinability in cutting, 
grinding and polishing processes. The resin was found to have a refractive 
index of 1.50, which was lower than the refractive index for inorganic 
lenses, around 1.52. 
To achieve optical equivalence to the inorganic glass lenses, it was 
necessary to increase the central and peripheral thickness along with the 
curvature of the lens. This increased thickness was undesired among users 
of optical lenses despite the obvious positive benefits of the organic 
resin lens. Therefore, newer resins and polymeric materials have and will 
be developed containing higher refractive indexes that will result in 
thinner and lighter lenses. 
As a method for increasing the refractive index of plastic lenses, there 
are known methods comprising copolymerizing a monomer mixture by adding to 
a conventional monomer another monomer, which imparts a higher refractive 
index to the resulting polymer. The higher refractive index polymer and 
plastic lens obtained is required to not only have a high refractive index 
(&gt;1.49), but also exhibit good physical, mechanical and chemical 
properties as an optical lens. The art of manufacture of optical lenses 
from plastics involves the use of a number of polymers and copolymers of 
acrylates, methacrylates, methyl methacrylates, polycarbonates, 
phthalates, isocyanates, polyethers, urethanes and other monomer 
structures, that are well known and documented. Recent monomer art has 
included the use of a halogen molecule such as chlorine or bromine which 
will contribute to increasing the refractive index. 
The lens and polymer industry continues to evolve as work continues on 
developing higher refractive index materials. Recent work has involved the 
use of sulfur as a part of the polymer. Adding sulfur to the polymer 
matrix greatly increases the refractive index of the polymer in addition 
to maintaining the desirable physical and optical characteristics. The 
addition of sulfur also increases the chemical resistance of the polymer 
making it more difficult to clean the apparatus used to manufacture the 
optical lens. 
The method of producing a plastic lens is well documented. The lens is 
produced by a method in which a monomer mixture is cast into a casting 
mold formed of a glass, metal or plastic mold piece and a gasket made from 
an elastomer (typically ethylene-vinyl acetate copolymer) or metal. The 
polymer may contain an additive, which aids in initiating, controlling and 
polymerizing the monomers. The mold is then heated to a predetermined 
temperature for a predetermined period of time, and may or may not be 
irradiated by ultraviolet light, for instance, or subject to chemical 
treatments that assist in initiating or controlling the polymerization of 
the plastic lens in a desirable manner. The process continues for a 
predetermined period of time until the desired level of polymerization is 
achieved. The lens is then usually taken out of the mold by separating the 
mold pieces and gaskets and then subjected to further processing. 
The mold pieces and gaskets are usually very expensive items that require 
cleaning prior to reuse. Often the mold pieces will be contaminated with 
polymer which has overflowed to the external sides of the mold, thereby 
requiring cleaning. In addition this overflowed polymer will be found on 
the holders, racks, tooling, and any other apparatus or equipment used in 
the manufacturing process that comes in contact with the polymer. Because 
the design of the optical polymer attempts to ensure a lens product with 
tough physical characteristics and chemical resistance, any overflowed 
polymer will likewise also display these characteristics. Therefore, the 
removal of the overflowed material from equipment is very difficult and 
can be very costly if the cleaning technique used damages the tooling or 
equipment. 
Current art employs a number of methods to remove the polymer, which fall 
into three general methods. The first method is mechanical, where the 
polymer is removed from desired equipment, tooling, and molds by physical 
means of scraping and sandblasting. This method has drawbacks in that it 
is labor intensive, messy, time consuming, and many times can damage the 
delicate molds and equipment. The second method is thermal, in which the 
polymer is burned off in ovens or by heated media such as sand. This 
method is undesirable because of the cost of energy, the volatile organic 
compounds it produces, and the potential for fire. In addition, the 
elevated temperature required to clean some of the parts may physically 
affect the part and render them useless. The third method is chemical in 
which the molds, tooling, and/or equipment is contacted with a chemical 
solution that allows the polymer to be removed. This method is desirable 
since it is usually more cost effective in labor and time than the other 
two methods. 
Chemical cleaning methods for removal of undesired or overflowed polymer 
falls into the use of strong inorganic acids or alkali. Most commonly used 
in the art are strong inorganic acids, such as sulfuric, nitric, or 
hydrochloric acid. The oxidizing action of these acids is most effective 
at elevated temperatures and they are, therefore, used mainly at 
temperatures in excess of 140.degree. F. (60.degree. C.) in order to 
remove most of the undesired polymers. The drawback of the use of these 
acids is that they are hazardous materials, and can be very aggressive on 
most molds and equipment, thereby reducing the useful life. 
In most instances, special equipment, handling, and special rooms are 
required to operate the cleaning process. The use of alkali, such as 
alkali metal hydroxides such as sodium and potassium hydroxide, have also 
been found in the art. Like strong acids, these materials will have 
similar limitations and drawbacks, and seem likewise to only be effective 
in high concentrations at high temperatures. In high concentrations, these 
materials have a negative impact on glass molds and can be costly in 
reducing the useful life of the mold. U.S. Pat. No. 5,130,393 discusses 
the use of a combination of methylene chloride and strong alkali for 
cleaning molds and also for assisting in releasing the lens from the mold. 
No reference was made to the conditions and/or concentrations used in 
cleaning, nor was any mention made as to the effectiveness with polymers 
that contain sulfur and or halogens. 
SUMMARY OF THE INVENTION 
The present invention overcomes the problems and disadvantages that 
currently exist by providing a cleaning mixture and process for cleaning 
efficiently, which exhibits superior properties or results over the 
previous methods. It is an object of the invention to provide an 
efficient, cost-effective process for cleaning a broad range of polymers 
and resins used in manufacture of optical organic lenses, which may also 
be suitable for use on an industrial scale. 
The present invention relates to solvent and solvent mixtures and methods 
of removing residues of plastic lens resins and polymers from materials 
that come in contact with the polymers and/or resins such as, but not 
limited to, lenses, molds, holders, racks, tooling devices and equipment 
used in the process of manufacturing organic lenses. 
In one aspect, the invention relates to novel cleaning compositions 
containing at least one nitrogen containing compound and having a pH of 
about 7 or greater. The preferred compounds of the cleaning compositions 
are nitrogen containing compounds that also contain one hydroxyl group. 
Other beneficial materials that can be added are one or more of the 
following materials: water; alcohols; inorganic hydroxides; esters; 
ethers; cyclic ethers; ketones; alkanes; terpenes; dibasic esters; glycol 
ethers; pyrrolidones; or low or non-ozone depleting chlorinated and 
chlorinated/fluorinated hydrocarbons. The compositions may also be 
enhanced by one skilled in the art by adding buffering agents, 
surfactants, chelating agents, colorants, dyes, fragrances, indicators, 
inhibitors, and other ingredients to modify the properties. 
More specifically, the cleaning composition of the invention generally has 
a pH greater than 7.0, and contains an effective amount of the following 
compound: 
EQU N.sub.x C.sub.y H.sub.z O.sub.a (Formula I) 
where x=1 to 2, y=0 to 30, z=3 to 63, and a=0 to 4. Examples of these 
nitrogen containing compounds are amines, diamines, alkanolamines, 
quaternary ammonium hydroxides, ammonium hydroxide, and ammonia. 
Preferred compositions and methods to clean polymers and resins in 
accordance with this invention contain an effective amount of at least one 
quaternary ammonium hydroxide of the formula: 
##STR1## 
wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each, independently, an 
alkyl group containing from 1 to about 10 carbon atoms, aryl group, alkoxy 
group containing 1 to about 10 carbon atoms, or R.sub.1 and R.sub.2 are 
each an alkylene group joined together with the nitrogen atom to form an 
aromatic or non-aromatic heterocyclic ring, provided that if the 
heterocyclic group contains a --C.dbd.N-- bond, R.sub.3 is the second 
bond. 
In preferred embodiments, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each, 
independently, alkyl groups containing from 1 to about 10 carbon atoms 
and, in a more preferred embodiment, the alkyl groups contain from 1 to 4 
carbon atoms. Specific examples of alkyl groups containing from 1 to about 
10 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, 
heptyl, octyl, nonyl, and decyl groups. Examples of various aryl groups 
include phenyl, benzyl, and equivalent groups. 
Examples of specific preferred quaternary ammonium hydroxides, which can be 
used in the method of the invention, include tetramethylammonium 
hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, 
trimethylethylammonium hydroxide, methyltriethylammonium hydroxide, 
dimethyldiethylammonium hydroxide, methyltributylammonium hydroxide, 
methyl tripropylammonium hydroxide, tetrabutylammonium hydroxide, 
phenyltrimethylammonium hydroxide, phenyltriethylammonium hydroxide, and 
benzyltrimethylammonium hydroxide. Most preferred is tetramethylammonium 
hydroxide, tetrabutylammonium hydroxide, and tetraethylammonium hydroxide. 
In another preferred embodiment, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 in 
Formula II are each, independently, alkoxy and/or alkyl groups containing 
from 1 to about 10 carbon atoms and, in a more preferred embodiment, the 
alkoxy/alkyl groups contain from 1 to 4 carbon atoms. Specific examples of 
alkyl/alkoxy groups containing from one to 10 carbon atoms include 
methyl/methoxy, ethyl/ethoxy, propyl/propoxy, butyl/butoxy, 
pentyl/pentoxy, hexyl/hexoxy, heptyl/heptoxy, octyl/octoxy, nonyl/nonoxy, 
and decyl/decoxy groups. 
Examples of specific quaternary ammonium hydroxides, which can be used in 
the method of the invention, include trimethyl-2-hydroxyethyl ammonium 
hydroxide (choline), trimethyl-3-hydroxypropyl ammonium hydroxide, 
trimethyl-3-hydroxybutyl ammonium hydroxide, trimethyl-4-hydroxybutyl 
ammonium hydroxide, triethyl-2-hydroxyethyl ammonium hydroxide, 
tripropyl-2-hydroxyethyl ammonium hydroxide, tributyl-2-hydroxyethyl 
ammonium hydroxide, dimethylethyl-2-hydroxyethyl ammonium hydroxide, 
dimethyldi(2-hydroxyethyl) ammonium hydroxide, and 
monomethyltri(2-hydroxyethyl) ammonium hydroxide. 
The quaternary ammonium hydroxides useful in the invention may include 
cyclic quaternary ammonium hydroxides. By "cyclic quaternary ammonium 
hydroxide" is meant compounds in which the quaternary substituted nitrogen 
atom is a member of a non-aromatic ring of between 2 and about 8 atoms or 
an aromatic ring of from 5 or 6 atoms in the ring. That is, in Formula II, 
R.sub.1 and R.sub.2 together with the nitrogen atom form an aromatic or 
non-aromatic heterocyclic ring. If the heterocyclic ring contains a 
--C.dbd.N-- bond (e.g., the heterocyclic ring is an unsaturated or 
aromatic ring), then R.sub.3 in Formula II is the second bond. 
The quaternary nitrogen-containing ring optionally includes additional 
heteroatoms such as sulfur, oxygen or nitrogen. The quaternary 
nitrogen-containing ring may also be one ring of a bicyclic or tricyclic 
compound. The quaternary nitrogen atom is substituted by one or two alkyl 
groups depending on whether the ring is aromatic or non-aromatic, and the 
two groups may be the same or different. The alkyl groups attached to the 
nitrogen are preferably alkyl groups containing from 1 to 4 carbon atoms 
and more preferably methyl. The remaining members of the quaternary 
nitrogen ring may also be substituted if desired. Cyclic quaternary 
ammonium hydroxides useful in the process of the present invention may be 
represented by the following formula: 
##STR2## 
wherein R.sub.3 and R.sub.4 are each independently alkyl groups containing 
from 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, and more 
preferably methyl, and A is an oxygen, sulfur or nitrogen atom. When the 
heterocyclic ring is an aromatic ring (i.e., a --C.dbd.N-- bond is 
present), R.sub.3 is the second bond on the nitrogen. 
Cyclic quaternary ammonium hydroxides can be prepared by techniques well 
known to those skilled in the art. Examples of these hydroxides include: 
N,N-dimethyl-N'-methyl pyrizinium hydroxide; N,N-dimethylmorpholinium 
hydroxide; and N-methyl-N'-methyl imidazolinium hydroxide. Other cyclic 
quaternary ammonium hydroxides may be prepared from other heterocyclic 
compounds such as pyridine, pyrrole, pyrazole, triazole, oxazole, 
thiazole, pyridazine, pyrimidine, anthranil, benzoxazole, quinazoline, 
etc., or derivatives thereof. When a solution of the quaternary ammonium 
hydroxides as described above is used, most commercial sources of these 
compounds are aqueous and may contain from about 0.1 to about 60% by 
weight or more of the quaternary ammonium hydroxide. 
In this embodiment, the solution may comprise from about 0.01 to about 100% 
by weight of the aqueous quaternary ammonium hydroxide, or from about 0.01 
to about 60% by weight of the neat quaternary ammonium hydroxide. Aqueous 
solutions of the quaternary ammonium hydroxides are presently preferred in 
the practice of the method of the present invention. 
Other useful nitrogen containing compositions used to clean the optical 
polymers or resins in accordance with this invention comprise at least one 
nitrogen containing compound of the formula: 
##STR3## 
wherein R.sub.5, R.sub.6, and R.sub.7 are each independently hydrogen, 
hydroxyl, an alkyl group containing from 1 to about 10 carbon atoms, an 
aryl group, an amine group containing from 1 to about 10 carbon atoms, or 
an alkoxy group containing 1 to about 10 carbon atoms. 
In a preferred embodiment, R.sub.5, R.sub.6, are hydrogen and R.sub.7 is 
alkyl, alkoxy or amine groups containing from 1 to about 10 carbon atoms 
and, in a more preferred embodiment, the alkyl or alkoxy or amine groups 
contain from 1 to 6 carbon atoms. 
Examples of specific nitrogen containing compounds, which can be used in 
the process of the present invention, include ammonia, hydroxylamine, 
methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, 
triethylamine, monoethanolamine, diethanolamine, triethanolamine, 
1-amino-2-propanol, 1-amino-3-propanol, 2-(2-aminoethoxy) ethanol, 
2-(2-aminoethylamino) ethanol, 2-(2-aminoethylamino) ethylamine, 
ethylenediamine, hexamethyldiamine, 1,3 pentanediamine, 
n-isopropylhydroxylamine, 2-methylpentamethylenediamine, and the like, and 
other strong nitrogen containing organic bases such as guanidine. Most 
preferred are monoethanolamine, diethanolamine, triethanolamine, 
1-amino-2-propanol, ethylenediamine, hexamethyldiamine, 1,3 
pentanediamine, n-isopropylhydroxylamine, and 2-methyl, 
pentamethylenediamine. 
The nitrogen containing compounds useful to clean the optical polymers and 
resins in accordance with this invention are soluble in various solvents, 
such as water, alcohols, aqueous inorganic hydroxides, esters, ethers, 
cyclic ethers, ketones, alkanes, terpenes, dibasic esters, glycol ethers, 
pyrrolidones, or low or non-ozone depleting chlorinated and 
chlorinated/fluorinated hydrocarbons. Thus, the composition or mixture 
utilized in the process of the invention, and which comprises one or more 
of the above-described nitrogen containing compounds, may be dissolved in 
any one or more of the before-mentioned solvents as an additional 
component of the cleaning composition. The detailed description below 
provides a non-limiting disclosure of the additional components that may 
be selected. The compositions of the invention, thus, may also include one 
or more of the above-mentioned solvents. Aqueous solutions of the 
quaternary ammonium hydroxides, organic amines and alkanolamines are 
preferred in the practice of the invention, but other solvents may be used 
in conjunction with them. The form the compositions are in when used for 
cleaning may vary from liquid at various temperatures, to vapor, to 
aerosol, or other dispersions appropriate for the components of the 
composition selected. Buffers, corrosion inhibitors and other additives 
may also be included in the cleaning compositions of the invention. 
The polymer to be removed from a surface or cleaned by this invention can 
be any polymeric substance that is used in the manufacture of optical 
products that has a refractive index greater than 1.49. In industrial 
practice, the most common is a polymeric material obtained by subjecting 
diethylene glycol bisallyl carbonate (DEGBAC) (PPG Industries, Inc. 
Trademark "CR-39") to radical polymerization. This material may be 
copolymerized with any number of other monomers including but not limited 
to acrylates, methacrylates, methyl methacrylates, polycarbonates, 
phthalates, isocyanates, polyethers, urethanes. 
Other popular polymers or resins that can be cleaned from or removed from 
manufacturing parts or manufactures articles by this invention include any 
acrylate, methacrylate, methyl methacrylate, polyester, polystyrene, 
polycarbonate, phthalate, isocyanate, polyether, urethane, thio or sulfur 
containing polymers, and halo or chlorine and/or bromine containing 
polymers. 
Specific examples of parts or articles cleaned by the process or 
compositions of this invention include lenses, molds, gaskets, holders, 
racks, tooling and equipment used in the process of manufacturing lenses 
made of one or more organic compounds. Contacting a cleaning composition 
to an article may be through a conventional process or means known in the 
art that includes but is not limited to those employing: wiping; spraying; 
immersing; high pressure spray agitation; ultrasonic agitation; vapor 
degreasing; and soaking. The equipment to perform these processes are 
known in the art or can be devised from other fields where applying a 
composition to a solid surface is involved. The process may be conducted 
at ambient conditions and temperature or up to the boiling point of the 
selected cleaning composition. Generally, temperature ranges from about 
32.degree. F. (0.degree. C.) to about 212.degree. F. (100.degree. C.) are 
used. The temperature used may also be determined by the selection of the 
manner of contacting the cleaning composition to the surface to be 
cleaned. The process is most commonly conducted at atmospheric pressure, 
but may be conducted at elevated pressure, in a vacuum, or at lower than 
atmospheric pressure conditions. 
The part or article is contacted with the desired cleaning composition for 
an adequate period of time in order to essentially remove the contaminant 
or remove the desired amount of the contaminant. The part or article can 
also be called a "surface" that is to be cleaned. It is not necessary for 
every detectable trace of a contaminant to be removed from the surface. 
The contaminant may be a resin or polymer from manufacturing, present in 
an amount ranging from a residue to a clearly visible amount. The 
contaminant may also be oils, grease, or other compositions that come into 
contact with a manufacturing part, the manufactured article, or the 
surface to be cleaned. 
It may, in most instances, be necessary or desirable to rinse the cleaning 
composition from the part or article with water or with one of the 
solvents listed above, or with any combination of water and solvents. One 
skilled in the art can devise numerous combinations of cleaning 
compositions and rinsing solutions from this disclosure and the known 
properties of the chemicals used. In addition, one skilled in the art can 
devise simple tests to determine the appropriate rinsing conditions for a 
cleaning composition selected. It is common in the art to select a rinsing 
solution that will effectively remove all of the cleaning agent or 
composition and allow the rinsing solution to dry from the part either 
through the use of moving air, heated air and/or natural evaporation. 
Compounds that affect the odor of a surface being cleaned, that inhibit 
the corrosion of the surface, that act as a surfactant can also be added 
to the cleaning compositions or rinsing solutions and used in the cleaning 
methods. 
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
In accordance with the invention, novel compositions have been used to 
clean manufacturing parts or manufactured articles having contaminating 
polymers or resins. The compositions of the invention comprise at least 
one nitrogen containing compound and have a pH of 7.0 or greater. The 
preferred materials of the disclosure are nitrogen containing compounds 
that also contain one hydroxyl group. The summary above discloses Formulae 
I-IV and the general structure of the nitrogen containing compound of the 
compositions and methods of the invention. 
Other materials that can be added to make a mixture as the composition 
and/or used in the method of the invention are one or more of the 
following materials: water; alcohols; inorganic hydroxides; esters; 
ethers; cyclic ethers; ketones; alkanes; terpenes; dibasic esters; glycol 
ethers; pyrrolidones; or low or non-ozone depleting chlorinated and 
chlorinated/fluorinated hydrocarbons. The resulting mixture may also be 
enhanced by one skilled at the art by the addition of buffering agents, 
surfactants, chelating agents, colorants, dyes, fragrances, indicators, 
inhibitors, and other ingredients to modify the properties of the mixture. 
Preferably, the alcohol component of the mixture disclosed above contains 
an effective amount of the alcohol material of the formula C.sub.x H.sub.y 
(OH).sub.z where x=1 to 18, y&lt;2x+2 and z=1 or 2. Examples of these 
alcohols are methanol, ethanol, propanol, isopropanol, butanol, 2-butanol, 
tert butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, methyl propanol, 
methyl butanol, trifluoroethanol, allyl alcohol, 1-hexanol, 2-hexanol, 
3-hexanol, 2-ethyl hexanol, 1-pentanol, 1-octanol, 1-decanol, 1-dodecanol, 
cyclohexanol, cyclopentanol, benzyl alcohol, furfuryl alcohol, 
tetrahydrofurfuryl alcohol, bis-hydroxymethyl tetrahydrofuran, ethylene 
glycol, propylene glycol, and butylene glycol. They can usable either 
singly or in the form of a mixture of two or more of them. In the 
composition listed x can be a number 1 to 12, preferably 1 to 8, more 
preferably 1 to 6. Among the most preferred are methanol, ethanol, 
isopropanol, tetrahydrofurfuryl alcohol and benzyl alcohol. 
Preferably, the inorganic hydroxide component of the mixture disclosed 
above contains an effective amount of the inorganic hydroxide based on 
alkali metal hydroxides. Examples of these are sodium hydroxide, potassium 
hydroxide and lithium hydroxide. They can be used singly or in the form of 
a mixture of two or more of them. Among the most preferred are sodium and 
potassium hydroxide. 
Preferably, the ester component of the mixture disclosed above contains an 
effective amount of the ester material of the formula R.sub.1 
--COO--R.sub.2 where R.sub.1 is C.sub.1 -C.sub.20 alkyl, C.sub.5 -C.sub.6 
cycloalkyl, benzyl, furanyl or tetrahydrofuranyl, R.sub.2 is hydrogen, 
C.sub.1 -C.sub.8 alkyl, C.sub.5 -C.sub.6 cycloalkyl, benzyl, phenyl, 
furanyl or tetrahydrofuranyl. Examples of these esters are methyl formate, 
methyl acetate, methyl propionate, methyl butyrate, ethyl formate, ethyl 
acetate, ethyl propionate, ethyl butyrate, propyl formate, propyl acetate, 
propyl propionate, propyl butyrate, butyl formate, butyl acetate, butyl 
propionate, butyl butyrate, methyl soyate, isopropyl myristate, propyl 
myristate, and butyl myristate. In the composition listed R.sub.1,R.sub.2 
can be a number C.sub.1 to C.sub.20 alkyl, preferably C.sub.1 to C.sub.8, 
more preferably C.sub.2 to C.sub.6 or hydrogen. Among the most preferred 
are methyl acetate, ethyl acetate and amyl acetate. 
Preferably, the ether component of the mixture disclosed above contain 
effective amounts of the ether material of the formula R.sub.3 
--O--R.sub.4 where R.sub.3 is C.sub.1 -C.sub.10 alkyl or alkynl, C.sub.5 
-C.sub.6 cycloalkyl, benzyl, phenyl, furanyl or tetrahydrofuranyl, R.sub.4 
is C.sub.1 -C.sub.10 alkyl or alkenyl, C.sub.5 -C.sub.6 cycloalkyl, 
benzyl, phenyl, furanyl or tetrahydrofuranyl. Examples of these ethers are 
ethyl ether, methyl ether, propyl ether, isopropyl ether, butyl ether, 
methyl tert butyl ether, ethyl tert butyl ether, vinyl ether, allyl ether 
and anisole. In the composition listed R.sub.3,R.sub.4 can be a number 
C.sub.1 to C.sub.10 alkyl or alkenyl, preferably C.sub.1 to C.sub.6 alkyl 
or alkynl, more preferably C.sub.1 to C.sub.4 alkyl. Among the most 
preferred are isopropyl ether and propyl ether. 
Preferably, the cyclic ether component of the mixture disclosed above 
contain effective amounts of the cyclic ether. The preferred materials for 
cyclic ethers are: 1,4 dioxane, 1,3 dioxolane tetrahydrofuran (THF), 
methyl THF, dimethyl THF and tetrahydropyran (THP), methyl THP, dimethyl 
THP ethylene oxide, propylene oxide, butylene oxide, amyl oxide, and 
isoamyl oxide. Among the most preferred is 1,3 dioxolane and 
tetrahydrofuran. 
Preferably, the ketone component of the mixture disclosed above contains an 
effective amount of the ketone material of the formula: R.sub.5 
--C.dbd.O--R.sub.6 where R.sub.5 is C.sub.1 -C.sub.10 alkyl, C.sub.5 
-C.sub.6 cycloalkyl, benzyl, furanyl or tetrahydrofuranyl, R.sub.6 is 
C.sub.1 -C.sub.10 alkyl, C.sub.5 -C.sub.6 cycloalkyl, benzyl, phenyl, 
furanyl or tetrahydrofuranyl. Examples of these ketones are acetone, 
methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, and 
methyl isobutyl ketone. In the composition listed R.sub.5 R.sub.6 can be a 
number C.sub.1 to C.sub.10 alkyl, preferably C.sub.1 to C.sub.6 alkyl or 
alkynl, more preferably C.sub.1 to C.sub.4 alkyl. Among the most preferred 
are acetone, methyl ethyl ketone, 3-pentanone and methyl isobutyl ketone. 
Preferably, the alkane component of the mixture disclosed above contain 
effective amounts of the alkane material of the formula: C.sub.n H.sub.n+2 
where n=1-20, or C.sub.4 -C.sub.20 cycloalkanes. Examples of these alkanes 
are methane, ethane, propane, butane, methyl propane, pentane, isopentane, 
methyl butane, cyclopentane, hexane, cyclohexane, dimethylcyclohexane, 
ethylcyclohexane, isohexane, heptane, methyl pentane, dimethyl butane, 
octane, nonane and decane. In the composition listed x can be a number 1 
to 20, preferably 4 to 9, more preferably 5 to 7. Among the most preferred 
are cyclopentane, cyclohexane, dimethylcyclohexane, ethylcyclohexane, 
hexane, methyl pentane, and dimethyl butane. 
Preferably, the terpene component of the mixture disclosed above contain 
effective amounts of the terpene material containing at least 1 isoprene 
group of the general structure: 
##STR4## 
The molecule may be cyclic or multicyclic. Preferred examples are 
d-limonene, pinene, terpinol, terpentine and dipentene. 
Preferably, the dibasic ester component of the mixture disclosed above 
contain effective amounts of the dibasic ester material of the formula: 
R.sub.7 --COO--R.sub.8 --COO--R.sub.9 where R.sub.7 is C.sub.1 -C.sub.20 
alkyl, C.sub.5 -C.sub.6 cycloalkyl, benzyl, furanyl or tetrahydrofuranyl, 
R.sub.8 is C.sub.1 -C.sub.20 alkyl, C.sub.5 -C.sub.6 cycloalkyl, benzyl, 
phenyl, furanyl or tetrahydrofuranyl, R.sub.9 is C.sub.1 -C.sub.20 alkyl, 
C.sub.5 -C.sub.6 cycloalkyl, benzyl, furanyl or tetrahydrofuranyl. 
Examples of these dibasic esters are dimethyl oxalate, dimethyl malonate, 
dimethyl succinate, dimethyl glutarate, dimethyl adipate, methyl ethyl 
succinate, methyl ethyl adipate, diethyl succinate, diethyl adipate. In 
the composition listed R.sub.7, R.sub.8 and R.sub.9 can be a number 
C.sub.1 to C.sub.10 alkyl, preferably C.sub.1 to C.sub.6 alkyl or alkynl, 
more preferably C.sub.1 to C.sub.4 alkyl. Among the most preferred are 
dimethyl succinate, and dimethyl adipate. 
Preferably, the glycol ether component of the mixture disclosed above 
contain effective amounts of the glycol ether material of the formula: 
R.sub.10 --O--R.sub.11 --O--R.sub.12 where R.sub.10 is C.sub.2 -C.sub.20 
alkyl, C.sub.5 -C.sub.6 cycloalkyl, benzyl, furanyl or tetrahydrofuranyl, 
R.sub.11 is C.sub.1 -C.sub.20 alkyl, C.sub.5 -C.sub.6 cycloalkyl, benzyl, 
phenyl, furanyl or tetrahydrofuranyl, R.sub.12 is hydrogen or an alcohol 
selected from claim 7 above. Examples of these glycol ethers are ethylene 
glycol methyl ether, diethylene glycol methyl ether, ethylene glycol ethyl 
ether, diethylene glycol ethyl ether, ethylene glycol propyl ether, 
diethylene glycol propyl ether, ethylene glycol butyl ether, diethylene 
glycol butyl ether, methyl methoxybutanol, propylene glycol methyl ether, 
dipropylene glycol, dipropylene glycol methyl ether, propylene glycol 
propyl ether, dipropylene glycol propyl ether, propylene glycol butyl 
ether, and dipropylene glycol butyl ether. In the composition listed 
R.sub.10, R.sub.11 and R.sub.12 can be a number C.sub.1 to C.sub.10 alkyl, 
preferably C.sub.1 to C.sub.6 alkyl, more preferably C.sub.1 to C.sub.4 
alkyl. Among the most preferred are propylene glycol butyl ether, 
dipropylene glycol methyl ether, dipropylene glycol, methyl methoxy 
butanol and diethylene glycol butyl ether. 
Preferably, the pyrrolidone component of the mixture disclosed above 
contains an effective amount of the pyrrolidone material that is 
substituted in the N position of the pyrrolidone ring of the formula: 
hydrogen, C.sub.1 to C.sub.6 alkyl, or C.sub.1 to C.sub.6 alkanol. 
Examples of these pyrrolidones are pyrrolidone, N-methyl pyrrolidone, 
N-ethyl pyrrolidone, N-propyl pyrrolidone, N-hydroxymethyl pyrrolidone, 
N-hydroxyethyl pyrrolidone, and N-hexyl pyrrolidone. Among the most 
preferred are N-methyl pyrrolidone and N-ethyl pyrrolidone. 
Preferably, the chlorinated hydrocarbon component of the mixture disclosed 
above contain effective amounts of the chlorinated hydrocarbon material of 
the formula: for alkanes are of the form: R.sub.13 --Cl.sub.x where 
R.sub.13 is C.sub.1 -C.sub.20 alkyl, C.sub.4 -C.sub.10 cycloalkyl, C.sub.2 
-C.sub.20 alkenyl benzyl, phenyl, and X&gt;1, and the Ozone Depletion 
Potential (ODP) of the molecule &lt;0.15. Examples of these chlorinated 
materials are methyl chloride, methylene chloride, ethyl chloride, 
dichloro ethane, dichloro ethylene, propyl chloride, isopropyl chloride, 
propyl dichloride, butyl chloride, isobutyl chloride, sec-butyl chloride, 
tert-butyl chloride, pentyl chloride, and hexyl chloride. 
The content of the additional components in the mixture of the present 
invention is not particularly limited, but for the addition of an 
effective amount necessary to improve or control solubility, volatility, 
boiling point, flammability, surface tension, viscosity, reactivity, and 
material compatibility. The mixture may also be enhanced by one skilled at 
the art by the addition of buffering agents, surfactants, chelating 
agents, colorants, dyes, fragrances, indicators, inhibitors, and other 
ingredients. 
Any compound or mixture of compounds suitable for reducing the pH of the 
nitrogen based cleaner solutions of this invention, and which do not 
unduly adversely inhibit the cleaning action thereof or interfere with the 
resulting cleaned parts, may be employed. As examples of such compounds 
are, for example, acids, bases and their salts acting as buffers, such as 
inorganic mineral acids and their salts, weak organic acids having a pKa 
of greater than 2 and their salts, ammonium salts, and buffer systems such 
as weak acids and their conjugate bases, for example, acetic acid and 
ammonium acetate. Preferred for use as such components are acetic acid, 
boric acid, citric acid potassium biphthalate, mixtures of ammonium 
chloride and ammonium acetate, especially a 1:1 mixture of these two 
salts, and mixtures of acetic acid and ammonia and other amines.

The following examples are illustrative of the present invention and are 
not meant to, and should not be taken to, limit the scope of the 
invention. 
EXAMPLE 1 
An optical mold is selected that has been contaminated with a diethylene 
glycol bisallyl carbonate (DEGBAC) based monomer. The polymer is hardened 
on the external side of the mold and the mold is further contaminated with 
fingerprint oils and dirt. The contaminated mold is immersed in a solution 
of 2.5% tetramethyl-ammonium hydroxide, 15% potassium hydroxide, 15% 
sodium hydroxide and 67.5% water at 150 to 160.degree. F. (ca 65.degree. 
to ca. 71.degree. C.) for 10 minutes. The mold is removed from the 
solution, rinsed with water and allowed to air dry. Upon visual inspection 
the contaminants were observed to be removed. 
EXAMPLE 2 
An optical mold is selected that has been contaminated with a diethylene 
glycol bisallyl carbonate (DEGBAC) based monomer. The polymer is hardened 
on the external side of the mold and the mold is further contaminated with 
fingerprint oils and dirt. The contaminated mold is immersed in a solution 
of 3.75% tetramethyl-ammonium hydroxide, 15% potassium hydroxide, 15% 
sodium hydroxide and 66.25% water at 180 to 185.degree. F. (ca. 82 to 
85.degree. C.) for 2 minutes. The mold is removed from the solution, 
rinsed with water and allowed to air dry. Upon visual inspection the 
contaminants were observed to be removed. 
EXAMPLE 3 
35 optical molds are selected for cleaning that have been contaminated with 
a polyurethane based monomer that contains a sulfur molecule (thioether). 
The polymer is hardened on the external side of the mold and the mold is 
further contaminated with fingerprint oils and dirt. The contaminated 
molds are immersed in series into a solution of 3.75% tetramethylammonium 
hydroxide, 15% potassium hydroxide, 15% sodium hydroxide and 66.25% water 
at 180 to 185.degree. F. (ca. 82 to 85.degree. C.) for 2 minutes. Each 
mold is removed from the solution, rinsed with water and/or methanol and 
allowed to air dry. Upon visual inspection greater than 98% of the 
contaminants were observed to be removed from 33 of the 35 molds and all 
35 molds had greater than 95% contaminant removal within the 2 minute 
cleaning time. 
EXAMPLE 4 
An optical mold is selected that has been contaminated with a diethylene 
glycol bisallyl carbonate (DEGBAC) based monomer. The polymer is hardened 
on the external side of the mold and the mold is further contaminated with 
fingerprint oils and dirt. The contaminated mold is immersed in a solution 
of 15% monoethanolamine, 13% potassium hydroxide, 13% sodium hydroxide and 
59% water at 180 to 185.degree. F. (ca. 82 to 85.degree. C.) for 2.5 
minutes. The mold is removed from the solution, rinsed with water and 
allowed to air dry. Upon visual inspection the contaminants were observed 
to be removed. 
EXAMPLE 5 
An optical mold is selected that has been contaminated with a polyurethane 
based monomer that contains a sulfur molecule (thioether). The polymer is 
hardened on the external side of the mold and the mold is further 
contaminated with fingerprint oils and dirt. The contaminated mold is 
immersed in a solution of 17.8% tetramethyl ammonium hydroxide, 3.8% 
surfactant and 78.4% water at 140.degree. F. (60.degree. C.) for 5 
minutes, 160.degree. F. (ca. 71.degree. C.) for 5 minutes, and 160.degree. 
F. for 7 minutes. The mold is removed from the solution, rinsed with water 
and allowed to air dry. Upon visual inspection the contaminants were 
observed to be removed in the 160.degree. F. for 7 minute process, 
although at 140.degree. F. the polymer was removed when exposed for a long 
time period. 
EXAMPLES 6-9 
Polymer physically removed from optical molds and tooling used in the 
optical lens manufacturing process is selected for determination of 
dissolution in the nitrogenated cleaning solution. The polymer 
contamination contained a mix of a diethylene glycol bisallyl carbonate 
(DEGBAC) based monomer and a polyurethane based monomer that contains a 
sulfur molecule (thioether). The nitrogen based solutions tested were 
commercially available quaternary ammonium hydroxide materials in aqueous 
solutions (Sachem, Inc.). The polymer was added at an approximate 4% 
addition by weight to the cleaning solution at 160.degree. F. and allowed 
to dissolve for a period of 5 minutes. At the end of the 5 minute, period 
visual observations were made to judge the percent dissolution. Below are 
the results of the test: 
______________________________________ 
Commercial Percent 
Material Concentration Dissolution 
______________________________________ 
Tetramethylammonium Hydroxide 
25% 100% 
Tetraethylammonium Hydroxide 35% 90% 
Tetrapropylammonium Hydroxide 20% 90% 
Tetrabutylammonium Hydroxide 55% 95% 
______________________________________ 
EXAMPLES 10-19 
Polymer physically removed from optical molds and tooling used in the 
optical lens manufacturing process is selected for determination of 
dissolution in the nitrogenated cleaning solution and compared to 
previously run examples listed above. The polymer contamination contained 
a mix of a diethylene glycol bisallyl carbonate (DEGBAC) based monomer and 
a polyurethane based monomer that contains a sulfur molecule (thioether). 
The nitrogen based solutions tested were commercially available nitrogen 
containing compounds from various sources, some of which were aqueous 
solutions. The polymer was added at an approximate 4% addition by weight 
to the cleaning solution at 160.degree. F. and allowed to dissolve for a 
period of 5 minutes. At the end of the 5 minute period visual observations 
were made to judge the dissolution. Below are the results of the test: 
______________________________________ 
Commercial Observed 
Material Concentration Dissolution 
______________________________________ 
Tetramethylammonium Hydroxide 
25% Complete 
2-methylpentamethylene diamine 100% Partial to full 
Ammonia 30% Very slight 
Trimethyl-2-hydroxyethyl 45% Partial to full 
ammonium hydroxide (choline) 
n-isopropylhydroxyamine 100% Partial 
Piperidine 99% Slight 
1-Piperidineethanol 100% Very Slight 
Monoethanolamine 100% Partial to full 
N-methyl pyrrolidone 100% None 
N-ethyl pyrrolidone 100% None 
______________________________________ 
EXAMPLES 20-23 
Polymer physically removed from optical molds and tooling used in the 
optical lens manufacturing process is selected for determination of 
dissolution in water diluted solutions of tetramethylammonium hydroxide 
(TMAH). The polymer contamination contained a mix of a diethylene glycol 
bisallyl carbonate (DEGBAC) based monomer and a polyurethane based monomer 
that contains a sulfur molecule (thioether). The polymer was added at an 
approximate 4% addition by weight to the cleaning solution at 160.degree. 
F. and allowed to dissolve for a period of 5 minutes. At the end of the 5 
minute period visual observations were made to judge the dissolution. 
Below are the results of the test: 
______________________________________ 
Tetramethylammonium Hydroxide Diluted TMAH 
Observed 
Commercial Conc./Dilution Concentration Dissolution 
______________________________________ 
25%/100% TMAH Solution 
25% Complete 
25%/75% TMAH Solution 18.8% Partial to full 
25%/50% TMAH Solution 12.5% Slight 
25%/25% TMAH Solution 6.3% Slight to None 
______________________________________ 
EXAMPLES 24-37 
Using various lens molds and polymer physically removed from optical molds 
and tooling used in the optical lens manufacturing process, tests were 
conducted on a number of mixtures representative of the art disclosed in 
the patent. The conditions mixtures, are listed below along with the 
results of the tests: 
______________________________________ 
24) Mixture: 34% Monoethanolamine 
40% Tetrahydrofurfuryl Alcohol 
20% Water 
1% Sodium Hydroxide 
5% Surfactant 
Conditions: 160.degree. F. for 6 minutes, no agitation 
Results: Slight cleaning of polymer from molds. 
25) Mixture: 44% Monoethanolamine 
40% Tetrahydrofurfuryl Alcohol 
10% Water 
1% Sodium Hydroxide 
5% Surfactant 
Conditions: 160.degree. F. for 7 minutes, no agitation 
Results: 99% cleaning of polymer from molds. 
26) Mixture: 10.5% Hexamethylenediamine (Commercial 70% 
Solution) 
40% Tetrahydrofurfuryl Alcohol 
4.5% Water 
5% Surfactant 
Conditions: 160.degree. F. for minutes, no agitation 
Results: Very slight cleaning of polymer from molds. 
27) Mixture: 100% 1,3 Pentanediamine 
Conditions: 160.degree. F. for 5 minutes, no agitation 
Results: Removed polymer from molds. 
28) Mixture: 15% 1,3 Pentanediamine 
85% Tetrahydrofurfuryl Alcohol 
Conditions: 160.degree. F. for 5 minutes, no agitation 
Results: Slight cleaning of polymer from molds. 
29) Mixture: 0.5% Trimethyl-2-hydroxyethyl ammonium 
hydroxide (Choline commercial 
45% solution) 
44% Monoethanolamine 
40% Tetrahydrofurfuryl Alcohol 
10.5% Water 
5% Surfactant 
Conditions: 160.degree. F. for 6 minutes, no agitation 
Results: Fair removal of polymer from molds. 
30) Mixture: 15% 2-Methylpentamethylene diamine 
85% N-Methyl Pyrrolidone 
Conditions: 150.degree. F. (ca. 65.degree. C.) for 5 minutes, no 
agitation 
Results: Fair to good cleaning of polymer from 
molds. 
31) Mixture: 3.8% Tetramethylammonium hydroxide (25% 
solution) 
27.5% Tetrahydrofurfuryl Alcohol 
68.7% Water 
Conditions: 160.degree. F. for 6 minutes, no agitation 
Results: Fair dissolution of polymer in beaker. 
32) Mixture: 15% 2-Methylpentamethylene diamine 
45% Monoethanolamine 
40% Amyl Alcohol 
Conditions: 150.degree. F. for 5 minutes, no agitation 
Results: Fair to good dissolution of polymer in 
beaker. 
33) Mixture: 15% Ethylenediamine 
45% Monoethanolamine 
40% Amyl Alcohol 
Conditions: 150.degree. F. for 5 minutes, no agitation 
Results: Fair to good dissolution of polymer in 
beaker. 
34) Mixture: 10% Ethylenediamine 
30% Monoethanolamine 
35% Amyl Alcohol 
25% Water 
Conditions: 150.degree. F. for 5 minutes, no agitation 
Results: Fair dissolution of polymer in beaker. 
35) Mixture: 15% Ethylenediamine 
45% Monoethanolamine 
40% Tetrahydrofurfuryl Alcohol 
Conditions: 150.degree. F. for 3 minutes, no agitation 
Results: Fair to good dissolution of polymer in 
beaker. 
36) Mixture: 10.5% Hexamethylenediamine (Commercial 70% 
Solution) 
4.5% Water 
84% Tetrahydrofurfuryl Alcohol 
1% Surfactant 
Conditions: 150.degree. F. for 3 minutes, no agitation 
Results: Fair to cleaning of polymer from mold. 
37) Mixture: 21% Hexamethylenediamine (Commercial 70% 
Solution) 
28% Monoethanolamine 
9% Water 
41% Tetrahydrofurfuryl Alcohol 
1% Surfactant 
Conditions: 150.degree. F. for 10 minutes, no agitation 
Results: 95% removal of polymer from mold. 
______________________________________ 
Although the invention has been described and illustrated in detail, it is 
to be clearly understood that the same is by way of illustration and 
example, and is not to be taken as a limitation. The spirit and scope of 
the present invention are to be limited only by the terms of the appended 
claims. One skilled in the art can make many adjustments, changes, or 
modifications to the components of the compositions used to clean polymers 
and resins without departing from the scope of this invention. And, for 
example, more than one combination of the cleaning compositions can be 
used sequentially to clean an article or part, optionally employing 
different types of methods for the composition to contact the article or 
part, and optionally under differing conditions. In addition, the above 
description enables the skilled artisan to make and use the invention of 
the following claims.