US3487088A - Process for preparing 1,3-dimethylol-4,5-dihydroxy-2-imidazolidinone - Google Patents

Description

United States Patent 3,487,088 PROCESS FOR PREPARING 1,3-DIMETHYLOL- 4,5-DIHYDROXY-2-IMIDAZOLIDINONE Kenneth Herald Remley, Warren Township, Somerset County, N.J., assignor to American 'Cyanamid Company, Stamford, Conn., a corporation of Maine No Drawing. Filed Apr. 14, 1967, Ser. No. 630,847

vInt. Cl. C07d 49/30 U.S. Cl. 260-309.7 1 Claim ABSTRACT OF THE DISCLOSURE A process for preparing stable aqueous solutions of 1,3-dimethylol-4,5-dihydroxy-Z-imidazolidinone in which urea glyoxal and formaldehyde are reacted under alkaline conditions of pH and at a temperature of from 30 to 130 C.

I This invention relates to a process for preparing stable, aqueous solutions of 1,3-dimethylol-4,5-dihydroxy-2-imidazolidinone, sometimes referred to as dimethylol monourein or dimethylol dihydroxyethyleneurea.

1,3-dimethylol-4,5-dihydroxy-Z-imidazolidinone has the following structural formula:

The above iniidazolidinone has become a valuable textile finishing agent particularly for use as a creaseproofing agent on cellulosic textile materials including blends of such materials with other fibers such as polyamides and polyesters. Although it may be employed as a conventional creaseproofing finish in the manner described in U.S. Patent No. 2,731,364, its present commercial importance is as a post-cure creaseproofing finish of the type employable in the process described in U.S. Patent No. 2,974,432.

At the present time there are three known processes for preparing 1,3 dimethylol-4,5-dihydroxy-2-imidazolinone from urea, glyoxal and formaldehyde. All of the known processes are 2-step procedures.

In one, urea and glyoxal are reacted under alkaline conditions to produce 4,5-dihydroxy-2-imidazolidinone, which is then reacted with formaldehyde under neutral or alkaline conditions. (See U.S. Patents 2,731,472 and 2,764,573.)

In a second process, urea and formaldehyde are reacted under alkaline conditions to produce dimethylol urea which is then reacted with glyoxal under alkaline conditions to form the imidazolidinone. (See U.S. Patent No. 2,876,062.)

According to U.S. Patent No. 3,049,446, the product of the first process, that described in U.S. Patents 2,7 31,- 472 and 2,764,573, is dark brown and discolors cloth unless the intermediate monourein is purified before it is reacted with formaldehyde.

In the third process, urea and glyoxal are reacted at a pH of from 3.8-4.2, followed by reaction with formaldehyde at a pH of 7.0-7.5. (See British Patent No. 1,032,379.)

In all of the above processes the yield is generally low and the products contain large amounts of unreacted formaldehyde and glyoxal. In the case of the second process, that described in U.S. Patent No. 2,876,062, the product has been found to be unstable as evidenced by discoloration on aging.

Accordingly, it is an object of the present invention 3,487,088 Patented Dec. 30, 1969 to provide a simplified, straight-forward process for preparing stable aqueous solutions of 1,3-dimethylol-4,5-dihydroxy-2-imidazolidinone that is characterized by good color, good stability and which is as effective as a creaseproofing agent for cellulosic textile materials as products prepared by the more costly two-step procedures of the prior art.

These and other objects and advantages of the present invention will become more apparent from the detailed description set forth hereinbelow.

According to the present invention, a process is provided for preparing a stable aqueous solution of 1,3-dimethylol-4,5-dihydroxy 2 imidazolidinone which comprises reacting relative amounts of 1 mole of urea with from between .8 and 1.3 moles of glyoxal and from 1.6 to 2.5 moles of formaldehyde in an aqueous medium at a pH maintained above 7 and at a temperature maintained between 30 and C.

As described above, the present invention is concerned with a single step or one pot procedure for preparing what is substantially the equivalent in performance as a creaseproofing agent as similar products prepared by the more costly procedures of the prior art.

Preferably, the mole ratios employed are relatively amounts of 1 mole of urea with between .9 and 1.1 moles of glyoxal and between 1.8 and 2.2 moles of formaldehyde. Applicant has found that uniformly good results have been achieved by adhering to mole ratios within the preferred limits.

As indicated above, the aqueous reaction medium must be maintained above 7 and preferably between 7.5 and 9.5. The alkaline pH is obtained by adding sufiicient alkali to provide the initial alkaline pH and by the continuous addition of suitable alkaline materials during the course of the reaction. Suitable alkalies include sodium hydroxide, potassium hydroxide, sodium carbonate and their equivalents.

As indicated above, the reaction mixture is heated at a temperature of between 30 and 100 C. and preferably between 60 and 70 C. It has been found convenient to permit the temperature of the reaction mixture to gradually rise until the desired reaction temperature is reached. The reaction temperature is maintained until it is essentially complete as evidenced by an unreacted aldehyde content of not over 2%, preferably not over 1.2%. The free formaldehyde content being determined by conventional analytical procedures.

When the reaction is finished the solution is normally cooled and suflicient acid added, preferably hydrochloric acid, to provide a pH of between 5.0 and 5.4.

If desired, sodium chloride or similar bleaching agents may be employed by addition to the aqueous solution to improve the color still further.

Textile finishes obtained by the procedure of this invention are stable, essentially colorless solutions. They are obtained economically and in excellent yield.

The products are applicable to cellulosic materials by known procedures and may be durably bound thereto by standard curing procedures. Cellulosic textile materials, illustratively cotton fabric, finished with the product of this invention have a high degree of wash-and-wear and other desirable properties, and are not discolored by the finish.

The product of this invention may be employed with other textile agents and auxiliaries such as softeners, brighteners, odorants and other creaseproofing agents.

In order to illustrate the present invention the following examples are given primarily by way of illustration. No specific details or enumerations contained therein should be construed as limitations on the present invention except insofar as they appear in the appended claims.

a All parts and percentages are by weight unless otherwise specifically designated.

Example 1 To a suitable reaction vessel there is added 2,840 parts (41.6 moles) of 44% formalin and 3,000 parts (20.7 moles) of 40% aqueous glyoxal. Suflicient sodium hydroxide, about 55 parts of 24% aqueous caustic soda, is added to provide a pH of 8.08.5, followed by 1,250 parts (20.8 moles) of urea. The temperature of the reaction is allowed to rise to about 50 C. and 45 parts of 24% aqueous caustic soda is added. The temperature is then allowed to rise to 65-70 C. and is maintained at this level for two hours. During the two-hour period, additional amounts of sodium hydroxide are added as 24% aqueous sodium hydroxide in order to maintain the pH at 8-8.5. Thus 50 parts of 24% sodium hydroxide is added after minutes, 25 parts after 30 minutes and 35 parts after one hour.

The reaction mixture is cooled to about 30 C. and 7 parts of sodium chlorite is added, followed by sufficient concentrated hydrochloric acid to provide a pH of 5.0- 5.4. To the solution there is added 1,320 parts of water.

The product is an aqueous solution of 1,3-dimethylol- 4,5-dihydroxy-2-imidazolidinone containing 45% solids and less than 1.0% of unreacted aldehyde. It is stable on storage and is suitable for application on textile materials without further processing.

Example 2 An aqueous pad bath is prepared containing 6.67% solids of the product in Example 1, 0.64% zinc nitrate, 3.0% of a nonionic softener, that is a 25% polyethylene emulsion containing polyethylene glycol monostearate and coconut oil monoethanolamine and 0.25% of a nonionic surface active agent, that is the condensation product of nonylphenol with an average of 9.5 moles of ethylene oxide. Cotton broadcloth is impregnated with the pad bath by a standard padding procedure obtaining a 75% wet pickup. The fabric, containing 5.0% solids of the product of Example 1, is dried at 225 F. for one minute and then heated at 350 F. for 1.5 minutes.

Crease recovery angles of the treated and untreated fabrics are determined by AATCC Tentative Test Method 661959T.

The tensile strengths of the fabrics are measured by ASTM Standard Method D-39 using a Scott tensile strength tester.

The test results are shown in Table I.

TABLE I Fabric Untreated Treated Crease recovery angle, WdzF, degrees 188 58 Tensile strength, W&F, lb t. 132 72 Example 3 Cotton/nylon twill 15%) is impregnated with a pad bath by standard padding procedures obtaining a 60% wet-pickup. The fabric containing 6.1% solids of the product of Example 1 is dried at 225 F. for 1.5 minutes, steamed for 5 seconds, pressed on one side for 8 seconds and then on the other side for 8 seconds at 310 F. using 45 pounds/ sq. in. pressure. The pressed swatches of cloth were heated at 320 C. for 10 minutes.

The crease recovery angles and tensile strengths of the treated and untreated fabrics are determined as indicated in Example 2.

The appearance ratings are relative, 5.0 being maximum, and are a measure of the smoothness of the fabric when viewed under an overhead light, after being washed five times.

The washes were carried out in a home-style Washing machine using water at -145 F. and a detergent with a 12-minute wash cycle followed by tumble drying at F. for 30 minutes.

The crease retention was determined by inspection of the fabrics after five wash and drying cycles.

The test results are shown in Table II.

TABLE II Fabric Untreated Treated 4. 8 Excellent Crease recovery angle, W&F, degrees Tensile strength, F., lb Appearance rating 1. 8 Crease retention References Cited UNITED STATES PATENTS 2,731,472 1/1956 Reibnitz 260309.7 2,755,198 7/1956 Stewart 260309.7 2,764,573 9/1956 Reibnitz et a1. 260309.7 2,777,857 1/1957 Konig 260309.7 2,876,062 3/1959 Torke et a1. 260309.7 3,112,156 11/1963 Vail et a1. 260-309.7 3,209,010 9/1965 Gagliardi et a1. 260309.7

HENRY R. JILES, Primary Examiner NATALIE TROUSOF, Assistant Examiner US. Cl. X.R.

@ 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. L ISLOSS Dated January 22, 1970 Inventor(s) KENNETH HERALD REI ILEY It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, Table I, cancel "5%" and "72" and substitute therefore --285-- and --76.

SIGNED AND SEALED A 121970 gm) Attest:

WILLIAM E. sum, an. Edward FL 151mm" comissiona'r of PM Attesfing Officer