US2297698A

US2297698A - Treating bibulous paper

Info

Publication number: US2297698A
Application number: US346658A
Authority: US
Inventors: Richard D Freeman
Original assignee: Dow Chemical Co
Current assignee: Dow Chemical Co
Priority date: 1940-07-20
Filing date: 1940-07-20
Publication date: 1942-10-06
Anticipated expiration: 1959-10-06

Description

Jmyhe substantially increased without matepamit a: the description of the invention pro-- improved reeultl. obtained-by coating 4 Oct-1 f zgzawe PATIENT-:1 OFFICE.

chameleon a mm TheDcw my. emu of Michigan mm rm 11-min. sail-amateur relatel to w .5 It moreiparfldularieconcerm an im- ,Wmtemt'ue, malivarietiee o! hihuious paper, such as.

or the watcrieeivariety, to: ex'amplc,

h itatendencyto disintecrate rapidly under the action oi'jvipingyet-hende. Varicuemethode 1-0- 'ln'vebem propoeedicroveroomingtbissenoule n w en? latiai'actory. For example-binding agent. have incorporated into the paper-to increaeeite present invention to a method of treating" paper whereby the wet strength the'reoi' rially itea beorptive properties. An-f ew me-(tom the .bibuiompapenmcham thntu ed' mkina p per towelin tor example, with a water. loluflon ot a mixture containing-a minor pro- Dcl'tipno! a Iater-mluble cellulose ether and a maicrimflcnot a mixture orcompound ct formaldehyde and a mb'hydric alcohol.

' at, and m utiuactory ablorptivityr 1 to one embodimentot the invention, 50

litofltparte c! an urea-formaldehyde tioh product.

hydric aicohoLiffrhie'eoluticn may then. be al pliedtotowelinz'inanyoithewayrcommcnl'y known in the art, such a; by 89mm, brushing, dinpina. or, the like The paper thue coated in then dried in airand heated to a i above 100 C. to, pet up-the urea-formaldehyde resin; A cataLvst,;euch as a trace of phosphoric acid, maybe'addedto thecompositionto i'aciii-' ta'te the aettihgupottMreeimJliter drying,

the paper vmay; be rolled or'iolded as desired.

"is then reatb for above proportime; 0! ingredients give a generally p coating, abaorptiye ropltranl'th, but these reduce the absorptive prop- 15 are secured whenthe coating material; are i the ratio of approximately 510 15 parts of 'a water-soluble c l l le ether, 85 to 96 parted urea-510mialdehyde condensation productand 70 v I to100parte0iD01yhydricalcoho1. Thiseolution,

' cults in the formation or aproduct oi exceptione 1 hizhw'et strength good abeorptivity, In

' addition-P per coated with asolution oi.the

, type described i not unpleasant to the touch, i. e., is neither harsh nor slimy, even when 'wet. I

- r Among suitable-interminable cellulose. ether:

when applied a a coating on 'bihuloue paper, re-

which'may he used according to the invention are various ceiiulosee, such'al dimethylcellwlose; hydroxy aikyl celluloaea, mohair hydrouethylcelluloee: alkali metal salt: carbon-aim ceihnoaee, such as g'ly'cciiate; etc.

- The urea-formaldehyde condensation I .mnthepolvhydn mcondima be museum. composition .as a mixture, .or alternativclv,; a

p yhydric Alcohol-modified wee-formaldehyderesin" may ire-used. Thus, I mayuaeeitherga mixture or a simple urea icrmaldehyde condennation as dimethylol urea'with a 40 chemical with urea and formaldeaicoholfsuch as ethylene glycol or Ilsceroi. or a resin containing ethylene 8 1cc]. 1;;

' 0! letter. W1 0 1'6 disclosed in I U. 's. no. 2,150,471,: to the 01' In the appended'cleima, the' expreuion poly hydric Alcohol-mm" v urea-formaldehyde reein"ie'intcndedtohelmerietomixtureeoia v lvhydnc alcohol and an urea-formaldehyde resin, J as well aa ;to thoee urea-formaldehyde which have been with polyhydric alcohols during their manufacture. 1

Theiomm examples illustrate the principle oi" but are not to be continued una tn vef j ahd!rom50to100parteoiapolv I Example 1 Test strips 15 millimeters by 180 millimeters were cut from sheets of an ordinary roll of commercial paper toweling manufactured under the trade name Wipemdri and water solutions containing varying proportions of methyl cellulose and a glycol-modified urea-formaldehyde resin were then deposited upon the sample strips at various wet coating thicknesses in the range between 0.002 and 0.020 inch. All solutions used were of 5 per cent by weight concentration. The strips were then air dried, heated briefly to 105 C. to set the resin, and conditioned for 24 hours water at 20 C. was administered to the sheet from a graduated pipette. The required time in seconds was noted for the drop to be completely absorbed. The end point was taken as the point at which no light reflection was obtained from the water spot. The wet strength was determined by means of 8. Scott tensile strength tester, test strips being placed between the jaws of the machine and tension being applied to the strip until breakage occurred. Results obtained indicated that a solution containing approximately 10 parts by weight of methyl cellulose for each 90 parts by weight of a modified urea-formaldehyde resin imparted the most desirable properties to the toweling. Test strips coated with this solution had a relatively high degree of absorptivity and satisfactory strength characteristics. In ad'- dition, the surfaces of these strips were not slimy or unpleasant to the touch. However, sample strips of toweling coated with methyl cellulose alone had a slimy surface and a relatively low tensile strength. When a solution of glycol-modifled urea-formaldehyde resin alone was applied to the test strips, considerable difficulty in casting was encountered due to the water-like viscosity of the solution. No improvement was noted in the paper strength. Results of the tests also indicated that a low viscosity cellulose ether imparts greater .absorptivity to the treated paper than does a high viscosity cellulose ether when both are employed in the composite coating solutions herein claimed.

Example 2 Tests were carried out on test strips prepared in a manner similar to those of Example 1 with solutions containing varying proportions oi. methyl cellulose and unmodified urea-formaldehyde resin. It was found that a test strip coated with a solution containing approximately 10 parts by weight of methyl cellulose for each 90 parts by weight of urea-formaldehyde had a satisfactory wet strength but unsatisfactory absorptivity. Increasing the methyl cellulose content of' claimed method, the following representative comparative data are given:

wez

Absorptivg i ity. seconds width (average oi (average of several) several) Blbulous paper (blank) 0.6-1.1 Bihulous paper+methyl cellulose 0.35-0.52 140-210 Bibulous paper+urea-formaldehyde resins. 1.5-2 120-200 Bibulous gaper-i-metgigl oellulose-i-ureaiormalde yde (unm illed) 2-4 600-810 Bibulous plaper+mcthyl cellulose-l-ureaormalde yde (unmodltled)+slycol 1.7-2.7 180-260 Bibulous paper-l-methyl cellulose-l-glycolmodified urea-formaldehyde 2.2-2.8 70-10.)

In the foregoing the proportions oi components in the treating solutions emplo were those herein recited.

Other modes of applying the principle of my invention may be employed instead of those explained, change being made as regards the method herein disclosed or the materials employed, provided the step or steps stated by any of the following claims be employed or the product claimed in any of the following claims he obtained.

I therefore particularly point out and distinctly claim as my invention:

1. A method of preparing absorptive paper products of high wet strength which comprises treating a bibulous paper base with a water solution whereof the solute comprises a minor proportion of a water soluble cellulose ether and a major proportion of a polyhydric alcohol-modified ureai'ormaldehyde resin, drying the so-coated paper, and heating the paper to a temperature of approximately to 120 C. to set the resin.

2. A method of preparing absorptive paper products of high wet strength which comprises treating a bibulous paper base with a water s'olution whereof the solute comprises from 5 to 40 parts of a water soluble cellulose ether, from 50 to parts of an urea-formaldehyde resin modifled with'from 50 to parts of a polyhydric alcohol, drying the so-called paper and heating the paper to a temperature of approximately 90 to C. to set the polyhydric alcohol-modifled a. A method of preparing absorptive P per products of high wet strength which comprises treating a bibulous paper base with a'water solution whereof the solute comprises from 5 to 40 parts of water soluble methyl cellulose, 50 to 95 parts or an, urea-formaldehyde condensation product modified with from 50 to 100 parts of a polyhydric alcohol, drying the so-coated paper and heating the paper to a temperature of apdrying the so-coated paper and heating the paper 10 to a temperature of approximately 90 to 120 C.

to let the poly ydric alcohol-modified resin.

6. Bibulous paper or improved wet strength hearing at least a superficial coating comprising a minor proportion of a water soluble cellulose ether and a major proportion of a polyhydric alcohol-modified urea-formaldehyde resin.

7. Bibulous paper of improved wet strength bearing at least a superficial coating comprising a minor proportion of water soluble methyl cellulose and a major proportion of glycol-modified urea-formaldehyde resin.

RICHARD D. m.