US1863799A

US1863799A - Method of making coated articles

Info

Publication number: US1863799A
Application number: US496988A
Authority: US
Inventors: Emil C Loetscher
Original assignee: Individual
Current assignee: Individual
Priority date: 1930-11-20
Filing date: 1930-11-20
Publication date: 1932-06-21
Anticipated expiration: 1949-06-21

Description

mm NW June E c LQETSCHER 1,863,799

METHOD OF MAKING COATED ARTICLES Original Filed Nov. 20. 1930 40 41 5'1 40 41 40 4 1 Inuenibr:

' Emil CZLoeZigchez;

Anya.

Patented June 21, 1932 UNITED STATES Parent OFFICE EMIL c. nonrscnnn, or nunuoun, Iowa mnrnon or me conrnn an'rrcnns Application filed November 20, 1930,'Ser1a1 No. 486,988 Renewed February 15, 1932.

The object of this invention is to provide a method or process for making toilet seats, table tops, and various other articles from a fibrous material such as wood pulp, corn stalk pulp, bagasse, or any other elastic fibrous material, and covering the same with a synthetic resin.

. Referring to the accompanying drawing, Fig. 1 is a perspective view of a closet seat. Figs. 2, 3 and& are vertical sectional views taken on the line az-a: of Fig. 1, and illustrating various steps in the manufacture of a closet seat having a pressed pulp base.

Figs. 5, 6 and 7 are views similar to Figs. 2, 3 and 4 illustrating simila'r'steps in the manufacture of a closet seat having a laminated base.

Figs. 8 and 9 are vertical sectional views illustrating the method of final coating and compressing the closet seat.

Referring to the drawing, reference numeral 15 designates an article produced under this invention, and while many articles may be made, including table tops and the like, a

closet seat has been selected as the example. The article constructed may have a core or base 16 formed with an inte al mass as in Figs. 2, 3, 4, 8 and 9 or may b; formed-with a laminated base 26, as in Figs. 5, 6 and 7.

In constructingthese bases the. material is sub ected to varlous degrees of compression until a very dense base product results, and this necessitates the selection of an elastic base material. This material may be wood pulp, corn stalk pulp, bagasse, or other simi lar fibrous material, with the fibers running in various directions to produce matting whereby a base structure is produced which is as strong, or even stronger than lami nated wood, and less expensive.

In forming the base 16, a mass of one of the fibrous materials-mentioned, as it comes from the beater, is placed in a pulp molding machine of the" general t pe illustrated in Patent No. 827,815, dated ugu'st7, 1906, and therein compressed to the general shape shown in Fig. 1, and the cross sectional shape illustrated in Fig.2, the base .being much thicker, though otherwise of substantially the same dimensions as it will be in its final form. In this machine the desired quantity of water is extracted, though it may be necessary in some cases to subject the base to further pressure in a cooled press to i remove the desired content of Water to produce a preliminary but overthick base of compact mass. This base is then dried to remove substantially all of the water until it contains not over two per cent of moisture or iess, producing the base 16 illustrated in to This dried preliminary base 16 of Fig. 2 then receives a varnish coating 18 consisting of a solution of synthetic resin phenolic condensation product dissolved in alcohol, such 06 as that known to the trade as-bakelite var nish. This varnish coating penetrates the base about 3 2 of an inch. The outermost fibers are thoroughly coated and as they are criss-crossed in every direction, and in all planes, they produce a very good bond w1th the uncoated fibers of the interior of the base. This base is then placed in a dry1ng inclosure at a temperature of approxlmately 110 -to 120 degrees centrigrade and drled until the alcohol is removed.

In making the laminated base 26'of Flg. 5, several fibrous boards or sheets, made from wood pulp, corn stalk pulp, bagasse or 511111- lar fibrous material, (the product known to the trade of Cellotex being well suited for the purpose) are glued together with a synthetlc resin phenolic condensation product such as bakelite cement, though caseln glue may be used. This adhesive, while coating the surfaces to be united, does not saturate the sheets, but only penetrates the same a. slight distance, approximately ofan inch. This laminated stock is then cut out on a band saw, shaper or the like, to-produce an overthick base corresponding in cross section to'that of Fig. 8 and having the same dimensions themes. The base. 26 then receives a. varnish coating at 28 in the nature of a solution of synthetic resin such as bakelite (118-: solved in alcohol, and lmown as bakehte varnish. The penetration of the coating 28 is the same in this case as that of the coating 18 in its case, and the following drying operation to remove thealcohol is the same.

Thus it will be seen that by the foregoing steps, there is produced a core base much thicker than, but otherwise of the same dimensions as the finally condensed base, and

that such base has an exterior synthetic resin phenolic condensation product varnish coating which penetrates the base only approximately of an inch, leaving the 'major' coating.

Heretofore, considerable difficulty has been experienced in producing core bases with pure white exterior coatings that will be virtually fire and water proof and resistant to the action of most alkalies and most acids. By the present method or process, the synthetic resin condensation product known as Aldur may be employed to advantage in securing the desired results. This product is made from formaldehyde and urea, though the latter may be replaced by theo-urea, and up to the present time has only been produced in powder from. It flows under heat and pressure and is not easily combustible and resists the action of alkalies, most acids, oils and practically all organic and inorganic solvents. In these characteristics it is superior to most synthetic resinsand furthermore, being of pure white form, has the advantage of producing a pure white coating, mottled coating or coatings of all shades including black by theuse of tints or dyes, whereas other synthetic resins being naturally of dark color (mostly brown) can only form coatings of dark shades.

In applying the final coating, and completing the compression of the base, the bottom of the cavity of a mold 30 is covered with enough of the selected synthetic resin 31 to make a final coating of approximately 3 2' of an inch in thickness on the bottom of the core or base. The previously shaped and coated base 16, (or 26 as the latter is under treatment), is then placed inthe mold cavity, and a sufficient amount of the same synthetic resin (31) is applied to the upper surface of the base to give the same a final coating of approximately of an inch in thickness and to join the coating material for the bottomof the base.

After the coating 31 has been applied to the base 16 (or 26) within the mold 30, the complementary mold section 35 is placed in position, and the whole mold assembly is placed in a hydraulic press. The press platens 36 and 37 are equipped with suitable means such as

chambers

40 and 41 respectively for steam heating or water cooling. Rather high hydraulic pressure, ranging from 1,000

to 1,500 pounds per square inch of work area, is then applied, and while maintained, steam is circulated through the chambers 40 to maintain the mold and its contents for approximately five minutes. With the pressure maintained, the steam circulation is dis- ]continued and water circulated through the chambers 41 for a few minutes to cool the mold and harden the coating 31 sufficiently to enable the article to be removed from the mold. Obviously instead of separate steam and

water passages

40 and 41, these fluids may be circulated through the same chambers 'accordingto the type of press employed.

Care must be taken not to coolv the mold too long, otherwise shrinkage of the coating will preventremoval of the article from the mold. Upon removal from the mold, the article will be found to have an exterior ure white coating of approximately 0 an inch, incapable of bemg ignited below approximately 600 degrees, or of being scratched with one's finger nail, and having the stated qualities of bein insoluble in most organic and inorganic so vents, or boiling water. I

Bosses, lugs or other formations may be molded directly on to the article by suitable depressions in the

mold parts

30 and 35 and with or without projections into these depressions, with room for the coatin 30, of corgspondin'g projections on the ase 16 or The synthetic coating 31, being roduced up to the present time only in pow ered form, does not, even when heated, have the penetrating effects of the material selected for the varnish coating 18 (or 28), and is more costly. The varnish coating, I the fibrous material of the base the desired distance without saturating the same arid under the heat treatment within the mo (1 flows, as is also the case with the material of the .coating 31, and forms a perfect union therewith. In other words by the use of the cheaper and more penetrating material employed for the coating 18 (or 28) the more expensive and less penetrating material'employed for the coating 31 is caused tobond perfectly with the fibers of the base, and since 0th coating materials flow underheat and pressure, they ofier no resistance-to the final compression of the base. It mi ht be added, that the varnish coatin 18 %or 28) because of'its inherent dark do or, is not applied in greater quantit than is essential to its proper functioning or the intended purpose, otherwise it will have a tendency, when mold heat and pressure are resin selected for the exterior on the other hand, freely pentrates applied, to flow outwardly and penetrate the coating 30 to mar its appearance when being worked in white and certain lighter color shades.

It might also be stated that it is absolutely necessary to have the fibrous material compressible, as this produces a yielding surface and enables the material to conform to the shape of the mold or die, and without penetratin the exterior coating 31 to cause an imper ect product, as would be the case w1th incompressible base materials.

What is claimed:

nishing the same with only slight interiorpenetration and without major saturation with a product that flows under heat and pressure; applying a coating to the varnished 1. The method of making a coated object, base with aproduct that flows under heat and consisting in forming an oversize compressible base of matted fibers, varnishing the same with only slight interior penetration with a product that flows under heat and pressure, applying a coating to the varnished base with a product that flows under heat and pressure, and then compressing the coated base to size under heat.

2. The method of making a coated object, consisting in forming an oversize compressible base of matted fibers, varnishing the same with only slight interior penetration with a synthetic resin that flows under. heat and pressure and has penetrating characteristic,

' to dry, applying to the varnished base a synthetic resin powder that flows under heat and pressure and has penetrating characteristic .below that of the varnish and which is capable of forming a bond with the varnish coating and is capable of producing alone a white coating or when tinted of producing black' or intermediate color shades, and then compressing the double coated base to size under heat.

4. The method of making a coated object, consisting in forming an oversize compressible base of matted fibers, varnishing the surface of the same with only slight interior penetration with a liquid synthetic resin phenolic condensation product that flows under heat and pressure and has high penetrating characteristic, permitting the varnish to dry, applying to the varnished base a synthetic resin condensation product of formaldehyde and a urea in powder form that flowsunder-heat and pressure and has penetrating characteristic below that of the varnish and which is capable of forming a bond with the varnish coating and is capable of producing alone a white coating or when tinted of producing black or intermediate color shades, and then compressing the double coated base to size under heat.

5. The method of making a coated object, consisting in forming a compressible base of matted fibres, overthick but otherwise having approximately the same dimensions as it will have whenreduced to finished size; var-