AU427691B2 - Paper production process - Google Patents

Description

32, 033/71

This invention relates to papers for cutting and

processes for the manufacture thereof.

By a paper for cutting there is meant a paper

intended for use in any operation which requires that the

paper be cut, punched or trimmed. Papers of all weights

and grades must be subjected to different finishing opera-

tions in preparing the paper for its ultimate end use.

Among these operations are cutting, punching and trimning

operations. Moreover, some kinds of paper must be specific-

ally designed for their own particular end use which may in

fact be a cutting or punching operation.

Generally, the above-mentioned finishing opera-

tions or end use functions of the paper are performed with

k ives, both rotating and fixed, or with dies and punches,

operating either in a punch type die-press or in a rotary

press. In each instance, the paper, or several blanks of the paper must be cut or punched smoothly and cleanly with-

out tearing or splitting the paper, Furthermore, for ef-

ficient and economical operation, the paper must exhibit

good release characteristics from the die or punch type

presses, and, the anti-static properties of the paper must

be superior to insure runnabilityo Finally, however, one

of the most important factors in developing a paper suit- able for the cutting, punching or trimming operations

hereinbefore mentioned, is the ability of the paper to 427.691

32,03 3/71 perform in such operations satisfactorily without causing undue wear on the element which effects the particular opera- tion to the paper. In order to avoid excessive wear of the dies, punches and knives often used in performing the above opera- tions, the paper is often treated with a lubricating oil. Conventionally, the oil is applied to the paper by the converteis by immersing the paper in oil or more often by applying the oil to the paper by an applicator roll. Dif- ferent kinds of paper absorb the oil in different amounts depending upon the method of application and kind of paper treated. Conventionally oiled paper may contain from 10 to oil by weight and usually contains from 15 to 22% oil. by weight. It is difficult to apply oil to paper at a level below about 10%, the minimum amount which can be applied uniformly by applicator roll. While oiling the paper pro- longs the life of the dies, punches and knives in the finishing and ultimate use applications,-and, may even lengthen the shelf life of the paper, oiled paper has had serious disadvantages over unoiled paper. First, the oiling process has been a separate proceS which in the past-has been performed by the converter. Applying oil to paper by applicator roll or by dipping has been a difficult and in- efficient process. Secondly, with the amounts of oil needed to achieve uniform distribution of oil, oil odor and bleeding have often-been problems with oiled paper because of the excessive amounts of oil employed. To date, there has been no satisfactory way to apply less oil in a- uniform manner. Furthermore, oiling.lowers the opacity of the paper and this can cause serious problems when 'the paper

2 7.691

3 2,03 3171 is used as code paper, for instance, which requires Inter- pretation with an optical reader. Less opacity In the no- hole areas 'of code paper tape Increases the light transmission there through and can lead to a misreading of the coded data on the encoded paper tape. Moreover, when the paper is utilized for envelope or card stock, or, for labels which must be printed, the amount of oil applied to thie, paper cannot be excessive or the brightness and pick-re'sistance of the paper become unacceptable. These factors are par- ticularly important when-coated papers are treated with oil to improve their handling characteristics. Initially, the addition of a pigmented coating to the paper will in itself drastically increase the wear on cutting knives and dies and on the punches used in typical finishing and end use appli- cations. Moreover, an imbalance between the quantity of binder, the quantity of pigment, and the quantity. of oil results in a poor coating composition for letterpress or web offset printing purposes. Thus the incorporation of an oil treatment in a coating composition applied to the paper, as ta ught by some of the prior art processes, is clearly un- desirable as regards printability, and, as regards satisfy- ing the other requirements. Accordingly, while the benefits of oiled paper, both coated and uncoated, are desirable, the problems attendant with the previous methods for applying the oil have been considerable. One particular kind of paper which has an end use that requires a punching operation which produces severe wear to the punches is code paper. Code paper is paper designed to be converted into perforator tape, the punched tape used in teletype machines, computers, autocaatic type

11 i97.691

SO3 3f' 1 setting systems, and various data processing systems. In

general, code paper Is made entirely from chemicapl wood pulp which is free of fillers and abrasive particles. The

paper may be unoiled or oiled by the converter for better lubricating properties, as discussed below. The paper is

converted into tapes by slitting it into widths ranging-from

about one-half Inch to three inches, the most frequently

used tape widtbs being In the order of 0.685, 0.875, and Inch. In use, letters, numbers, punctuation and certain machine-function instructions are represented on the code paper tape by a code consisting of holes punched across the tape. 'The small piece of papez-which is removed by the punch is called .achad. The holes are placed in the tape by a tape punch or perforator 'whichIs usually an electro--- mechanical device-~wich uses pins to punch data on the tape. Some punches are activated by a keyboard, some by electrical impulses from another machine such as a computer or data transmission device, and others are activated by both means. The codes placed on the tape employ various hole/no-hole combinations In channels which may range In number from five to eight. In addition to the code holes across the tape, the tape usually, carries feed holes so that in a five- channel code, for example, a fully punched tape would have three code holes, a feed hole, and two more code holes centered on a line _perpendicular to the lengthwise direction of the tape.. Coded tapes are read in tape readers which sense the holes and translate them into electrical Impulses. The

tape readers are either mechanical or optical. -Mechanical

32033?, readers have feelers for sensing the hole/no-hole combina-

tions. Optical readers use light which passes through the

code holes but is hopefully opaqued out in the no-hole areas.

In order to avoid excessive wear of the punches#

code paper has been subjected to lubricating treatments-

particularly as taught by United States Letters Patent No.

3,535,155. Accordingly, it is an object of this invention to treat code paper with the novel process described herein

for achieving the desired improved punch wear without en-

countering the undesired effects of the prior known treatments.

In addition, it has also been found that uncoated

paper, for use as envelope basestock for instance, can also achieve improved runnability when treated with the novel

process disclosed herein. Typically, envelope basestock is sheeted in a conventional sheeting operation which requires

passing the paper web through a sheeter, the cut sheets are then stacked on skids, and, then taken to a second cutting

station where the envelope panels are cut from the paper.

Finally, the partially formed envelopes are then transferred

to another cutter where the remaining cut-outs are made for

coupons or window areas. Each of these cutting steps requires

the use of a knife, die or punching type mechanism which is

subject to severe wear when the par ticular cuts are performed.

Thus to prolong the life of the cutting instruments used in

the manufacture of envelopes from uncoated envelope base-

stock, the basestock can be treated with the novel process

described and claimed herein. Therefore, thera is a need

for a method of producing an improved self-lubricating

envelope paper basestock, by applying the novel oil-in-water

emulsion claimed, to the paper, to improve the runnability*

3 2.033/71 of the paper and achieve prolonged die life. Moreover, other and different papers have problems. As mentioned before, different grades of papers both coated and uncoated, need Improvement from the point of knife, die and punching equipment wear, when the paper is subjected to any cutting, punching or trimming operation. Thus, it has been found that label paper, including pressure sensitive, self-facing label paper, and, conventional coated-one-side (CIS) label paper need improvement in runnability on the die press-and reduced die wear, 'Generally, self-facing label paper is uncoated, and, It is cut into labels of the prescribed dfiens ions as the last step in its manufacture. For this purpose, a sand- wich construction is prepared which includes, reading from top to bottom, the label or facing paper, a layer of pressure sensitive adhesive, a layer of silicone type release coating, and (4j) the release paper itself. Webs of this sandwich construction are then conducted to a cutting section, or, die press, (either rotary or punch-type) where the cutting elements of the- die penetrate the first or facing (label) layer of the sandwich construction and the adhesive layer, wh~ile only""kissingt the release paper.

Thus the labels are cut only from the label paper itself leaving the release coating and release sheet intact. For Lisa, the labels are simply peeled off of the release paper, ,rith the pressure sensitive adhesive adhering to the labels lue to the-~presence of the release coating. In this opera- bion, the die wear in the label forming operation is both ,onsiderable and a serious matter. Furthermore, when the Label paper itself for prassure sensitive labels is coated,

-7-69

3%0O3371 or when conventional coated label papers, without the pres-

sure sensitive adhesive, are cut into labels for a particular

end use, the effects of die wear are more troublesome simply

because of the presence of the pigmented coating. Hence,

yet there is a need for a technique to increase the runnability,

and die life of cutting elements when papers, both coated and

uncoated are cut, punched or trimmed, by treating the papers

with a process vhich papers may then be used as pressure

sensitive or conventional label papers.

According to the invention there is provided a

process for producing a paper for cutting in which an oil-

in-water emulsion of a lubricating oil in an aqueous disper-

sion of st arch is applied to paper at a rate which distributes 0.16 je-. to pounds of oil per ream of paper and the paper is

dried,

Thus, there is generally provided an oiled paper

which does not suffer from oil odor and bleeding as in the

past, and which is self-lubricating to increase the life of

any cutting, punching or trimming element that operates on

the paper. The paper is produced in one basic operation and

elimirvites the need for a separate oiling procedure by the

converter. The new prelubricated paper has greatly improved

opacity over oiled papers known in the past. Surprisingly,

it has been found that the same degree of lubrication as

that found in known oiled papers containing as much as

oil. by weigiica 6e* achieved by use of much less oil if the oil is applied to the paper made from chemical wood

pulp as part of a starch sizing while the paper is being

manufactured on the paper-machine. It has been found that 0.i6 as little oil aslO--a pound per ream of paper, applied

2 69

32,O3371 according to the process of the present invention, provides the final oiled paper with as much lubricity as._paper'treat- ed in a separate converting operation to contain 15; pounds per ream of oil. Because the oil level is low in the code paper when applied according to the present invention, the final product has a much higher opacity than previously known oiled papers. As mentioned in the past one could not pigment oiled paper to improve opacity because the abrasive pigment would damiage the cutting, punching and trirmming elements when the paper was used. Yet while oiled paper has been desirable to lubricate the knives, punches and trfimers, and, prolong the shelf life of the paper, oiling has seriously affected the opacity of the paper* By the present invention, opacity of the oiled paper is maintained at no expense of lubricity. Generally, a dispersion of starch in water is first prepared. Under agitation, an emulsifier is added to the aqueous starch dispersion and then a lubricating oil is slowly added to produce an oil-in-water emulsion* The resultant oil-in-water emulsion may be applied to the base paper web by any suitable means such as dipping, spraying, and brushing, but preferably is applied by means of a con- ventional or gateroll size press on a paper-machine. The paper is impregnated with the emulsion at the size press and is subsequently dried to a moisture content of About to The r esultant prelubricated paper is then suitable for use in most cutting, punching or trimming operation- without the necessity of-any further-oil treatment of the paper. Furthermore, the oil is uniformly contained within and on the paper in an amount which heretofore could not be

di27691

3 2033/7f

applied uniformly to paper in a separate oiling treatment. If desired a pigmanted coating can be applied on at least one aide of the paper which is coated with emulsion. Usually the emulsion coated paper is dried before the application of pigment. Generally, there is no limitation to the use of a particular type of starch in the sizing. Pearl, acid modified, cationic, oxidized, and ethylated starches can be used in the sizing, with the preferred being pearl corn starch. The amount of starch in the oil-in-water emulsion can be varied from about 1.5% to by weight, with the preferred being about 5 to 7% by weight. Above about 15% starch by weight, the oil-in-water emulsion leads to become too viscous for easy handling. Below about starch by weight, the emulsion becomes unstable and is not suitable for size press application. The oil used in the present invention can be one of the known liquid lubricating oils, including motor oils, paraffiLn- based oils, and mineral oils. The viscosity of the oil compo- nent can be quite variable and may for example range from a Brookfield of about 27 centipoises (No. 1 spindle, 20 r.p.m.) to about 870 centipoises (No. 2 spindle, 20 when measured at about 25 0 0. The amount of oil in the emulsion Is quite small, usually ranging from about 1% to 12%, and preferably from about 3% to by weight of the total emulsion Including starch, water, emulsifier and oil. At these concentrations, the amount of oil1 picked up by the paper at the size press has ranged from about 0.16 pound to 1.5 pounds per ream, with the preferred pickup being in the range of about 0.5 to 1.1 pounds per ream of paper (500 sheets, 25 x 38 inches). Obviously, the

Sa 033f/71 amount of oil used can be above that stated, but oil odor and oil bleeding may occur as well as losses in opacity when increased amounts of oil are used. As previously stated, oil applied in accordance with the present invention is uniformly distributed throughout the paper even though it is present in a very limited quantity.

As stated, a lubricating oil forms the internal phase of

the oil-in-water emulsion when the oil is emulsified or

dispersed in the aqueous starch dispersion. The internal oil phase is present in the external phase of the aqueous starch

dispersion as droplets, such as is true for oil-in-water

emulsions. Any suitable emulsifier can be used in sufficient

quantity to effect an oil-in-water emulsion. Preferred, but not limited-thereto, are such emulsifiers known commercially as

Tween 80(Tween is a Registered Trade Mark), a polyoxyethylene

sorbitan monooleate, and Tergitol-NP27 (Tergitol is a Registered

Trade Mark) a nonyl phenylethylene glycol ether. The emulsifier preferably is added to the aqueous starch dispersion before the

oil is added thereto, but the emulsifier optionally may be

added to the dispersion of starch simultaneously with the

addition of the lubricating oil, or the lubricating oil may be

mixed with the emulsifier prior to being added to the starch

dispersion. The usual base paper used for purposes of the present invention has been referred to as paper made wholly from chemi- cal wood pulp. As those skilled in the art will readily appreciate, chemical wood pulp is obtained by digestion of wood with various cooking solutions and includes pulp prepared by the known sulfate (or kraft process), sulfite, and neutral

.11 427.691--

3 033P7 sulfite semichemical processes. The chemical wood pulp used

herein is preferably bleached to produce a white pulp.

One surprising feature of the code paper produced by the

process of this invention is its low coefficient of

32,033/7f friction as compared to paper oiled conventionally by the converter and containing many times the amount of oils The lower coefficient of friction is a benefit because tapes produced from the code paper made by the present process have good antistatic properties. Because static charges do not tend to build dur~ing the encoding operation, chads punch- ed from the tapes do not tend to gather -and hamper the rimn- ability of the tapes or the operation of the punches. In addition, the envelope basestock produced by the process of this invention was found to have improved rtmfl- ability in both the conventional dias press and the programm- ed die press. 'The die operators found that the paper as treated with the disclosed process was smoother and more slippery, -yet higher lifts (or stacks of blanks) could be cut in the die presses with even worn dies, and there was substantially no top to bottom variation in the cuts made. That is, with other envelope basestock, the die operators found that with nominally high lifts, and, when using new, sharp dies, the paper tended to move or shift in the lift as the die passed through the stack. This movement generally caused a variation in the dimensional size of the envelope blank cut at the bottom of the lift as compared with the blank at the top of the lift, With the prelubricated paper produced while practicing applicant's process, the -die made a clean cut with substantially no top to bottom variation- in cut. This factor was attributed directly to the lower coefficient of friction of the treated paper as compared with -the coefficient of friction of the control-, Moreover, the same prelubricated paper printed satisfactorily with, oil base ink, aniline ink, and in an aniline

23- 427691

32.033 /71 printer on a folding machine.

In sumary, based on actual production tests of

the prelubricated paper produced by the present invention,

the following improvements generally were noted: longer

die wear, higher lifts cut, ease of cutting and

release from the die, substantially no top to bottom

variation in cutting, better quality cutting, i.e.,

elimination of pressure points, pronounced burr, and no

chipping, cracking or splitting, considerably fewer

damaged or "sprung" dies, a somewhat diminished noise

level on hard to cut paper, and better panel cutting on window folding machinese With the application of the herein disclosed pro- cess to label paper both coated and uncoated, and, particu- larly to self facing pressure sensitive label papers, reduced die wear was the most noticeable improvement found with the prelubricated paper. Because of the extremely close

tolerances required in the cutting area of the cutter used

in manufacturing self facing pressure sensitive label paper,

die wear was always a problem. However with the present

prelubricated paper, die wear was substantially reduced.

Embodiments of the invention will be described in

greater detail-with the aid of the following Examples. EXAMPLE I

An aqueous dispersion of pearl starch was prepared by .cooking the starch as an aqueous slurry of about 5 to solids in a continuoxts jet cooker at a temperature of

about 3200F., pressure of about 80 psi., for about

minutes, and then diluting the resultant cooked starch with t

4 sufficient water to produce 1000 gallons of a 6% by weight .14. .6 9 1

32.o33/ aqueous dispersion of starch. Under agitation, 1 gallon of

Tergitol-NP27 emulsifying agent was added to the starch

dispersion. Then with continuous agitation, 40 gallons of Faxam-L$0lubricating oil (one of a line of lubricating oils

produced by Humble Oil Refining Company), having a

Brookfield viscosity of about 40 centipoises (No. I spindle# room temperature), were added to the aqueous

starch dispersion over a period of about two hours, to

produce an oil-in-water emulsion. The amount of oil in the resultant emulsion was about 4% by weight. The viscosity of the milky-white size press emulsion was about 90 centipoises Brookfield (No. 2 spindle, 60 1060F.). The emulsion was stirred for about one-half hour prior to screening and pumping to-a size press located between two drier sections on a commercial papermaking machine. 'The paper being made on the papermachine was comprised of about 80% neutral sulfite semichemical pulp and about 20% sulfate pulp. The paper had a basis weight of about 54 pounds per ream. The emulsion was applied to the paper by a conventional vertically-oriented size press, with the web of paper entering the nip of the press in straight- through fashion. The emulsion was placed on the top of the travelling web by means of shower pipes located immediately before the nip formed by the press rolls. The underside of the web was likewise sized with the oil-in-water emulsion by applying the emulsion to the lower press roll which delivered the emulsion to the paper web as it passed into the nip formed by the upper and lower press rolls. After the travelling web was impregnated with the emulsion at the size press, the web was dried to a moisture content of about 6%. A427.691

33/71 An analysis of the paper so-produced showed that it contained about 1.1 pounds of oil per ream of treated paper. The oil, which represented only about 1.9% by weight of the paper, was uniformly distributed throughout the paper. The opacity of the paper with a starch sizing only was about B L 75, and the opacity of the paper with the oil-in-water emulsion was about B L 72. The paper was later slit into appropriate widths to produce code paper for perforator tape, and the tapes performed exceptionally well when encoded and used as coded tapes. This Example represents a preferred embodiment of the present invention. There was no oil odor attendant with the code paper of Example 1 and it did not suffer from oil bleeding in use. EXAITLES Size press emulsions were prepared as in Example with the amounts of oil being present in the emulsions by weight per cent as shown below. The emulsions were applied by size press to paper made from chemical pulp, with the amount of oil impreg- nated into the paper as set forth below. After the sized paper was dried, opacity measurements were made. Oil in Oil in Paper B& L EXAMPLE Siin Op./em)acity Lubricity 2 (control) 0 0 73.3 19 3 3 .16 72.7 28 4 6 .21 71.7 31 9 .28 71.9 31 It can be seen that the opacity of the paper treated by the present invention-was-only slightly different from that of Exam- pie 2 which was sized with a starch sizing containing no oil.

32.033171 Part of the paper from Example 2 was oiled by con- ventional means employed heretofore to produce oiled code paper* At minAimun applications, sufficient to provide a uniformly oiled product, the sur'face treatment 'with oil produced a paper containing about 8 pounds per ream oil'. The B L opacity of the conventional product was only about 51.7, a drastic opacity reduction over the starch-sized paper and the paper treated according to the present Inven- tion in Examples EXAMPLES 6-9 Size press emulsions were prepared as in Exampls with the emulsions containing about 6%a by weight ethyl- ated rather than pearl starch* The' oil used in the emulsions was Unicdol.motor oil (SAE-lOW), and the amount of oil by weight used in the emulsions is set forth below. The emul- sions were applied to paper at a size press and after drying, the lubricities and coefficients of friction of the papers were determined: Oil in Static Coefficient EXAMPLE Sizing Of Friction Lubricity 6 (control) 0 0.40 19 7 3 0.36 27 8 6 0.34 28 9 9 0.34& 28

The oil pickup in the paper was again in the range of that shown in Examples from about 0.16 to about 0~.O0 pound of oil per reamn of paper, going from those emulsions containing thes smaller quantities of oil to those containing higher quantities. Paper from Examnple 6, which had been sized with a

D7 427.691

3 033p7 6% ethylated starch sizing and dried, was treated convention-

ally with the Unico oil. The paper contained about 15 pounds of oil per ream of paper. The lubricity of the oiled paper was about 29 and the coefficient of friction was O.40. It can be seen that the papers treated according to the present

process had lubricities about the same as the conventionally

oiled paper containing much more oil, and had lower coef- ficients of friction than either unoiled paper or paper oiled

in the conventional manner.

EXAMPLES 10-11 Further size press emulsions were prepared as in

Example 1 with a 5% pearl starch solution and Faxam-4O lubricating oil, with the amounts.of oil being present in the emulsions by weight per cent as shown below. The emulsions were applied by size press to envelope basestock paper made

from chemical pulp, with the amount of oil impregnated into

the paper as set forth below.

Oil in Oil in Paper Static Comficient EXAMPLE Sizing _(lb./ream) Of Friction Ltbrlcity (control) 0 0 0.44 18 11 l 1.03 0.31

Each paper, produced as a control with no oil in Example and, as the prelubrlcated paper of Example 11, was tested as

a potential paper for envelope basestock. The paper of Example 11 was then utilized in a trial to make envelope paper to observe the runnabflity and die wear as mentioned hereinbefore.

The substantial improvement noted for both factors was at-

tributed directly to the higher lubricity and lower co-

efficient, of friction of the prelubricated basestock.

18- 2 a I

32 033/71 EXAMPIES 12-13 In these Examples, a basestock of 61 pound basis

weight was prepared for self facing label paper substantially

as described-in Example 1. Part of the paper thus produced

was used as a control, with no oil treatment, and part was

.treated with the size press emulsion as prepared in Example

1 using a 5% pearl starch solution and Faxamj40 lubricating

oil. The amount of oil present in the emulsion by weight

per cent is shown below and the amount of oil impregnated

into the paper is also shown.

Oil in Oil in Paper EXAMPLE Sizing (#/ream) Lubricity

12 (control) 0 0 18

0. 84 26 13. 4

The paper of Example 13 was then utilized in a trial to make

self-facing pressure sensitive label paper and a substantial

reduction in die wear was observed as noted hereinabove.'•

The fact that the paper of Example 13 had a higher lubricity

than the control paper of Example 12 obviously accounted for

the increase in die life and overall improved performance of

the prelubricated paper. EXAMPLES l4_16

To test the general utility of the disclosed

process on both coated and uncoated basestock, a 50 basis

weight paper of low moisture content (less than made

from 60% pine and 40% hardwood was prepared. The uncoated-

paper was then surface sized with a size press emulsion

substantially as prepared in Example 1. The size press

emulsion included a 5% pearl starch emulsion, with ona part

per thousand_.Tegitol NP-27. To this dispersion, there was d27.69 1

3Zo033 /1 added an amcunt of Faxam-40 lubrioating oil and the mixture was agitated with a lightening mixer to form a stable oil- in-water emulsion* Lubricity tests were then performed as before on both the surface sized paper and on the control (Example with the following results, Oil in Oil in Paper EXAMPLE 'Sizing (#/ream) Lubricity V4l. (control) 0 0 27 6 0,38 1l 16, 12 0.8 41l

These tests illustrated that the maximum effect of the novel process disclosed herein, as regards lubricity, was reached at application-of oil in the size press. The lubricity numbers obtained also illustrated that, with applicant's pre- lubricated paper, substantial improvement could be expected in regard to the wear of any cutting, punching or trimming element that was used in performing a finishing or end use operation on the paper thus produced, EXAMPLES 17-19 In these two Examples, the paper produced f or the tests in Examples 14~-16 was dried after the size press treat- mernt and then overcoated with a 6-8 pounds pigmented coating per ream of paper on a knurled roll applicator. After dry- ing the paper, the data for these two Examples was taken with coated paper as a control (Example 17) and with coated paper treated with the novel process disclosed herein. -Oil ihW- Oil in Paper EXAMPLE Sizing (#/ream) Lubricity 17 (control) 0 0 -21 .18 6 0.28 28 19 12 0.39 34g 4127.69 1

0,3 3p1 The control with coating showed a poorer lubricity than the uncoated basestock (Example 14), and, the amount of oil impregnated in the paper was less at the same two levels of oil addition used in Examples 1$5 and 16. However, the lubricity of the coated paper did increase with applications of oil higher than the 6% level which was noted as yielding the maximumu effectiveness in Example 15. Thus it can be seen that even coated paper treated with applicant's novel process should show the same improved die wear and runnability that was found in actual tests on code paper, envelope stock and self-facing label paper. Presently, there is no industr -wide standard for measuring lubricity, but the Stanley' Knifei test is kniown for use in such determinations. A number of sheets in pad form (35-50 sheets, for example) are subjected to a series of ton cuts, and the final sheet penetrated by at least three of the ten cuts is taken as a measure of the lubricity of the sheets* Determinations of lubricity according to the Stanley Knife test have correlated well with actual field results on the wear of p-.nches used to encode paper. From the above Examples, it can be seen that an improved process for making oiled paper has been disclosed. By sizing paper made of chemical pulp with an oil-in-water emulsion containing starch in sufficient quantity to render the emulsion stable under sizing conditions, an oiled paper can be produced which has equal lubricity, better antistatie piroperties, and significantly better opacity, and which does not suffer from oil- odor or oil bleeding, as compared to conventionally oiled papers. By the improved process, the amount of oil in the paper can be greatly reduced over that

32ZO3371 previously kmown by applying it as part of a starch sizing. The oil is uniformly distributed throughout the paper to yield a uniformly oiled paper having great utility f or any intermediate or end use operation involving the cutting# punching or tri~aing of the paper*

22- '427.69 1

Claims (1)

1. S033z71 The claims defining the invention are as follows:

   1. A process for producing a paper cor cutting in which an

   oil-in-water emulsion of a lubricating oil in an aqueous

   dispersion of starch is applied to paper at a rate which

   distributes 0.16 to 1.5 pounds of oil per ream of paper and

   the paper is dried.

   2. A process according to claim 1, in which the paper is a

   code paper.

   3. A process according to either of claims 1 and 2, in which

   the starch is from 1.5% to 15% by weight of the emulsion.

   4. A process according to any one of claims 1 to 3, in which

   by weight of the emulsion the starch is 1.5 to 15% and the oi

   1 to 12%.

   A process according to claim 4, in which the starch is

   to the oil is 3 to 5% and the emulsion is applied to provide

   to 1.1 pound of oil per ream of paper.

   6. A process according to any one of claims 1 to 5, in which

   the emulsion is applied to a web of paper derived from a

   chemical wood pulp by a size press on a papermaking machine.

   7. A process according to any one of claims 1 to 6, in which

   the emulsion contains an emulsifying agent.

   8. A process according to any one of claims 1 to 7, in which

   after the paper is coated with emulsion, a pigmented coating

   is applied on at least one side.

   9. A process according to claim 8, in which the emulsion

   coated paper is dried before the pigment is applied.

   A process for producing a paper for cutting, substantially

   as hereinbefore described in Example 1.

   11. A process for producing a paper for cutting, substantially

   d27.691

   32033/71 as hereinbefore described in Example 3.

   12. A process for producing a paper for cutting, substantially

   as hereinbefore described in Example 4.

   13. A process for producing a paper for cutting, substantially as hereinbefore described in Example

   14. A process for producing a paper for cutting, substantially

   as hereinbefore described in Example 7. A process for producing a paper for cutting, substantially as hereinbefore described in Example 8.

   16. A process for producing a paper for cutting, substantially

   as hereinbefore described in Example 9. 17. A process for producing a paper for cutting, substantially

   as hereinbefore described in Example 11.

   18. A process for producing a paper for cutting, substantially as hereinbefore described in Example 13.

   19. A process for producing a paper for cutting, substantially

   as hereinbefore described in Example

   A process for producing a paper for cutting, substantially

   as hereinbefore described in Example 16.

   21. A process for producing a paper for cutting, substantially

   as hereinbefore described in Example 18.

   22. A process for producing a paper for cutting, substantially

   as hereinbefore described in Example 19. 23. A paper for cutting when produced by a process according to

   any of the preceding claims.

   DATED this TWENTY -FOURTH day-of AUGUST,--1972...

   WESTVACO CORPORATION

   Patent Attorneys for the Applicant SPRTSOIT FERGUSON

   427.691