Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
1997-12-03
2001-07-31
Moore, Margaret G. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C525S100000, C525S101000, C525S102000, C556S420000, C556S421000, C556S434000, C556S431000
Reexamination Certificate
active
06268456
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to a coating composition useful for providing a finish on a variety of substrates. In particular, this invention is directed to an organosilane composition useful for finishing automobiles and trucks.
2. State of the Art
It is well-known that consumers prefer automobiles and trucks with an exterior finish having an attractive aesthetic appearance including high gloss and excellent DOI (distinctness of image). While ever more aesthetically attractive finishes have been obtained, deterioration of the finish over time, whereby the exterior finish of an automobile or truck loses its luster or other aspects of its aesthetic appearance, is all the more noticeable. An increasingly observed cause of this deterioration is etching of the finish caused by exposure to environmental chemical attack. Chemicals that can cause etching of a finish include acid rain and chemical smog.
In order to protect and preserve the aesthetic qualities of the finish on a vehicle, it is generally known to provide a clear (unpigmented) topcoat over a colored (pigmented) basecoat, so that the basecoat remains unaffected even on prolonged exposure to the environment or weathering. It is also generally known that alkoxysilane polymers, due to strong siloxane bonding when cured, exhibit excellent chemical resistance. Exemplary of prior art literature disclosing silane polymers for coating are U.S. Pat. Nos. 5,244,696 and 5,223,495.
There is a continuing need for a commercially practical clearcoat finish having excellent appearance, including high gloss and DOI, that is also resistant to etching caused by chemical attack. To be commercially practical, such a clearcoat must not be prone to cracking. It is also important that the finish have good scratch and mar resistance and be derived from compositions that are characterized by low levels of volatile organic chemicals such as solvents and the like. Finally, such a clearcoat should be capable of application over a variety of basecoats and have excellent adhesion.
SUMMARY OF THE INVENTION
This invention concerns a sprayable, curable, liquid coating composition comprising:
i) at least one film-forming reactive silyl group-containing compound having at least two functional groups of the formula, —SiR
n
X
3-n
, the functional groups being attached to the compound by a silicon-carbon bond, wherein:
n is 0, 1 or 2;
R is oxysilyl or unsubstituted hydrocarbyl or hydrocarbyl substituted with at least one Asubstituent containing a member selected from the group O, N, S, P, Si; and
X is a hydrolyzable moiety selected from the group C
1
to C
4
alkoxy, C
6
to C
20
aryloxy, C
1
to C
6
acyloxy, hydrogen, halogen, amine, amide, imidazole, oxazolidinone, urea, carbamate, and hydroxylamine;
the compound having a number average molecular weight between about 300 and 3000 and volatility such that no more than about 30 parts by weight of silyl group-containing compound per 100 parts of the compound evaporate during cure;
ii) an optional second film-forming reactive silyl group-containing component which, together with i, produces an average —SiR
n
X
3-n
functionality of more than one,
iii) polymer microparticles, substantially insoluble in the liquid coating composition, in an amount of 5 to 100 parts per 100 parts by weight of all other film-forming components; and
iv) from 0 to about 100 parts by weight of a liquid organic carrier, based on weight of i, ii, and iii; and
v) sufficient catalyst to effect crosslinking.
The present invention is also directed to a process for making a film-forming reactive silyl group-containing oligomeric compound comprising the steps:
i) reacting a silane selected from the group disilylated limonene and disilylated vinylnorbomene with a controlled amount of water in the presence of a catalyst,
ii) stripping methanol from the reaction product of (i) to complete the oligomerization, and
iii) optionally removing (a) insoluble byproducts of step (ii) and (b) inert solvent employed to facilitate removal of insoluble byproducts;
whereby the reactive compound that is formed has at least 4 silyl groups.
The term “compound” as employed herein excludes all polymers of random chain lengths such as obtained in free-radical initiated vinyl polymerization. The term “component” in item (ii) includes polymers, oligomers, compounds and mixtures thereof. The average number of silyl groups in the composition, when (i) and (ii) are both present, will always be more than one.
The invention also includes a process for coating a substrate with the above coating composition. The invention further includes certain oligomeric compounds (i), (see Examples A and B); a process for making the oligomer, (see Examples C and D); and a substrate having adhered thereto a coating derived from the described composition.
The composition of the invention is especially useful for forming a clear topcoat over a pigmented basecoat. Such a clear topcoat can be applied over a variety of colorcoats, such as water or organic solvent based colorcoats or powder colorcoats.
DETAILS OF THE INVENTION
The Silyl-Containing Compound (i)
Compound (i) is selected from at least one of the following groups 1 to 12.
1.) Amino-functional silanes reacted with isocyanate.
wherein:
R is a moiety independently selected from the group consisting of alkylene, cycloalkylene, heterocyclic, arylene, alkoxylene, aralkylene, alkenylene, cycloalkylene and low molecular weight polymer moiety;
R
1
is independently C
1
-C
16
alkyl;
R
2
is independently H or C
1
-C
12
alkyl;
R
3
is a moiety independently selected from the group consisting of alkylene, cycloalkylene, heterocyclic, arylene, alkoxylene, aralkylene, alkenylene, cycloalkylene and low molecular weight polymer moiety;
n is an integer of 2 to 12; and
m is 1 to 16.
Representative low molecular weight polymer values for R and R
3
are polyester, polyurethane, polyether, polyamine and the like. Preferred for R
1
are alkyls of C
1
to C
4
, most preferably C
1
to C
2
. Alkyl substituents can be linear or cyclic and the amine function can be primary or secondary. By “low molecular weight” is meant no more than about 3000 (number average). When R and/or R
3
are low molecular weight polymers, m=1.
Hereafter, in groups 2 to 10, R, R
1
, R
2
, R
3
,n and m are as defined above except where indicated. The following reactions need not go to completion provided the product contains at least two silyl groups.
2.) Amino-functional silane reacted with anhydride.
Both R groups can be taken together and when taken together a ring structure of C
3
-C
12
cycloalkyl is formed.
3.) Amino-functional silane reacted with an epoxide.
R
4
is independently selected from H and C
1
-C
12
alkyl; or R
4
can be taken together to form a C
3
-C
12
cycloalkyl.
4.) Amino-functional silane reacted with acid.
5.) Epoxy-functional silane reacted with amine.
wherein R
2
is H, then n is 1-12.
6.) Epoxy-functional silane reacted with anhydride.
wherein R can be taken together as defined in group 2 above. The acid group can be further reacted at 100°-150° C. with catalyst to have disubstitution at each anhydride, in which case n is 1 to 12.
7.) Epoxy-functional silane reacted with acid.
8.) Reaction of [A]+n [B].
n is 1 or 2; n is 2 when R
2
is H.
9.) Isocyanate-containing alkoxysilanes reacted with a polyol.
10.) Reaction of [A]+n[C].
n is 1 or 2; n is 2 when R
2
is H.
With respect to Group 9 Compounds, one mole of 1,4-cyclohexanedimethanol can be reacted with 2 moles of isocyanatopropyltrimethoxysilane to give a silane compound having two trimethoxysilyl groups per molecule. Alternatively, one mole of pentaerythritol can be reacted with 3 moles of methylhexahydrophthalic anhydride to give a carboxylic acid compound having 3 carboxylic acid groups and 1 hydroxyl group. The carboxylic acid compound can then be reacted with 3 moles of the glycidyl ester of a 10-carbon, branched, aliphatic carboxylic acid to give a polyol compound having 4 hy
Gregorovich Basil V.
Hazan Isidor
Matheson Robert Rudolph
Wilczek Lech
Costello James A.
Deshmukh Sudhir G.
E. I. Du Pont de Nemours and Company
Moore Margaret G.
LandOfFree
Coating composition containing silane functionality does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Coating composition containing silane functionality, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating composition containing silane functionality will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2566833