US2103776A - Novel glue product for gluing veneers and cross-ply sheets - Google Patents

Description

Patented Dec.28,'1937- v Q 2,103,776

UNITED STATES PATENT OFFICE- '-NOVEL GLUE PRODUCT FOR GLUING VENEERS AND onoss-PLY SHEETS Edouard Geistlich, Wolhusen, Switzerland No Drawing. Original application December24, 1934, Serial No. 759,085. Divided and this application November 18, 1936, Serial No. 111,555 In Germany October 28, 1933 7 Claims. (01. 134-233) This application is a division of my application ample urea or thio-urea or derivates thereof, and for United States patent filed December 24th, aldehydes, particularly formaldehyde or poly- 1934, Serial No. 759,085, and has for its object merides thereof such as paraformaldehyde, the a novel glue product for gluing veneers and crossrelation of glue to urea varying between 3:1 to

5 ply sheets of wood. I 6:1 and the relation of carbamide to aldehyde 5 It is known to utilize for gluing wood solutions between 3:1 to 2:1. in water of mixtures of animal adhesives, i. e. This novel product has the remarkable quality gluten containing adhesives, such as bone, skin of binding under the influence of pressure and or leather glues, with urea, thio-urea or derivates heat which hitherto was unheard of 'for gluten of the latter substances. containing adhesives. 10 Glues of this kind have, however, the draw- Alternatively, the animal glue can be partly backs of binding too slowly during applying heat replaced by filling materials, for example up to to the glue joints and of being too little resistive an amount of 60%. against. the influence of moisture. The considerable technical advance thus ob- It has also already been proposed to use as' tained by means of the invention consists in the adhesives compositions of casein, urea, formalnovel glue product providing after its dissolution dehyde and water. Such adhesives are, however, in water. at room temperature or when slightly not applicable. for gluing wood, their usefulness heated (40 C.) and its application to the joinbeing restricted to the production of, surface ing surface for a glued joint to ensue which is coats and plastic masses. fast to the influence of moisture andis distin- 20 It is further known to render materials of guishcd by the fact that even if the joining presglue-like nature or gelatine water soluble again sure is exerted at a temperature of 90 C. and by means of solutions of urea after these matemore and fine veneers for example of oak or nut rials have become insoluble by effect of formalwood of minimum thickness are glued on,- no glue dehyde. I can penetrate through the pores of the veneer 25 Thus by treating glues that had been tanned to form pools on the upper side thereof. by means of formaldehyde or else gelatines with In consequence of the high initial strength of urea it is, admittedly, possible to partly recover the work blanks held together by means of the the starting materials, for example from spent novel adhesive which strength accrues from the roller laggings, but this regenerating operation simultaneous presence of urea, thio-turea or der- 30 results, due to deterioration of the agglomerated ivates of these substances, and formaldehyde, gluten molecules in such a considerable reduction viz. polymerides o-r derivates thereof, if desired of quality that the adhesive product obtained in in combination with filling materials, acids, acid this way is no longer applicable for gluing wood. or acid giving 011 salts, the glued together pieces F t erm s regenerated g e cks the can be removed from the heated press after hav- 35 quality to bind under the influence of presing been acted upon. in the latter for a few sure and heat since for a modified regeneratminutes and without being cooled off, so that ing operation it has been proposed to admix the considerable savings of time and heating steam urea to gluten containing substances prior to apare obtained. In this way is rendered possible 40 plying formaldehyde thereto with a view to afto utilize animal glues instead of casein glues 40 fecting the applicability of the glue within wide I and artificial resin glues, which 'was hitherto limits of temperature or in other words to prounknown.

vide for maintaining the adhesive product in In distinction from the already proposed gluing liquid state for a relatively long time also at methods in which foils are employed, the adraised temperature. vantage obtained by means of the invention con- 45 Moreover, adhesives have hitherto been used sists in the fact, that the temperatures and preswhich consist of condensation products of an sures required for carrying out the gluing are' early stage of urea-formaldehyde, if desired in much lower and that the novel method is reliable combination with a slight percentage amount -(at even under severe conditions in which gluing by I the most 10%) of glue. Adhesives of this sort, means of foils fails. 1 do however, endure only for a limited length of time. The method according to the invention permits According to the present invention, the novel of adapting the qualification of the adhesive to product, which can be applied for gluing veneers the special purpose for which it is to be used in and cross-ply sheets of wood, is a water soluble wide limits by varying the relation of the permixture of animal glue, carbamide, as for ex'- centage amounts of animal glue to urea, thio- 55 the one hand and for example formaldehyde in form of its polymerides or derivates on the other hand (within the limits stated), if desired by:

Hereinafter two examples are given from which it will be evident in which manner the method according to the invention can be applied.

Example 1 10 kilograms of a mixture consisting of 78.0 percent by weight ofpowdered bone glue (50 meshes per square centimeter), 14.0 percent by weight of urea, 7.0 percent by weight of paraformaldehyde and 1.0 by weight of liquid paraifin are admixed to 6 to 8 liters of water of 40" C. by stirring.

The viscous solution thus obtained is for example applied to both sides of two veneers of alderwood of 1.5 millimeters thickness in thin coats, whereupon between the two alder-wood veneers an intervening ply of alder-wood of 2 millimeters thickness is inserted and on top of each alder-wood veneera strong okoum veneer of 1 millimeter thickness is placed.

This sheet thus composed of five plies is then subjected during 12 minutes to the action of a hydraulic heated press at a temperature of 100 C. and a. pressure of 6 to 8 kilograms per square centimeter. On opening the press a five cross-ply sheet definitely glued is obtained without prior cooling.

If it is desired to produce a three cross-ply sheet 10 minutes pressing sumces under similar working conditions.

- Example 10 kilograms of a mixture consisting of 27.8 percent by weight of powdered bone glue (50 meshes per square centimeter), 23.0 percent by weight of urea, 9.0 percent by weight of paraformaldehyde, 37.0 percent by weight of heavy spar'or prepared chalk, 0.2 percent by weight of oxalic or lactic acid and 3.0 percent by weight of liquid paraflln are dissolved in 4 to 6 liters of water of room temperature.

The viscous solution thus obtained is for example applied to the wooden sheet carrier in a thin coat and then slightly allowed to dry, where-,

upon on the plating with fine veneers for examurea or'derivates of the latter substances on ple of nut or oak-wood of 0.4to 0.6 millimeter thickness, the assembly is inserted in the heated press. The pressing operation is effected preferably at a temperature of 90 C. and a pressure of from 3.5 to 5 kilograms per square centimeter. After ,10 minutes duration the definitely veneer plated sheet is taken out of the press without prior cooling.

Veneers and cross-ply sheets of wood produced as specified in the above examples are devoid of of an animal glue material, carbamide, and alde- 'hydes in a relation of said glue material to carbamide varying between 3: 1 and 6: 1, and a relation of carbamide to aldehyde varying between 3:1 and 2:1.

2. A glue product comprising a water solution of an animal glue material, urea, and aldehydes in a relation of said glue material to urea varying between 3:1 and 6:1, and a relation of urea to-aldehyde varying between 3:1 and 2:1.

3. A glue product comprising a water solution .of an animal glue material, thio-urea, and

aldehydes in a relation of said glue material to thio-urea varying between 3:1 and 6:1, and a relation of thio-urea to aldehyde varying between 3:1 and 2:1.

4. A glue product comprising a water-solution of an animal glue material, a derivate of a carbamide, and aldehyde in a relation of said glue material to said derivate varying between 3:1 and 6:1, and a relation of said derivate to 'aldehyde varying between 3:1 and 2:1.

5 A glue product comprising a water solution of an animal glue material, carbamide and formaldehyde in a relation of said glue material to carbamide varying between 3:1 and 6:1, and a relation of carbamide to formaldehyde varying between 3:1 and 2:1.

6. A glue product comprising a water solution of an animal glue material, carbamide, and a polymeride of formaldehyde in a relation of glue material to carbamide varying between 3:1 and 6:1, and a relation of carbamide to said polymeride varying between 3:1 and 2:1.

7. A glue product comprising a water solution of a mixture of animal glue material and a EDOUAIiD GEISTLICH.