Thickeners

Details Thickeners Thickeners

2002-12-05

2004-08-03

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

At least one aryl ring which is part of a fused or bridged...

C524S539000, C524S808000

Reexamination Certificate

active

06770704

ABSTRACT:

The present invention relates to the use of an amine functional polymer as a rheology modifier for non-aqueous paints, inks, filled thermosetting resins, thermosetting resin-based gelcoats and to millbases, paints and inks, filled thermosetting resins and thermosetting based gelcoats containing said rheology modifier. The ink includes that used in either impact or non-impact printing, including drop-on-demand (DOD) printing.
Solvent based coatings have a tendency to “sag” or run down when the coating is applied to inclined and particularly vertical surfaces. This is particularly true in the case of high solids coating formulations which are becoming increasing important with the need to reduce the Volatile Organic Compound (VOC) content of the coatings. There is thus a clear need for rheology modifying agents which reduce the tendency of coatings to sag. Ideally such rheology modifying agents should impart shear thinning properties on the coating such as high viscosity under low shear conditions to inhibit sag after application of the coating and low viscosity under high shear to permit flow and levelling of the coating during application.
Thermosetting resin based gelcoats, and filled thermosetting resins when used in spray and hand lay-up applications, also have a strong tendency to sag when applied to vertical surfaces. Typically this difficulty is addressed through the use of thixotropes such as fumed silicas, but their ultra-fine particulate state makes them difficult to handle in terms of both their ease of incorporation into formulations, and extremely dusty nature.
The relatively high density of most fillers used in thermosetting resins means that the said fillers may have a strong tendency to settle on storage, even for quite short periods of time, leaving an uneven distribution of filler between the different levels within the formulation, and even a dense sediment on the base of the container. This problem may be addressed by mechanical means (stirring or rolling the container), or by incorporation of an appropriate agent that will help the formulation to resist settling. Ideally such anti-settling agents should show shear thinning behaviour.
U.S. Pat. No. 3,979,441 discloses oil-soluble polymers of N-3-amino alkyl acrylamides such as N-(1,1-dimethyl-3-dimethylaminopropyl) acrylamide which are obtained by copolymerisation with a monomer such as an alkyl (meth)acrylate containing an alkyl group with at least 8 carbon atoms. The polymers are used as viscosity modifiers in lubricants but their use in paints is neither disclosed nor envisaged.
U.S. Pat. No. 5,312,863 discloses cationic latex coatings obtained by polymerising at least one ethylenically unsaturated monomer wherein at least one of the monomers contains a cationic functional group. Preferably, the concentration of the cationic functional monomer is from 0.5 to 15% by weight of the total polymerisable monomers used to prepare the cationic polymer, and more preferably from 1 to 5% by weight. There is no disclosure that such cationic polymers can be used as a rheology modifier (hereinafter “RM”) in non-aqueous based paints and inks.
More recently, U.S. Pat. No. 5,098,479 discloses a process for preparing a hydrocarbon-soluble thickener for zinc-containing metal resinate inks which comprises the reaction product of
a) up to 99% by weight of an alkyl or cycloalkyl ester of (meth) acrylic acid;
b) up to 98% by weight styrene;
c) 1 to 40% by weight of an amine-containing monomer;
d) up to 20% by weight of a carboxyl-containing monomer; and
e) a catalytic amount of a free-radical polymerisation initiator.
These thickeners have all been specifically developed for use with metal resinates in gravure printing inks and none of the specific thickeners are made using more than 15% by weight amine-containing monomers.
It has now been found that improved resistance against sag, running or settling can be obtained if the RM polymer contains not less than 42% by weight of the residue of an amine containing monomer.
According to the invention there is provided the use of an amine functional polymer, including salts thereof, as a rheology modifier for solvent-based paints, inks, filled thermosetting resins and thermosetting resin-based gelcoats, whereby the amine functional polymer contains not less than 42% by weight of the residue of one or more amine-containing monomers, or salts thereof, relative to the total weight of the polymer.
The amine functional polymer, including salts thereof, is referred to hereinafter as AFP.
Preferably, the AFP contains not less than 45% and more preferably not less than 50% by weight of the residue of an amine-containing monomer relative to the total weight of the polymer.
It is also preferred that the AFP contains not greater than 90% and more preferably not greater than 80% by weight of the residue of an amine-containing monomer relative to the total weight of the polymer.
The weight average molecular weight (Mw) of the AFP is preferably between 30,000 and 250,000, more preferably between 40,000 and 100,000 and especially between 65,000 and 85,000.
The AFP is preferably obtainable from two or more monomers which contain at least one, and preferably, only one ethylenically unsaturated group.
In one preferred class of AFP, the amine-containing monomer is a compound of formula 1
wherein
R is hydrogen or C
1-6
-alkyl;
A is oxygen, sulphur, a group —COO— or a group —CONR
3
— wherein R
3
is hydrogen or C
1-12
-alkyl;
X is C
2-10
-alkylene;
R
1
and R
2
is each, independently, hydrogen, hydroxyalkyl or C
1-12
-alkyl; or
R
1
and R
2
together with the nitrogen atom to which they are attached, form a ring.
When R is C
1-6
-alkyl, it is preferably C
1-4
-alkyl such as methyl.
When X is alkylene, it may be linear or branched. Preferably at least two carbon atoms of the alkylene group are in a chain connecting A with the nitrogen atom.
When R
1
and/or R
2
is hydroxyalkyl it is preferably hydroxy-C
2-4
-alkyl.
When R
1
and R
2
together with the nitrogen atom to which they are attached form a ring, the ring preferably contains 6 members such as morpholinyl, piperazinyl, pyridyl, pyrrolidinyl and N-alkylpiperidinyl such as N—C
1-18
-alkyl- and especially N—C
1-6
-alkyl piperidinyl.
Examples of the compounds of formula 1 are:
10-aminodecyl vinyl ether;
9-aminooctyl vinyl ether;
6-(diethylamino)hexyl (meth)acrylate;
2-(diethylamino)ethyl vinyl ether;
5-aminopentyl vinyl ether;
3-aminopropyl vinyl ether;
2-aminoethyl vinyl ether;
2-aminobutyl vinyl ether;
4-aminobutyl vinyl ether;
3-(dimethylamino)propyl (meth)acrylate;
2-(dimethylamino)ethyl vinyl ether;
N-(3,5,5-trimethylhexyl)aminoethyl vinyl ether;
N-cyclohexylaminoethyl vinyl ether;
3-(t-butylamino)propyl (meth)acrylate;
2-(1,1,3,3-tetramethylbutylamino)ethyl (meth)acrylate;
N-t-butylaminoethyl vinyl ether;
N-methylaminoethyl vinyl ether;
N-2-ethylhexylaminoethyl vinyl ether;
N-t-octylaminoethyl vinyl ether;
beta-morpholinoethyl (meth)acrylate;
4-(beta-acryloxyethyl) pyridine;
beta-pyrrolidinoethyl vinyl ether;
5-aminopentyl vinyl sulfide;
beta-hydroxyethylaminoethyl vinyl ether;
(N-beta-hydroxyethyl-N-methyl) aminoethyl vinyl ether;
hydroxyethyidimethyl (vinyloxyethyl) ammonium hydroxide;
2-(dimethylamino)ethyl (meth)acrylate;
2-(dimethylamino)ethyl (meth)acrylamide;
2-(t-butylamino)ethyl (meth)acrylate;
3-(dimethylamino)propyl (meth)acrylamide;
2-(diethylamino)ethyl (meth)acrylate;
2-(dimethylamino)ethyl (meth)acrylamide.
In a further preferred class of AFP, the amine containing monomer is a compound of formula 2
wherein
R
4
is hydrogen or C
1-12
-alkyl; and
n is from 1 to 4.
Examples of amine functional monomers of formula 2 are 4-vinylpyridine, 2,6-diethyl-4-vinylpyridine, 3-dodecyl-4-vinylpyridine and 2,3,5,6-tetramethyl-4-vinylpyridine.
The quaternised form of weak base functional monomers such as those weak base functional monomers which have been reacted with alkyl halides, such as benzyl chloride and ethyl bromide or with epoxides such as ethyleneoxide and propyleneoxide, or with dialkylsulphate such as dimethylsulphate, can also be u

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