US2784106A - Glue - Google Patents

Description

1 2,784,106 GLUE,

Moss B. Christian and Horace F. Ladd, Tallulah, La.,

assignors to Chicago Mill & Lumber Company, Chicago, Ill., a corporation of Illinois No Drawing. Application February 21, 1955 Serial No. 489,772 6 Claims. (Cl. 166-154) The present invention is directed to improved glue compositions and is particularly directed to glue compositions adapted to secure paper sheets on wet and swollen wood veneer panels.

While the glue composition of the present invention has general applicability, it finds particular use in the preparation of paper-covered wood veneer in which the paper is applied to the veneer while the latter is in a wet, swollen condition. Briefly, this type of process includes the steps of peeling or cutting undried green Wood in the conventional manner to form veneer sheets of the desired thickness, after which the veneer sheets are con nected together to form a continuous ribbon. A tough, water absorbent paper such as unsized kraft paper is unreeled from rolls which are positioned above and below the continuous ribbon of veneer. Suitable coating machines apply a glue to one face of each of the paper sheets from the rolls, and the glue coated faces of the paper are then deposited on the veneer ribbon as it advances. Pressure rolls are provided to squeeze the paper firmly against the wood so that intimate contact between the wood and the glue coated faces of the paper is insured. If the characteristics of the glue are as required, the glue will bond the paper to the wood before the wood is dried to a point where shrinkage can occur. After the bond has been formed between the paper and the veneer, the paper covered veneer is dried so that the paper and wood simultaneously loose their moisture. During the drying operation, the paper, holds the Wood in its expanded, swollen condition even after the wood loses most of its moisture. Since wood does not begin to shrink until its moisture content is reduced below about it is necessary that a glue bond be formed while the moisture content of the wood is still above that value.

For reasons of availability and economy, it would be desirable to use alkalinized proteinaceous vegetable flour glues, such as soya bean glues, locust bean glues, cotton seed glue, linseed glue, and the like for this bonding action. However, such materials are very deficient when utilized on wet materials in appreciable amounts. This deficiency is particularly marked in the process outlined previously because a satisfactory glue for the above described process must be capable of forming a strong States Patent bond at relatively high moisture contents, it must not a be efiected adversely by the passage of steam through the glue as the paper covered veneer is heated to drive off the moisture, and it must not become brittle either during the drying process or upon setting. In addition to the foregoing, the glue must retain its free flowing characteristics for a substantial period of time and must be capable of being mixed and applied without the presence of foam or air bubbles.

Accordingly, an object of the present invention is to provide a glue composition from seed protein material which has sufficient water and steam resistance to be useful in securing continuous webs of paper to a Wet, swollen wood veneer.

Another object of the invention is to provide an improved composition which has excellent flow characteristics, and which retains those characteristics for sub stantial periods of time.

Another object of the invention is to provide an'ima 2,784,106 a l-" a'tentecl'lvlar. 5. 5

Another object of this invention is to provide a soy' bean glue composition which not only has improved properties compared to soy bean compositions of the past, but can be compounded at a lower cost.

The glue composition of the present invention contains a vegetable bean protein such as soya flour as its essential ingredient, and sufficient alkali to put the soya flour in suspension in water, and to develop its adhesive properties. In addition, the adhesive composition contains sodium silicate and lime. Preferably, although not necessarily, the composition may also include a preservative to control molds, stains, and similar bacterial growth.

- One of the features of the present invention resides in the inclusion, in glue compositions, of a mixture of a phenolic compound and a petroleum distillate. The phenolic compound may be a material such as cresylic acid (a mixture of the three isomeric cresols), or it may be phenol, or coal tar distillates containing substantial amounts of hydroxy substituted aromatic compounds.

In the glue composition of the present invention, the phenolic compound replaces the mixture of carbon bisulphide and carbon tetrachloride which has been previously added in many glue compositions of this type. It has been found that the substitution of the phenolic compound for the carbon bisulphide-tetrachloride solution increases the adhesive life ofv the glue remarkably, usually on the order of about four times. Furthermore, when used in combination with the petroleum distillate, the phenolic compound provides a much smoother consistency to the glue, resulting in a better physical mixfree foam or air bubbles. The employment of the petroleum hydrocarbon has been found to permit the use of smaller amounts of water in the glue formula, resulting in a tacky adhesive without excessive viscosity. The reduction in the amount of water is advantageous because it decreases the amount of time required to set the glue. In addition, the presence of the petroleum distillate apparently reduces the expansion of the paper which Was previously troublesome because in. wide widths, glue compositions without the petroleum distillate would sometime cause wrinkling of the paper. The combination of the petroleum distillate and the phenolic com.- pound also maintains the glue viscosity at a constant level over a longer period oftime. Heretofore, trouble has been experienced in soya bean. glues because they tend to increases in viscosity very. rapidly and, after thickening, to become thin and lacking in adhesiveness.

The elimination of the carbon bisulphide as an ingredient of the composition has the further advantage that it eliminates the problems of handling and storing a compound which, due to its low flash point, presents a definite fire hazard.

In addition to the foregoing ingredients, the improved glue composition of the present invention also preferably includes a residual resin from wood which is substantially freed of wood rosin. The resin, unlike wood rosin, is substantially insoluble in light petroleum hydrocarbons such as gasoline. A particularly suitable resin is known under the trade name Vinsol and has a melting point by the drop method of C., an acid number of about 93, and a methoxyl content of about, 3 to 6%. it is obtained by extracting southern long-leaf pine wood with a coal tar hydrocarbon to produce a coal tar hydrocarbon extract containing turpentine, pine oil, rosin, and a residue. I Volatiles are removed from the extract by evaporation, and rosin is then separated from the residue by extraction with gasoline.

The gasoline-insoluble residual material is the material which has been referred to in this specification and claims as a gasoline insoluble resin from southern long-leaf pine.

In compounding the adhesive composition of the present invention, 'we prefer to addthe petroleum distillate early in the compounding of the mixture, because it has been found the presence of distillate aids in dispersing the remainder of the ingredients. While various petroleum distillates can be employed for the purpose of the invention, we prefer to employ a kerosene fraction boiling between about 150 C. and 300 C., and having a specific gravity of about 0.80 to 0.85.

Based upon a soya flour content of 200 lbs., the composition of the present invention contains the following ingredients in the following proportions:

2 to 30 lbs. of lime 4 to 20 lbs. sodium hydroxide to 40 lbs. of gasoline insoluble resin from southern long-leaf pine to 40 lbs. of sodium silicate .05 to 2 lbs. of a phenolic compound 1 to 15 quarts of petroleum distillate Expressed in terms of parts by weight, the composition becomes:

Petroleum distillate 1.66 to 25 The solids listed above are combined With sufiicient water to make a dispersion having a solids content from about to 50% by weight.

In order to aid in dispersing the phenolic compound in the aqueous mixture, we prefer to add the compound in the form of pre-emulsified composition containing small amounts of an alcohol, alkali, and other dispersing agents.

The following is a specific example of the method employed in the compounding of the glue in the present invention.

About 525 lbs. of water at a temperature of about 80 to 90 F., where introduced into a mixer, followed by the addition of 10 quarts of kerosene. About 200 lbs. of soya flour were blended with 20 lbs. Vinsol resin and this blend was added to the mixture and agitated until all the lumps disappeared, and a smooth physical mixture was obtained. Next, 26 lbs. of lime having a particle size of about 400 mesh were mixed in 50 lbs. of water at a temperature of 180 to 212 F. After thorough agitation, the hot, slaked lime was added to the mixer. About 13 lbs. of sodium hydroxide in flake form were dissolved in lbs. of water at room temperature. This mixture was agitated until the caustic was dissolved, and then added to the mixer.

Next, 6 lbs. of a preservative, Dowicide A (sodium ortho-phenyl phenate) plus 1 lb. of sodium hydroxide were dissolved in 20 lbs. of water at a temperature of 180 to 212 F. After the solids were completely dissolved, the solution was added to the mixer.

Next, 30 lbs. of sodium silicate was added to the mixer. The mixer was then agitated for three to five minutes.

Finally, a cresol composition was added in an amount of ,4 lb. of the cresol composition in 2 lbs. of water. The cresol composition contained about 52% cresylic acid, 32% fatty acids, 4 /z% isopropyl alcohol, 4 /z% caustic soda, 3% glycerine, and 4% water. After thorough agitation, this solution was added to the mixer.

The glue which resulted was smooth flowing, and free from foam or entrained air bubbles. It maintained the desired flow viscosity for extendedperiods of time, and exhibited a strong bond between the paper and the wood veneer.

While the glue of the present invention has been described primarily in connection with processes for securing paper to wood, the glue here described also makes a superior glue for the manufacture of plywood and other general uses.

It will be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.

W e claim as our invention:

1. A glue composition particularly adapted to bond paper to wood veneer consisting essentially of an aqueous dispersion of soya bean flour containing, for every 200 lbs. of soya bean flour, from 2 to 30 lbs. of lime, from 4 to 20'lbs. of sodium hydroxide, from 10 to 40 lbs. of a gasoline insoluble resin from southern long-leaf pine, from 15 to 40 lbs. of sodium silicate, from .05 to 2 lbs. of a phenolic compound selected from the group consisting of phenols and cresols, and from 1 to 15 quarts of a petroleum distillate.

2. A glue composition particularly adapted to bond paper to wood veneer consisting essentially of an aqueous dispersion of soya bean flour containing, for every 200 lbs. of soya bean dorm-from 2 to 30 lbs. of lime, from 4 to 20 lbs. of sodium hydroxide, from -10 to 40 lbs. of a gasoline insoluble resin from southern long-leaf pine, from 15 to 40 lbs. of sodium silicate,- from .05 to 2 lbs. of a phenolic compound selected from the group consisting of phenols and cresols, and from 1 to 15 quarts of kerosene.

3. A glue composition particularly adapted to bond paper to Wood veneer consisting-essentially of an aqueous dispersion of soya bean' flour containing, for every 200 lbs. of soya bean flour, from 2 to 30 lbs. of lime, from 4 to 20 lbs. of sodium hydroxide, from 10 to 40 lbs. of a gasoline insoluble resin from southern long-leaf pine, from 15 to 40 lbs. of sodium silicate, from .05 to 2 lbs. of cresylic acid, and from 1 to 15 quarts of a petroleum distillate.

4. A glue composition particularly adapted to bond paper to wood veneer consisting essentially of an aqueous dispersion of soya bean fiour containing, for every 200 lbs. of soya bean flour, from 2 to 30 lbs. of lime, from 4 to 20 lbs. of sodium hydroxide, from 10 to 40 lbs. of a gasoline insoluble resin fromsouthern long-leaf pine, from 15 to 40 lbs. of sodium silicate, from .05 to 2 lbs. of cresylic acid, and from 1 to 15 quarts of kerosene.

5. A glue composition particularly adapted to bond paper to wood veneer consisting essentially of an aqueous dispersion of soya bean flour containing, for every 200 lbs. of soya bean flour, from 2 to 30 lbs. of lime, from 4 to 20 lbs. of sodium hydroxide, from 10 to 40 lbs. of a gasoline insoluble resin from southern long-leaf pine, from 15 to 40 lbs. of sodium silicate, from .05 to 2 lbs. of a phenolic compound selected from the group consist-v ing of phenols and cresols, and from 1 to 15 quarts of a petroleum distillate, said dispersion having a solids content of from 20 to 50% by weight.

6. A glue composition particularly adapted to bond paper to wood veneer consisting essentially of an aqueous dispersion of soya bean flour containing, for every 200 lbs; of soya bean flour, from 2 to 30 lbs. of lime, from 4 to 20 lbs. of sodium hydroxide, from 10 to 40 lbs. of a gasoline insoluble resin from southern long-leaf pine, from 15 to 40 lbs. of sodium silicate, from .65 to 2 lbs. of cresylic acid, and from 1 to 15 quarts of kerosene, said dispersion having a solids content of from 20 to 50% by Weight.

References Cited in the file of this patent UNITED STATES PATENTS 1,833,772 Bradshaw Nov. 24, 1931 2,206,369 Salzberg July 2, 1940 2,494,744 Christian Jan. 17, 1950 2,527,643 Morison Oct. 31, 1950

Claims (1)

1. 6. A GLUE COMPOSITION PARTICULARLY ADAPTED TO BOND PAPER TO WOOD VENEER CONSISTING ESSENTIALLY OF AN AQUEOUS DISPERSION OF SOYA BEAN FLOUR CONTAINING, FOR EVERY 200 LBS. OF SOYA BEAN FLOUR, FROM 2 TO 30 LBS, OF LIME, FROM 4 TO 20 LBS. OF SODIUM HYDROXIDE, FROM 10 TO 40 LBS. OF A GASOLINE INSOLUBLE RESIN FROM SOUTHER LONG-LEAF PINE, FROM 15 TO 40 LBS. OF SODIUM SILICATE, FROM .05 TO 2 LBS. OF CRESYLIC ACID, AND FROM 1 TO 15 QUARTS OF KEROSENE, SAID DISPERSION HAVING A SOLIDS CONTENT OF FROM 20 TO 50% BY WEIGHT.