CA1128954A

CA1128954A - Viscosity increasing additive for non-aqueous fluid systems

Info

Publication number: CA1128954A
Application number: CA323,395A
Authority: CA
Inventors: Claude M. Finlayson
Original assignee: NL Industries Inc
Current assignee: NL Industries Inc
Priority date: 1978-03-27
Filing date: 1979-03-14
Publication date: 1982-08-03
Also published as: DE2912069A1; IT1113319B; US4208218A; FR2421203B1; NL7902318A; NO790743L; BR7901826A; NL192042C; GB2017072B; IT7921155A0; MX6811E; AU4520579A; SE7902644L; GB2017072A; JPS54160571A; NL192042B; NO151449C; NO151449B; AU528911B2; SE427246B

Abstract

ABSTRACT:
An organoclay rheological additive for non-aqueous fluid systems comprising an organophilic clay comprising the reaction product of a smectite-type clay having a cation exchange capacity of at least 75 milliequivalents per 100 grams of clay and methyl benzyl dialkyl ammonium compound or dibenzyl dialkyl ammonium compound wherein the alkyl groups contain specific amounts of 8 to 22 carbon atoms and the amount of said ammonium compound reacted with said clay being from 100 to 130 milliequivalents per 100 grams of clay based upon 100? active clay.

Description

11~8~S~

In the prior art many di~ferent types of rheological agents are used in non-aqueous fluid systems such as paints, varnishes, enamels, waxes, epoxies, mastics and the like.
These fluid systems often contain finely divided suspended materials, such as pigments and the like, and the rheological agent is added to thicken the system to produce a thixotropic flow behavior with high viscosity at a low shear rate.
Various organo modified clays and other inorganic and organic compounds have been used in the past to produce these rheological effects. The organophilic clays, however, which have been used by the prior art require the use of polar sol-vent activators which must be added to the system to produce the rheological effect. If the polar solvent activators are not used, the desired rheological properties, viscosity build, pigment setting control, and sag control are not fully achieved, that is, only a portion of the clay's thickening ability is obtained. In addition, when the polar solvent activators are eliminated, the compositions containing organoclays known to date will increase in viscosity on storage, thus having a deleterious effect on the original rheological properties designed into the system.
Some of these polar additives, such as acetone, alcohols and the like have low flash points and therefore shculd be avoided if possible. In addition, these polar additives must he added as a separate step at the time of preparing the systems. This separate step adds to the cost of the system.
In addition, some polar additives may react with other system formulation components and eliminate essential rheological properties.
~n contrast to the prior art, a self-activating rheolog-ical agent has been produced by the instant invention which does not require the addition of polar solvent activators.

~8~S4 A sel~-activating rheological agent has been produced com-prising the reaction product of a methyl benzyl dialky] ammon-ium compound or a dibenzyl dialkyl ammonium compound wherein the alkyl group is selected from the group consisting of 14 to 22 carbon atoms wherein 20 to 35% have 16 carbon atoms and 60 to 75% having 18 carbon atoms, and 8 to 20 carbon atoms wherein at least 5~ have 8 to 14 carbon atoms, and a smectite-type clay having a cation exchange capacity of at least 75 milliequivalents per 100 grams of said clay, and wherein the amount of said ammonium compound is from 100 to 130 millie-quivalents per 100 grams of said clay, 100~ active clay basis.
The clays used to prepare the organophilic clay gellants of this invention are smectite-type clays which have a cation exchange capacity of at least 75 milliequivalents per 100 grams of clay. Particularly desirable types of clay are the naturally-oecurring Wyoming varieties of swelling bentonites and like clays, and hectorite, a swelling magnesium-lithium silicate clay.

The clays, especially the bentonite type clays, are pref-erably converted to the sodium form if they are not already in this form. This ean eonveniently be done by preparing an aqueous clay slurry and passing the slurry through a bed of eation exchange resin in the sodium form. Alternatively, the clay can be mixed with water and a soluble sodium compound .such as sodium carbonate, sodium hydroxide and the like, and shearing the mixture with a pugmill or extruder.
Smectite-type clays prepared synthetically by either a pneumatolytie or, preferably a hydrothermal synthesis process ean also be used to prepare the present organophilic clays.
Representative of such clays are montmorillonite, bentonite, beidellite, hectorite, saponite, and stevensite. These clays may be synthesized hydrothermally by forming an aqueous ..i ,8~S~

reaction mixture in the form of a slurry containing mixed hydrous oxides or hydroxides of the desired metals with or without, as the case may be, sodium (or alternate exchange-able cation of mixture thereof) fluoride in the proportions for the particular synthetic smectite desired. The slurry is then placed in an autoclave and heated under autogenous pressure to a temperature within the range of approximately 100 to 325C, pr~ferably 274 to 300C, for a sufficient period of time to form the desired product.
The cation exchange capacity of the smectite-type clays can be determined by the well-known ammonium acetate method.
The quaternary ammonium compounds which are reacted with these smectite-type clays is a methyl benzyl or dibenzyl dialkyl ammonium salt wherein the alkyl groups comprise from 14 to 22 carbon atoms, preferably 16 or 18 carbon atoms and most preferably 20% to 35% of the alkyl radicals contain 16 carbon atoms and 60% to 75~ contain 18 carbon atoms or 8 to 20 carbon atoms wherein at least 5% have 8 to 14 carbon atoms and preferably at least 20% have 12 carbon atoms. The salt anion is preferably selected from the group consisting of chloride and bromide, and mixtures thereof, and is more preferably chloride, although other anions such as acetate, hydroxide, nitrite, etc., may be present in the quaternary ammonium salt to neutralize the quaternary ammonium cation.
These quaternary ammonium salts can be represented by the formula:

IRl R2 N ~ R4 M

_ 3 C

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wherein R~ is CH3 or C6H5CH2; R2 is C6H5CH2; and R3 and R4 are alkyl groups containing long chain alkyl radicals having either 14 to 22 carbon atoms, preferably 16 or 18 carbon atoms, and most preferably wherein 20% to 35% of said long chain alkyl radicals contain 16 carbon atoms and 60% to 75% of said long chain al~yl radicals contain 18 carbon atoms, or 8 to 20 carbon atoms wherein at least 5% have 8 to 14 carbon atoms and most preferably at least 20% 12 carbon atoms, and wherein M is selected from the group con-sisting of chloride, bromide, nitrite, hydroxyl, acetate, methyl, sulfate, and mixtures thereof.

llZ,85~5~1 The preferred quaternary ammonium salts are methyl benzyl dihydrogenated tallow ammonium chloride and methyl benzyl dicoconut fatty acid ammonium chloride. Commercially prepared hydrogenated tallow typically analyzes 2.0% C14, 0.5% C15, 16~ 5~ C17; 66.0~ C18 and 1.0~ C20 alkyl groups Commercially prepared coconut fatty acid typically analyses 5.9% C8, 4-10~ C10, 44-51% C12, 13-18% C14, 7-10% C16, and 1-4% C18 alkyl groups.
The organophilic clays of this invention can be prepared by admixing the clay, quaternary ammonium compound and water together, preferably at a temperature within the range of from 100F (38C) to 180F (82C), more preferably from 140F
(60C) to 170F (77C) for a period of time sufficient for the organic quaternary ammonium compound to react with the clay particules, followed by filtering, washing, drying, and grinding. If using the organophilic clays in emulsions, the drying and grinding steps may be eliminated. When admixing the clay, quaternary ammonium compound and water in such con-centrations that a slurry is not formed, then the filtration and washing steps can be eliminated.
Preferably, the clay is dispersed in water at a concentra-tion from about 1% to 7~ by weight, the slurry optionally centrifuged to remove non-clay impurities which constitute about 10% to about 50% by weight of the starting clay compos-ition; the slurry agitated and heated to a temperature in the range of from 140F (60C) to 170F (77C); the quaternary amine salt added in the desired milliequivalent ratio, prefer-ably as a liquid in isopropanol or dispersed in water; and the agitation continued to effect the reaction.
The amount of the quaternary ammonium compound added to the clay for purposes of this invention must be sufficient to impart to the clay the enhanced dispersion characteristics desired.

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The milliequivalent ratio is defined as the number of milli-equivalents of the quaternary ammonium compound in the organo-philic clay, per 100 grams of clay, 100~ active basis. The organophilic clays of this invention have a milliequivalent ratio of from 100 to 130. At lower milliequivalent ratios the organophilic clays are ineffective gellants even though they may be effective gellants when dispersed in a conventional manner with a polar additive. At higher milliequivalent ratios, the organophilic clays are poor gellants. However, the preferred milliequivalent ratio within the range of from 100 to 130 will vary depending on the characteristics of the organic system to be gelled by the organophilic clay.
The non-aqueous fluid compositions in which the self activating organophilic clays are useful include paints, varnishes, enamels, waxes, epoxies, mastics, adhesives, cos-metics and the like. These fluids may be prepared by any conventional method, such as with colloid mills, roller mills, ball mills, and high speed dispersers, in which the fluid pigment materials become well dispersed in the organic vehicle by the high shear used in processing.
The organophilic clay gellant is employed in amounts suf-icient to obtain the desired rheological properties such as high viscosity at low shear rates, control of sagging of fluid films and prevention of settling and hard packing of pigments present in the fluid compositions. Amounts of organophilic clay gellant employed in the non-aqueous fluid system should preferably be between about 0.1~ and about 5.0%
based on the weight of the treated non-aqueous fluid system and preferably between 0.3% and 2.0% to yield the desired rheological effects.

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The following examples are given to illustrate the invention, but are not deemed to be limiting thereof. All percentages given throughout the specification are based upon weight unless otherwise indicated.

About 1500 grams of a 29 slurry of Wyoming bentonite in water which had been previously treated by centrifuga-tion to remove all non-clay impurities and ion-exchanged to provide the clay in the sodium form was heated to about 150F and combined with 39.3 grams of 77.8~ active methyl benzyl dihydrogenated tallow ammonium chloride. The mix-ture was stirred for 45 minutes, filtered to remove solids, dried at 150F and finally ground to yield an organophilic clay gellant containing 112.0 milliequivalents of quater-nary ammonium compound per 100 grams of clay.
The methyl benzyl dihydrogenated tallow ammonium bentonite was employed as the rheological additive in a gloss enamel, using a mixture of 95% methanol and 5~ water as the polar solvent activator, in one case, and eliminat-ing the polar activator in the other.
For comparison, two enamels were made using dimethyl,dihydrogenated tallow ammonium bentonite as the organo-philic clay. In one case the mixture of 95~ methanol and 5% water was used as the polar solvent activator and no polar solvent activator used in the other. In addition, an enamel was prepared without the addition of any rheological additive.
The enamels were prepared using a high speed disperser using the following formulation:

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5~

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o ~ ~ ~D I I I U~ O 1` r~ co ~ ~ ~
~ S ~) 1-- CO ~ ~ O
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~ ~ o .,1 ~ ~ CO Ll Cl~ O ~ U~ ~ O a~ o o~
~ c o ~s . . ~ . ~ . .... .
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~ O
O
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>1 J.J ~ t~ ~ I ~ (~ 11~ O 1~ 1 G
s 3 .,~ ~ ~ ~
v O 3 ~ ~ ~ ~ o ~ ~ o E~ ~( ~:
.,~
~5 C ~ ~ O U~
a)-,l o ra ,~; cO u~ ~ O ~ u~ ~ O ci~ o a~
~C ~ ~ C . . . . . . .... .

~ O O ~ ~ ::~ (~ O r~ o N,--I O
W ~ .IJ ~ O ~ I ~1 0 ~
~3 U ~i ~) G r~l O
SR
.,~

C
N O ~
C E~ O
~ ~ JJ 00~ ~ O ~ U~ ~ O a~ o o Q 0 S t~ . . . . . . . ., .... .

3 . ~ (~ o r~
:~ O ~ ~ ~ ~r ~ o s ~ U
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o v v v al V
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y V ._( ~o\ ~ ~ Y ~ S a v s a~
~ ~ ~ ~ s ~:: V
O ~ ~ V ~ ~ O V V QS ~:
~ JJ ~ ~:4~ ~ a~ s o ~ o ~ r ~ V ~ ~ ~ æ
- O ~ -1 ~ N ~ Q ~ 0 _~ ~L) O ~ 1 :~ ~ Z ~:
u~ c~ ~ u~ ~ ~,v ~
O u~ v ~ ~ ~ O u~ ~ v C
U) ~D ~ 0 ~ C ~ u~ ~ C
t~ ~ ~ 3 c v ~
O o c ~ ~ ~ c s o o a~ o c ~ ~ ~ Q Y
c.,, ~ a.~, ~. o v ~ ~ ~ v c E~ o u~
u~ aJ ~~ s ~ ~ ~ C x ~ ~ c ~ u~
~C O C 3 v-~ -,1v C -1 C a~ C ~ ~ v LlO L~ ,, v ~ Lr~ O ~ ~
O ~ ~ ~ ~ ~E~ ~ ~ ~ ~ ~r ~D

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-Viscosity data for these enamel compositions are given in Table II. The viscosity determinations were made using a Brookfield RVT cone and plate viscometer at 10 rpm, equivalent to a shear rate of 40 sec. 1.

TABLE II
Brookfield Viscosi~ies (cps) at 40 sec. ~

Organophilic Clay With Without activator activator Methyl Benzyl Dihydrogenated 307 300 tallow ammonium bentonite Dimethyl dihydrogenated 341 186 tallow ammonium bentonite No organophilic clay - 150 The table shows that when conventionally employed di-methyl dihydrogenated tallow ammonium bentonite is employed in the enamel without the use of a polar solvent activator, only a small increase in viscosity is seen over that of the enamel containing no organophilic clay rheological additive.
When the methanol and water mixture is added, activation of the organoclay occurs and significant viscosity increase is obtained.
In contrast when the methyl benzyl dihydrogenated tallow ammonium bentonite is used, the viscosity obtained does not depend upon whether a polar solvent activator is used; full rheological properties (including viscosity, sag control and pigment suspension) are achieved in both cases.

About 1500 grams of a 2.8~ slurry of Wyoming bentonite in water which had been previously treated by centrifugation to remove all non-clay impurities and ion-exchanged to provide the clay in the sodium form was heated to about 150 F and combined with 28.0 grams of 90.0%
active methyl benzyl dicoconut fatty acid ammonium chloride.
The mixture was stirred for 45 minutes, filtered to remove solids, dried at 150 F and finally ground to yield an 10 organophilic clay gellant containing 122.7 milliequivalents of quaternary ammonium compound per 100 grams of clay.
The methyl benzyl dicoconut fatty acid ammonium bentonite was employed as the rheological additive in the gloss enamel formulation of Example 1, in one case in-corporating a 95~ methanol and 5% water mixture as the polar solvent activator, and eliminating the activator in the other.
The results indicate that the viscosity build, thixotropy, sag control and pigment settling control 20 properties were essentially equivalent in both the presence and absence of a polar solvent activator. This would not occur with conventionally employed organophilic clays.

95~

The procedure of Example 1 was repeated except that a different non-aqueous system, namely a basic lead silicochromate-alkyl primer was employed as set forth below instead of the gloss enamel.
The following formulation was prepared on a high speed disperser:

Pounds Pounds With Without Activator Activator Medium Oil Linseed and Soya Alkyd Resin Solution 505 505 Mineral Spirits 101 101 Basic Lead Silico Chromate519 519 Iron Oxide 43 43 Zinc Oxide (Acicular) 43 43 Methyl Benzyl Dihydrogenated Tallow Ammonium Bentonite 5 5 Methanol - Water (95-5) 1.7 80 Grind Add:
Lead Naphthenate (24~)10.5 10.5 Cobalt Naphthenate (6~) 4.2 4.2 Manganese Naphthenate (6%) 4.2 4.2 Anti-Skinning Agent 3.7 3.7 TOTAL 1240.3 1238.6 The results indicate that viscosity build, thixo-tropy, sag control and pigment settling control properties were essentially equivalent in both the presence and absence 30 of a polar solvent activator. This would not occur with conventionally employed organophilic clays.

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The procedure of Example 1 was repeated except that the alkyd-urea baking enamel non-aqueous system described below was employed instead of the gloss enamel.
The formulation was prepared on a high speed disperser:

Pounds Pounds With Without Activator Activator 1~ Short Oil Castor Alkyd Resin Solution (50% N.V.) 493 493 Urea-Formaldehyde Resin (60~ N.V.) 98 98 Xylol 121 1~1 Titanium Dioxide (Rutile~ 240 240 Methyl Ben7,yl Dihydrogenated Tallow Ammonium Hectorite4.5 4.5 Methanol-Water (95-5) 1.4 Butanol 28 28 Grind 20 Add:
Cobalt Naphthenate (6%)0.4 0.4 Manganese Naphthenate (6~) 0.4 0.4 TOTAL 986.7 985.3 The results indicate that viscosity build, thixotropy, sag control and pigment settling control properties were essentially equivalent in both the pre-sence and absence of a polar solvent activator. This would not occur with conventionally employed organophilic clays.

The procedure of Example 1 was repeated except that the exterior wood stain non-aqueous system described below was employed instead of the gloss enamel, and that a ball mill was used rather than a high speed disperser.

With Without Activator Activator Pounds Pounds Charge to a ball mill:

Long oil soya alkyd resin solution (70% N.V.) 345 345 Aromatic Mineral Spirits 104 104 Mineral Spirits 276 276 Chromium Oxide 45 45 Methyl benzyl dihydrogenated tallow ammonium bentonite 6 6 Methanol water (95-5) 2 ---Grind Add:
Pentachlorophenol Solution (5%)5.2 5.2 Lead Naphthenate (24%)5.2 5.2 Cobalt Naphthenate (6%)1.8 1.8 Total 790.2 788.2 The results indicate that pigment suspension was essentially equivalent in both the presence and absence of a polar solvent activator. This would not occur with conventionally employed organophilic clays.

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3$54 EXAMPI,E 6 -The procedure of Example 1 was repeated except that a solvent based caulking compound (as described below) was employed instead of the gloss enamel of Example 1. The caulk was prepared using a Sigma Mixer.
CAULKING COMPOUND

__ _ With Without Activator Activator Pounds Pounds Calcium Carbonate 800 800 Fibrous Talc 200 200 Blown Soya Oil 246 246 Polybutene Resin 112 112 Soya Fatty Acids 16 16 Mineral Spirits 60 60 Cobalt Naphthenate (6%) 4 4 Methyl benzyl dihydrogenated tallow ammonium bentonite 7 7 Methanol-Water (95-5) 2.2 ---Total1447.2 1445.0 The results indicate that sag and slump control properties were essentially equivalent in both the presence and absence of a polar solvent activator. This would not occur with conventionally employed organophilic clays.

S~

The procedure of Example 1 was repeated except that a different non-aqueous system (as described below) was employed instead of the gloss enamel of Example 1.
The following formulation was prepared using a Lighting mixer:

Hair Cream Pounds Pounds With Without Activator Activator U.S.P. Mineral Oil 35.0 35.0 Ethoxylated Hydrogenated Castor Oil 8.0 8.0 10 Petrolatum 53 0 53 0 Methyl Benzyl Dihydrogenated Tallow Ammonium Bentonite3.0 3.0 Propylene Carbonate 1.0 TOTAL 100.0 99.0 The results indicate that the viscosity build was essentially equivalent in both the presence and absence of polar solvent activator. This would not occur with conventionally employed organophilic clays.

1~8~S4 EXAMPLE _ The procedure of Example 1 was repeated except that a different non-aqueous system (as described below) was employed instead of the gloss enamel of Example 1.
The following formulation was prepared using a Lightninq mixer and packaged in aerosol cans:

Aerosol Antiperspirant Pounds Pounds With Without Activator Activator _. _ Isopropyl Myristate 4.0 4.0 Silicon Oil (Polysiloxane) 6.0 6.0 Methyl Benzyl Dihydrogenated Tallow Ammonium Bentonite 3.0 3.0 Propylene Carbonate 1.0 Mix Add:

Aluminum Chlorohydrate 5.0 5.0 Mix and Package With Propellant (Isobutane) 81.0 81.0 TOTAL 100.0 99.0 The results indicate that the viscosity build and 20 the aluminum chlorohydrate suspension in the aerosol package were essentially equivalent in both the presence and absence of polar solvent activator. This would not occur with conventionally employed organophilic clays.

The procedure of Example 1 was repeated except that a different non-aqueous system (as described below) was employed instead of the gloss enamel of Example 1.

One-Package Epoxy Adhesive Pounds Pounds With Without Activator Activator (Prepared on a 3-roll mill) Epoxy Resin 815 815 Dicyandiamide 45 45 Aluminum Oxide 180 180 Methyl Benzyl Dihydrogenated Tallow Ammonium Hectorite 15 15 Methanol-Water (95-5) 5 The results indicate that viscosity build, thixotropy, and sag control properties were essentially equivalent in both the presence and absence of a polar solvent activator. This would not occur with convention-ally employed organophilic clays.

1~2.8~S~
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention and all such modifications are intended to be included within the scope of the following claims.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A self-activating organophilic clay rheological composition useful as an additive for non-aqueous fluid systems, which comprises the reaction product of a methyl benzyl dialkyl ammonium compound or a dibenzyl dialkyl ammonium compound wherein the alkyl group is selected from the group consisting of 14 to 22 carbon atoms wherein 20 to 35% have 16 carbon atoms and 60 to 75% have 18 carbon atoms, and 8 to 20 carbon atoms wherein at least 5% have 8 to 14 carbon atoms, and a smectite-type clay having a cation exchange capacity of at least 75 milliequivalents per 100 grams of said clay, and wherein the amount of said ammonium compound is from 100 to 130 milliequivalents per 100 grams of said clay, 100% active clay basis.

2. A self-activating organophilic clay rheological composition useful as an additive for non-aqueous fluid systems which is capable of increasing the viscosity of said non-aqueous fluid systems without the addition of a polar organic dispersant, which comprises the reaction product of a material selected from the group consisting of a dibenzyl dialkyl ammonium compound wherein the alkyl group contains 14 to 22 carbon atoms and wherein 20 to 35%
have 16 carbon atoms and 60 to 75% have 18 carbon atoms, and a a methyl benzyl dialkyl ammonium compound or a dibenzyl dialkyl ammonium compound wherein the alkyl group contains 8 to 20 carbon atoms wherein at least 5% have 8 to 14 carbon atoms, and a smectite-type clay having a cation exchange capacity of at least 75 milliequivalents per 100 grams of said clay, and wherein the amount of said ammonium compound is from 100 to 130 milliequivalents per 100 grams of said clay, 100% active clay basis.

3. The composition of claim 1 or 2 wherein the smectite-type clay is selected from the group consisting of hectorite and sodium bentonite.

4. The composition of claim 1 or 2 wherein the methyl benzyl dialkyl ammonium compound is methyl benzyl dihydrogenated tallow ammonium chloride.

5. The composition of claim 1 or 2 wherein the dibenzyl dialkyl ammonium compound is dibenzyl dihydrogenated tallow ammonium chloride.

6. The composition of claim 1 or 2 wherein the methyl benzyl dialkyl ammonium compound is methyl benzyl dicoconut fatty acid ammonium chloride.

7. The composition of claim 1 or 2 wherein the dibenzyl dialkyl ammonium compound is dibenzyl dicoconut fatty acid ammonium chloride.

8. A self-activating organophilic clay rheological composition useful as an additive for non-aqueous fluid systems, which comprises the reaction product of an ammonium compound having the formula:
wherein R1 is CH3 or C6H5CH2,R2 is C6H5CH2,R3 and R4 are alkyl groups containing either 14 to 22 carbon atoms wherein 20 to 35% have 16 carbon atoms and 60 to 75%
have 18 carbon atoms, or 8 to 20 carbon atoms wherein at least 5% have 8 to 14 carbon atoms, based on 100% and where M is selected from the group consisting of chloride, bromide, nitrite, hydroxyl, acetate, methyl sulfate and mixtures thereof, and a smectite-type clay selected from the group consisting of hectorite and sodium bentonite, and wherein the amount of said ammonium compound is from 100 to 130 milliequivalents per 100 grams of said clay, 100% active clay basis.

9. The non-aqueous fluid system of claim 8 wherein said organophilic clay composition comprises from 0.1% to 5% by weight of said fluid system.

10. The non-aqueous fluid system of claim 8 wherein said organophilic clay composition comprises from 0.3% to 2.0 by weight of said fluid system.