U.S. patent application number 10/723489 was filed with the patent office on 2005-05-26 for blocked polyisocyanate.
Invention is credited to Jacobs, Patricia B., Pethiyagoda, Dinesh, Riggio, Tabitha H., Roesler, Richard R., Salek, Marianne M., Yuhas, Emery.
Application Number | 20050113550 10/723489 |
Document ID | / |
Family ID | 34465709 |
Filed Date | 2005-05-26 |
United States Patent
Application |
20050113550 |
Kind Code |
A1 |
Roesler, Richard R. ; et
al. |
May 26, 2005 |
BLOCKED POLYISOCYANATE
Abstract
The present invention is directed to a blocked polyisocyanate
based on nonane triisocyanate. More particularly, the invention is
directed to a blocked polyisocyanate useful in solvent borne
coating compositions and comprising the reaction product of: a)
nonane triisocyanate; b) a pyrazole blocking agent; and c) a diol
or polyol.
Inventors: |
Roesler, Richard R.;
(Wexford, PA) ; Jacobs, Patricia B.; (Pittsburgh,
PA) ; Pethiyagoda, Dinesh; (Pittsburgh, PA) ;
Riggio, Tabitha H.; (Murryville, PA) ; Salek,
Marianne M.; (Oakdale, PA) ; Yuhas, Emery;
(McDonald, PA) |
Correspondence
Address: |
BAYER MATERIAL SCIENCE LLC
100 BAYER ROAD
PITTSBURGH
PA
15205
US
|
Family ID: |
34465709 |
Appl. No.: |
10/723489 |
Filed: |
November 26, 2003 |
Current U.S.
Class: |
528/45 ;
252/182.22 |
Current CPC
Class: |
C08G 18/10 20130101;
C08G 18/73 20130101; C08G 18/10 20130101; C08G 18/807 20130101 |
Class at
Publication: |
528/045 ;
252/182.22 |
International
Class: |
C08G 018/00; C08G
018/81 |
Claims
What is claimed is:
1. A blocked polyisocyanate comprising the reaction product of: a)
nonane triisocyanate; b) a pyrazole blocking agent; and c) a diol
or polyol having a number average molecular weight of from about 62
to about 600 and wherein i) the isocyanate to hydroxy equivalent
ratio of component a) to component c) is from 1:0.15 to 1:0.6 and
ii) the equivalent ratio of isocyanate groups to blocking groups is
from 1:0.4 to 1:0.85.
2. The blocked polyisocyanate of claim 1, wherein the number
average molecular weight of component c) is from about 62 to about
200.
3. The blocked polyisocyanate of claim 1, wherein i) the isocyanate
to hydroxy equivalent ratio of component a) to component c) is from
1:0.15 to 1:0.25 and ii) the equivalent ratio of isocyanate groups
to blocking groups is from 1:0.75 to 1:0.85.
4. The blocked polyisocyanate of claim 1, wherein said pyrazole
blocking agent is selected from the group consisting of
3,5-dimethylpyrazole, 4-nitro-3,5-dimethylpyrazole,
4-benzyl-3,5-dimethypyrazole,
methyl-5-methylpyrazole-3-carboxylate, pyrazole,
3-methyl-5-phenylpyrazol- e, 3-methylpyrazole,
4-bromo-3,5-dimethylpyrazole and
3,5-dimethylpyrazole-4-carboxanilide.
5. The blocked polyisocyanate of claim 1, wherein said pyrazole
blocking agent is 3,5-dimethylpyrazole.
Description
BACKGROUND OF THE INVENTION
[0001] Nonane triisocyanate (NTI or 4-isocyanatomethyl-1,8-octane
diisocyanate) is a known material. Various uses for NTI have been
suggested. See, e.g., U.S. Pat. Nos. 4,314,048; 5,714,564;
5,854,301; 6,084,051; 6,090,939; 6,100,326; 6,291,578; 6,399,691;
6,432,485; 6,433,072; 6,531,535; 6,566,444; and 6,605,669.
[0002] A market need exists for a high functionality, high NCO
content, low unblocking temperature polyurethane crosslinker.
Pyrazoleblocked isocyanates unblock at relatively low temperatures
(see, e.g., U.S. Pat. Nos. 4,976,837, 5,246,557, 5,521,272 and
5,986,033). The fully blocked reaction product of nonane
triisocyanate and a pyrazole meets the market need as far as
functionality, NCO content and unblocking temperature but is not
soluble in commercially used coating solvents (see U.S. application
Ser. No. ______, fled on the same day as the present application
(attorney docket number PO-7999)) and as a result has limited
usefulness in the coating area.
DESCRIPTION OF THE INVENTION
[0003] The present invention is directed to a blocked
polyisocyanate based on nonane triisocyanate. More particularly,
the invention is directed to a blocked polyisocyanate useful in
solvent borne coating compositions and comprising the reaction
product of:
[0004] a) nonane triisocyanate;
[0005] b) a pyrazole blocking agent; and
[0006] c) a diol or polyol having a number average molecular weight
of from about 62 to about 600 and preferably from about 62 to about
200,
[0007] wherein i) the isocyanate to hydroxy equivalent ratio of
component a) to component c) is from 1:0.15 to 1:0.6 and ii) the
equivalent ratio of isocyanate groups to blocking groups is from
1:0.4 to 1:0.85. The invention provides a composition useful in
commonly used urethane grade solvents.
[0008] The pyrazole blocking agents are known and are disclosed,
e.g., in U.S. Pat. Nos. 4,976,837, 5,246,557, 5,421,272 and
5,986,033, the disclosures of which are hereby incorporated by
reference. The preferred pyrazole blocking agents are selected from
the group consisting of 3,5-dimethylpyrazole,
4-nitro-3,5-dimethylpyrazole, 4-benzyl-3,5-dimethylpyrazole,
methyl-5-methylpyrazole-3-carboxylate, pyrazole,
3-methyl-5-phenylpyrazole, 3-methylpyrazole,
4-bromo-3,5-dimethylpyrazole and
3,5-dimethylpyrazole-4-carboxanilide, with 3,5-dimethylpyrazole
being most preferred.
[0009] As used herein, "NTI" is intended to mean nonane
triisocyanate. As is clear from the art, in addition to being
called nonane triisocyanate (U.S. Pat. No. 6,084,051), nonane
triisocyanate has been called i) 4-isocyanate
methyl-1,8-octamethylene diisocyanate (U.S. Pat. No. 4,314,048),
ii) 4-isocyantomethyl-1,8-octamethylene diisocyanate, (U.S. Pat.
No. 5,714,564), iii) 4-isocyanatomethyl-1,8-octane diisocyanate
(U.S. Pat. No. 6,090,939), iv) triisocyanatononane and TIN (U.S.
Pat. No. 6,090,939), and v)
4-isocyanatomethylocatane-1,8-diisocyanate (U.S. Pat. No.
6,100,326).
[0010] The diols and polyols useful herein have number average
molecular weights of from about 62 to about 600 and preferably from
about 62 to about 200. Specifically useful diol and polyols include
ethylene glycol; diethylene glycol; triethylene glycol; propylene
glycol; dipropylene glycol; butane diols; hexane diols; glycerin;
trimethylolethane; trimethylolpropane; pentaerythritol; hexane
triols; mannitol; sorbitol; glucose; fructose; mannose; sucrose;
and propoxylated and/or ethoxylated adducts of any of the
above-noted hydroxy functional materials having number average
molecular weights of up to about 600.
[0011] The three components can be reacted in any order. For
example, in the presently preferred method, the NTI and the diol or
polyol are first reacted and the pyrazole is reacted with the
resultant product. Alternatively, the pyrazole could first be
reacted with the NTI and the diol or polyol could be reacted with
the resultant product in a less preferred embodiment, the
components could be reacted all at once. Regardless of the method
chosen, the amounts of reactants are such that i) the isocyanate to
hydroxy equivalent ratio of component a) (the NTI) to component c)
(the diol or polyol) is from 1:0.15 to 1:0.6, preferably from
1:0.15 to 1:0.25 and ii) the equivalent ratio of isocyanate groups
to blocking groups is from 1:0.4 to 1:0.85, preferably from 1:0.75
to 1:0.85.
[0012] Reaction times will depend on the reaction temperatures and
the % solids during reaction, but are typically between one and
eight hours. Reaction temperatures can be from 50.degree. C. to
120.degree. C., with temperatures of between 60.degree. and
80.degree. C. being preferred to give reasonable reaction times
with low color. The solids content is typically between 50 and 90%.
Higher solids are preferred, but viscosities can be too high for
practical use. Typical non-hydroxyl urethane grade solvents can be
used and include ketones, esters, aromatic hydrocarbons and even
aliphatic hydrocarbons in combination with one of the previous
solvents.
[0013] The invention is further illustrated by the following
examples in which all parts and percentages are by weight unless
otherwise indicated.
EXAMPLES
[0014] In the examples, the NTI used was a commercially available
NTI having an isocyanate equivalent weight as determined by NCO end
group titration of 87 (in theory, the pure NTI would have an
equivalent weight of 84).
Example 1
[0015] A 500 ml round bottom flask fitted with stirrer, nitrogen
inlet, condenser and thermocouple was filled with 86.53 grams (1.0
equivalent) of NTI and 9.18 grams (0.2 equivalent) of
1,3-butanediol. The reaction mixture was heated with stirring to
85.degree. C. and held for two hours at which time the NCO content
was 35.20% by weight (theoretical 35.11%). The reaction mixture was
cooled to room temperature and 31.85 g methyl propyl ketone and
77.04 grams (0.8 equivalent) of 3,5-dimethyl pyrazole was added.
The reaction mixture had a strong exotherm and an ice bath was used
to keep the temperature to no higher than 65.degree. C. When the
exotherm was complete, heat was applied to maintain a reaction
temperature of 60.degree. C. The 60.degree. C. reaction temperature
was maintained for four hours when an IR spectrum showed no
isocyanate remaining. The solids were 85% and the viscosity was
>100,000 cps @ 25.degree. C. The isocyanate content of the
solution was 256 g/eq. No crystals formed after one month, even
after seeding with pure DMP blocked NTI from Comparison Example
1.
Example 2
[0016] The procedure of Example 1 was used except that 87.37 grams
(1.0 equivalent) of NTI, 14:97 grams (0.33 equivalent) of
1,3-butanediol, 30.21 grams of methyl propyl ketone and 64.57 grams
(0.67 equivalent) of 3,5-dimethyl pyrazole were used. The
isocyanate content of the adduct was 27.8% by weight (theoretical
27.5%). The final product had a solids content of 85% and the
viscosity was >100,000 cps @ 25.degree. C. The isocyanate
content of the solution was 294 g/eq. No crystals formed after one
month, even after seeding with pure DMP blocked NTI from Comparison
Example 1.
Comparison Example 1
[0017] A one liter round bottom flask fitted with stirrer, nitrogen
inlet, condenser and thermocouple was filled with 203.9 grams
(2.361 equivalents) of NTI and 75.0 grams of methyl propyl ketone.
The reaction mixture was heated with stirring to 50.degree. C. and
231.2 grams (2.409 equivalents) of 3,5-dimethyl pyrazole was added
slowly. The reaction mixture had a strong exotherm and an ice bath
was used to keep the temperature to no higher than 55.degree. C.
When the exotherm was complete, heat was applied to maintain a
reaction temperature of 50.degree. C. The 50.degree. C. reaction
temperature was maintained for two hours when an IR spectrum showed
no isocyanate remaining. The solids were 85% and the viscosity was
3,500 cps @ 25.degree. C. The isocyanate content of the solution
was 216 g/eq. Crystals formed spontaneously in less than one
week.
Comparison Example 2
[0018] The procedure of Example 1 was used except that 86.60 grams
(1.0 equivalent) of NTI, 4.66 grams (0.1 equivalent) of
1,3-butanediol, 31.32 grams of methyl propyl ketone and 87.4 grams
(0.9 equivalent ) of 3,5-dimethyl pyrazole were used. The
isocyanate content of the adduct was 40.85% (theoretical 41.59%).
The final product had a solids content of 85% and the viscosity was
2,300 cps @ 25.degree. C. The isocyanate content of the solution
was 210 g/eq. Crystals formed spontaneously after one week.
Example 3
[0019] A paint formulation was prepared from 39 grams of the
blocked isocyanate of Example 1, 100 grams of Desmophen A870 BA,
0.2 grams of Byk 306, 0.2 grams of Byk 358 and 34.7 grams of a
mixture of n-butanol:propylmethyl ether acetate:3-ethoxypropanoic
acid ethyl ester (4:5:6 weight ratio). When the DMP adduct of NTI 2
was used, the formulation was adjusted for the NCO content.
[0020] Desmophen A870 BA is an acrylic polyol at 70% solids in
butyl acetate, having an OH number of 97 and a viscosity at
23.degree. C. of 3500 cps, available from Bayer Polymers LLC. Byk
306 is a silicone surfactant, available from Byk Chemie. Byk 358 is
an acrylic leveling additive, available from Byk Chemie.
[0021] The clear coating was drawn down with a 3 mil draw down bar
on an e-coated steel panel and cured at 285.degree. C. for 30
minutes.
[0022] The results are given in the following table.
1 DMP adduct of NTI DMP adduct of NTI Test prepolymer 1 prepolymer
2 Equivalent weight, 294 216 g/eq MEK double rubs Pass 100 Pass 100
Adhesion Pass Pass Pendulum hardness, 178 178 sec
[0023] The "MEK double rubs" was conducted as follows:
[0024] 1. The ball of a 2 pound ball peen hammer is securely
wrapped with several layers of cloth (8".times.8" cloth folded
twice) and secured by using a rubber band.
[0025] 2. The cloth is saturated with methyl ethyl ketone
(MEK).
[0026] 3. The wet ball peen is laid on the coating surface, so that
the ball peen is at a 90-degree angle to the surface. Without
applying downward pressure, the hammer is pushed back and forth
over an approximately 4" long area of the coating. One forward and
back motion is counted as 1 double rub.
[0027] 4. The cloth is resaturated with MEK after every 25 double
rubs.
[0028] The adhesion was measured using ASTM D3359-95 Standard Test
Method for Measuring Adhesion by Tape.
[0029] Although the invention has been described in detail in the
foregoing for the purpose of illustration, it is to be understood
that such detail is solely for that purpose and that variations can
be made therein by those skilled in the art without departing from
the spirit and scope of the invention except as it may;be limited
by the claims.
* * * * *