Note: Descriptions are shown in the official language in which they were submitted.
~0~34~39
BACKGROUND
Polyurethane varnishes are superior in a number of
characteristics to a great many other varnishes, including
reactive varn~shes. In particular they are distinguished
by hi~h resistance to chemicals, especially acids, by
high elasticity combined with great hardness in some cases,
and by good resistance to wear.
The prototype of the polyurethane varnishes is the~
two-component varnish, consisting of synthetic resins con-
taining hydroxyl groups (e.g., polyesters, polyethers,
polyacrylates) and an NC0 terminal adduct on the basis of
diisocyanates. Such a two-component varnish by its very
nature has the disadvantage of a lim$ted pot life ranging,
15 as a rule, from 6 to 20 hours. -
Another approach to the preparation of polyurethane
varnishes is to react resins containing hydroxyl groups
(polyesters, polyethers, polyacrylates) with diisocyanates
in an 0~ : NC0 ratio of l : 2 or the like, or in any event
- with an excess of N00 groups. The resulting prepolymers
containing NC0 groups then set under the influence of
`~ atmospheric humidity to form films. To all intents and
purposes this is a one-component system, but one which
~'~ 25 must be protected against the action of moisture. This :
implies that special precautions must be taken in the
~- manufacture, pigmentation, etc., of these varnishes.
.~ - - . . .
i In a number of technical applications, as for example
ln roller varnishing, where the insensitivity of the system
-2-
~ ' '
10 4 3 4 8 9
to surrounding influences, such as air and humidity,
and constancy of viscosity over long periods of time are -
important, such systems cannot be used. It has hitherto
been necessary to get along without the good character-
istics of the polyurethane varnishes in such applications.
It is known that there are a number of substances
which react with isocyanates to fosm chemically neutral
substances, which can in turn be cleaved at elevated tem~-
lO perature to form isocyanates again. These blocked prod-
ucts would be ideally suited for the composition of the
types of varnishes desired for this kind of application.
A number of these products, however, must be re~ected
because they tend to yellow from the heat during the
setting process. Furthermore, one must distinguish be-
tween the aromatic isocyanates and the aliphatic or cyclo-
aliphatic isocyanates, since only the latter group of
substances assures resistance to light and to weather
` simultaneously.
Now, if -caprolactam is used as the blocking agent,
i.e., as the reagentt in order to transform isocyanates
` to a form that is non-reactive at lower temperatures, no --
difficulty is encountered in achieving a setting process -
that is free of yellowing. This cannot be done in prac-
tice, of course, since ~-caprol~tam blocked isocyanates ~
are incompati~le in solvents commonly used in varnishes. -
- , -
., -
1~)43489
THE INVENTION
It has now surprisingly been found that the diffi-
culties regarding compatibility will not be encountered
in fast-setting varnishes for covering substrates, preferably metallic
materials with highly pliant coatings by heat treatment
at temperatures exceeding 175C and preferably tempera-
tures of 180 to 450C, consisting of a binding agent mix-
ture dissolved in high-boilin~ varnish solvents having a boiling point of
not less than about 110C, if the said mixture consists of 50 to 90%, by
weight, of polyesters of great molecular weight containing hydroxyl
groups and prepared on the basis of mainly aromatic di-
carboxylic acids and a mixture of diols and triols having
4 to 12 carbon atoms in a ratio of at least 1.5:1, and 10 to 50%, by weight,
of ~-caprolactam-blocked adducts of 3-isocyanatomethyl-3,5,5-tri-
; methylcyclohexylisocyanate (also called ~isophorone di-
isocyanate~ or ~IPDI~), plus, if desired, varnish addi- -
tives, dyes and/or pigments, it being often advantageous
` to permit a small percentage, i.e., 0.01 to 5% by weight
- 20 of free NCO groups in the blocked isocyanate adduct. It -
is additionally to be found that the IPDI is distinguished
from other aliphatic diisocyanates by an outstanding
thermal stability. ; ~
. : .
Inasmuch as sheet metals coated by a roller coating
method, especially the coil coating method, are afterwards
sub~ected to deformation in various ways, the elasticity -~
and adhesion of the films must satisfy stringent require-
m~nts, and these qualities must be achieved without loss
; 30 of hardness.
1043489
50 to 90%, by weight, of the binding agent of the
varnishes of the invention consist of polyesters of high .
molecular weight containing hydroxyl groups, whose gen-
e~al properties can be described preferably by the f~llo~ing chem-
5 ical and physical data:
1. Mainly aromatic dicarboxylic acids are used as the
acids, the molar ratio of aromatic to aliphatic or
cycloaliphatic dicarboxylic acids being greater than
4 ~
2. The required high flexibilization is achieved through
the glycol components. Usable glycols are products
having 3 to 8 carbon atoms, and preferably 4 to 6
carbon atoms, in the chain.
3. The branching is achieved in the conventional manner
by means of trifunctional or higher functional poly-
ols, the molar ratio of glycols to higher functional
~; polyols being greater than 1.5 : 1, preferably 2.5- -~
3.5 : 1. :-:
4. The hydroxyl number of the polyesters used is to be - -
. 20 between S0 and 150 mg KOH/g, preferably between 80
and 125 mg KOH/g. -
5. Furthermore, the suitable,hydroxyl-group-containing
polyesters are to be described by the glass trans- ~
formation.temperatures which are to be determined by -. means of differential thermoanalysis. The glass trans-
formation temperature of the claimed hydroxyl poly-
esters is below +20qC, preferably ranging from -20
to +lOqC.
7~ :
~ . . . ~ . . .
~0434~
Suitable aromatic or aliphatic and cycloaliphatic poly-
carboxylic acids (the aromatic polycarboxylic acids can
be mono- or polynuclear) are, for example, oxalic acid,
succinic acid, adipic acid, sebacic acid, terephthalic
acid, methylterephthalic acid, 2,5- and 2,6-dimethyltereph-
thalic acid, chloroterephthalic acid, 2,5-dichlorotereph-
thalic acid, fluoroterephthalic acid, isophthalic acid,
trimellitic acid~ naphthalinedicarboxylic acid, especially
the 1,4-, 1,5-, 2,6- and 2,7-isomers, phenylenediacetic~
acid, 4-carboxyphenoxyacetic acid, m- and p-terphenyl-4,-
4~-dicarboxylic acid, dodecahydrodiphenic acid, hexahydro-
terephthalic acid, 4,4'-diphenic acid, 2,2'- and 3,3'-
dimethyl-4,4'-diphenic acid, 2,2'-dibromo-4,4'-diphenic
acid, bis-(4-carboxyphenyl)-methane, 1,1- and 1,2-bis-
(4-carboxyphenyl)-ethane, 2,2-bis-(4-carboxyphenyl)-pro-
- pane, 1,2-bis-(4-carboxyphenoxy)-ethane, bis-4-carboxy- ~
phenyleth~r, bis-4-carboxyphenylsulfide, bis-4,carboxy- ~ -
phenylketone, bis-4,carboxyphenylsulfoxide, bis-4-carboxy-
phenylsulfone, 2,8-dibenzofurandicarboxylic acid, 4,4'-
stilbenedicarboxylic acid and octadecahydro-m-terphenyl-
4,4~-dicarboxylic acid, etc. Mixtures of the above-named
compounds may also be used.
~,, ~ ..
In the preparation of the hydroxyl-group-containing
polyesters, diols are used predominantly as the alcohol
component. The partial use of other polyols in the stated
molar ratios is possible, such as triols for example.
Examples of suitable compounds are: ethylene glycol, pro- --
pylene glycol such as 1,2- and 1,3-propanediol, 2,2-di-
30 methylpropanediol-(1,3), butanediols such as butanediol- ;-
-6-
,. .
_ . ..... .
, ,, . ~ , .
lV43489
(~,4), hexanediols such as hexanediol-(1,6), 2,2,4-tri-
methylhexanediol-(1,6), 2,4,4-trimethylhexanediol-(1,6),
heptanediol-(1,7), octadecane-9, 10-diol-(1,12), thio-
diglycol, octadecanediol-(1,18), 2,4-dimethyl-2-propyl-
heptanediol-(1,3), butene- or butinediol-(1,4), diethylene-
glycol, triethyleneglycol, cis- or trans-1,4-cyclohexane-
dimethanol, 1,4-cyclohexanediols, glycerine, hexanetriol-
(1,2,6), l,l,l-trimethylolpropane, l,l,l-trimethylolethane,
`pentaerythritol, etc. Mixtures of the above-named com-
~10 pounds may also be used.
.~ , .
In the preparation of the polyester, the polyol is
used in such amounts that there will be more than one
hydroxylgroup equivalent for each carboxyl group equiv-
alent.
The hydroxyl-group-containing polyesters can be pre-
pared in a known and conventional manner. Particularly
the following two processes are available. -
In the first case the starting product is a dicar-
boxylic acid free of mineral acid, which is to be refined,
if necessary, by recrystallization. The ratio of the
equivalents of acid to alcohol depends, of course, on
the desired molecule size and on the hydroxyl number that
is to be established. Upon the addition of 0.005 to 0.5%,
preferably 0.05 to 0.2%, by weight, of a catalyst such as
a tin compound, e.g., di-n-butyl tin oxide, di-n-butyl
tin diester, etc., or a titanium ester, especially tetra-
isopropyltitanate, the reaction components are heated in -
a suitable apparatus under a current of an inert gas suc~
as nitrogen, for example- At approximately 180qC the first
. ' ' .
, -: . , ., , :
1043489
forming of water occurs. The water is removed f~om the
reaction mixture by distillation. Over a period of sevèral
hours the reaction temperature is raised to 240qC. The
reaction medium remains inhomogenous until shortly before
the end of the complete esterification. After about 24
hours the reaction is ended.
In the second process the starting substances are
dimethyl esters of the dicarboxylic acid ester, and they
are esterified under a current of an inert gas such as
nitrogen, for example, with the desired alcohol component.
The transesterification catalysts can again be titanium
esters, dialkyl tin esters or di-n-butyl t~n oxide in
concentrations of O.Q05 to 0.5 wt.-X. After a tempera- -
ture of about 120C is reached, the first production of
- methanol occurs. Cver a period of several hours the tem- ;
perature is increased to 220-230~C. The transesterifica-
`!i, tion is ended after 2 to 24 hours, depending on the mixture
!'` Used.
Suitable high-boiling varnish solvents are those whose
lower boiling point or limit is llOqC. The upper limit
of the solvent depends on the conditions of the baking-on
~ process. For this purpose inert high-boiling compounds
i 2S as well as mixtures thereof can be used. The term ~inert~
in this connection is considered to mean that the solvents ~ -
beha~e in a chemically neutral manner towards the binding
agent components under the conditions of mixing and stor- -
age. The following are named as examples of suitable pure
compounds: aromatic compounds such as toluene, xylenes,
,........ .
, j . .: ; .
~)43489
cumene, tetrahydronaphthalene, decahydronaphthalene;
ketones, such as methylisobutylketone, diisobutylketone,
isophorone; esters, such as acetic acid-n-butyl ester,
acetic acid-n-hexyl ester, acetic acid isoamyl ester,
acetic acid cyclohexyl ester, acetic acid-3,3,5-trimethyl-
cyclohexyl ester, lactic acid-n-butyl ester, ethylene glycol
acetate, butylene glycol acetate, and the like.
The amount of the solvent is not critical. It is de~-
sirable first to prepare a highly concentrated solution
in which the solid content ranges from 50 to 70%. ~his -
concentrated solution can be diluted to the concentration
specified for the desired application ~ust prior to use.
Agents for the improvement of leveling and gloss are,
for example, polyvinyl butyrals, copolymers of n-butyl
acrylate and vinyl isobutyl ether, ketone-aldehyde con- -
densation resins, solid silicone resins, silicone oils,
or mixtures of zinc soaps of fatty acids and aromatic
carboxylic acids.
.~ ..
Common commercial,sterically impeded, polyvalent phe-
nols of high molecular weight have proven valuable as
heat stabilizers and antioxidants, but others can also
~ 25 be used.
: ' ': .`
The quantity of the additives to be used will depend
on the ~ndividual case and on the desired properties of
the product. No general pronouncement can be made in this
.
regard.
_g _ .
.' ~ ~'-'.
lV43489
The polyester resin, blocked isocyanate, high-boiling
varnish solvent, the described varnish additives, and the
desired pigment or dye, if any are to be used, are mixed
together by known methods below the cleavage temperature
of the blocked isocyanate. If incompletely blocked iso-
cyanates are used, it is recommendable to sub~ect the dis-
solved resins to a thermal treatment between 80 and 160C
before proceeding with the rest of the varnish formulation.
The time of this treatment will amount to from 3 hours ~o
15 minutes, depending on the established temperature. The
solution can be brought to the desired solid content prior
to use by the addition of more solvent. -
." ` ' ' , . .
The varnishes of the invention find application in
coil coating processes for weather-resistant one-coat and
two-coat applications. In modified states they can also
be used in the spray painting field by the airless or
electrostatic spray method, especially for aluminum.
. .
. . - ,
.
.. . . .
-10- , .
. .
,
~)43489
The preparation and the application of the varni6hes
of the present invention is illustrated by the following
Examples:
Example 1
A. PreParation of the Hydroxvl-GrouD_Containina ~olvester
In a six-liter glass flask~ 10 moles (1,940 9) o tereph-
thalic acid dimethyl ester were sub~ected to transesterifica-
tion with 8 moles (1,280 g) of 2,2,4- and 2,4,4-trimethyl-
hexanediol-1,6 isomer mixture (approx. 40:60) and 3 molSs
(402 g) of l,l,l-trimethylolpropane. 0.05 wt.-% of tetra-
isopropyl titanate was used as transesterification catalyst.
The mixture was slowly heated until a uniform melt was
obtained, methanol being formed after a temperature of 185qC
was reached. In accordance with the methanol formation,
15 the temperature was increased over a period of 8 hours to -
` - a maximum of 215~C^ When virtually no more methanol was
being produced, the temperature was reduced to 200~C and
the reaction mixture was exposed for about 30 minutes to
` a ~acuum of 1 to 3 mm Hg~ whereupon the volatile content
was substantially removed from the melt.
;~ Chemical and ~hvsical characteristics of the Dolvester
` Hydroxyl number 93 - 95 mg KOH/g
Acid number Less than 1 mg KOH/g
Molecular weight 1,600 to 1,700
Glass transformation
temperature -5qC to +8C
B. PreDaration of the ~-CaDrolactam-Blocked Diisocvanates
In accordance with the following general specifications,
virtually completely capped diisocyanates were produced in
a known manner from hexamethylenediisocyanate-1,6 (HDI),
z .
' . -11- ' .
.;, ~ - .
.
.. . . . . . . . .
lV434~9
4,4'-diphenylmethanediisocyanate (HMDI) and 3-isocyanato-
methyl-3,5,5-trimethylcyclohexylisocyanate (IPDI).
Diisocyanate and ~-caprolactam were mixed in a glass
flask in a molar ratio of 1.0 : 2.0 and this mixture was
heated to about 80C. At about 80C the very exothermic
reaction started. The reaction mixture was kept below
150~C by appropriate cooling. After the temperature had
diminished to about 110C the reaction product was kept~
for an additional 2 hours at this temperature to complete
the reaction.
The reaction products, -caprolactam-blocked diiso-
cyanates, are solid resins whose free NC0 content is less
than 0.3% by weight.
! C.
To test the shelf life of these products, stoichio-
metric mixtures of the hydroxyl polyester with the various
, ,:
-~` 20 ~-caprolactam-blocked diisocyanates were dissolved to
form 60 wt.-% solutions in a 2 : 1 (weight-parts) mixture
of Solvesso(R) 150 and ethyleneglycol acetate. This procedure
was performed preferably with heating at about lOO~C.
(Solvesso(R) 150 is a mixture of aromatics boiling in a ~ -
25 range of 180 to 212qC and has a flame point of at least
65C. Supplier: Esso. Recommended as solvent for bake-on
1 varnishes and enamels.)
,,
-12-
~ r~
.r ~'
', ' .' ' ' ' .' ' `, , ' ` . ' ' , . '
.
1043489
Composition of the Solutions
Solution Polyester HDI+cap. HMDI~cap. IPDI+cap Solvent
No.(see above (see
under A) above)
C 1 45.0% 15% - - 40%
C 2 42.5% - 17.5% - 40%
C 3 43.5% - - 16.5% 40%
(All percentages in this table are percentages by weight.)
, .
D. Shelf Life of Solutions C 1~ C 2 and C, 3,
Solution State after storage at room temperature for
No.
O days 1 day 1 week 1 month 1 year
C 1 clear very much
solution turbid sedi-
solu- ment
` tion
.
. 15 C 2 clear clear little much
solution solu- sedi- sedi-
tion ment ment
C 3 clear clear clear clear clear
solution solu- solu- solution solution
tion tion
. .
E. ExamDle of Application
Starting with the solution identified as C 3, a pig-
mented varnish was formulated as specified below, hardened
, under ~coil coating~ conditions and tested. -
~- ,, .
Formula: 67.9 wt.-% of Solution C 3 ~ ~
2.0 wt.-% of n-butyleneglycol acetate -:~ -
30.0 wt.-% of white pigment (TiO2)
0.1 wt.-% of silicone oil OL leveling
agent, mfr.: Bayer AG
1 mm thick aluminum and steel sheet materials were ;~
coated with this varnish and hardened for 75 seconds at
-13-
* Trade Mark
~043489
- 310 to 320C in a circulating air drying oven. The tests
on a 25 micron thick coating showed the following charac- -
teristics:
Hardness Pendulum hardness (Konig) DIN 53157 175 sec.
measure- Impression hardness DlN 5315~ 100
(Buchholz)
ments Rocker hardness (Sward) 50
Lead pencil hardness 2 H
. _ . . _ . . _
Elasticity Erichsen cupping DIN 53156 ~10 m~m
Impact (reverse) >82 in~lb
T-bend test
.
Gloss Gardner ASTM-D-523 20 95
Gardner ASTM-D-523 45 60
Gardner ASTM-D_523 60 95-100
Adhesion Criss-cross slash test DIN 53151 0
-- ~ .
:.. . ..
ExamDle 2
A. PreDaration of the hYdroxYl-~rouP-containinq PolYester
7 moles of isophthalic acid (1,163 g), 6 moles of hex-
anediol-1,6 (709 9) and 2 moles of l,l,l-trimethylolpropane
(268 9) were subjected to esterification in a 4-liter glass
flask with the addition of 0.1 wt.-% of n-dibutyl tin oxide.
As the temperature increased a homogeneous melt formed and
water first began to form at about 195C. Over a period of
8 hours the temperature was increased to 220C and the
esterification was carried to completion at this tempera-
30 ture for an additional 6 hours. The acid number was then `
-14_
i
lV43489
less than 1 mg KOH/g. After the polyester melt had cooled
down to about 200C, the volatile components were removed
under a vacuum of 20 to 30 mm Hg for 30 to 45 minutes.
During the entire reaction a weak current of nitrogen
gas was passed through the reaction system.
Chemical and PhYsical Characteristics
OH number 105 mg KOH/g
Acid number <1 mg KOH/g
Molecular weight 2,400
Glass transformation temp. -12C to ~SC
`:
B. Pre~aration of the ~_Caprol,ac~,am-Blocked Diisocvanates
In accordance with the general specifications (cf.
Example 1), ~-caprolactam-blocked diisocyanates were pre-
- 15 pared which, in contrast to the products described in Ex- ~
ample 1, still had a content of free NCO groups after the - --
,~ reaction.
- The following list shows the composition of the
batches in parts by weight,and the free NCO group contents
experimentally determined after the blocking process.
Number Diisocyanate Blocking Agent Free NCO group content ,~
B 1 1000 p. HDI 1211 p. cap. 2.05 weight-percent
B 2 1000 p. HMDI 776 p. cap. 2.01 weight-percent
B 3 1000 p. IPDI 914 p. cap. 1.98 weight-percent ~ ~
,i 25 '~ " ',
'C. PreDaration of the Varnish Solutions -
The polyester described under A and one of the blocked
i isocyanate adducts described under B were dissolved in a
t' ~tolehlom~tric ratio in a solvent mixture of Solvesso(R) 150
and ethyleneglycol acetate (EGA) in a ratio of 2 : 1 by weight
-15-
:6~ "
' ' ':"
~: . .. . . . . . .
lV43489
- to form 60 weight-percent solutions, and the free NC0
groups were made to react. For this purpose the solu-
tion was heated to lOOqC and held at that temperature
for 1 to 2 hours.
Com~osition of the Solutions
Solution Polyester Blocked Diisocyanate Solvent
(see A) (see B)
. . . . . ...
C 1 45.1% 14.9% 40%
C 2 42.4~ 17.6% 40X
lo c 3 43.5% 16.5X 40%
. .
(All percentages in this table are percentages by weight.)
D. Shelf Life Tests
~ 15 Specimens of the solutions described under C were
; stored at temperatures between 5 and 8C and samples
were taken at certain intervals for testing for turbid-
ity and precipitation.
Solution State after storage at 5 to 8C for
~ O days 1 week 4 weeks 3 months
C 1 slightly very sediment
turbid turbid
` C 2 clear clear decidedly very
turbid turbid -
C 3 clear clear clear clear
. ~
E. ExamD,le of ADDlication ¦-
With the solution described under C 3, a varnish ~`
was prepared according to the following formula:
~'
- -16- : `
~043~89 .;
Formula: 62.5% solution C 3 (see above)
8.0% solvent mixture: . .
Solvesso( ) 150/EGA, 2 : 1
29.5% white pigment (TiO2)
0.1% silicone oil
`~ Aluminum and steel sheets 1 m~ thick were coated
with this pigmented varnish and hardened for 75 seconds
at 310-320C in a circulating air drying oven~ The test-
ing of a 25-m~cron thick coating showed the following:
Hardness Pendulum hardness (Konig) DIN 53157 170 sec.
measure- Impression hardness DIN 53153 111
(Buchholz)
ments Rocker hardness (Sward) 45-55
Lead pencil hardness H - 2H
Elasti- Erichsen cupping DIN 53156 ~10 mm
city Impact (reverse) ~82 inch-lb
T-bend test 0 -
, . ` :.
3, Adhesion Criss-cross slash test DIN 53151 0
__
. Gloss Gardner ASTM-D-523 20 70-75
50-55
60 85-90
-
25 . ~`
.' . - .
.~, ' ' J'' '''` '.
., ' ". ' .
. -17~
.- ' . , ' '
~.
., .
~043489
Examples for Purposes of Comparison
Exam~le 3
In the polyester described in Example 2, one of the
seven moles of isophthalic acid was replaced with adipic
acid. The polyester was thus prepared from 6 moles (1000
g) of isophthalic acid, 1 mole (146 9) of adipic acid, 6
moles (709 g) of hexanediol-1,6 and 2 moles (268 g) of
l,l,l-trimethylolpropane in the manner described in Ex-
ample 2.
Chemical and ~hysical Characteristics
OH number 117 mg KOH/g
Acid number <1 mg KOH/g
Molecular weight 2000
Glass transformation temp. -20 to -15C
`~ On the basis of this polyester and the adduct of
3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate
~` (IPDI) described in Example 1, a pigmented varnish of
` the following formula was prepared and applied:
27.4 wt~-% polyester (see above)
13.4 wt.-% adduct (see Ex. 1)
29.1 wt.-% white pigment (TiO2)
10.0 wt--% ethyleneglycol acetate
20.0 wt.-% Solvesso( 150
0.1 wt.-X silicone oil OL
Evaluation will be given at the end of Example 5.
...
., .
- :,
; 30
~ ~ -18-
..
. .. .. . . . . ..
1()434~39
Example 4
In the polyester described in Example 1, the tereph-
thalic acid was replaced with hexahydroterephthalic acid.
10 moles of hexahydroterephthalic acid dimethyl ester
(2000 g), 8 moles (1280 g) of 2,2,4- and 2,4,4-trimethyl-
hexanediol-1,6 isomer mixture (appxox. 40:60) and 3 moles
(402 g) of l,l,l-trimethylolpropane were transesterified
in the manner described in Example 1.
Chemic~ d P)~Ysi-c~al5~i~i~ ~
Hydroxyl number 98 mg KOH/g ~ --
Acid number ~1 mg KOH/g
Molecular weight 1600
Glass transfoxmation temp. -30C
. ~ .
With this polyester and the adduct of isophorone-
d~isocyanate (IPDI) described in Example 1, a pigmented
varnish was prepared in accordance with the following
formula and applied to 1 mm steel and aluminum sheets
and set for 90 seconds at 300C:
29.0 wt.-% polyestex of Example 4
11.0 wt.-% IPDI adduct (see Example 1)
- 30.0 wt.-% white pigment (TiO2) ~
10.0 wt.-% ethyleneglycol acetate .
20.0 wt.-% Solvesso(R) 150
0.1 wt.-% silicone oil OL
See evaluation at end of Example 5.
. ~ .;
. ..
., ~ ~
-19-
' r~D'`~ ', ;~
, . : . " . .
1()434~9
Example 5
6 moles (740 g) of phthalic acid anhydride, 3 moles
(438 9) of adipic acid, 2 moles (208 ~) of 2,2-dimethyl-
propanediol-1,3, 4.5 moles (531 g) of hexanediol-1,6, and
5 2 moles (268 g) of l,l,l-trimethylolpropane were subjected
to esterification in the usual manner under the catalytic
effect of 0.1 wt.-% of di-n-butyl tin oxide.
Chem~cal and PhYsical Characteristics
Hydroxyl number 76 mg KOH/g
10Acid number 3 mg KOH/g
Molecular weight 2700
Glass transf. temp. -20 to -15C
A varnish was prepared in accordance with the follow-
- ing formula, from this polyester and the adduct of iso-
15 phoronediisocyanate described in Example 1, for testing
purposes:
27.7 wt.-% polyester (see above)
`~ 8.7 wt.-% adduct (cf. Example 1)
27.5 wt.-% white pigment (TiO2)
2012.0 wt.-% ethyleneglycol acetate ~:
24.0 wt.-% Solvesso(R) 150 ~
0.1 wt.-% Silicone oil OL --
~..
Comparative Review of the Most ImDortant Test Results ~
2~iObtained with Varnishes from ExamDles 1. 2. 3. 4 and 5 --
- Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5
Pendulum 175 170 140 60 20 -
hardness sec. sec. sec. sec. sec. -
Lead pen- :
C~1 hardn. 2H H-2H F F-HB B-HB
30 T-bend 1 0 1-2 0-1 0
test
,.
.. . . . . . . . . . . . . . .
. . . , . : :
1043489
Example 6
The polyester described in Example 1 was modified
by changing the molar ratio of glycol to higher-function
alcohols from 2.65 : 1 to 1 : 1.
10 moles (1940 9) of terephthalic acid dimethyl ester,
5.85 moles (785 g) of l,l,l-trimethylolpropane and 5.85
moles (940 9) of 2~2,4- and 2,4,4-trimethylhexanediol-1,6
isomer mixture were subjected, after the addition of 3.7 9
of tetraisopropyltitanate, to transesterification in th~
manner described in Example 1 to form a hydroxyl polyester.
Chemical and PhYsical Characteristics
Hydroxyl number 150 mg KOH/g
Acid number <1 mg KOH/g
Molecular weight 2600
Glass transformation temp. 14 to 28qC
In the following table the most important test results
obtained with the varnish described in Example 1 are com-
pared with a varnish prepared on the basis of the polyester ~
described in this example and made in accordance with the '
20 following formula: --
; 22.6 wt.-X hyd~oxyl polyester (see abcve)
- 13.8 wt.-% adduct (cf. Example 1)
30.2 wt.-% white pigment (TiO2)
ll.l wt.-% ethyleneglycol acetate
22.2 wt.-% Solvesso(R) 150
^ 0~1 wt.-% silicone oil OL
Varnish Pendulum Lead Pencil T-bend Test
formula hardness hardness
- Example 6 170 sec. 3H 4 _ 5
Example 1 175 sec. 2H
-21-
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