US1939616A

US1939616A - Pulpboard

Info

Publication number: US1939616A
Application number: US501669A
Authority: US
Inventors: Hubert L Becher
Original assignee: AGASOTE MILLBOARD CO
Current assignee: AGASOTE MILLBOARD CO
Priority date: 1928-10-30
Filing date: 1930-12-11
Publication date: 1933-12-12
Anticipated expiration: 1950-12-12

Description

Fatenied Dec. 32, if

, our sass Hubert llZ. Becher, Trenton, Bl. It, assignor to The Auasote board ilomuany, Ewing Townshia, N. 3., accretion of? New .llersey No Drawing.

@riginal application Qctober 30,

1928, Serial No. 318,109. Divided and this application December ll, 1930, Serial No. 501,669, and in ilanada @ctoher it), 31929. lB/enewed May 19, 1933 1 e (or. er -r) My invention relates to a pulpboard compris=- ing a compressed mixture of fibres, parafin, and Montan wax, a substantial portion of which is present in the form of a metallic salt of Montan wax, such paramn and metallic salt of Montan wax being present in a uniform state of distribution and in a fine state of subdivision, which states are obtained when these substances are precipitated from an emulsion prepared from parafin and saponified Montan wax.

Parafin has heretofore been emulsified with the aid of an emulsifying agent, such as a resin soap or soap prepared from palxnitic or stearic acid. I have found that a better and more suitable emulsion of parafin, useful in the manuiacture of molded pulp board, card board and paper, may be produced by the use oi a soap made oi Montan wax. An emulsion thus produced will retain its stability even in the presence of very large amounts of water. Pulp board,

card board or paper sized with this emulsion is therefore very highly water-proof.

In the manufacture of my new pulp board in accordance with my invention 1 have obtained 5 best results with pulp board which is made by heating paper pulp, wood pulp, or the like, in a heater, and then running such pulp into a mold and by means of pressure removing the majority of the water (see, for instance, United States Letters Patent No. 971,935, dated Gctober i, 191d, and lie. 1,272,568, dated July it, i918), and subsequentlydrying out the remainder oi the water by the application of heat.

My preferred method or" preparing the emuls5 sion for use with my new pulp board is to acid from 2il%25% or more, by weight, oi? Montan wax to parafin and then to add to the mixture an alkali, for instance, caustic soda, for saponiiy= ing the Montan wax in quantity suncient to chest as complete a saponification oi such was as its nature will permit. The parafiin and the Montan wax are first melted in hot water and thoroughly agitated therein until they are broken up as finely as possible; the alkali is then added and the stirring is continued unth substantially all the saponiilcation has taken place and the paraffin has been thoroughly emulsified. The emulsion is then cooled with continued agitation until the paraffin has become hard. The amount of water used in this process should be sufiicient to permit the formation of a proper emulsion but not much more than this amount. The mixture shoidd be stirred at all times, stirring being particularly advisable during the cooling stage in order that the character of the emulsion may not be destroyed byagglomeration and settling of the waxes.

Instead of diluting with hot water prior to cooling the emulsion, I may permit the emulsion to cool and during the cooling stage add cold water slowly so as to dilute the cooling emulsion gradually about in proportion to what otherwise would be the increase of its viscosity, and without suddenly chilling it. .I may also instead .of diluting the emulsion with either hot water or 55 cold water pass it through a colloid mill suitably cooled, thus'efiecting the same result.

The emulsion may be used in the preparation of my pulp board either by mixing the same directly with the paper pulp, preferably in the beater, or by first converting it into an extremely fine suspension by efiecting the double decoru position thereof with a metallic salt, for instance, magnesium sulfate or aluminum sulfate, thus rendering unnecessary the subsequent adclltion of a precipitant in the beater, the para and the metallic salts of the saponifled wax being so finely divided that the precipitant may be added at anearly stage of the fibre treating process. The suspension, moreover, lends itself more readily to prolonged storing and does not crearn asreadily as the emulsion. In the case oi an emulsion, if any paraihn should work its way up to the surface after the emulsion has been allowed to stand, slight agitation will easily $5 restore homogeneity.

The precipitant, which may be added during the heating process, is the same material, for instance, magnesium sulfate or aluminum sulfate. by which the line suspension referred to is pro- W duced. The suspension will thus contain thev metallic salts of the saponified l flontan wax which. are produced when the emulsion is precipitated by the usual precipitants, namely, the metallic (f. i. aluminum) salt oi the fatty acid (Montan wax) and the metallic salt of the alkali metal (hi. sodium).

As Montan was for some reason apparently not definitely known is not completely saponifiable, the saponified Montan was, and the metallic salt Mm oi l /iontan wax, will contain a substantial ad mixture of an unsaponified ingredient or portion of the Montan wax.

A board thus produced is very highly water- 105 proof and highly dielectric. The proportion or the combined waxes present in the emulsion or suspension to the weight of the fibre in the final product may vary within wide limits but is preer= ably from 1% to 5% or approximately to i no part of Montan wax and from 1 to 4 parts of parafiin to 100 parts of fibre, dry weight.

Example 100 lbs. of Montan wax and 300 lbs. of paramn are placed into 900-1000 lbs. of water heated suficiently to melt both waxes and" then thor-= oughly stirred. After the waxes have been broken up into fine particles, 7 lbs. of caustic soda in solution are added gradually and the heating and stirring are continued for 10-15 minutes after the addition of the caustic soda has been completed. The emulsion is then complete. In order aeeaeie double decomposition of substantially all of the Montan wax soap has been efiected. The fibre is then run into a mold, and subsequently processed to form the board in the manner hereinabove referred to.

4 The metallic salt of the alkali metal (f. i. sodium sulfate), being soluble in water, is washed out with the drainage water.

This application is a division of my application Serial No. 316,109, filed hot. so, 1928.

I claim:

Pulp board comprising a compressed mixture of about 1 to a parts of parafin and from to 1 part of Montan wax, a substantial portion of which is present in the form of a metallic salt of lvlontan wax, to 100 parts of fibre, such paramn and metallic salt of Montan wax being present in a uniform state of distribution and in a very' fine I state of subdivision which states are obtained when these substances are precipitated from an emulsion prepared from paraffin and saponified Montan wax. a i I i ERT L. BECKER.

Mil

see

the