 |
Description  |
|
|
The present invention relates to a method for stabilizing thermoplastic
nitrile resins against discoloration resulting from thermal degradation
during processing. More particularly, this invention relates to the
stabilization of thermoplastic copolymers and graft copolymers containing
a high proportionate amount of olefinic nitrile against thermal
discoloration by the inclusion of minor amounts of monoesters of certain
organic dicarboxylic acids in the polymer.
It has been reported in Faserforschung und Textiltechnik, Vol. 21, No. 3,
pages 105-110 (1970), that maleic acid and some of its derivatives are
useful as inhibitors for the thermal discoloration of polyacrylonitrile.
They mention "the complete indifference of the maleic acid esters" for
this purpose. We have discovered that the half esters of maleic acid or
fumaric acid are unique for the stabilization of thermoplastic olefinic
nitrile resins against thermal discoloration in spite of the fact that the
diesters have been found by others to be ineffective for this purpose.
Half esters of maleic acid and fumaric acid are compatible with the nitrile
resins of this invention, and they do not impart any appreciable haze or
reduced light transmission to the resin, nor do they have any adverse
effects on the physical properties of the resins when they are present
within specified concentration ranges. Additionally, the low cost of the
half esters of maleic acid and fumaric acid and their ready availability
make these compounds attractive inhibitors for thermoplastic nitrile
resins.
Half esters of maleic acid and fumaric acid can be advantageously
incorporated into the resin by intimately mixing or blending with the
powdered resin. Improvement in color is observed by adding half esters of
maleic acid and fumaric acid in concentrations as low as about 0.1 part
per hundred parts of resin, on a weight basis, and although no greater
color improvement is obtained with concentrations beyond about 1.5 parts
per hundred parts of resin (phr), there appears to be no adverse effect on
the properties of the resin with higher concentrations. The greatest
degree of color improvement, however, is obtained when the stabilizers of
this invention are employed in concentrations ranging from about 0.3 to
about 1.2 parts by weight per hundred parts by weight of resin.
The half esters of maleic acid and fumaric acid which are useful in the
present invention include those conforming to the structure HOOCCH =
CHCOOR.sub.3 wherein R.sub.3 is a hydrocarbon group having from 1 to 20
carbon atoms.
The resins useful in this invention are composed of polymers of an
olefinically unsaturated nitrile, another monomer component
copolymerizable with said olefinically unsaturated nitrile, and optionally
a diene rubber.
The polymers are those produced by polymerizing a major proportion of a
monounsaturated nitrile, such as acrylonitrile, and a minor proportion of
another monovinyl monomer component copolymerizable with said nitrile, in
an aqueous medium, preferably in the presence of a preformed diene rubber
which may be a homopolymer or a copolymer of a conjugated diene monomer.
The conjugated diene monomers useful in the present invention include
butadiene-1,3, isoprene, chloroprene, bromoprene, cyanoprene,
2,3-dimethyl-butadiene-1,3, 2-ethyl-butadiene-1,3,
2,3-diethyl-butadiene-1,3, and the like, and others. Most preferred for
the purpose of this invention are butadiene and isoprene because of their
ready availability and their excellent copolymerization properties.
The olefinically unsaturated nitriles useful in the present invention are
the alpha,beta-olefinically unsaturated mononitriles having the structure
##STR1##
wherein R is hydrogen, a lower alkyl group having from 1 to 4 carbon
atoms, or a halogen. Such compounds include acrylonitrile,
alpha-chloroacrylonitrile, alpha-fluoroacrylonitrile, methacrylonitrile,
ethacrylonitrile, and the like. The most preferred olefinically
unsaturated nitriles in the present invention are acrylonitrile and
methacrylonitrile, and mixtures thereof.
The other monovinyl monomer component copolymerizable with the olefinically
unsaturated nitriles which are useful in this invention includes one or
more of the vinyl aromatic monomers, esters of olefinically unsaturated
carboxylic acids, vinyl esters, vinyl ethers, alpha-olefins, and others.
The vinyl aromatic monomers include styrene, alpha-methyl styrene, the
vinyl toluenes, the vinyl xylenes, and the like. Most preferred is
styrene.
The esters of olefinically unsaturated carboxylic acids include those
having the structure
##STR2##
wherein R.sub.1 is hydrogen, an alkyl group having from 1 to 4 carbon
atoms, or a halogen, and R.sub.2 is an alkyl group having from 1 to 6
carbon atoms. Compounds of this type include methyl acrylate, ethyl
acrylate, the propyl acrylates, the butyl acrylates, the amyl acrylates,
and the hexyl acrylates; methyl methacrylate, ethyl methacrylate, the
propyl methacrylates, the butyl methacrylates, the amyl methacrylates, and
the hexyl methacrylates; methyl alpha-chloroacrylate, ethyl
alpha-chloroacrylate, and the like. Most preferred in the present
invention are methyl acrylate, ethyl acrylate, methyl methacrylate, and
ethyl methacrylate.
The alpha-olefins useful in the present invention are those having at least
4 and as many as 10 carbon atoms and having the structure
##STR3##
wherein R' and R" are alkyl groups having from 1 to 7 carbon atoms, and
more specifically preferred are alpha-olefins such as isobutylene,
2-methyl butene-1, 2-methyl pentene-1, 2-methyl hexene-1, 2-methyl
heptene-1, 2-methyl octene-1, 2-ethyl butene-1, 2-propyl pentene-1, and
the like. Most preferred is isobutylene.
The vinyl ethers include methyl vinyl ether, ethyl vinyl ether, the propyl
vinyl ethers, the butyl vinyl ethers, methyl isopropenyl ether, ethyl
isopropenyl ether, and the like. Most preferred are methyl vinyl ether,
ethyl vinyl ether, the propyl vinyl ethers, and the butyl vinyl ethers.
The vinyl esters include vinyl acetate, vinyl propionate, the vinyl
butyrates, and the like. Most preferred is vinyl acetate.
Polymers of particular utility in this invention and details of their
methods of preparation are described in U.S. Pat. Nos. 3,426,102,
3,586,737 and 3,763,278.
The polymers useful in this invention are those prepared by the
polymerization of 100 parts by weight of (A) at least 50% by weight of at
least one nitrile having the structure
##STR4##
wherein R has the foregoing designation and (B) up to 50% by weight based
on the combined weight of (A) and (B) of at least one member selected from
the group consisting of (1) styrene, (2) an ester having the structure
##STR5##
wherein R.sub.1 and R.sub.2 have the foregoing designations, (3) an
alpha-olefin having the structure
##STR6##
wherein R' and R" have the foregoing designations, (4) a vinyl ether
selected from the group consisting of methyl vinyl ether, ethyl vinyl
ether, the propyl vinyl ethers, and the butyl vinyl ethers, and (5) vinyl
acetate, in the presence of from 0 to 40 parts by weight of (C) a rubbery
polymer of a conjugated diene monomer selected from the group consisting
of butadiene and isoprene and optionally at least one comonomer selected
from the group consisting of styrene, a nitrile monomer having the
structure
##STR7##
wherein R has the foregoing designation, and an ester having the structure
##STR8##
wherein R.sub.1 and R.sub.2 have the foregoing designations, said rubbery
polymer containing from 50 to 100% by weight of polymerized conjugated
diene and from 0 to 50% by weight of comonomer.
Preferably, component (A) should be present in from about 60 to 90% by
weight based on the combined weight of (A) and (B) and the rubber polymer
(C) should contain more than 50% by weight of conjugated diene and more
preferably from 60 to 90% by weight of the conjugated diene.
The polymers useful in this invention can contain in addition to the half
ester of maleic acid other compounding ingredients and additives,
pigments, colorants, stabilizers, etc., as is well known in the art so
long as the balance between impact strength, flexural strength, tensile
strength, processability, heat-distortion temperature, and the like, is
not affected to such a degree that the article is no longer useful for its
intended purpose.
Polymeric products of the present invention are thermoplastic materials
which can be thermoformed into a wide variety of useful articles in any of
the conventional ways employed with known thermoplastic polymeric
materials, such as by extrusion, milling, molding, drawing, blowing, and
the like. These polymers have excellent solvent resistance and their
impact strength and low permeability to gases and vapors make them very
useful in the packaging industry, and they are particularly useful in the
manufacture of bottles, film, and other types of containers for liquids
and solids.
The following examples will further illustrate the present invention in
greater detail, however, it is to be understood that the scope of this
invention is not to be limited by these examples.
The following polymers were prepared and used as designated in the specific
examples.
______________________________________
Polymer A
(1) Preparation of Elastomer
Components Parts by Weight
______________________________________
water 200
butadiene 75
styrene 25
t-dodecyl mercaptan 0.7
ethylenediamine tetraacetic
0.1
acid, tripotassium salt
(Hampol K.sub.3 -120)
Gafac RS-710* 0.7
potassium persulfate 0.2
polydimethyl siloxane
0.01
(50% solution)
(antifoam (Dow FG-10))
______________________________________
*.alpha.-tridecyl-.omega.hydroxypoly(oxyethylene) mixture of dihydrogen
phosphate and mnohydrogen phosphate esters having an acid number of 58 to
70, manufactured by GAF Corporation.
To 200 parts of water were added 0.7 part of Gafac RS-710 and 0.1 part of
Hampol K.sub.3 -120. The ingredients were stirred until well dispersed,
and the pH was adjusted to 6.7 with a 25% aqueous solution of KOH. 0.2
Part of potassium persulfate was added to the reactor along with 0.7 part
of t-dodecyl mercaptan dissolved in 25 parts of styrene. The reactor was
purged with nitrogen, evacuated and 75 parts of butadiene were added to
the mixture. The reactor was slowly heated to 60.degree. C, and the
reaction was allowed to continue for 19 hours at which time the solids
level of the latex reached 27.3% by weight. 0.01 Part of Dow FG-10
antifoam agent was added to the reactor with the aid of nitrogen pressure.
The reactor was slowly vented and vacuum stripping was begun while the
temperature remained at 60.degree. C. The unreacted monomers were removed
over a period of 2 hours under a vacuum of 20" Hg. The reactor was
brought to atmospheric pressure with nitrogen, and the latex was allowed
to cool. The latex was then filtered through cheesecloth, and the final
total solids of the filtered latex measured 29% by weight.
______________________________________
(2) Preparation of Graft Polymer
Components Parts by Weight
______________________________________
water 250 (includes water
in elastomer)
acrylonitrile 75.5
styrene 24.5
pentaerythritol tetrakis
2.1
mercaptopropionate
(Evans Q-43)
elastomer from step (1)
51.7 (5 parts rubber)
(29% T.S.)
Gafac RS-710 1.2
tridecyloxypoly 0.8
(ethyleneoxy) ethanol
(Emulphogene BC-420)
citric acid 0.2
2,2' azobis-(.alpha.,.gamma.-dimethyl
0.165
valeronitrile) (Vazo 52)
(initiator)
bis-(mixed mono- and 0.01
di-nonyl phenyl phosphite)
(Naugard PHR)
butylated hydroxytoluene
0.01
(Naugard BHT)
______________________________________
155 Parts of water in addition to the 37 parts of water present in the
elastomer latex were charged to a reactor. To this was added with slow
mixing a water-emulsifier solution containing 1.2 parts of Gafac RS-710,
0.8 part of Emulphogene BC-420, and 0.2 part of citric acid in 30 parts of
water.
This was followed by the addition of 51.7 parts of the above elastomer and
8.25 parts of water with stirring. A mixture of 8 parts of acrylonitrile
and 2 parts of styrene was added continuously over a period of 25 to 30
minutes. Agitation was stopped, the contents of the vessel were allowed to
stand for 2 hours, and the latex was then filtered through cheesecloth.
The rubber-monomer mixture prepared above was then added to a second
reactor and the first container was then rinsed into the reactor with 20
parts of water. The reactor was purged with nitrogen while being heated to
65.degree. C. 0.085 Part of Vazo 52 dissolved in 0.5 part of acrylonitrile
was then added to the reactor. The monomer addition of 67.5 parts of
acrylonitrile, 22.5 parts of styrene, 2.1 parts of Evans Q-43, 0.01 part
of Naugard PHR, and 0.01 part of Naugard BHT was started immediately under
nitrogen purge and was continued over a period of 4 hours and 20 minutes.
0.045 Part of Vazo 52 in 0.5 part of acrylonitrile was added after 1 and
1/2 hours and 0.035 part of Vazo 52 in 0.5 part of acrylonitrile was added
after 3 and 1/2 hours. With each addition of the Vazo 52 solution, 0.5
part of acrylonitrile was used as a rinse. Vacuum stripping was begun
after 4 hours and 50 minutes of reaction time. The temperature was held at
65.degree. C while the unreacted monomers were removed under a vacuum of
18" Hg. The total solids content of the resulting latex was 28% by
weight. The latex was coagulated in 1 and 1/2 volumes of an aqueous
solution of Al.sub.2 (SO.sub.4).sub.3 .18H.sub.2 O containing 3 grams of
the aluminum salt per hundred grams of resin solids, which had been heated
to a temperature of 88.degree. to 90.degree. C.
______________________________________
Polymer B
Components Parts by Weight
______________________________________
water 225
acrylonitrile 77
styrene 23
Gafac RE-610** 1.35
pentaerythritol tetrakis
1.65
mercaptopropionate
(Carlisle Q-43)
2,2' azobis- 0.16
(isobutyronitrile)
(Vazo 64)
butylated hydroxytoluene
0.01
______________________________________
**A mixture of R--O--(CH.sub.2 CH.sub.2 O--).sub.n PO.sub.3 M.sub.2 and
[R--O--(CH.sub.2 CH.sub.2 O--).sub.n ].sub.2 PO.sub.2 M wherein n is a
number from 1 to 40, R is an alkyl or alkaryl group, and M is hydrogen,
ammonia or an alkali metal, produced by GAF Corporation.
195 Parts of water were charged to a reactor followed by the addition of
1.35 parts of Gafac RE-610. An additional 20 parts of water were utilized
to rinse the Gafac RE-610 into the reactor.
The reactor, containing the emulsifier solution, was purged with nitrogen
and heated to 70.degree. C. The precharge, consisting of 1 part of styrene
in 8 parts of acrylonitrile, was charged to the reactor followed by the
addition of an additional 10 parts of water. After a period of 15 minutes,
0.1 part of Vazo 64 in 0.5 part of acrylonitrile was added to the reactor.
An additional 0.5 part of acrylonitrile was added to rinse the entrance
port of the reactor. The remaining water (10 parts) was then added.
Another 0.03 part of Vazo 64 was added after a period of 1 and 1/2 hours
and 0.03 part after 3 and 1/2 hours. A total of six portions of 0.5 part
of acrylonitrile, 0.5 part as a solvent and 0.5 part as a rinse was used
each time the initiator was added.
The addition of the monomer-chain transfer solution prepared by adding 1.65
parts of Carlisle Q-43 to 66 parts of acrylonitrile and 22 parts of
styrene was begun immediately, and pumping was conducted linearly over a
period of 4 hours. The reaction was continued for an additional 45 minutes
and was terminated by the addition of 0.01 part of Naugard BHT. The
temperature was held at 70.degree. C while the unreacted monomers were
removed under a vacuum of 20" Hg. The total solids content of the
resulting latex was 29.5%. The latex was coagulated in 1 and 1/2 volumes
of water, heated to 88.degree. to 90.degree. C and contained 3 grams of
Al.sub.2 (SO.sub.4).sub.3 .18H.sub.2 O per hundred grams of resin solids.
______________________________________
Polymer C
Components Parts by Weight
______________________________________
water 156
acrylonitrile 75
methyl acrylate 25
Gafac RE-610 3
(emulsifier)
pentaerythritol tetrakis
1.27
mercaptopropionate
potassium persulfate 0.06
tetraethylenediamine 0.05
tetraacetic acid,
tetrapotassium salt
(41% aqueous solution)
(Hampene K.sub.4 100)
______________________________________
148 Parts of water were charged to a container. 0.3 Part of Garfac RE-610
was added with stirring. The pH of the mixture was adjusted to 5.1 with
NH.sub.4 OH, and the solution was charged to the reactor along with 0.13
part of Carlisle Q-43 dissolved in 7.5 parts of acrylonitrile and 2.5
parts of methyl acrylate. To this was added 0.05 part of Hampene K.sub.4
100 to complete the initial reactor charge.
The reactor and its contents were purged with nitrogen and sealed. The
reactor was then heated to 68.degree. C with stirring. When the
temperature had leveled off at 68.degree. C, a solution of 0.006 part of
K.sub.2 S.sub.2 O.sub.8 in 1.48 parts of water was added under a nitrogen
stream, then the addition of the two solutions, one consisting of 2.7
parts of Gafac RE-610 and 1.14 parts of Carlisle Q-43 dissolved in a
mixture of 67.5 parts of acrylonitrile and 22.5 parts of methyl acrylate
and the other consisting of 0.054 part of K.sub.2 S.sub.2 O.sub.8 in 7.4
parts of water, was begun. Both solutions were pumped in linearly over a
6-hour period. The total reaction time was 8 and 1/4 hours. The final
solids content in the latex was 36.5%. The unreacted monomers were removed
by vacuum stripping under a pressure of 20" Hg for 2 hours at 68.degree.
C. The latex was coagulated in 1 and 1/2 volumes of water containing 3
grams of Al.sub.2 (SO.sub.4).sub.3 .18H.sub.2 O per hundred grams of resin
solids. The coagulation was conducted at 71.degree. C.
POLYMER D
1. Preparation of Elastomer
An elastomer was prepared by reacting the following ingredients for 9 hours
at 53.degree. C in a nitrogen atmosphere:
______________________________________
Components Parts by Weight
______________________________________
butadiene 70
acrylonitrile 30
t-dodecyl mercaptan 0.71
P & G soap flakes 1.4
azobisisobutyronitrile
0.4
ethylenediamine 0.05
tetraacetic acid
sodium salts of polymerized
0.1
alkylnaphthalene sulfonic
acids
water 200
______________________________________
The final pH of the reaction mixture was 9.5 and the total solids after
completion of the reaction was 30%.
2. Preparation of Graft Polymer
A graft resin was prepared utilizing the above elastomer by reacting the
following components at 57.degree. C over a period of 3.1 hours:
______________________________________
Components Parts by Weight
______________________________________
acrylonitrile 75
methyl acrylate 25
elastomer solids 9
(obtained from (1)
above)
sodium salt of dioctyl
1.21
sulfosuccinate
polyvinylpyrrolidone 0.3
pentaerythritol tetrakis
1.55
(mercaptopropionate)
potassium persulfate 0.06
antifoam (Dow FG-10) <.04
water 230
______________________________________
All of the above materials were added initially to the reactor with
agitation with the exception of the chain transfer agent, which was added
20 minutes after the start of the reaction. Completion of the reaction was
determined on the basis of total solids of 28% and a conversion of 85%.
The latex was coagulated in methanol with aqueous aluminum sulfate,
filtered and dried.
EXAMPLES 1-12
The various half-ester stabilizers were added to the dried powders of the
polymers described in A through D above in the amount of 0.5 part by
weight per hundred parts of resin, as indicated in Table 1. These resin
compositions were then evaluated for their color stability and optical
properties by a method based on the use of a Brabender Plasticorder. The
method was designed to enable the prediction of the optical properties
such as haze, color, and light transmission resulting from processing
various resin batches into fabricated articles. It was found that 5- to
7-minute residence time in the Brabender at 200.degree. C is equivalent to
the total heat history that the resin would encounter during normal
processing.
The instrument used consisted of a dynamometer, Type PL-U33AA (No.
2162-64), and its accompanying roller style measuring head (No.
A-30/S.B.). The roller style measuring head was electrically heated and
was equipped with a Rosemont temperature controller. Fifty-gram samples of
each resin were screened in the Brabender set for a temperature of
200.degree. C and 35 rpm. Four samples, approximately 1.5 grams in weight,
were removed at 3-minute intervals from the Brabender for optical
measurements. The initial sample was taken 4 minutes after the start of
sample loading. Torque values and temperature were also noted at the
4-minute mark. Discs having a uniform thickness of 40 mils were prepared
for optional measurements by pressing the fused polymer under mild
conditions. The conditions selected for the pressing of discs from
Brabender samples did not contribute significantly to measured optical
values. The disc was prepared by placing a mold 40-mils thick and 11/4
inches in diameter in a press between two parallel mirror-finished,
chrome-plated brass platens, 1/8-inch thick. The platens were heated to
154.degree. C. A 1.5-gram sample of the cooled resin removed at the
various times from the Brabender was placed in each of the four cavities
of the mold or in two cavities diagonally across from one another if only
two discs were being processed. The heated plates containing the resin and
the mold therebetween were positioned in the press so that the melt
samples were pressed between the two highly polished surfaces. Fifteen
thousand pounds' ram pressure was applied and held for 5 to 10 seconds.
The pressure was then released and the entire unit transferred to a cold
press where 20,000 pounds' ram pressure was applied. After approximately
30 seconds, the plates were sufficiently cool to handle. The unit was then
removed and the discs were removed from the cavities. The percent light
transmission was measured with the Hunter Lab Colormeter, and the
yellowness index and percent haze were determined by ASTM Standard Methods
D 1925-70 and D 1003-61, respectively.
It is apparent from the data shown in Table 1 that the half esters of the
present invention are unique among the compounds tested, including the
magnesium dodecyl maleate described as being a stabilizer for
polyacrylonitrile in U.S. Pat. No. 2,719,140.
Table 1
__________________________________________________________________________
Stabilizer
Yellowness Index
Concentration
(minutes)
Example
Polymer
Stabilizer phr (wt.)
4 7 10 13
__________________________________________________________________________
1 B none 0 15.1
49.6
74.4
88.8
2 B monobutyl maleate
0.5 12.9
19.9
26.9
33.0
3 B monooctyl maleate
0.5 12.4
18.8
27.3
33.7
4 B monolauryl maleate
0.5 12.6
19.2
28.1
36.5
5 B monocetyl maleate
0.5 15.3
22.4
31.3
40.1
6 B magnesium dodecyl maleate
0.5 13.5
20.6
32.3
44.2
7 A (2) none 0 12.2
23.2
33.7
42.0
8 A (2) monooctyl maleate
0.5 8.9
11.4
13.6
15.9
9 D (2) none 0 10.8
15.7
22.2
27.9
10 D (2) monooctyl maleate
0.5 10.2
13.7
18.1
22.1
11 C none 0 11.1
27.9
49.8
66.8
12 C monooctyl maleate
0.5 10.3
15.0
19.4
22.4
__________________________________________________________________________
EXAMPLES 13-19
The procedures described in Examples 1-12 were repeated using varying
amounts of monooctyl maleate in polymer B. The results are given in Table
2.
Table 2
__________________________________________________________________________
Stabilizer
Yellowness Index
Concentration
(minutes)
Example
Polymer
Stabilizer phr (wt.)
4 7 10 13
__________________________________________________________________________
13 B none 0 15.6
47.4
75.3
87.5
14 B monooctyl maleate
0.1 12.8
25.6
43.4
61.5
15 B monooctyl maleate
0.2 11.3
19.4
32.0
43.2
16 B monooctyl maleate
0.4 11.2
18.5
27.8
34.6
17 B monooctyl maleate
0.8 12.4
18.6
26.1
31.2
18 B monooctyl maleate
1.2 13.8
20.7
28.2
33.5
19 B monooctyl maleate
1.6 15.3
22.9
30.9
35.4
__________________________________________________________________________
EXAMPLES 20-26
The procedures described in Examples 1-12 were repeated using various
esters described in the prior art which are outside the scope of the
present invention. The results are given in Table 3 wherein a comparison
of properties of the resulting products is also made with the control
resin and a stabilized resin within the scope of the present invention. It
is readily apparent that the stabilized resins according to this invention
are superior in properties to those of Examples 20-26 shown in Table 3.
Table 3
__________________________________________________________________________
Stabilizer
Yellowness Index % Haze
Concentration
(minutes) (minutes)
Example
Polymer
Stabilizer
phr (wt.)
4 7 10 13 4 7 10 13
__________________________________________________________________________
1 B none 0 15.1 49.6
74.4
88.8
2.7 3.8 4.0 5.8
2 B monobutyl
0.5 12.9 19.9
26.9
33.0
3.3 3.4 3.5 4.9
maleate
20 B dibutyl 0.5 14.8 34.4
54.2
69.1
3.2 2.3 3.6 5.1
maleate
21 B di-2-ethyl-
0.5 16.3 35.1
55.7
68.4
4.1 4.0 4.1 4.4
hexyl
maleate
22 B monooctyl
0.5 18.0 47.9
78.8
90.6
5.1 4.9 6.8 4.3
succinate
23 B monomethyl
0.5 23.4 58.2
84.2
96.0
3.2 2.9 4.5 5.1
succinate
24 B dioctyl 0.5 17.0 45.2
74.4
87.3
4.3 4.2 4.6 4.1
phthalate
25 B dimethyl 0.5 15.3 51.4
81.1
93.8
2.3 2.3 2.6 4.7
fumarate
26 B dimethyl 0.5 15.9 47.8
74.7
88.6
2.0 2.3 3.2 4.5
phthalate
__________________________________________________________________________
* * * * *
|
|
 |
|
 |
Description |
|
