US2275583A - Dispersion compositions - Google Patents

Description

Patented Mar. 10,

f DISPERSION com'rosrnons William R. Catlow, In, and Harold r. Wakefield,

1., aszignors to Bakelite Corporation, a corporation of New Jersey No Drawing. Application April serial no. 5,541 7 12 Claims.

The present invention relates to compositions 1 No. 76,394 filed April 25, 1936, which since the filing of this case has become Patent No. 2,152,633 granted April 4, 1939. As disclosed in the prior application the invention comprises the conversion or advancement of oil-resin compositions to a condition of substantial chemical inertness and non-solubility, and the products are. generally in the form of soft plasticsolids or further heattreated to hard brittle resin-like solids. These products include amagent such as zinc oxide for rendering them dispersible in hydrocarbon thinners.

The present application relates more particularly to that form of the invention in which the resinous component is a member of the group consisting of natural resins and their compounds, such as the salts, esters or oxidation products as typified by rosin, limed rosin, ester gum, Vinsol, vetc. Compositions made for example from drying oils and members of the natural resin group, when brought or advanced to the condition of inertness and insolubility in the presence of a control agent whereby they become dispersible are found to yild coatings which harden directly upon evaporation of the solvent content into donot lift or dissolve upon application of lacpeers or other finish coatings, and they are markedly superior to the ordinary rosin-drying oil films.

As explained in theprior application-the advancement of oil-resin compositions can be determined by measuring the extractability with acetone, i. e. the proportion of non-extractable material remaining is a direct measure of the degree of advancement; by advancement is intended a conversion, preferably caused by heating, of the composition. Heretofore ithas been considered '30 homogeneous films inert tooxidizing action and lacquer solvents. Films can be so obtained which acetone-extractable material is converted by advancement into acetone non-extractable material; such compositions yield films of requisite resistance to the solvent action of lacquers and other superposed coatings.

Oils suitable for the purposes of this invention include the drying and semi-drying fatty oils such as tung, linseed, oiticica, soyabean, fish, D n p ppyseed, etc.; all such oils are herein designated as drying oils. Non-drying oils such as rape. cotton seed, corn, etc. may be included or substituted at least in part. Likewise compatible plasticizing agents such as aryl or alkyl phosphates or phthalates may be incorporated. The preferred compositions are in general those which contain tung oil as a major portion of the V oilcontent. fl, A Widely varying proportions of resins and oils can be used, but conditions such as the solvent resistance of the film, drying time, flexibility, etc. indicate the upper limiting ratio of resin to oil to be about 60 parts of resin to 40 parts of oil. The best results apparently are'obtained with a ratio approximating 30 parts of resin to 70 parts of oil. Zinc oxide is preferred as a control agent in obtaining dispersibility of the compositions in hydrocarbon thinners. In general the minimum quantity of zinc oxide to be included in compositions having as their resinous component a member of the natural resin group is about 10 per cent based on the total weight of oil; on the basis of the total composition amounts as small as five per cent have been found useful as is hereinafter set out in the examples. In place of zinc oxide there can be substituted theoxides of lead, calcium or the hydroxides,

-' naphthenates, tungates", etcfof these metals, other metallic soaps; carbon black, etc. The oxides and hydroxides can be substituted in about 40 equivalent proportions for the zinc oxide, butfor other agents the proportions may vary widely. The advanced or converted oil-resin compositions, made dispersible'by theinclusion of control agents, are employed as dispersions in hydrocarbon thinners such as toluol, xylol, benzol, hy-, drogenated petroleum, etc. The dispersions are readily obtained merely by adding the compositions tothinners at room temperature; but'the compositions in solid form are preferably coarsey round or broken up before their addition to thinners. The particle size of thecompositions in the, dispersed form usually does notexceed two microns. If the concentration of the compositions in thedispersions is not less than 50 per cent the dispersions remain completely stable and show no substantial separation on aging; when the concentration is less than50 per cent there may be some separation but without impairing the usefulness as coating compositions.

' The dispersions possess the characteristics of low viscosity, high percentage of solid flow and level-: ing which make them useful as coating compositions to be applied by spraying, dipping or brushing. The solvents or thinners readily escape from the films and there is no apparent tendency during drying to retard evaporation with consequent shrinkage. The films .dry rapidly (inabout 3 to 5 minutes when highly volatile thinners are used) and they are prac tically inert to the oxidizing action of air with no apparent tendency to lift, blister or crack when finish coats such as cellulose ester lacquers are i no mixing is intended for it results in a decreased -drying time, improves the gloss, and promotes more even hardening throughout the film to thereby further decrease the tendency to dimensional change during the drying of the film.

The converted or advanced oil-resin compositions with or without thinners can be admixed with other oils, resins or varnishes, and when so blended accelerate the drying and hardening of the latter sometimes as much as 30 to 50 per cent or more. This is especially trr 2 when added to alkyd resin coating compositions and the like which ordinarily remain tacky for 6 to 3 hours;

zinc oxide was included the mixture set up to an indispersible gel. Mixtures including 10, and percent of zinc oxide with rosin forming 30, 25 and 20 per cent respectively of the'composition gave solids dispersible in xylene, etc. Approximately 80 per cent of the acetone extractable material was converted into acetone non-extractable material by advancement. Films obtained by depositing dispersions were found to resist the solvent-action of lacquers; normally 20 per cent or more of zinc oxide is required for useful films. Example II.-In place of the rosin of Example I compositions of the same proportions were made substituting ester gum. These compositions were likewise heated at 250 C. for about 3 hours. The compositions were dispersible in xylene and approximately 76 to 90 percent of the acetone extractable-material was converted into acetone and their hardening time can be shortened to'as little as one-half hour by the addition of per cent of an advanced composition of an oil and resin as herein described.

,While dispersions of these advanced oil-resin compositions have proven particularly suitable for use as priming coats on metal, wood, and the like, they can also be usedto coat paper, cloth, w

parchment, leather, etc. They have provencvaluable as well in the coating of porous surfaces such as plaster, wallboard, adobe; concrete, papier mach, etc., since they deposit a stable, rapid drying film resistant to solvent and. water and thus .provide an effective sealer coat on the surface of porous materials. The converted compositions or their-dispersions can also be applied to surfaces of asphalt, Wax haIogenated naphthalene waxor the like, and when so applied provide a sealing coat which prevents bleeding from an asphalt or wax surface into any lacquer or varnish coat that may be applied subsequently;

this has proven effective in the coating of wire I which is first given a wax coating, then a coating of an advanced oil-resin dispersion and then a lacquer or varnish.

For a more complete understanding of the mvention the following examples are given but it is to be understood that they are merely'illustrative and not restrictive.

Example I.- A wood rosin melting at about '7'? C. was mixed with China-wood oil and zinc oxide in varying proportions and the mixtures.

heated for about 3 hours at 250 C. When no non-extractable material by advancement with increasing percentages of zinc oxide. The films were resistant to the solvent action of lacquers.

Example III.Limed rosin was substituted for rosin using the same proportions of zinc oxide and China-wood oil and applying the same treatment of heating for three hours at 250 C. The compositions were dispersible in xylene but only those containing 20 per cent or more of zinc oxide and having approximately per cent of the acetone extractable material converted into acetone non-extractable material by advancement gave films resistant to the solvent action of lacquers.

Example IV.-High melting point resins were I obtained by mixing rosin with maleic anhydride (or other dicarboxylic acid) and esterifying with glycerol giving a product having a melting point of over 120 C. A series of compositions were prepared but only those containing 20 per cent or more ofzinc oxide with'approximately twice as much China-wood oil were found to be dispersible in xylene, etc. when cooked for' three hours at 250 C. Approximately 80 per cent of the acetone extractable material was converted into acetone non-extractable material by advancement.

Example V.-Vinsol resins comprise pine wood pitch obtained as a residue in the separation of rosin from pine wood extract and include oxidized resin acids, terpenes, etc.'; they can be otherwise defined as resins comprising oxidized abietic acid. Aunumber of mixtures were prepared including a resin of this type with varying amounts of-China-wood oil and zinc oxide and in each case the mixtures were heated for three hours at 250 C. At the end of the three hour while warm in xylene. The acetone extractions (in this and the previous examples) were determined by coarsely grinding the samples (when not too soft), placing in a Soxhlet extraction apparatus using a hardened filter paper cone,-

and extracting with acetone over a period of 16 hours; the retained material was dried for 4 hours at 70 C. and the loss of weight gave the amount of acetone-extractable material. The xylene dispersions were thinned to 25 per cent's'olids and the viscosities were determined on" these solutions. Other samples, further thinned-to about k.v. were poured out on'tin plate, allowed to dry for fifteen minutes (with toluene or similar highly volatile solvent three to five minutes drying is ample), and spray coated with a white pig'- ented nitro-cellulose lacquer. 75

The following table 0 tlinesspecific Vinsol resin-oil range" and some of the properties:-

compositions covering in the main the useful to 40 parts of the latter and the control agent being Present to the extent of at least per Per cent by weight Sample Color 7 Z110 I i s,

Vinsol owo Acetone non-ertract Xylene dispersion Color Brogn almost black O sassa'ssesaaeaea aaeaeasseaeaeas assaaaasssamw Light yellow 182 The behavior of the Vinsol primer coatings under the lacquer coatings divided theminto three'groups:

A. Vinsol primer coatings having an acetone 3. Process according to claim 1 in which the non-extractable portion 82 per cent or more by weight based on the oil plus the'resin' were-entirely unaffected by the lacquerand its solvent content as shown by the gloss andsmoothness of the surface, the lack of penetration by the dark pimpling or pulling at the edges.

B. Coatings having an acetone non-extractable;

' portion of more than 72 per cent but less than 82 per cent were slightly affected by the lacquer in one ormore of the ways mentioned under A but provided a reasonably good coating system acceptable for ordinary uses and much superior to Vinsol varnishes made without a control agent.

C. Coatings with an acetone non-extractable portion of less than 72 per-cent were affected by .40 the superposed lacquer coatings to the extent of presentinga' dingy brown cast to the surfaces occasioned by penetration of the lacquer into the undercoating or the reverse. The surfaces were somewhat rough and there wasa pulling away at the edges of the undercoatings. a

The limits given under A, B and C are approximations and may vary from 2 to 3 per cent with different batches of materials.

What is claimed is: p

1. In a process of preparing an oil-resin composition dispersible ina hydrocarbon thinner to yield a film forming composition, thestep which comprises advancing by heating a composition of a fatty oil which in part at, least is a drying oil and a member of the group consistingofnatural resins, their salts, esters and oxidation products in the presence of a control agent selected from the group consisting of the oxides, hydroxides, so

and naphthenates of zinc, lead, magnesium and calcium and metallic soaps untilat least thirty percent of oil-resin is converted into acetone non-extractable material, the upper limiting ratio oi resin to oil being about 60 parts of the former 65 fatty oil, which in part at least is a drying oil,

cent on the weight of the oil calculated aszinc oxide.

2. Process according to claim 1 in which the drying oil constituent is tung oil.

resin is a natural resin.

4. Process according to claim 1 in which the resin is one comprising oxidized abietic .acid.

5. Process according to claim 1 in which the undercoat and the absence of toughening, control aeentiszinc i l 6. Process according to claim 1 in which the 7. Compositions suitable for use in coatings and a member of the group consisting of natural resins, their salts, esters and oxidation products advanced by heatingin the presence of a control agent selected from the group consisting ofthe oxides, hydroxides and naphthenates of zinc,

lead, magnesium and calcium and metallic soaps, to a state characterized by a conversion of at 1 least thirty per cent of oil-resin into acetone nonextractable material, the upper limiting ratio of resin to oil being about 60 parts of the former to 40 parts ofthe latter and the control agent being present to the extent of. at least 10 per cent on the weight of the oil calculated as zinc oxide.

8. Composition according to'claim 7 in which the drying oil constituent is tung oil.

9. Compositionaccording to. claim 7 in which the resin is a natural-resin. v

10. Composition according to c1aim 7 in which the resin is one comprising oxidized abietic acid.

11 Composition according to claim 7 in which the control agent is zinc oxide.

12. Composition according to claim 7 in which the control agent is zinc oxide and the resin is one comprising oxidized abietic acid, the agent constituting at least five per cent and the resin not more than forty-five per cent of the total composition.

WILLIAM R. CA'I'LOW. Jr. HAROLD F. WAKEFmD.