U.S. patent application number 17/115056 was filed with the patent office on 2021-03-25 for curable fluorocopolymer formed from tetrafluoropropene.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. The applicant listed for this patent is HONEYWELL INTERNATIONAL INC.. Invention is credited to SHIJUN FENG, WANCHAO JIANG, YUN LIN, ANDREW J. POSS, SIYUAN ZHANG.
Application Number | 20210087308 17/115056 |
Document ID | / |
Family ID | 1000005260908 |
Filed Date | 2021-03-25 |
United States Patent
Application |
20210087308 |
Kind Code |
A1 |
JIANG; WANCHAO ; et
al. |
March 25, 2021 |
CURABLE FLUOROCOPOLYMER FORMED FROM TETRAFLUOROPROPENE
Abstract
The present invention is directed to partially fluorinated
copolymers and the production thereof. More specifically, the
copolymers, which are preferably produced by a solution
polymerization process, preferably have at least three units, the
first unit selected from 2,3,3,3-tetrafluoropropene and
1,3,3,3-tetrafluoropropene, the second unit having a polymerized
monomer selected from the vinyl esters and vinyl ethers, and the
third unit having a polymerized monomer derived from a hydroxyl
group-containing vinyl ether. The resulting copolymer is
environmentally friendly, has favorable molecular weight
characteristics, and may be shipped economically in high
concentration.
Inventors: |
JIANG; WANCHAO; (SHANGHAI,
CN) ; FENG; SHIJUN; (SHANGHAI, CN) ; ZHANG;
SIYUAN; (SHANGHAI, CN) ; LIN; YUN; (SHANGHAI,
CN) ; POSS; ANDREW J.; (KENMORE, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HONEYWELL INTERNATIONAL INC. |
Morris Plains |
NJ |
US |
|
|
Assignee: |
HONEYWELL INTERNATIONAL
INC.
MORRIS PLAINS
NJ
|
Family ID: |
1000005260908 |
Appl. No.: |
17/115056 |
Filed: |
December 8, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16220189 |
Dec 14, 2018 |
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17115056 |
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15477645 |
Apr 3, 2017 |
10189918 |
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16220189 |
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14463747 |
Aug 20, 2014 |
9624325 |
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15477645 |
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61894146 |
Oct 22, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C09D 127/12 20130101;
C08F 214/188 20130101; C08F 214/18 20130101; C08F 214/186 20130101;
C08F 14/18 20130101; C08F 14/185 20130101; C08F 4/76 20130101 |
International
Class: |
C08F 14/18 20060101
C08F014/18; C08F 4/76 20060101 C08F004/76; C08F 214/18 20060101
C08F214/18; C09D 127/12 20060101 C09D127/12 |
Claims
1-10. (canceled)
11. A copolymer composition comprising a copolymer, the copolymer
comprising: (a) a first unit comprising a polymerized monomer of
2,3,3,3-tetrafluoro-propene; (b) a second unit comprising a
polymerized monomer selected from the group consisting of vinyl
esters and vinyl ethers; and (c) a third unit comprising a
polymerized monomer comprising a hydroxyl group-containing vinyl
ether.
12. The copolymer composition of claim 11, wherein the copolymer
comprises 40 to 60 mol % of said first unit.
13. The copolymer composition of claim 12, wherein the copolymer
comprises 5 to 45 mol % of said second unit, wherein said second
unit is selected from the group consisting of alkyl vinyl ethers,
vinyl esters, and mixtures thereof.
14. The copolymer composition of claim 13, wherein the copolymer
comprises 3 to 30 mol % of said third unit, wherein said second
unit consists of hydroxyalkyl vinyl ethers.
15-18. (canceled)
19. The composition of claim 11, wherein said copolymer consists
essentially of said polymerized 2,3,3,3-tetrafluoropropene, vinyl
esters, vinyl ethers; and hydroxyl group-containing vinyl
ether(s).
20. The composition of claim 11, wherein the copolymer has a number
average molecular weight of between 5000 and 50000.
21. The composition of claim 11, wherein the copolymer has a number
average molecular weight of between 5000 and 10000.
22. The composition of claim 11 wherein the composition further
comprises a solvent.
23. The composition of claim 22 wherein said solvent comprises
15-25 wt % of said composition.
24. The composition of claim 11 wherein said composition comprises
at least 70 wt % of said copolymer.
25. A process for the production of the copolymer of claim 11,
wherein said monomers are polymerized in a solution to produce the
copolymer.
26. A copolymer composition comprising a copolymer, the copolymer
comprising: (a) from 40 mol % to 60 mol % of polymerized monomers
of 2,3,3,3-tetrafluoropropene; (b) from 5 mol % to 45 mol % of
polymerized monomers of vinyl esters, or vinyl ethers, or a
combination thereof; and (c) from 3 mol % to 30 mol % of
polymerized monomers of hydroxyl group-containing vinyl
ether(s).
27. The composition of claim 26, wherein said vinyl ester is a
compound of formula CH.sub.2.dbd.CR.sup.1--O(C.dbd.O)R.sup.2, and
said vinyl ether is a compound of formula
CH.sub.2.dbd.CR.sup.3--OR.sup.4, wherein each of R.sup.1 and
R.sup.3 individually is hydrogen or a methyl group, and wherein
each of R.sup.2 and R.sup.4 individually is an unsubstituted
straight-chain, branched-chain or alicyclic alkyl group having 1 to
12 carbon atoms.
28. The composition of claim 27, wherein said vinyl ester is a
vinyl versatate ester formed from a C9 carboxylic acid or a vinyl
versatate ester formed from a C10 carboxylic acid.
29. The composition of claim 26, wherein said hydroxyl
group-containing vinyl ether(s) is a compound of formula
CH.sub.2.dbd.CR.sup.5--OR.sup.6, wherein R.sup.5 is hydrogen or a
methyl group, and R.sup.6 is an unsubstituted straight-chain,
branched-chain or alicyclic alkyl group having a hydroxyl
groups.
30. The composition of claim 29, wherein said vinyl ether is ethyl
vinyl ether.
31. A copolymer composition comprising a copolymer, the copolymer
comprising: (a) from 45 mol % to 55 mol % of polymerized monomers
of 2,3,3,3-tetrafluoropropene; (b) from 25 mol % to 45 mol % of
polymerized monomers of ethyl vinyl ether and a vinyl versatate
ester formed from a C10 carboxylic acid; and (c) from 5 mol % to 20
mol % of polymerized monomers comprising hydroxyl butyl vinyl
ether.
32. The composition of claim 31 wherein said composition comprises
at least 70 wt. % of said copolymer.
33. The composition of claim 31 wherein said composition further
comprises a solvent.
34. The composition of claim 33 wherein said solvent comprises
15-25 wt % of said composition.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Continuation of co-pending U.S.
patent application Ser. No. 16/220,189 filed Dec. 14, 2018, which
is a Continuation of U.S. patent application Ser. No. 15/477,645
filed Apr. 3, 2017, now U.S. Pat. No. 10,189,918 as granted on Jan.
29, 2019, which is a Continuation of U.S. patent application Ser.
No. 14/463,747 filed Aug. 20, 2014, now U.S. Pat. No. 9,624,325 as
granted on Apr. 18, 2017, which claims the benefit of U.S.
Provisional Patent Application Ser. No. 61/894,146, filed Oct. 22,
2013, the disclosures of which are hereby incorporated herein by
reference. U.S. Provisional Patent Application Ser. No. 61/894,146
is related to U.S. patent application Ser. No. 13/645,444, filed on
Oct. 4, 2012, U.S. patent application Ser. No. 13/645,437, filed on
Oct. 4, 2012, U.S. Provisional Patent Application Ser. No.
61/543,780, filed on Oct. 5, 2011, and U.S. Provisional Patent
Application Ser. No. 61/543,714, filed on Oct. 5, 2011, the
disclosures of which are hereby incorporated herein by reference in
their entireties.
BACKGROUND OF THE DISCLOSURE
Field of the Invention
[0002] The present invention generally relates to novel curable
copolymers formed, at least in part, from tetrafluoropropene. More
specifically, the present invention relates to curable copolymers
formed in part from monomeric material comprising
2,3,3,3-tetra-fluoropropene (CF.sub.3CF.dbd.CH.sub.2, "HFO-1234yf")
and/or 1,3,3,3-tetrafluoropropene (CH.sub.2.dbd.CFCF.sub.3,
"HFO-1234ze"), and to compositions and uses thereof.
Description of the Related Art
[0003] Fluoropolymers such as polytetrafluoroethylene (PTFE),
polychlorotrifluoro-ethylene (PCTFE) and polyvinylidene fluoride
(PVDF) are well known for having excellent thermal, chemical, and
weather resistance, along with favorable properties like water and
oil resistance. Unfortunately, the use of such fluoropolymers in
coatings is difficult owing to their poor solubility in industrial
solvents--such as xylene and butyl acetate--which are typically
used in the coating industry. Instead, more exotic solvents must
often be used, which not only affect the economics of a coating,
but can also present environmental issues owing to, e.g., potential
toxicity of the exotic solvents.
[0004] Accordingly, there is a need to formulate alternative
coatings which have superior performance properties, yet can use
economical industrial solvents and be environmentally friendly.
[0005] Furthermore, polymerization of fluorinated polymers presents
a number of challenges, e.g., as detailed in prior application Ser.
No. 13/645,437 (now U.S. Patent Publication No. 2013/0090439 A1),
incorporated herein by reference. Although several types of
polymerization methods to make tetrafluoropropene copolymers have
been described in prior application Ser. No. 13/645,437, Applicants
have come to further appreciate that these polymerization methods
have undesirable aspects or limitations, and/or that the polymers
produced thereby can be formed with different and/or improved
properties.
[0006] Accordingly, Applicants have come to appreciate a need to
develop improved processes for making tetrafluoropropene copolymers
having different and/or improved properties for uses in various
applications.
SUMMARY OF THE INVENTION
[0007] In accordance with a first aspect of the present invention,
a curable fluorocopolymer can be formed by solution
copolymerization of the monomers represented by (a), (b) and
(c):
(a) 40 to 60 mol % of tetrafluoropropene; (b) 5 to 45% of vinyl
ether or vinyl ester or both of them, represented by formula
CH.sub.2.dbd.CR.sup.1--O(C.dbd.O).sub.xR.sup.2 and
CH.sub.2.dbd.CR.sup.3--OR.sup.4 respectively, wherein R.sup.1 and
R.sup.3 is hydrogen or a methyl group, and wherein R.sup.2 and
R.sup.4 is an unsubstituted straight-chain, branched-chain or
alicyclic alkyl group having 1 to 12 carbon atoms; and (c) 3 to 30
mol % of hydroxyalkyl vinyl ether, represented by formula
CH.sub.2.dbd.C--R.sup.5--OR.sup.6, wherein R.sup.5 is hydrogen or a
methyl group, and R.sup.6 is an unsubstituted straight-chain,
branched-chain or alicyclic alkyl group having a hydroxyl
groups.
[0008] In accordance with a second aspect of the present invention,
the tetrafluoro-propene is selected from either or both of
HFO-1234yf and HFO-1234ze. In accordance with the present
invention, the applicants have found that environmentally friendly
HFO-1234yf and HFO-1234ze can each, and in combination, be employed
advantageously as fluorinated monomers for the production of
polymeric coatings.
[0009] In accordance with a third aspect of the present invention,
a product containing the curable fluorocopolymer has a solvent
content of 15-50%, and preferably, 15-25%, so as to provide a
concentrated product which is economical to ship to the user of the
product.
DETAILED DESCRIPTION OF THE INVENTION
[0010] In accordance with a preferred embodiment of the present
invention, the 40-60 mol % tetrafluoropropene in the form of
HFO-1234yf and/or HFO-1234ze is used as component (a), and most
preferably, 45 to 55 mol %. If a mixture of HFO-1234yf and
HFO-1234ze is used, the blending ratio of HFO-1234yf and HFO-1234ze
is used can be any ratio, but preferably is 0.3 to 0.7:0.7 to
0.3.
[0011] A copolymer in accordance with the present invention may
contain vinyl ether units, vinyl ester units, or a combination
thereof as component (b). Preferably, 5 to 45 mol % is used, and
most preferably, 25-45 mol % is used. Examples of vinyl ether
include alkyl vinyl ethers such as methyl vinyl ether, ethyl,
propyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether,
hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether and lauryl
vinyl ether. Vinyl ethers including an alicyclic group can also be
used, for example, cyclobutyl vinyl ether, cyclopentyl vinyl ether
and cyclohexyl vinyl ether. Examples of vinyl esters include vinyl
acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl
capronate, vinyl laurate, VEOVA-9 (vinyl versatate ester formed
from a C9 carboxylic acid, produced by Momentive), VEOVA-10 (vinyl
versatate ester formed from a C10 carboxylic acid, produced by
Momentive) and vinyl cyclohexanecarboxylate.
[0012] Examples of the hydroxyalkyl vinyl ether of component (c)
include hydroxyl-ethyl vinyl ether, hydroxypropyl vinyl ether,
hydroxybutyl vinyl ether, hydroxypentyl vinyl ether and
hydroxyhexyl vinyl ether. Preferably 3 to 30 mol % is used, and
most preferably, 5 to 20 mol % is used.
[0013] The fluorocopolymer is preferably produced in a solution
polymerization system. Examples of solvents for solution
polymerization include: esters, such as methyl acetate, ethyl
acetate, propyl acetate and butyl acetate; ketones, such as
acetone, methyl ethyl acetone and cyclohexanone; aliphatic
hydrocarbons, such as hexane, cyclohexane, octane, nonane, decane,
undecane, dodecane and mineral spirits; aromatic hydrocarbons, such
as benzene, toluene, xylene, naphthalene, and solvent napthta;
alcohols, such as methanol, ethanol, tert-butanol, iso-propanol,
ethylene glycol monoalkyl ethers; cyclic ethers, such as
tetrahydrofuran, tetrahydropyran, and dioxane; fluorinated
solvents, such as HCFC-225 and HCFC-141b; dimethyl sulfoxide; and
the mixtures thereof.
[0014] Preferably, polymerization is conducted in a range of
-30.degree. C. to 150.degree. C. depending on the polymerization
initiation source and type of the polymerization medium.
[0015] The copolymer of the present invention is preferably
prepared by copolymerizing those monomers and having a number
average molecular weight of 5000 to 50000, and more preferably 5000
to 10000. Preferably, the copolymer has a molecular weight
distribution of 2 to 10, more preferably 2.5 to 8, and most
preferably 3 to 6. When the number average molecular weight is less
than 5000, the copolymer is inferior in weatherability and chemical
resistance, and when more than 50000, high viscosities may cause
operational difficulties.
[0016] The copolymer of the present invention has hydroxyl groups
and it is curable with a curing agent such as melamine resin curing
agent, urea resin curing agent, polybasic acid curing agent and a
non-blocked polyisocyanate curing agent or a blocked polyisocyanate
curing agent which are used for conventional thermosetting acryl
coating. Examples of melamine resin curing agents include butylated
melamine resin, methylated melamine resin, epoxymelamine resin and
the like. Examples of non-blocked polyisocyanate include 2,4- and
2,6-diisocyanatotoluene (TDI), diphenylmethane-2,4'- and/or
-4,4'-diisocyanate (MDI), 1,6-hexamethylene diisocyanate (HDI),
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI),
dicyclohexylmethane diisocyanate (H12MDI), 1,4-diisocyanatobutane,
2-methyl-1,5-diisocyanatopentane,
1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or
2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanato-decane,
1,3- and 1,4-diisocyanatocyclohexane, 1,3- and
1,4-bis-(isocyanatomethyl)-cyclohexane,
4,4'-diisocyanatodicyclohexylmethane,
1-isocyanato-1-methyl-4(3)-isocyanato-methylcyclohexane (IMCI),
bis-(isocyanatomethyl)-norbornane, 1,3- and
1,4-bis-(2-isocyanato-prop-2-yl)-benzene (TMXDI),
1,5-diisocyanatonaphthalene, 2,4'-,
4,4'-diisocyanatodiphenylmethane, and their dimers, trimers and
polymers thereof. As to blocked polyisocyanate, preferred blocking
groups employed for blocking polyisocyanates include metal
bisulfite, diethyl malonate (DEM) 3,5-dimethylpyrazole (DMP),
methyl-ethylketoxime (MEKO) e-caprolactam (e-CAP),
diisopropylamine, dimethyl-pyrazole, methyl ethyl ketoxime
(butanone oxime), malonic acid diethyl ester, secondary amines and
triazole and pyrazole derivatives. When the curing is conducted at
an ordinary temperature by using polyisocyanate, it is possible to
accelerate the curing by an addition of a conventional catalyst
such as dibutyltin dilaurate
[0017] Various solvents can be used for the preparation of
solution-type paints or coatings with the copolymer of the present
invention. Preferred solvents include aromatic hydrocarbons such as
xylene and toluene; alcohols such as n-butanol; esters such as
butyl acetate; ketones such as methyl isobutyl ketone, and glycol
ethers such as ethyl cellusolve and various commercial thinners.
When the copolymer of the present invention is used for producing a
thermosetting composition for coating, a curing agent such as a
melamine type curing agent, a urea type curing agent, a polybasic
acid type curing agent, a polyisocyanate type curing agent or the
like is simultaneously mixed in the mixing step mentioned above to
produce a one-pack type coating.
[0018] On the other hand, when the composition is a normal
temperature setting type coating which uses a polyisocyanate, the
curing agent component is separately prepared to provide a two-pack
type coating. In this case, the coating can be cured at room
temperature for from several hours to several days, and has good
properties by controlling the type of isocyanate and catalyst and
their amounts to be added, the concentration of the copolymer, the
contents of the hydroxyalkyl vinyl ether in the copolymer, and the
like.
[0019] When the copolymer of the present invention is used as resin
for paint or coating, it is possible to form under a mild
condition, a film having excellent hardness of finish and gloss,
flexibility, chemical resistance, stain resistance and weathering
resistance. Such films are useful not only as a coating for
pre-coated galvanized steel, colored aluminum plate and aluminum
frames, but also as an on-site paintable non-thermally dryable
paint. The paint or coating may be used for a number of substrates,
including: metallic substrates; inorganic substrates such as glass,
cement and concrete; organic substrates, for example, plastics
(such as polyethylene, polypropylene, ethylene-vinyl acetate
copolymer, nylon, acryl polyester ethylene-polyvinyl alcohol
copolymer, vinyl chloride, vinylidene chloride) and wood materials.
Specific applications for the paint or coating include, but are not
limited to, the coating of aluminum swimming pools, the coating of
colored glass intended for exterior use, and the coating of cement
tile used for roofing.
[0020] The present invention is further illustrated by the
following non-limiting examples.
EXAMPLE 1
[0021] 19.0 g of butyl acetate, 9.5 g of ethyl vinyl ether, 20.8 g
of VEOVA-9, 8.0 g of hydroxybutyl vinyl ether, and 0.62 g of
tert-butyl peroxypivalate were charged into a 300 ml stainless
steel autoclave equipped with a stirrer. The mixture was solidified
with liquid nitrogen, and deaerated to remove the dissolved air.
Then, 50 g of 1,3,3,3-tetrafluoro-propene was added to the mixture,
and the mixture was gradually heated to 65.degree. C. in an
autoclave. The mixture was stirred for 18 hours. After the
autoclave was cooled to room temperature, the unreacted monomers
were purged and the autoclave was opened. Excess solvent was
removed via evaporation.
[0022] Yield 92%; T.sub.g (glass transition temperature) of final
copolymer=15.degree. C.; Mn=7348; Mw=13789; Mw/Mn=1.87; final
polymer concentration=74.7%; viscosity<500 cps.
EXAMPLE 2
[0023] 20.0 g of butyl acetate, 9.1 g of ethyl vinyl ether, 6.0 g
of vinyl acetate, 6.7 g of hydroxybutyl vinyl ether, and 0.4 g. of
tert-Butyl peroxypivalate were charged into a 300 ml stainless
steel autoclave equipped with a stirrer. The mixture was solidified
with liquid nitrogen, and deaerated to remove the dissolved air.
Then, 40 g of 2,3,3,3-tetrafluoro-propene was added to the mixture,
and the mixture was gradually heated to 65.degree. C. in an
autoclave. The mixture was stirred for 18 hours. After the
autoclave was cooled to room temperature, the unreacted monomers
were purged and the autoclave was opened. Excess solvent was
removed via evaporation.
[0024] Yield 91%; T.sub.g of final copolymer=11.degree. C.;
Mn=5314; Mw=12646; Mw/Mn=2.38; final polymer concentration=73.8%;
viscosity<600 cps.
EXAMPLE 3
[0025] 20.0 g of butyl acetate, 8.0 g of ethyl vinyl ether, 17.4 g
of VEOVA-9, 6.7 g. of hydroxybutyl vinyl ether, and 0.63 g. of
tert-butyl peroxypivalate were charged into a 300 ml stainless
steel autoclave equipped with a stirrer. The mixture was solidified
with liquid nitrogen, and deaerated to remove the dissolved air.
Then, 60 g of 1,3,3,3-tetrafluoro-propene was added to the mixture,
and the mixture was gradually heated to 65.degree. C. in an
autoclave. The mixture was stirred for 18 hours. After the
autoclave was cooled to room temperature, the unreacted monomers
were purged and the autoclave was opened. Excess solvent was
removed via evaporation.
[0026] Yield 93%; T.sub.g of final copolymer=32.degree. C.;
Mn=7136; Mw=24103; Mw/Mn=3.37; final polymer concentration=81.1%;
viscosity<700 cps.
EXAMPLE 4
[0027] 20.0 g of butyl acetate, 8.2 g of ethyl vinyl ether, 22.3 g
of VEOVA-9, 3.4 g of hydroxybutyl vinyl ether, and 0.66 g of
tert-butyl peroxypivalate were charged into a 300 ml stainless
steel autoclave equipped with a stirrer. The mixture was solidified
with liquid nitrogen, and deaerated to remove the dissolved air.
Then, 50 g. of 1,3,3,3-tetrafluoro-propene was added to the
mixture, and the mixture was gradually heated to 65.degree. C. in
an autoclave. The mixture was stirred for 18 hours. After the
autoclave was cooled to room temperature, the unreacted monomers
were purged and the autoclave was opened. Excess solvent was
removed via evaporation.
[0028] Yield 85%; T.sub.g of final copolymer=12.degree. C.;
Mn=4640; Mw=8079; Mw/Mn=1.74; final polymer concentration=78.1%;
viscosity<600 cps.
EXAMPLE 5
[0029] 30.0 g of butyl acetate, 7.6 g of ethyl vinyl ether, 18.4 g
of VeoVa-9, 6.7 g of hydroxybutyl vinyl ether, and 0.60 g of
tert-butyl peroxypivalate were charged into a 300 ml stainless
steel autoclave equipped with a stirrer. The mixture was solidified
with liquid nitrogen, and deaerated to remove the dissolved air.
Then, 60 g of 1,3,3,3-tetrafluoro-propene was added to the mixture,
and the mixture was gradually heated to 65.degree. C. in an
autoclave. The mixture was stirred for 18 hours. After the
autoclave was cooled to room temperature, the unreacted monomers
were purged and the autoclave was opened. Excess solvent was
removed via evaporation.
[0030] Yield 82%; T.sub.g of final copolymer=22.degree. C.;
Mn=7640; Mw=17620; Mw/Mn=2.31; final polymer concentration=71.7%;
viscosity<600 cps.
APPLICATION EXAMPLE
[0031] 26.1 g of the resulting copolymer was dissolved in 17.9 g of
butyl acetate, and then blended with 22.3 g of titanium oxide. The
mixture was mixed for 1 hour by a paint shaker, then subsequently
mixed with 14.8 g of DESMODUR BL4265, and 0.3 g of dibutyl tin
dilaurate (1% concentration). The mixture was then used to coat an
aluminum substrate. About 72 hours later, the physical properties
of the surface were tested.
[0032] The gloss (ISO 2813) of the surface=70 (20.degree. C.);
Hardness (Pencil Test; ASTM D3363)=3H; Flexibility (ASTM D4145)=3T;
Adhesion (ASTM D3359)=5B.
[0033] From the foregoing, it will be appreciated that although
specific examples have been described herein for purposes of
illustration, various modifications may be made without deviating
from the spirit or scope of this disclosure. It is therefore
intended that the foregoing detailed description be regarded as
illustrative rather than limiting, and that it be understood that
it is the following claims, including all equivalents, that are
intended to particularly point out and distinctly claim the claimed
subject matter.
* * * * *