US1869881A - Process of preparing glue stocks - Google Patents

Description

Patented Aug. 2, 1932 vireo STATES CHARLES H. CAMPBELL, OF ASPINWALL, PENNSYLVANIA PROCESS OF PREPARING GLUE STOCKS No Drawing.

Glue stock, such as that consisting of hide trimmings, hide fleshings or pieces of chrome tanned hide suitable for the glue making process under the present practice are subjected to the simmering or boiling operationwithout previous grinding or other preparation eX- cept washing, aciduating and other cleansing processes. g

I have found that by first grinding such stock the extraction of the glue is greatly facilitated and the quality is greatly improved.

This process is the subject inatter of my pending patent applications Serial No.

383,164, filed in the United States Patent Gffice August 2, 1929 Serial No. 425,063, filed January 31, 1930, and Serial No. 486,193, filed October 3, 1930. r

The subject matter of this application com- 0 prises a further improvement in the process of grinding the glue stock, and more specifically it comprises the grinding of the glue stock in the presence of an abrasive.

Many types of raw glue stock carry high percentages of grease, and even after the most careful preparation and washing of the stock this grease is still present and frequently to such an extent that the mere handling of the stock will leave a greasy film on the hand. In this condition it is at times diflicult to grind the stock in accordance with theprocesses described in my said patent applications because the grease on the surface of the stock acts as a lubricant and prevents the mill parts from properly biting the stock aand pulling it between the coacting parts. This can be overcome to a degree by exerting a ressure upon the stock during the grinding rocess, but I have discovered that by the use of my present invention better results are obtained.

In my present invention I grind the stock to any size desired by the glue-maker in a suitable grinder or other mill in the presence of a suitable abrasive agent.

I prefer to take the stock after it has been thoroughly washed and treated and before it is placed in the grinder and sift over the surface of the stock a suitable abrasive material, such as a coarse Washed river sand or crushed silica. The abrasive is preferably relatively Application filed January 29, 1931. Serial no. 512,220.

sive in accordance with the setting of the mill. For instance, where the setting is such as to provide a ten thousandths of an inch gap I prefer to employ a coarser abrasive than I would employ where the setting is fromthree to fivethousandths of an inch gap.

The abrasive should not be so coarse as to in jur-e the milling surface.

' It. is preferable to accomplish this grinding with abrasive in the presence of water,

Other abrasives may be used, but

but it is possible that in the case of a stock containing a relatively large percentage of moisture the addition of free water may not be necessary.

It is of course necessary to avoid such high speeds of the moving parts of the mill which would tend to cause an emulsification during the grinding process of the fats liberated. Usually if the speed of the moving parts be kept below two thousand feet per minute there is no danger of emulsificatio'n.

The employment of the abrasive material enables the grinder parts to grip and pass the material and to size the stock for any subsequent glue making operation, including, if desired,.the reduction of the stock to a gel.

By" my improvedmethod large tonnages of the most greasy glue stock can be reduced to the desired size without diliiculty and Without loss or delay in the grinding operation.

' After the stock has been ground and properly sized the presence of the abrasive in any further grinding or reducing operationis advantageous, as it assists and aids in the cutting of the membranous sacs which contain the fatty particles and it also assists in further reducing the particles of hide fabric. i

The presence of the abrasive in nowise interferes with the subsequent glue-making operation because the abrasive, if it has been properly Washed and treated before used,

contains no soluble material that will discolor the glue or interfere with any of the subsequent operations.

During the various simmering or boiling 5 operations the abrasive, whether it be sand or any other suitable material, will naturally separate itself from the stock and will settle to the bottom of the kettle, when it can be removed by washing or flushing. The last traces of the abrasive may be easily removed from the glue by filtration. In the manufacture of lue the smaller pieces or particles or gel to which the stock is reduced the more readily will the glue be cooked out and the better the quality of the glue, thus enabling the omission of the many successive boilings and treatments which are characteristic of the present practice.

Hitherto it has been found impossible to 2 obtain a grinder or mill which will commercially prepare the stock except at an excessive cost to the manufacturer. While it has been possible to grind glue stocks in the laboratory in an experimental way the commercial reduction of the raw stock has always been ditficult and expensive.

What I desire to claim is 1. The process of preparing glue stock which comprises adding to the same a granular abrasive material and then subjecting the stock to disintegration between relatively movable grinding elements, the relative speed of which elements is such that the fats of the stock are not emulsified.

2. The process of preparing glue stock which comprises adding to the same in the presence of water a granular abrasive material and then subjecting the stock to disintegration between relatively movable grinding elements, the relative speed of which elements is such that the fats of the stock are not emulsified. V

The process of preparing glue stock which consists in adding to the same a granular abrasive material and then subjecting the stock todisintegration between relatively movable grinding elements to rupture the membranous sacs by the combined effect of grindin and abrasion, the relative speed of the movable elements being such as to prevent the emulsification of the fats ofthe stock. f Signed at Pittsburgh, Pa, this 28 day of January, 1931. V

I CHARLES H. CAMPBELL- 56 a