US1737917A - Phenolic condensation products and process for preparing same - Google Patents

Description

' lowed by operation.

Patented Dec. '3, 1929' I UNITED" STATES oscan a. cnmmr, or cnrcaeo,

rnnnomc commiwsa'rron rnonuc'rs No Drawing.

The present invention relates to improvements in methods for. producing phenoliccondensation products.

More particularly the present invention relates to improvements in methods for the production of material from the condensation of phenolic bodies and formaldehyde which material is adapted for casting. The present invention relates particularly to the production of material suitable for the casting of transparent articles.

An object of the present invention is to provide an improved process which will materiall reduce the length of time required for boiling the phenolic body and the formaldehyde, tion of the product, and for reducing the loss of formaldehyde which is unavoidable even with the use of reflux condenser-s.

A further object is to provide an improved method for the production of material for manufacturing transparent cast articles,

which improved method will reduce the cost.

from the present figures and which will resultin an improved product.

Further ob'ects will appear as the description proceeds.

It has been proposed to obtain the material for transparent condensation products by condensing phenolic bodies in the presence of a small amount of a basic condensing agent such as potassium hydroxide. It has been found necessary in this process to add considerable amounts. of alcohol ,while distilling off the water which is present in the formal dehyde and which is formed as a result of the reaction. If the alcohol is not added, rubbery products are often obtained.

It has "also been proposed to condense phenol and formaldehyde without the use of a condensingagent by-prolonged boiling under a reflux condenser. The'boiling is fola distillation process and a casting Said prolonged boiling operation, which sometimes exceeds a period of 120 hours, is decidedly objectionable.

The present invention contemplates a method according to which the prolonged boiling referred to may be 'obv-iated without decreasing the transparency of the products.

rumors, rac'runmo couramr or cnrcaoo, rumors,

Application filed April 21,

for reducing the danger of discolora- ASSIGNOB TO ECONOMY FUSE AND MANU- A CORPORATION OF NEW YORK annrnoonss FOR PREPARING sum 1926. Serial mi. 108,621.

In fact, the transparency of the resulting product is improved due to the fact that discoloration which accompanies prolonged boiling is materially reduced.

According to the present invention a condensing agent is used, which condensing agent is formic acid. By the use of formic acid as a condensing agent, provided a suitable proportion of said formic acid is employed, the period of boiling under a reflux condenser may be reduced from a long period of time to a period of from 1 to 4 hours. Other advantages inherent in the use of formic acid as a condensing agent are the fact that there is no tendency for the initial products to become rubbery during the distillation process and that substantially all of the acid is eliminated with the water during said distillation process. Provided substantiall pure materials are used, the products obtalned are of a fine amber color and have a high degree of transparency. In the final state they are infusible and may be readily machined, sandpaperedor buffed.

Applicant is aware that the use of acids has been proposed for the making of cast articles. A serious objection to the use of acids as heretofore known in this connection, however, has been that even with small proportions of acid opaque articles have been obtained. These opaque articles can be rendered transparent only by a long careful heating. According to the present invention, in order to obtain transparent articles it is only necessary to eliminate substantially all of the water and acid by distillation from the initial condensation products. Applicant is aware that commercial formaldehyde contains formic acid in amounts not exceeding .12 of 1 per cent of the weight of the solution. This proportion of formic acid is insufficient for accomplishing the results of the present invention, and the improved method consists in condensing a phenolic body and formaldehyde or other methylene containing substance in the presence of decidedly greater amountsof formic acid than are present in commercial formaldehydef Referring to figures for purposes of illustration, 200 parts of phenolic body may be A degrees C., until infusible. The. term eraturev should be suflicient in amount to a thickening of the lower resinous layerlias occurred.

At this point two procedures are possible. The supernatant Water ma be removed by distillation, preferably under reduced pressure, whereupon a clear, yiscous, almost colorless mass is obtained; or the supernatant water may be decanted and an additional quantity of formaldehyde added to replace that lost by decantation, after which the mixture is distilled until clear. The advantage of the latter method is that a lesser quantity of water needs to be distilled. The viscous transparent product referred to is poured into suitable molds and heated at temperatures gradually increased from degrees C. to 90 is then raised to 100 degrees C. and nally to about 130 degrees C. The length. of heating required varies vwith the size of-the articles cast.

The process above outlined may be varied,

in that a two-step process maybe used. Ac-

cording to the two-step process, the initial mixture may consist of a phenolic body. for- H110 acid and an insufficient amount of formaldehyde to cause the production of an in fusible body upon continued heating. After heating for a suflicient length of time to cause combination of substantially all of the. formaldehyde with the phenolic body, the supernatant water may be decanted and an addi tional quantity of formaldehyde may be added. The second quantity of formaldehyde render the initial condensation product infusible upon continued heating. It is also desirable to add an additional quantity of formic acid to replace that decanted with the "water. This mixture may be distilled with or without previous boiling under a reflux condenser, and the condensation product may be treated as above described. x

The proportions recited above are merely illustrative and should not be conside'red'in a limiting sense. A lesser amount of formaldehyde will usually give satisfactory results.

The amount of formic acid may be varied over acid used, the reaction. r

In the claims the applicant defines the amount of formic acid employed as being that of an added amount, and by this the applicant means that the reaction ofthe phenolic body and the methylene containing substance greater being the speed of the is conducted in the presence of formic acid in 7 amount greater than that which is normally found in the commercial methylene containing substances, which are suitable for this re- .ing th action. It is to be understood that the term added does not necessarily imply that there is already some formic acid present in the methylene containing substance employed, and in cases where no formic acid ispresent the entireamount is introduced, but in cases where some formic acid is present an additional amount is introduced to bring the quan tity up to the amount desired.

lVhat is claimed is r 1. The method of preparing a material suitable for casting which consists in heat treating a phenolic body and an active methylene containing substance in the presence of formic acid, the amount of formic acid being in substantial excess of the amount present when commercial: formaldehyde is employed commercial .ormaldehyde is employed .to supply the methylene groups, and eliminate aqueous layer formed as a result thereof.

3. The method of preparing a material suitable; for casting which consists in heat treating a phenolic body and formaldehyde in the presence of formic acid, the amount of formic acid being in substantial excessof-the stantial excess of the amount present when amount present by virtue of the presence of commercial formaldehyde.

4. The composition of matter produced by heat treating a phenolic body and an activemethylene containing substance in the presence of formic acid, the amount of formic acid being in substantial excess of the amount present when commercial formaldehyde is employed to supply the methylene groups.

'Signedat Chicago, Illinois, this 9th day of April, 1926. OSCAR A. CHERRY.