Water Reducible Short Oil Alkyd Resins and Process of Making Same

This invention relates to novel water reducible short oil alkyd resin compositions and to a process of making same. More particularly, this invention is directed to water reducible short oil alkyd resins comprising the reaction product of a polyethylene glycol, a triglyceride, a polyol, and an aromatic dicarboxylic acid. This invention further relates to the use of the herein disclosed novel alkyd resins as superior quality coatings either alone or in suitable blends and articles coated therewith.

No prior art practices are known to applicants wherein water reducible short oil alkyd resins are prepared using selected polyethylene glycols to control molecular weight, promote excellent solubility and solution stability of water reducible short oil alkyd resin compositions.

In accordance with this invention, water reducible short oil alkyd resins and a process of preparing same are provided wherein said resins are the reaction product of a polyethylene, glycol, a triglyceride, a polyol and an aromatic dicarboxylic acid or anhydride. More specifically, the alkyd resin compositions disclosed herein comprise from about 10-15 wt. %, based on the total weight of the reactants, of the polyethylene glycol; from about 20-25 wt. %, based on the total weight of the reactants, of the triglyceride; from about 18-23 wt. %, based on the total weight of reactants, of a polyol and from about 43-48 wt. %, based on the total weight of the reactants, of an aromatic dicarboxylic acid or anhydride. The final polymer based on the above-described reactants should preferably have an alcoholic acid number in the range of from about 45 to about 65. Additionally, the final polymer may be neutralized or partially neutralized by any suitable means, e.g., by triethylamine.

Polyethylene glycols suitable for use in this invention are commercially obtainable, e.g., Carbowax Polyethylene Glycols, or Polyglycol/Polyethylene Glycols. Such glycols having a molecular weight from about 200-2000 are preferred; especially preferred are those within the molecular weight range of from about 350-1500.

Representative Carbowax Polyethylene Glycols are described in the Table A below:

Any suitable triglyceride may be used in the invention. Triglycerides of oleic, palmitic, lauric, linoleic and linolenic acids are suitable. Specially preferred are triglycerides derived from natural sources such as soya oil, safflower oil, tall oil, palm oil and the like. Accordingly, suitable triglycerides have from about 30-60 carbon atoms per molecule (C.sub.30 -C.sub.60).

Polyols suitable for the invention should preferably contain from about 2 to about 6 hydroxy groups, e.g., glycerine, propylene glycol, trimethlylol ethane, trimethylol propane, pentaerythritiol and the like.

Aromatic dicarboxylic acids or anhydrides may both be advantageously used in these compositions. In general the acid or anhydride should contain from 8-12 carbon atoms, that is it should be a C.sub.8 -C.sub.12 dicarboxylic acid or anhydride. Representative compounds are isophthalic, phthalic and terephthalic acids, and phthalic anhydride.

In general, the water reducible short oil alkyd resins embodied in this invention are prepared by placing appropriate amounts of a polyethylene glycol, a polyol and a triglyceride as disclosed in a suitable reaction vessel; applying heat in excess of approximately 200.degree. C; and removing air from the reaction chamber. The reaction may be catalyzed by minor amounts of an alcoholysis catalyst, such as litharge (a fused lead oxide) or lithium hydroxide, using from about 0.005 to about 0.0075 mole which may be conveniently added to the reaction zone after the air purge. The reaction vessel is then cooled prior to adding the aromatic dicarboxylic acid or anhydride and the reaction temperature is gradually raised to approximately 215.degree. - 225.degree. C and the temperature is held there until the dicarboxylic component has reacted to the point where it is no longer visible in the reaction mixture. Generally, the reaction is continued until the mixture has an alcoholic acid number from about 45 to about 65 whereupon it is cooled and then quenched with a suitable coupling solvent and/or diluent, such as Butyl Cellosolve and t-butyl alcohol to afford the desired alkyd resin. Additionally, the alkyd resins so prepared may be neutralized in any suitable manner with any suitable amine such as for example triethylamine or N,N-dimethylethanolamine and distilled water to provide a clear resin having a substantially neutral pH, i.e., approximately 6.5 - 7.5.

The following examples illustrate the process of the present invention and in no way are intended to limit the scope of this invention. The specific examples below, thus illustrate the water-reducible alkyd resins as embodied herein and process of making same.

A 12 liter round bottom flask was charged with 1105.0 gm of soya oil, 945.0 gm of glycerine, and 600.0 gm of Carbowax 600. The mixture was heated to 205.degree. C using a subsurface nitrogen purge to remove any air present in the reaction vessel. One and five tenths grams of litharge were added, the nitrogen purge removed, and the temperature raised to 230.degree. C where it was maintained for 40 minutes. The reaction mixture was then cooled to 210.degree. C and 2350.0 gm of isophthalic acid were added. The reaction temperature was gradually raised to 225.degree. C while removing any water formed during the esterification process. This temperature was maintained until the isophthalic acid had reacted to the point where it was no longer visible in the reaction mixture. The temperature was then reduced to 215.degree. C. and held there until an alcoholic acid number of 57.8 was attained. The reaction mixture was then cooled to 190.degree. C and quenched with 250.0 gm of Butyl Cellosolve. An additional 869.0 gm of Butyl Cellosolve and 1119.0 gm of t-butyl alcohol were then added to afford an alkyd having a Gardner-Holdt viscosity of Z4-Z5 (25.degree. C), a % NVM of 66.1 (2 hrs. ca 150.degree. C), and an alcoholic acid number of 58.3 (on % NVM). To this resin were added 422.0 gm of triethylamine and 1744.0 gm of distilled water to afford a clear resin having a Gardner-Holdt viscosity of W-X, a % NVM of 50.8 (2 hrs. ca 150.degree. C), and a pH of 7.1.

A 3 liter round bottom flask was charged with 200.0 gm of safflower oil, 220.0 gm of glycerine, and 120 gm of Carbowax 1540. The mixture was heated to 205.degree. C using a subsurface nitrogen purge to remove any air present in the reaction vessel. Three tenths gm of litharge was added, the nitrogen purge removed, and the temperature raised to 230.degree. C where it was maintained for 30 minutes. The reaction mixture was cooled to 220.degree. C and 460.0 gm of isophthalic acid were added. The reaction temperature was gradually raised to 220.degree. while removing any water formed during the esterification process. This temperature was maintained until the isophthalic acid had reacted to the point where it was no longer visible in the reaction mixture. The temperature was then reduced to 210.degree.-212.degree. C and held there until an alcoholic acid number of 60.8 was attained. The reaction was then cooled to 190.degree. C and quenched with 100.0 gm of Butyl Cellosolve. An additional 90.0 gm of Butyl Cellosolve and 190.0 gm of t-butyl alcohol were then added to afford an alkyd having a Gardner-Holdt viscosity of Z5-Z6 (25.degree. C), a % NVM of 69.7 (2 hrs. ca 150.degree. C), and an alcoholic acid number of 57.2 (on % NVM). To 500.0 gm of this resin were added 11.0 gm Butyl Cellosolve, 11.0 gm t-butyl alcohol, 32.3 gm of triethylamine and 143.0 gm of distilled water to afford a clear resin having a Gardner-Holdt viscosity of U, a % NVM of 50.5 (2 hrs. ca 150.degree. C) and a pH of 7.1.

A 3 liter round bottom flask was charged with 221.0 gm of safflower oil, 185.0 gm of glycerine, and 100 gm of Carbowax 400. The mixture was heated to 205.degree. C using a subsurface nitrogen purge to remove any air present in the reaction vessel. Three tenths gm of litharge was added, the nitrogen purge removed, and the temperature raised to 230.degree. C where it was maintained for 30 minutes. The reaction mixture was cooled to 220.degree. C and 470.0 gm of isophthalic acid and 24.0 gm of propylene glycol were added. The reaction temperature was gradually raised to 220.degree. C. while removing any water formed during the esterification process. This temperature was maintained until the isophthalic acid had reacted to the point where it was no longer visible in the reaction mixture and the alcoholic acid number was 52.6. The reaction was cooled to 200.degree. C and quenched with 100.0 gm of Butyl Cellosolve. An additional 94.0 gm of Butyl Cellosolve and 194.0 gm of t-butyl alcohol were then added to afford an alkyd having a Gardner-Holdt viscosity of Z4+ (25.degree. C), a % of NVM of 69.3 and an alcoholic acid number of 53.6 (on % NVM). TO 502.0 gm of this resin were added 10.0 gm of Butyl Cellosolve, 10.0 gm of t-butyl alcohol, 31.0 gm of triethylamine, and 150.0 gm of distilled water to afford a clear resin having a Gardner-Holdt viscosity of T, a % NVM of 49.1 (2 hrs. ca 150.degree. C) and a pH of 7.3.

A 12 liter round bottom flask was charged with 800.0 gm of safflower oil, 780.0 gm of glycerine, and 480.0 gm of Carbowax 1540. The mixture was heated to 205.degree. C using a subsurface nitrogen purge to remove any air present in the reaction vessel. One and two tenths grams of litharge were added, the nitrogen purge removed, and the temperature raised to 230.degree. C. where it was maintained for 40 minutes. The reaction mixture was then cooled to 210.degree. C and 1840.0 gm of isophthalic acid and 100.0 gm of propylene glycol were added. The reaction temperature was gradually raised to 225.degree. C while removing any water formed during the esterification process. This temperature was maintained until the isophthalic acid had reacted to the point where it was no longer visible in the reaction mixture. The temperature was then reduced to 215.degree. C and held there until an alcoholic acid number of 57.0 was attained. The reaction mixture was then cooled to 190.degree. C and quenched with 400.0 gm of Butyl Cellosolve. An additional 376.0 gm of Butyl Cellosolve and 776.0 gm of t-butyl alcohol were then added to afford an alkyd having a Gardner-Holt viscosity of Z3+ (25.degree. C), a % NVM of 69.5 (2 hrs. ca 150.degree. C), and an alcoholic acid number of 55.7 (on % NVM). To this resin were added 286.0 gm of triethylamine and 1499.0 gm of distilled water to afford a clear resin having a Gardner-Holdt viscosity of R-S, a % NVM of 50.0 (2 hrs. ca 150.degree. C), and a pH of 6.5.

A 12 liter round bottom flask was charged with 1000.0 gm of safflower oil, 1035.0 gm of glycerine, and 600.0 gm of Carbowax 1540. The mixture was heated to 205.degree. C using a subsurface nitrogen purge to remove any air present in the reaction vessel. One and five tenths grams of litharge was added, the nitrogen purge removed, and the temperature raised to 230.degree. C where it was maintained for 40 minutes. The reaction mixture was cooled to 210.degree. C and 2300.0 gm of isophthalic acid and 65.0 gm of diethylene glycol were added. The reaction temperature was gradually raised to 225.degree. C while removing any water formed during the esterification process. This temperature was maintained until the isophthalic acid had reacted to the point where it was no longer visible in the reaction mixture. The temperature was then reduced to 215.degree. C and held there until an alcoholic acid number of 55.2 was attained. The reaction was then cooled to 190.degree. C and quenched with 500.0 gm of Butyl Cellosolve. An additional 470.0 gm of Butyl Cellosolve and 970.0 gm of t-butyl alcohol were then added to afford an alkyd having a Gardner-Holdt viscosity of Z4-(25.degree. C), a % NVM of 69.3 (2 hrs. ca 150.degree. C), and an alcoholic acid number of 55.5 (on % NVM). To this resin were added an additional 127.0 gm of Butyl Cellosolve and t-butyl alcohol, 401.0 gm of triethylamine and 1831.0 gm of distilled water to afford a clear resin having a Gardner-Holdt viscosity of T+, a % NVM of 49.9 (2 hrs. ca 150.degree. C), and a pH of 6.85.

A 3 liter round bottom flask was charged with 200.0 gm of safflower oil, 195.0 gm of glycerine, and 120.0 gm of Carbowax 1540. The mixture was heated to 205.degree. C using a subsurface nitrogen purge to remove any air present in the reaction vessel. Three tenths gm of litharge was added, the nitrogen purge removed, and the temperature raised to 230.degree. C where it was maintained for 30 minutes. The reaction mixture was cooled to 220.degree. C and 322.0 gm of isophthalic acid and 138.0 gm of phthalic anhydride were added. The reaction temperature was gradually raised to 220.degree. C while removing any water formed during the esterification process. This temperature was maintained until the isophthalic acid had reacted to the point where it was no longer visible in the reaction mixture. The temperature was then reduced to 210.degree.-212.degree. C and held there until an alcoholic acid number of 53.9 was attained. The reaction was then cooled to 190.degree. C and quenched with 100.0 gm of Butyl Cellosolve. An additional 89.0 gm of Butyl Cellosolve and 189.0 gm of t-butyl alcohol were then added to afford an alkyd having a viscosity of Z4-(25.degree. C), a % NVM of 69.4 (2 hrs. ca 150.degree. C), and an alcoholic acid number of 54.8 (on % NVM). To 500.0 gm of this resin were added 13.0 gm Butyl Cellosolve, 13.0 gm t-butyl alcohol, 31.0 gm of triethylamine, and 167.0 gm of distilled water to afford a clear resin having a Gardner-Holdt viscosity of S-T, a % NVM of 50.8 (2 hrs. ca 150.degree. C), and a pH of 7.0.

A 3 liter round bottom flask was charged with 221.0 gm of soya oil, 12.0 gm of pentaerythritol, 180.0 gm of glycerine, and 120.0 gm of Carbowax 600. The mixture was heated to 205.degree. C using a subsurface nitrogen purge to remove any air present in the reaction vessel. Three tenths gm of litharge was added, the nitrogen purge removed, and the temperature raised to 230.degree. C where it was maintained for 30 minutes. The reaction mixture was cooled to 220.degree. C and 470.0 gm of isophthalic acid were added. The reaction temperature was gradually raised to 220.degree. C while removing any water formed during the esterification process. This temperature was maintained until the isophthalic acid had reacted to the point where it was no longer visible in the reaction mixture. The temperature was then reduced to 210.degree.-212.degree. C and held there until an alcoholic acid number of 64.5 was attained. The reactants were cooled to 190.degree. C and quenched with 100.0 gm of 2/1 n-Butanol/Cellosolve. An additional 290.0 gm of this solvent combination was then added to afford an alkyd having a Gardner-Holdt viscosity of Z3-Z4 (25.degree. C), a % NVM of 69.3 (2 hrs. ca 150.degree. C), and an alcoholic acid number of 61.0 (on % NVM). To 500.0 gm of this resin were added 38.0 gm of triethylamine, and 155.0 gm of distilled water to afford a clear resin having a Gardner-Holdt viscosity of W-X, a % NVM of 49.8 (2 hrs. ca 150.degree. C), and a pH of 8.0.

A 12 liter round bottom flask was charged with 844.0 gm of safflower oil, 740.0 gm of glycerine, and 480.0 gm of Carbowax 400. The mixture was heated to 205.degree. C using a subsurface nitrogen purge to remove any air present in the reaction vessel. One and two tenths grams of litharge was added, the nitrogen purge removed, and the temperature raised to 230.degree. C where it was maintained for 40 minutes. The reaction mixture was cooled to 210.degree. C and 184.0 gm of isophthalic acid and 96.0 gm of propylene glycol were added. The reaction temperature was gradually raised to 225.degree. C while removing any water formed during the esterification process. This temperature was maintained until the isophthalic acid had reacted to the point where it was no longer visible in the reaction mixture. The temperature was then reduced to 215.degree. C and held there until an alcoholic acid number of 44.3 was attained. The reaction was then cooled to 190.degree. C and quenched with 400.0 gm of Butyl Cellosolve. An additional 370.0 gm of Butyl Cellosolve and 770.0 gm of t-butyl alcohol were then added to afford an alkyd having a Gardner-Holdt viscosity of Z4-(25.degree. C), a % NVM of 69.1 (2 hrs. ca 150.degree. C), and an alcoholic acid number of 44.8 (on % NVM). To this resin were added an additional 93.0 gm of Butyl Cellosolve and t-butyl alcohol, 228.0 gm of triethylamine and 1531.0 gm of distilled water to afford a clear resin having a Gardner-Holdt viscosity of R, a % NVM of 50.9 (2 hrs. ca 150.degree. C), and a pH of 6.5.

A 3 liter round bottom flask was charged with 206.0 gm of safflower oil, 190.0 gm of glycerine, and 120.0 gm of Carbowax 600. The mixture was heated to 205.degree. C using a subsurface nitrogen purge to remove any air present in the reaction vessel. Three tenths gm of litharge was added, the nitrogen purge removed, and the temperature raised to 230.degree. C where it was maintained for 30 minutes. The reaction mixture was cooled to 220.degree. C and 460.0 gm of isophthalic acid and 24.0 gm of propylene glycol were added. The reaction temperature was gradually raised to 220.degree. while removing any water formed during the esterification process. This temperature was maintained until the isophthalic acid had reacted to the point where it was no longer visible in the reaction mixture. The temperature was then reduced to 210.degree.-212.degree. C and held there until an alcoholic acid number of 50.4 was attained. The reaction was then cooled to 190.degree. C and quenched with 100.0 gm of Butyl Cellosolve. An additional 92.0 gm of Butyl Cellosolve and 192.0 gm of t-butyl alcohol were then added to afford an alkyd having a Gardner-Holdt viscosity of Z3+ (25.degree. C), a % NVM of 69.7 (2 hrs. ca 150.degree. C), and an alcoholic acid number of 50.7 (on % NVM). To 500.0 gm of this resin were added 10.0 gm Butyl Cellosolve, 10.0 gm t-butyl alcohol, 24.5 gm of triethylamine, and 150.0 gm of distilled water to afford a clear resin having a Gardner-Holdt viscosity of R, a % NVM of 50.1 (2 hrs. ca 150.degree. C), and a pH of 6.5.

A 3 liter round bottom flask was charged with 211.0 gm. of safflower oil, 247.0 gm of trimethylol ethane, and 120.0 gm of Carbowax 400. The mixture was heated to 205.degree. C using a subsurface nitrogen purge to remove any air present in the reaction vessel. Three tenths gm of litharge was added, the nitrogen purge removed, and the temperature raised to 230.degree. C where it was maintained for 30 minutes. The reaction mixture was cooled to 220.degree. C and 460.0 gm of isophthalic acid and 24.0 gm of propylene glycol were added. The reaction temperature was gradually raised to 220.degree. while removing any water formed during the esterification process. This temperature was maintained until the isophthalic acid had reacted to the point where it was not longer visible in the reaction mixture. The temperature was then reduced to 210-212.degree. C and held there until an alcoholic acid number of 46.4 was attained. The reaction was then cooled to 190.degree. C and quenched with 175.0 gm of Propasol P.* An additional 233.0 gm of Propasol P were then added to afford an alkyd having a Gardner-Holdt viscosity of Z3+ (25.degree. C), a % NVM of 68.8 (2 hrs. ca 150.degree. C), and a alcoholic acid number of 46.1 (on % NVM). To 600.0 gm of this resin were added 19.0 gm of Propasol P, 30.5 gm of triethylamine, and 386.0 gm of distilled water to afford a clear resin having a Gardner-Holdt viscosity of U-V, a % NVM of 40.2 (2 hrs. ca 150.degree. C), and a pH of 7.6.

This example illustrates the preparation of a typical paint formulation containing the disclosed water reducible short oil alkyd resins. A 600 ml stainless steel beaker was charged with 50 grams of alkyd resin prepared in accordance with the invention and placed under a high speed mixer equipped with a 1 and 3/4 inch saw-tooth blade. Approximately 150.0 gm of TiO.sub.2 white pigment were then added to the resin at a moderate rate, and mixed for approximately 5-10 minutes to attain proper pigment dispersion (7-7 1/2 on Hagman scale). The mixer speed was lowered and 250.0 gm of said alkyd resin were added along with 15.0 gm of Cymel 303 (crosslinking agent) and 1.5 gms of Catalyst 1010 (p-toluene sulfonic acid in isopropyl alcohol). About 2-4 minutes of mixing were required to insure a completely homogeneous mixture.

Examples 3, 4, 5, 8, 9 and 10 illustrate alternative means of controlling the resins' molecular weight by adding an additional minor amount of described polyol, e.g., propylene glycol or diethylene glycol. The minor amount of polyol may vary from about 1.5 to about 3.5 wt. % based on the total amount of the reactants.

Typical data relative to the subject alkyd resins and their improved characteristics as compared to other alkyd resins is shown in Tables I - VI infra. These data clearly demonstrate the overall excellence of resins embodied in this invention.

A water reducible alkyd resin, prepared in accordance with Example 4, was aged for 45 days at 54.degree. C while being monitored for changes in pH and viscosity. The initial pH and viscosity were respectively 6.5 and 1040 cps. After 45 days at 54.degree. C, the pH was 6.2 and the viscosity was approximately 800 cps. Periodic determinations were also made. The results are present in Table I.

The aged sample (Example 4) was then pigmented and compounded with Cymel 303/Catalyst 1010 (as in Example 11) and the film properties evaluated and compared with the initial results. Very little difference in film properties was observed between the initial and aged sample. The results are presented in Table II.

The water reducible alkyd resin composition of Example 2 was formulated into a paint, according to the procedure of Example 11 and its film physical properties compared in Table III with paints prepared from two commercially available water reducible alkyds.

The package stability of these three paints was then monitored for 12 days at 54.degree. C by following changes in pH and viscosity, and some of the film properties described in Tables II and III.

It was found that the paint prepared from Commercial Alkyd No. 2 had poor stability and was not usable after less than three days at about 54.degree. C. The alkyd from Example 2 and Commercial Alkyd No. 1 were quite stable. However, the generally more acceptable hardness -- flexibility characteristics of the alkyd from Example 2 can be seen from an examination of Table IV.

Coating formulations (paint vehicles) comprising the subject resins may consist entirely of said resins, as in the case of air dried coatings, or the resins may be combined or blended with other suitable resins to form superior coating compositions.

The effect of the crosslinking resin on the subject alkyd short oil resins was evaluated as follows (any suitable crosslinking agent may be used). Five commercial crosslinking resins* were evaluated with the alkyd from Example 1 to determine their effect on film physical properties and to demonstrate the excellent utility of such coating formulations:

The five crosslinking resins tested were:

Agent 1. Methylated melamine

Agent 2. Ethylated melamine

Agent 3. Butylated melamine

Agent 4. Hexylated melamine

Agent 5. Methylated benzoguanamine

Film physical properties were tested over Alodine 1200 treated aluminum and over blackplate. Coatings were prepared using 10 parts of melamine per 100 of alkyd resin solids by weight and 1 phr Catalyst 1010. All samples were pigmented with DuPont's TiPure R-900 and prepared according to the procedure of Example 11. Panels were prepared by drawdown and baked 15 minutes at 325.degree. F. Results are presented in Tables V and VI. The generally excellent film performance of our formulations is clearly shown.

Although the examples disclosed and/or exemplified are the preferred embodiments of this invention, variations or modifications apparent to one skilled in the art are intended to be within the scope of this invention.