US3392176A - Solventless coating vehicle and process for preparing it - Google Patents

Description

United States Patent 3,392,176 SOLVENTLESS COATING VEHICLE AND PROCESS FOR PREPARING IT David Eric Tweet, Minneapolis, Minn., assignor to Cargill, Incorporated, a corporation of Delaware No Drawing. Filed Jan. 2, 1964, Ser. No. 335,425 7 Claims. (Cl. 260-404.8)

ABSTRACT OF THE DISCLOSURE The present invention generally relates to a coating vehicle, and more particularly relates to a 100 percent solids vehicle for use in coatings such as paints, varnishes and the like.

Various vehicles are known for use in coating formulations such as paints and varnishes and, in the past, drying oils, e.g., linseed oil and soybean oil, have been employed alone as coating vehicles, in the absence of other eonstituents. The drying oils set or dry to form hardened films upon exposure to air and/ or heat due to oxidation and/or polymerization of the oils. However, the use of drying oils alone as coating vehicles has certain limitations since the coating films formed upon drying of the oils do not have a high degree of hardness and best weather resistance. Accordingly, in order to provide coating vehicles having improved hardness and weather resistance, various other constituents are added to the drying oils along with thinners. The thinners are volatile materials, such as water or an organic compound, e.g., benzene, turpentine, or other light organic solvent which, when combined with the drying oils and other constituents, provide a mobile coating vehicle having the desired coating characteristics. The use of volatile thinners is generally necessary to impart mobility and fluidity to the coating vehicle and/ or coating formulation containing additional agents and other constituents, since the addition of these materials, which are necessary to provide durable coatings, having the desired characteristics, generally cause the coating vehicle and/ or coating formulation to be so vis cous as to be unsuitable for application with a brush or spray gun. When the coating formulation containing the volatile thinner is applied to a surface and allowed to dry the thinner evaporates, exposing the drying oils and other constituents in the formulation to the atmosphere and causing drying of the coating to a hard, weather resistant surface.

There are certain disadvantages in the use of coating vehicles which include vaporizable thinners or other volatile constituents. In this connection, if the coating vehicle comprises a substantial amount of vaporizable material which evaporates during drying, this material does not contribute to the ultimate body or thickness of the dried coating. Thus, the use of volatile thinners generally necessitates the application of two or more coatings in order to provide complete covering of the surface to be coated. Moreover, the volatile constituents in the coating vehicle may evaporate either before or after preparation of the coating formulation so that the coating vehicle does not have the desired characteristics upon application. Problems arise in connection with shipping and/ or storage of organic thinners or other volatile constituents.

3,392,176 Patented July 9, 1968 In an attempt to overcome the disadvantages associated with the use of volatile thinners and other constituents in coating vehicles, percent solids vehicles have been formulated. A 100 percent solids coating vehicle is considered to be a vehicle which is free from vaporizable constituents under ambient conditions. Such a vehicle should provide desired hardness in the coating when applied, and should also provide suitable Weather resistance and durability. At the same time, the 100 percent solids vehicle must be sufiiciently mobile under ambient conditions that it may be applied to the surface to be coated by brush or by spray gun.

Generally, the 100 percent solids coating vehicles presently known provide a sufiicient degree of physical hardness and weather resistance to coatings only when the coating is oven dried or baked at an elevated temperature. The available 100 percent solids vehicles do not provide air dried coatings, i.e., coating dried by exposure'to the atmosphere at ambient conditions, which have the desired physical hardness and weather resistance.

One example of a 100 percent solids vehicle suitable for use Where the coating is oven baked is described by United States Patent No. 2,867,593. However, the 100 percent solids vehicle described in Patent No. 2,867,593 is not capable of providing a suitable air-dried coating having the desired physical properties.

It is the principal object of the present invention to provide an improved vehicle for coating formulations. It is a further object to provide a 100 percent solids coating vehicle which, upon drying, provides a coating having desired hardness and Weather resistance under ambient conditions. An additional object is to provide a 100 percent solids coating vehicle for use in coating formulations which provides increased coating film thickness upon normal application.

Further objects and advantages of the present invention will become apparent from the following detailed description.

Generally, the coating vehicle of the present invention comprises a reaction product of (1) an adduct of (a) 2-hydroxymethyl-S-norborene (hereinafter sometimes referred to as Cyclol), (b) trimethylol propane diallylether and (c) maleic acid or anhydride and/or fumaric acid; and (2) a drying oil. The adduct generally comprises equal molar amounts of its constituents. Other known nonvolatile constituents designed to modify or augment the characteristics of the coating vehicle may be mixed with the reaction product. More specifically, the coating vehicle of the present invention is a 100 percent solids vehicle comprising a reaction mixture of Cyclol, trimethylol propane diallylether maleate and/or fumarate, and from about 40 percent to about 60 percent by weight thereof of a drying oil.

Z-hydroxymethyl-S-norborene, more commonly known by its trade name Cyclol, is an unsaturated monohydric alcohol having the following physical properties:

TABLE 1 Molecular weight 124.

Color APHA Maximum 20.

Boiling point (760 mm. Hg) 205 C.

Freezing point -ll.5 C.

Flash point, open cup 84 C.

Specific gravity (25 C.) 1.022.

Refractive index, N d 1.4994.

Viscosity 55 cps.

Solubility Organic solvents;

insoluble in cold water; slightly soluble in hot Water.

Cyclol may be reacted with equimolar amounts of either lations and dried under ambient conditions to provide maleic acid or anhydride or fumaric acid, and a particular coating films having good physical hardness characteristics monohydn'c ether in order to provide an adduct which and resistance to weathering and abrasion. It is apparent can he further reacted with drying oils to form a 100 perthat the coating vehicle may also be employed in coating cent solids coating vehicle which can be air dried under formulations that are baked, if this is desired.= ambient conditions to form acoating film having desirable Certain tests have been conducted on the coating hardnessand resistance characteristics. vehicles of the invention after drying to hardened films It has been discovered that in order to provide a mobile in order to determine the physical characteristics of the 100 percent solids vehicle that can be dried under ambient films. The hardness of the films, after various periods of conditions, it is necessary to employ a particular ether drying, were determined by the standard Sward hardness as a reactant in the formation of the adduct. One such f a mils thick film. Th ri l s f the films Was ether is trimethylol propane diallyl ether (TMPDAE). tested by a standard /3 inch mandrel test as described TMPDAE is a monohydric alcohol having the following in Gardener and SWHrd, Physical and Chemical h i l Structure; nation of Paints, Varnishes, Lacquer, and Colors, 10th CHPCH; 15 Edition, 1946, at page 171. In accordance with the man drel test a one mil thick film of the coating vehicle is ap- CHFCH OHZ OCF2O CH2 OOH2 CH=CH2 plied to a inch thick tin plate and air dried under CH OH ambient conditions for 72 hours. In order to pass the TMPDAE is soluble in acetone, methanol, ethyl acetone, mandrel test the hhh ehehld hot eraek when the Plate is n-butanol and benzene, but is insoluble in water. heht Over a lheh hlahdrel- Cyclol trimethylol propane diallylether maleate or The reverse Impact test 15 the hhmher P foot pehhds fumarate may be formed by reacting togethgr equimolar necessary to crack or fracture a one mil thick film applied amounts of Cyclol, TMPDAE and either maleic acid or to a 5 web cold rolled steel plate that has been dried for anhydride or fumaric acid, or mixtures thereof, at an 7 hours when struck on the reverse slde by a Gardner elevated temperature of between about 300 F. to 500 hhpaet e E, preferably about 400 F., to an acid value of 2 to 20, e reslstahee of the eeahhg hhh e deterhhhed and preferably an acid value of 10. Any unreacted mahy sthklhg the hhh Sharp glahemg b with the finger terials remaining are preferably removed from the adhalls- In h e Pass the mar reslstahee test the h duct by steam stripping. It is contemplated that the adduct Should hot exhlhlt marks of any land when struck may be prepared according to other equivalent processes the hhgerhahsand the exact mode of preparation of the adduct is not Example I considered to be an essential part of the present inven- A 10.0 percent lid Vghicle i formed b reacting one tion. mol of Cyclol, one mol of trimethylol propane diallyl- The 100 Percent Solids Vehicle is formed y blending ether and one mol of maleic anhydride at 400 F. to an tOgether and reacting y adduct With a drying 01-1 acid value of 10 to form a Cyclol adduct. Any unreacted a mixture of drying 0115- It has been found that Superior materials are stripped from the Cyclol adduct by heating. air dried coating films are obtained when the drying oil The Cycle] adduct is blended with 100 percent by is Present in an amount of 66 Pbrbbbt to about 150 P weight of the adduct of linseed oil and the blend is heated Cent y Weight of the adduct, although it is contemplated at 420 F. until a sample thereof is clear at room temper-ato e p y about Pe to about 400 b b 0f the 40 ture. The coating vehicle thus formed is cooled to room drying 0115 In Certain Instances Known drymg olls may temperautre and 0.33 percent of azo-bisisobutyronitrile is be p y to form the 100 P Sohds Vehlcle of added to stabilize the coating vehicle in the presence of the present invention. Specific examples of drying oils (in-em include linseed oil safilower oil, dehydrated castor oil, h coating hi l i mobile, having a viscosity of 3.0 soybean 011 and mlxtllres tbereofpoises, measured by the standard Gardner-Holdt viscosity e blend of the adduct and the drylhg 011 15 heated tubes, and when mixed with various pigments and other at a temperature between about 3 50 F. to about h constituents of coating formulations, provides a coating Fa Preferably about hhhl a shmple thereof 15 composition that is easy to apply and which dries rapidly clear at room temperature. The precise reaction that in air to form coating films of good physical properties occurs during the heatlng of the adduct and drying 011 blend is not completely understood, and it is not clear Example H whether polymerization occurs. However, it is known that A coating vehicle is prepared in accordance with Examif the blend is heated at an elevated temperature until ple I except that linseed oil in an amount of 150 percent a sample is clear at room temperature, a particularly deby Weight of the Cyclol adduct is employed. The coating sirable 100 percent solids vehicle is obtained. As with the vehicle is mobile, having a viscosity of 1.6 poises, measpreparation of the adduct, the precise manner of reacting ured by the standard Gardner-Holdt viscosity tubes. The the adduct and drying oil is not considered critical, so long coating vehicle of this example can be incorporated in as a method of manufacture is selected that is equivalent various coating formulations to form air dried films of to that described above. acceptable physcial characteristics.

It is preferable to add a stabilizer to the 100 percent The coating vehicles of Examples I and II are mixed solids vehicle in order to stabilize the vehicle in the preswith 1 gram per grams of vehicle of cobalt naphence of the usual paint driers, e.g., cobalt naphthenate or thenate drier and are employed to form air dried films on manganese driers. One suitable stabilizer is azo-bisvarious surfaces and are subjected to the previously deisobutyronitrile. scribed tests to determine the physical characteristics of 100 percent solids coating vehicles of the type described the dried films. The results are set forth in the following herein may be incorporated in suitable coating formutable:

TABLE II Drying Time, Hours Sward Hardness Reverse Mar Resistance of 1.5 mils film Impact Mandrel Set To Tack Print 24 hr. lwk. 2wk. inch/lbs Test 24hr. 48 hr. lwk. Touch Free Free Example N 0.:

1 3.2 4.2 5.0 4 1s 30 36 Fail. Pass Pass Pass. 2 6.6 8 9.2 2 12 18 Pass do "do Do.

Dried films of the coating vehicles are free from surface irregularity at all film thicknesses up to a wet film thickness greater than 3 mils. The films dry very rapidly under ambient conditions and exhibit good cohesion characteristics on all surfaces to which the vehicle is applied and can be used for coating metals as well as woods, plastics and other materials. The physical characteristics of dried films of the coating vehicles of Examples I and II set forth in Table II illustrate that a coating vehicle has been provided which, when air dried in the form of a coating film, has superior physical characteristics of hardness and resistance to cracking and abrasion.

It can be seen that a 100 percent solids vehicle has been provided which can be utilized to form dried films under ambient conditions of improved hardness and resistance. The coating vehicle may be employed in place of conventional volatile vehicles in most conventional coating formulations that are air dried. As used herein, the term air dried means that the coating film is dried under conditions approximating atmospheric temperature and pressure in the absence of elevated temperatures and forced oxidation.

Various of the features of the present invention are set forth in the following claims.

What is claimed is:

1. A 100' percent solids vehicle comprising a reaction product of (a) an adduct formed by reacting equimolar amounts of 2-hydroxymethyl-5norborene, trimethylolpropane diallyether, and a member selected from maleic acid, maleic anhydride or fumaric acid at a temperature of between about 300 F. and about 500 F. to an acid number of between about 2 and about 20, (b) between about 66 percent and about 150 percent by weight of the adduct of a fatty :acid drying oil, the reaction product being formed by blending together and heating the adduct and the fatty acid drying oil at a temperature of between about 350 F. and about 500 F. until clear at room temperature.

2. A 100 percent solids vehicle comprising a reaction product of (a) an adduct formed by reacting equimolar amounts of 2-hydroxymethyl-5-norborene, trimethylolpropane diallylether, and a member selected from maleic acid, maleic anhydride or fumaric acid at a temperature of between about 300 F. and about 500 F. to an acid number of between about 2 and about 20, and (b) between about 66 percent and about 150 percent by weight of the adduct of a fatty acid drying oil, selected from lineed oil, safiiower oil, soybean oil and dehydrated castor oil, the reaction product being formed by blending together and heating the adduct and the fatty acid drying oil at a temperature of between about 350 F. and about 500 F. until clear at room temperature.

3. A 100 percent solids vehicle comprising a reaction product of (a) an adduct formed by reacting equimolar amounts of 2-hydroxymethyl-5-norborene, trimethylolpropane diallylether, and a member selected from maleic acid, maleic anhydride or fumaric acid at a temperature of between about 300 F. and about 500 F. to an acid number of between about 2 and about 20, and (b) between about 100 percent and about 150 percent by weight of the adduct of a fatty acid drying oil, selected from linseed oil, safflower oil, soybean oil and dehydrated castor oil, the reaction product being formed by blending together and heating the adduct and the fatty acid drying oil at a temperature of between about 350 F. and about 5 00 F. until clear at room temperature.

4. A percent solids vehicle comprising a reaction product of (a) an adduct formed by reacting equimolar amounts of 2-hydroXymethyl-5-norborene, trimethylolpropane diallylether, and a member selected from maleic acid, maleic anhydride or fumaric acid at a temperature of between about 300 F. and about 500 F. to an acid number of between about 2 and about 20, and (b) between about 66 percent and about percent by weight of the adduct of linseed oil, the reaction product being formed by blending together and heating the adduct and the linseed oil at a temperature of between about 350 F. and about 500 F. until clear at room temperature.

5. A method for manufacturing an improved 100 percent solids vehicle, which method comprises, forming an adduct by reacting equimolar amounts of 2-hydroxymethyl-S-norborene, trimethylolpropane diallylether and a member selected from the group consisting of maleic acid and anhydride and fumaric acid, at an elevated temperature to an acid number of from about 2 to about 20, blending said adduct with about 66 percent to about 150 percent by weight of said adduct of a drying oil and heating said blend until clear at room temperature.

6. A method for manufacturing an improved 100 percent solids vehicle, which method comprises, forming an adduct by reacting equimolar amounts of Z-hydroxymethyl-5-norborene, trimethylolpropane diallylether and a member selected from the group consisting of maleic acid and anhydride and fumaric acid, at a temperature of from about 300 F. to about 500 F. to an acid number of from about 2 to about 20, blending said adduct with about 66 percent to about 150 percent by weight of said adduct of a drying oil and heating said blend at a temperature of about 350 F. to about 500 F. until clear at room temperature.

7. A method for manufacturing an improved 100 percent solids vehicle, which method comprises, forming an adduct by reacting equimolar amounts of 2-hydroxymethyl-S-norborene, trimethylolpropane diallylether and a member selected from the group consisting of maleic acid and anhydride and fumaric acid at a temperature of about 400 F., to an acid number of about 10, blending said adduct with about 66 percent to about 150 percent by weight of said adduct of a drying oil selected from the group consisting of linseed oil, safflower oil and dehydrated caster oil and heating said blend at about 420 F. until clear at room temperature.

References Cited UNITED STATES PATENTS 3,192,061 6/1965 Wilson et al 106250 NICHOLAS S. RIZZO, Primary Examiner.

R. GALLAGHER, Assistant Examiner.