US2173430A - Pigmented base for paints and the like - Google Patents

Description

Patented Sept. 19, 1939 Max Raymond Vogel, Easton, Pa., assignor to Binney and Smith Company, New York, N. Y., a corporation of New Jersey No Drawing. Application July 16, 1937, Serial No. 154,103

' 10 Claim.

This invention relates to improvements in pigmented bases for use in the manufacture of paints, varnishes, lacquers, enamels, inks, plashicle. Various methods and machineshave been devised for the mechanical manipulation of mixr tures of the pigment and vehicle to produce a thorough and uniformdispersion'but no single method has proven completely successful. The

more common machines vused are the, ball and pebblemills, dough mixers, two roller mills, three roller mills and stone mills. Many addition 20 agents have been suggested which when used in combination with the various mechanical means of grinding somewhat improve the resulting product. These agents appearto be specific to the type of vehicle chosen; that is, an agent which 25 may operate satisfactorily with nitrocellulose may .not function with asynthetic resin, and vice versa.

It has now been discovered that if the pigmentation of a solid, water-insoluble resin is 30 conducted in the presence of a stable organic amine containing a plurality of --NH2 groups, unusually good, stable dispersions are obtained. Coating compositions prepared from these dispersions or pigmented bases exhibit, when applied 5 to the surface to be coated, a much higher gloss and a more pronounced depth of color than is the case when such polyamines are omitted.

The process of pigmentation is preferably conducted by a two-step process corresponding to 49 that disclosed in the patent of William B.-Wiegand, No. 2,045,006, dated June 23, 1936. In the first step-of this process the dispersion medium, preferably an alkyd resin vehicle, is coalesced, agglomerated, agglutinated or massed with a pis- 45 ment, for example carbon black, and with the polyamine under conditions most favorable to ready mixing, and either with or without the application of high shearing stresses, such as are produced by passing the mass between pressure 50 rolls of the type commonly used in the rubber industry. In the second step of the processthe mass resulting from the initial treatment is subjected to unusually high shearing stresses, these high shearing stresses being obtained by subject- 55 ing the mass while in a state of unusually stiff consistency to verystrenuous mechanical manipulation.

The stable organic amine may be incorporated at any point prior to or during the colloidal dispersing of the pigment in the medium. Stable 5 organic amines containing a plurality of un-' substituted -NH2 groups found most suitable for this purpose are triethylenetetramine, metaphenylenediamine, diethylenetriamine, ethylenediamine, metatoluylenediamine and benzidine. However, the invention is not restricted to the use of the specific amines mentioned above but may include other stable unsubstituted polyamines of the general class, whether aryl, alkyl, aralkyl, alkaryl, cycloalkyl or heterocyclic amines. By the term amine" it isnot intended to include amido type compounds .of the nature of urea and its derivatives, such as guanidine. This latter compound, guanidine, furthermore is unsuitable for use in pigmented bases because of its relative instability. Nor is it intended to include within the scope of the invention the use i of such insoluble or complex organic compounds as, dyes which contain a plurality of amino groups of the substituted type. The quantity of polyamine can be varied over a broad range but it has been found that proportions between one and fifteen percent have the most beneficial effect in dispersing the pigment. While the free amines produce the most desirable results, the soaps of 'such' amines may be used with some success.

The Wiegand two-step process of pigmentation referred to above is to be distinguished from the other commonly employed methods of dispersing pigment in paint media, in that the massed pig- 'ment and vehicle mixture in the Wiegand process is in a stiflly plastic or leather-like condition and is subjected to exceptionally high shearing stresses. Neither of these conditions exist in the 4 other processes, since the mixture of pigment and vehicle is usually'in a condition ranging from relative liquidity in ball or stone mill grinding to a "rubbery or flexibly plastic condition in the dough. mixer or the two roller (rubber) mill grind- 'ing. This relatively fiuid or soft plastic condition,

resulting from the addition of solvents, plasticiz ers, softeners, soft resin and the like to the vehicle and pigment mixture; prevents the application of high shearing stresses which are essential in preparing relatively complete andper- I manent colloidal disp of the Pi'Kmen'tim' 7' the vehicle.

The leather-like oonsistencyof the plastic mass in the Wiegand process corresponds in g ,eral to the stiffness of sole leather.

My invention will be more clearly understood from the following examples of the mode of pre-. paring a concentrated pigmented base'following generally the mechanical procedure described in the above-mentioned Wiegand patent.

pigmented alkyd resin base is as follows:

Parts by weight Alkyd resin modified with 50% drying oil fatty acids (acid No. 53) 500 Carbon black .300 Textile spi 215 Triethylcnetetramine y Example I' A typical charging composition for a black In the first step of preparing the base the above ingredients may be massed by passing between the'pressure rolls of a roller mill of the general type used in the rubber industry. The mixture is repeatedly passed between the rolls while the resin vehicle is in a viscous plastic condition until the pigment and polyamine have been suitably distributed throughout the resin, and the combined product has reached the degree of consistency best adapted for the application thereto of high shearing stresses. Alternatively, or prior thereto, the mixture of ingredients may be massed in a .mixer such as a. dough mixing machine.

The petroleum hydrocarbon solvent, textile spirits, in the above formula is used simply to wet down the carbon black pigment, and evaporates substantially completely during the process.

In the second step the resin vehicle, having the carbon black and polyamine incompletely dispersed therein and being of a stifily plastic or leather-like consistency, is passed between the same or a second pair of pressure rolls set closely together, the function of which rolls is to subject the mass to exceptionally high shearing stresses.

The leather-like consistency of the mass being operated upon may be maintained, if necessary, by heating or cooling the rolls. The rolls are suitably driven at different speeds so as to increase the shearing stresses and are set tight so. ithat when the mass is passed through the rolls it is sheeted out to a thickness of about onesixteenth to one thirty-second inch. Thesheets issuing from the rolls may be repeatedly passed between the rolls until a thorough and permanent colloidal dispersion of the pigment in the resin medium is assured.

These pigmented sheets, from the Wiegand process, at .normal room temperature will usually be brittle permitting the same to be broken into 'fiaky fragments of paper-like thinness, which when dissolved in a. suitable solvent with or without additional ingredients will form a paint, varnish, enamel or lacquer possessing an unusual depth of coloring, a high lustre and an exceptional degree of permanency.

The drying oil fatty acid modified glycerol phthalate resin in the above example is sold under the trade name of Rezyl #110. Other drying oil fatty acid modified alkyd resins may be substituted for this resin such asa 29% modification which has an acid number of about 57 and which is available under the trade name Rezyl #1102. These resins are made in ac-- cordance with theprocedure outlined in the U. 8.

Patents 1,893,873 and 1,893,874 to Kienle and Adams respectively. Pure alkyd plasticresins free from phenol and resin modifying agents such as fBeckosol #7 may also be used. This latter resin has a low acid number ranging from about five .to ten. Alkyd resins modified with saturated fatty acids such as Rezyl #12 which is modified with 28% non-drying fatty acids and has an acid number of 24, likewise may be substituted for v or used in combination with the alkyd resin in Example I. Pigmented bases prepared with Rezyl #12 are generally compatible with nitrocellulose compositions. Natural resin or rosin or other modifiedalkyd resins such as the Teglacs and Beckosol #1 may also be used in preparing these pigmented bases.

Other water-insoluble resins than the alkyd resins such as the phenol-aldehyde, urea-aldehyde and the coumarone-indene resins and even the natural and modified natural resins may replace or be combined with the foregoing alkyd resins. "Beckacite #1001 is a phenolic resin which has been found satisfactory in preparing the improved pigmented bases. Rosin, ester gum and Amberol 801 will also function satisfactorily in the process.

Although the invention is especially applicable to the manufacture of carbon black pigmented bases, other common color pigments, for example, Prussian blue, organic maroonsandtitanium dioxide,-may be substituted for or be used with carbon black in combination with the resin and polyamine. The following examplesshow charging combinations for other pigments than carbon black.

Bramble II A grinding composition for a grey pigmented resin base is as follows:

- rat. by weight Alkyd resin modified with 28% non-drying fatty acids (Rezyl #12) 500 Antimony oxide 3700 Carbon black 80 Textile spir 215 'Iriethylenetetramine 30 Example III A typical "blue charging composition is as follows:

Parts by weight Alkyd resin modified with 29% unsaturated fatty acids (acid No. 57) 500 Prussian blue-(C. P. non-bronzing type) 600 Textile spirits 215 'Iriethylenetetramine 30 mented base is combined with a suitable solvent such as toluenein a dough mixer to form a paste or solution. The paste is usually prepared so that it contains between 50 and 60 percent solids. Either the dry flake or the paste may be added to any liquid vehicle with which the resin'in the base is compatible, in preparing a coating composition. I I

metal) 22 Lead naphthenate in mineral spirits (34% metal) 39 Xylene 39 100 NrmoomULosn Lacquer Example VII M Parts by I weight Fatty-acid modified alkyd resin pigmented base (Example 11) 100 Butyl alonhol 200 Nitrocellulose solution (25% solids) 800 llkyd resin modified with 28% non-drying fatty acids e 100 Dibutyl phathalate 68 Rnsmoos ENAMa'Ls Example IV Parts by weight Fatty-acid modified alkyd resin pigmented base 130 Toluene 210 Phenol and oil modified alkyd resin solution (50% solids) 840 Drier solution 20.7

The phenol modified alkyd resin solution mentioned above may be the grade sold under the trade name of Beckosol #1 Solution which is cut with equal parts of mineral spirits. The acid number is between 10 and 15.

Example V Parts by weight Fatty-acid modified alkyd resin pigmented bas 130 Toluene 350 Alkyd resin modified with 37% drying oil fatty acids and 14% rosin (60% solids) A 700 Drier solution 20.7

The alkyd resin recited above is marketed under the trade name of Rezyl Solution J (114). The acid number of this resin is 33.

The toluene referred to in these two examples may be replaced by any of the common organic liquids used in such resinous enamels, namely coal tar solvents such as xylene, solvent naphthaand benzene; petroleum solvents such'as white spirits, Solvesso and petroleum spirits; turpentine and the alcohols such as butyl alcohol.

The proportion of drier solution can be varied over wide limits depending on the type finish desired, that is, whether low bake, high bake or air-dry. The drier used in the above example contains about .145 gram of metal for each gram of solution. The composition of the drier is as follows:'

Example VI Parts by weight Cobalt naphthenate in mineral spirts (6% with other modes of pigment In the above example it will be understood that all solvents, plasticizers, resins, etc., are compatible with nitrocellulose solutions. The alkyd resin mentioned above is sold in the trade under the name of Rezyl #12.

While in the specific examples given above alkyd resins are employed, it will be understood that in a broader sense the pigmented base is not limited to use with alkyd resins but other compatible paint and lacquer ingredients. such as resins, natural or synthetic, cellulose derivatives and oils may be substituted for or used in combination with the alkyd resins. Other-synthetic resins which may be used in the coating compositions include "Beckolin, Amberol 801, Glyptal Solution #2452 and Beckosol #1323".

The stable organic polyamine is preferably added to the mixture of resin and pigment while agglomerating' these materials but may be incorporated therein at any point in the process so long as it is present as a freeamine when the pigment is to be colloidally dispersed in the plastic mass.

Although the invention is best practiced by employing the two-step mechanical treatment .disclosed in the above-mentioned Wiegandpatent by which the most striking and'unusual results are attained, it is nevertheless within the contemplation of my invention in its broad aspects to employ the stable organic primary polyamine 'spersion in a resin while the later is in a solid p astic state. Softer resins can of course be used with these other methods of pigmentation since the stifily plastic condition-is not employed in such processes and the flaked pigmented base is not produced.

The present invention is not to be restricted to any specific proportions or manner of procedure beyond the limitation of the appended claims.

I claim:

1. A pigmented resin base comprising a ground intermixtu're of a pigment with a solid, plastic, water-insoluble resin and a stable,'s'oluble, organic amine containing a plurality of unsubstituted NH2 groups, said amine serving as a dispersing agent for the pigment.

2. A pigmented resin base comprising a ground intermixture of carbon black with a solid, plastic, water-insoluble resin in the presence of 'a stable, soluble, organic amine containing a plurality of unsubstituted -NH2 groups, said amine serving as a dispersing agent for the carbon black.

3. A pigmented resin base comprising a pi ment uniformly massed and mechanically worked with a solid, plastic, water-insoluble resin and a stable, soluble, organic amine containing a plurality of unsubstituted e-NH: groups, said amine serving as a dispersing agent for the pigment.

4. A pigmented resin base comprising carbon black uniformly massed and mechanically worked with a solid, plastic, water-insoluble, alkyd resin and a stable, soluble, organic amine containing a plurality of unsubstituted --Nm groups, said amine serving as a dispersing agent for the carbon black. Y

5. A pigmented resin base comprising carbonblack uniformly massed and mechanically worked with a. solid, plastic, water-insoluble, fatty-acid modified alkyd resin and ten percent triethylene tetramine based 0n. the weight of the carbon black, said triethylenetetramine serving as a dis'-' worked with a solid, plastic water-insoluble, 15

rosin-modified alkyd resin and metaphenylenediamine, said metaphenylenediamine serving as a dispersing agent'for the pigment.

7. A pigmented resirffiase comprising carbon black uniformly massed and mechanically worked with a solid, plastic, water-insoluble, synthetic resin and diethylenetriamine said diethylenetriamine serving as a dispersing agent for the carbon black.

8. A high gloss'resin enamel including a solution of a pigmented resin base, said pigmented resin base comprising a ground intermixture of a pigment with a solid, plastic, water-insoluble resin and a stable, soluble, organic amine containing a plurality [of unsubstituted NH: groups, said amine serving as a dispersing agent for the pigment.

9. A high gloss resin enamel including a solution or a pigmented resin base, said pigmented resin base comprising carbon black uniformly massed and mechanically worked with-a solid,

plastic, water-insoluble, alkyd resin and a stable. soluble, organic amine containing a plurality oi unsubstituted -NH: groups.

\ 10. A grey nitro-cellulose lacquer including an organic solvent'solution of nitrocellulose, synthetic resin, plasticizer and a grey pigmented base, said pigmented base comprising carbon black, antimony oxide, and triethylenetetramine uniformly massed and mechanically worked with a .solid, plastic, water-insoluble, fatty-acid modiiied alkyd resin which is compatible with nitrocellulose, said triethylenetetramine serving as a 15 dispersing agent for the carbon black.

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