US2394682A - Glue - Google Patents

Description

Patented Feb. 12, 1946 Julius Brody, Boston. Mass. iulslxllor of one-third to Bernard E. Proctor, Melrose, Mass.

No Drawing. Application December 1, 1942, Serial No. 481,560

ZOlalms. (c1. loo-137) The present invention relates to glue, and more particularly to so-called high-testing and intermediate-testing glues used in high concentrations wherein strength of joint is of primary importance. The invention relates more particularly to animal glue in its several forms (hide, bone, blood albumin, ossein and chrome) and fish glues.

I have discovered that the addition of a relatively small quantity of a hydrophilic colloidal clay, such as bentonite, to glues of this character results in a marked increase of strength, or, with greater dilution, in an exceptional increase of spreadability without loss of strength. The reason for this action isnot clearly'understood, although a tentative explanation will be given later in this specification.

Although the use of bentonite and other clays in mixture with adhesives has been known, such uses have, so far as I am aware, been limited to pastes and mucilages, with a relatively large amount of clay as a filler. Such adhesives are used in the manufacture of paper bags, envelopes, etc., wherein strength of joint is oi only secondary importance. My invention has to do with hightesting and intermediate-testing glues, and its object is to make the strength at least as great as, if not greater than, that of the unmixed glue. For his purpose, only a relatively small amount cedures: first, substituting a small proportion of bentonite forthe glue and mixing with substantially the same amount of water as would be dictated for the straight glue, whereby an increase of strength is obtained; and second, diluting with a larger amount of water to obtain increased spreadability but without loss of strength as compared to straight glue. In either case, the proportion of bentonite may range from about 2% to of the amount of glue. vWhere increased strength without additional spreadability is desired, the percentage of bentonite to glue is preferably not over 10%. For increased spreadability without loss of strength, the amount of bentonite,

may be increased to 15%. It has been found that beyond that amount of bentonite, while greater spreadability may be obtained, the mixture suffers some loss of strength.

The following Table I illustrates the usefulness of. the present invention as applied to glues in order to obtain amarkedly increased strength.

This table has been prepared from actual tests on a large number of samples, the tests being can responding glue mixed with various percentages of bentoniie (all amounts by weight).

Table 'I hm: a Amt oi l t m ercsn I Amt. Shearing straight bontonbentontotalois she in its m a ba an o 0 mo 2:01 1.94:; Dg o smod m 1.5 a 100 .am aooo 0.... 41 3 a 100 am 3,190

of colloidal clay, usually notinexccss of 15% of I water into the glue. Immediately before wi l.

ing, the mixture is heated in a glue pot to a temerature of about 85 C. and stirred for several minutes at that temperature. The glue may then be applied in the usual fashion.

The invention contemplates either or two pro- 55 loss or strength. This is shown in the following In each case the best water-to-glue ratio for the straight .glue was determined, and this ratio was followed in the tests involving the addition of bentonite. It will be noted that a marked increase of joint strength was obtained. The addition of bentonite also resulted in a substantial saving in the straight glue, amounting to 6% in one of the examples above. vAn increase in visincrease -may be obtained by diluting the mixture of the original glue and bentonite. A large increase of bility may be obtained without suil'erin'g Table 11, which also gives the results of actual tests.

Boththe glue andthe clay are hydrophlllc colloids, the particles of which are negatively In the as of hide glue, the addition of bentonite allowed a substantial dilution of the glue without substantially afiecting the strength. The addition of bentonite from 2% to 8% resulted in obtaining 200 parts of the total mixture as against 162.5 parts of straight glue. This is an increase in spreadability of about 23%. It will be noted that with this particular glue, the

efiects are approximately the same for any percentage of bentonite between 2% and 8%. In general, for reasons of economy, the maximum percentage of hentonite will be used. It has been found, however, that the use of bentonite in excess of 15% tends to reduce the strength.

The example for chrome glue given in the above table shows that the addition of 4% hentonite with substantial dilution increases both the strength and spreadabllity.

The advantages of the present invention are believed to be due to the amnity of bentomte for water. Bentonite in particles of colloidal size will absorb as much as 15 times its volume of water. When a mixture of glue and bentonite is added to water, the bentonite is believed to absorb a large part of the water, thereby reducing I the amount that remains availablefor ahsorpthe unfortified glue, so that a higher concentration is obtained.

charged at the pH values ordinarily used in commercial glues, namely in the general pH range the glue and clay carry the same charge, there is no tendency for them to precipitate each other.

Consequently, they remain mutually in dispersion until the glue hardens at the joint. It is known that the colloidal particles of bentonite, upon drying, lnterlink; It is believed that in the present invention, the colloidal particles of bentonite interlock with one another and with the similarly charged colloidal particles of glue. Therefore, the added bentonite acts in a manner wholly different from an inactive filler, since it contributes to the bonding action, of the glue, as indicated by actual'tests.

Having thus described my inventioml claim:

1. A high-testing or intermediate-testing glue consisting of a glue selected from the group consisting of animal and fish glues, a relatively small quantity of hydrophilic colloidal clay, the pro- I three times the weight of glue and clay.

2. A high-testing or intermediate-testing glue consisting of a glue selected from the group consisting of animal and fish glues, a relatively small quantity of bentonite, the proportion of bentonite to glue being between 2% and 15%, and an amount of water between two and three times the-weight of glue and bentonite.

S BRODY."