US1898484A - Art of gluing - Google Patents

Description

Patented Feb. 21, 1933 UNITED STATES PATENT OFFICE HARRY GALQBER, OF LOCKPORT, NEW YORK, ASSIGNOR, IBY MESNE ASSIGNMENTS, TO

LAMINATING PATENTS CORPORATION, OF SEATTLE, WASHINGTON, A CORPORA- TION OF DELAWARE ART OF GLUING .Applz'ication filed February 24, 1932. Serial No. 594,857.

This invention relates to the art of gluing, and, more particularly, to processes for the formation of plywooc An object of the invention is to provide an improved process for uniting a wood member and another member.

A further object is to provide an improved method for the formation of plywood.

Uther objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others thereof, which will be exemplified in the process hereinafter disclosed, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which The figure illustrates somewhat diagrammatically a mode of procedure in accordance with the invention.

The invention contemplates the provision of an improved procedure for uniting a memher composed of wood to a member formed of such material or other material. It is particularly adapted for the formation of plywood composed of two or more substantial layers, at least one of which is formed of wood. It is to be understood that the term wood as used herein includes any porous material of a fibrous or cellular structure having sufficient body to permit the adhesive to obtain a firm grip thereon.

Tn the formation of such a product the provision of an adhesive base in discrete-particle form at the glue line, possesses a number of advantages and various proposals to this end have been made, as, for instance, in various copending applications of Theodore Williams Dike and others.

It is customary in the formation of plywood to place the assembly between pressure plates and to subject it to pressure, or to heat and pressure therein, in order to set the adhesive.

When the adhesive base is applied in discrete-particle form, many difficulties occur in obtaining the proper degree of plasticization and penetration before the final setting of the adhesive, and in properly correlating the plasticization and setting factors. The difficulties in obtaining sufiicient penetration are particularly marked in the use of difiicultly plasticizable material such as casein, soyabean flour, other oil-seed flours, etc.

In accordance with the present invention a gluing procedure may be carried out in such a manner that these difliculties are reduced or avoided.

Certain of these difiiculties result from a premature setting of the adhesive before the same has been fully plasticized, i. e., brought into a sufficiently fluid state to properly penetrate the pores of the wood, so that, when the adhesive sets. forces tending to separate the members will encounter resistance of a substantial body of the wood rather than merely the surface fibres which are easily pulled off. With a view to avoiding this and other difficulties, the invention contemplates the removal of the assembly from the press after the formation of a preliminary bond sufficient to hold the members together while further plasticization and setting occur, and preferably discontinuing the application of heat and pressure at a time when a layer of substantially independent particles remains between the members, (i. e., when there is between the members a layer of discretepar ticles of the adhesive which present a substantially unbroken sandy appearance to the eye if the members are separated), and also when a plasticizing liquid is still present at the glue line.

The preliminary bond need be more than 2-1 blood albumin.

suflicient to hold the members together while the assembly is removed from the press and set. aside for further action. Such preliminar bond may be formed by that portion of a iflicultly plasticizable, slow-setting adhesive, which is first plasticized and set, or, desirably by a quick-setting adhesive included :n the adhesive base material supplied. Such quick-setting adhesive may desirably be an albuminous material such, for example, as The conjoint use of blood albumin and soya-bean flour, casein, or the like is disclosed and claimed in the copending application of Theodore lVilliams Dike, Serial No. 455,978, filed May 28, 1930, and patented March 29, 1932, Patent No. 1,851,951, and no claim is made herein broadly to the conjoint use of such materials.

As diflicultly plasticizable materials, reference may be made to casein, soya-bean flour, other oil-seed flours, etc. These are applied in discrete-particle form, preferably in powdered form. The quick-setting adhesive is desirably supplied also in powdered form, but in certain instances may be carried in a liquid vehicle.

A l quid, ordinarily water, is utilized in the plasticization of such material, and the liquid may be provded in any desired manner. The invention permits the liquid to exert its effect as the formation of the bond proceeds.

In accordance wfth the invention, moreover, a plasticization promoter is given an opportunity to exert its effect slowly while the plasticization and setting of the adhesive proceeds. Caustic soda is the preferred example of such a plasticization promoter. This material not only assists in the plasticization of the adhesive base, but also has a desirable effect on the fibres of the wood adjacent the glue line. promoting materials such as hydroxides of other alkali metals, or, in some instances, alkaline earth hydroxides, such as lime, or other materials may be utilized. Such a plasticization promoter maybe applied or produced at the glue line in any manner which may be desirable in a; particular instance.

Preferably, in many instances, only a moderate heat is applied with the pressure, for example, heat in the neighborhood of 220 F. to 260 F. By avoiding high heats too rapid action at the glue line is prevented.

It is to be understood that the term slowsetting adhesive, as used herein, is designed to cover an adhesive, the setting of which when applied in discrete-particle form is relatively slow, regardless of whether the slowness of the setting is due to slowness in obtaining complete plasticization or for other reasons.

As examples of procedures which may be carried out in accordance with the invention, reference is made to the following:

Three-ply panels may be formedof com- Other plasticizationmercially dry one-sixteenth inch birch veneer by supplying to one of each pair of surfaces water at the rate of 12 lbs. per thousand square feet of double glue line, soyabean flour at the rate of 24 lbs. per thousand square feet of double glue line, and 10% caustic soda solution at the rate of 24 lbs. per thousand square feet of double glue line; forming an assembly; and placing the assembly in a hot plate press and applying pressure in the neighborhood of 200 lbs. pressure per square inch, and heat of approximately 230 F., for 40 seconds. The assembly is then removed and set aside while the plasticization and setting of the adhesive at the warm glue lines continues, forming a strong, secure bond.

Three-ply panels may be formed of commercially dry one-sixteenth, inch birch veneer by applying to one of each pair of surfaces water at the rate of 12 pounds per thousand square feet of double glue line, a mixture of 80 parts of soya bean flour or powdered casein with 20 parts .of powdered dried blood at the rate of 24 pounds per thousand square-feet of double glue line, and a 10% sodium hydroxide solution at the rate of 24 pounds per 1,000 square feet of double glue line; forming an assembly; and subjecting the assembly in a hot plate press to pressure in the neighborhood of 200 pounds per square inch' and a temperature of 230 F. for thirty seconds; and then removing the assembly from the press and permitting the plasticization and setting of the adhesive to proceed. -The blood in this case provides an especially secure clamp for'holding the v members together.

As above indicated, the blood may be in certain instances included in the water applied, and may be so applied at a desired stage in the procedure.

In the drawing there is exemplified a form of apparatus and procedure which may be utilized in carrying out the invention. There is shown a conveyor 10 above which is a disseminatin mechanism indicated diagrammaticalTy at 11 and which may be of a form such as disclosed in the copending application of Louis G. Merritt and Ericsson H. Merritt, Serial No. 542,257, filed June 5, 1 931. Ahead of and beyond this disseminating mechanism are spray means indicated diagrammatically at 12 and 13 and which may be of the type disclosed in the copending application of Ericsson H. Merritt and Richard W. Stanley, Serial No. 535,822, filed May 8, 1931. In the use of such an apparatus wooden squares or plies 14 are disthence under the disseminating means 11 whereby a powdered adhesive material, with or without the other ingredients in powdered and another member, which comprises form, is applied thereto, and thence under the spray means 13 whereby the powdered materials are wet down by a spraying liquid. T he squares 14 may be disposed one on top of another and an additional square 15 disposed on the uppermost surface, as indicated. A square 15 may be disposed on square 14; and the partial assembly thus formed may be re-disposed on the conveyor 10 and moved under the mechanism 12, 11 and 13, or may be disposed on another conveyor and passed under similar means, and an additional square disposed thereon. Other procedures may be followed. A twoply or multiple-ply assembly thus formed may be inserted in the press indicated at 16 as a conventional plywood press, and subjected to heat and pressure, or may be subjected to pressure and heat,

Since certain changes may be made in carrying out the above process without departing from the scope of the invention it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of I the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. The process of uniting a wood member and another member, which comprises providing between said members adhesive-base material in discrete-particle form, applying heat and pressure for a period sufiicient to form a preliminary bond between the members, discontinuing the application of heat and pressure while a layer of substantially independent particles remains between the members, and permitting the plasticization and setting of the adhesive material to continue.

2. The process of uniting a'wood member roviding between said members adhesivease material in discrete-particle form, applying 1 heat and pressure for a period sufiicient to form a preliminary bond between the members, a liquid being present, discontinuing the application of heat and pressure while a layer of substantially independent particles remains between the members and while liq uid is still present, and permitting the plasticization and setting of the adhesive material to continue. I

3. The process of uniting a wood member, and another member, which comprises providing between said members vproteinous adhesive-base material in discrete-particle form, applying heat and pressure for a period suflicient to form a preliminary bond between the members, discontinuing the application of heat and pressure while a layer of substantially independent particles remains between the members, and permitting the plasticization and setting of the adhesive material to continue.

4. The process of uniting a wood member and another member, which comprises providing between said members difiicultly plasticizable adhesive-base material in discreteparticle form, applying heat and pressure for a period sufficient to form a preliminary bond between the members, a liquid being present, discontinuing the application of heat and pressure while a layer of substantially independent particles remains between the members and while liquid is still present, and permitting the plasticization and setting of the adhesive material to continue.

5. The process of uniting a wood member and another member, which comprises providingbet'ween said lnembers difiicultly plasticizable adhesive-base material in discreteparticle form and a plasticization promoter, applying heat and pressure for a period sufficient to form a preliminary bond between the members, a liquid being present, discontinuing the application of heat and pressure while a layer of substantially independent particles remains between the members, and. I

while liquid is still present, and permitting the plasticization and setting of the adhesive material to continue.

6. The process of uniting a wood member and another member, which comprises providing between said members powdered casein and a plasticization promoter,applying. heat and pressure for a period sufficient to form a preliminary bond between the members, a liquid being present, discontinuing the application of heat and pressure while a layer of substantially independent particles remains between the members and while liquid is still present, and permitting the plasticization and setting of the adhesive to continue.

'7. The process of uniting a wood member and another member, which comprises providing between said members soya-bean flour and a plasticization promoter, applying heat and pressure for a period suflicient to form a preliminary bond between the members, a liquid being present, discontinuing the application of heat and pressure while a layer of substantially independent particles remains between the members and while liquid is still present, and permitting the plasticization and setting oi the adhesive to continue.

4 bon base, the slow-setting adhesive base being in discrete-particle form and a softening liquid therefor being provided, applying heat and pressure for a period suflicient to form a preliminary bond between the. members, discontinuing the application of heat and pressure, and maintaining the members free from pressure while the plasticization and setting of the slow-setting adhesive proceeds.

9. The process of uniting a wood member to another member involving the use of a slow-setting adhesive, which comprises providing between the members a slow-setting adhesive base and an albuminous adhesive base, the slow-setting adhesive base being in discrete-particle form and a softening liquid therefor being provided, applying heat and pressure for a period suflicient to form a preliminary bond between the members, discontinuing the application of heat and pressure, and maintaining the members free from pres-' sure while the plasticization and setting of the slow-setting adhesive proceeds.

10. The process of uniting a wood member to another member involving the use of a slow-setting adhesive, which comprises providing between the members a slow-setting adhesive base and blood albumin, both of said adhesive bases being applied in powdered form, applying heat and pressure for a period sufficient to form a preliminary bond between the members, discontinuing the application of heat and pressure, and maintaining the members free from pressure while the plastieization and setting of the slow-setting adhesive proceeds.

11. The process of uniting a Wood member to another member involving the use of a slow-setting adhesive, which comprises providing between the members a slow-setting adhesive base and blood albumin, the slowsetting adhesive being applied in discreteparticle form and the blood albumin being applied in a liquid vehicle, applying heat and pressure for a period suflicient to form a preliminar Y bond between the members, discontinuing the application of heat and pressure, and maintaining the members free from pressure while the plasticization and setting of the slow-setting adhesive proceeds.

12. The process of uniting a wood member to another member, which comprises providing between the members adhesive-base material in discrete-particle form, applying to the members pressure and a moderate heat for (periods sufiicient to form a preliminary discontinuing the application of heat and pressure while a layer of substantially independent particles remains between the members, and permitting the plasticization and setting of the adhesive material to continue.

13. The process of uniting a wood member to another member involving the use of :1.

slow-setting adhesive, which comprises providing between the members difiieultly plasticizable slow-setting adhesive-base material in discrete-partic1e form and a plasticization promoter and a quick-setting adhesive, applying to said members pressure and a moderate heat sufficient to form a preliminary bond between the members, a liquid being present, discontinuing the application of heat and pressure, and maintaining members free from pressure while the plasticization and setting of the slow-setting adhesive proceeds.

14. The process of uniting a wood member to another member involving the use of a slow-setting adhesive, which comprises providing between the members soya-bean flour and a plasticization promoter and an albuminous adhesive base, applying to said members pressure and a moderate heat sufiicient to form a preliminary bond between the members, a liquid being present, discontinuing the application of heat and pressure, and maintaining members free from pressure while the plasticization and setting of the slow-setting adhesive proceeds.

15. The process of uniting a wood member to another member involving the use of a slow-setting adhesive, which comprises providing between the members powdered casein and a plasticization promoter and an albuminous adhesive base, applying to said members pressure and a moderate heat suflicient to form a preliminary bond between the members, a liquid being present, discontinuing the application of heat and pressure, and maintaining members free from pressure while the plasticization and setting of the slow-setting adhesive proceeds.

16. The process of forming plywood comprising thin outer plies, which comprises providing adhesive-base material in discreteparticle form between the members and forming an assembly, applying heat and pressure to the assembly for a period sufficient to form a preliminary bond between the members, discontinuing the application of heat and pressure While a layer of substantially independent particles remains at each glue line, and maintaining the assembly free from pressure while the plasticization and setting of the adhesive material continues.

1?. The process of forming plywood comprising thin outer pli'es, which comprises providing diflicultly plasticizable adhesive-base material in discrete-particle form between the members and forming an assembly, applying heat and pressure to the assembly for a period in the neighborhood of thirty to forty seconds, discontinuing the application of heat and pressure, and maintaining the assembly free from pressure while the plasticization and setting of the adhesive proceeds,

18. The process of forming plywood comprising thin outer plies, which comprises pro

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