US1893717A - Creping webs of paper and the like - Google Patents

Description

Jan. 10, 1933. w w, ROWE 1,893,717

CREPING WEBS OF PAPER AND THE LIKE Filed Dec. 31, 1930 IN VEN TOR.

Mallkm fam A TTORNEYfi Patented Jan. 10,. 1933 UNITED STATES PATENT OFFICE WILLIAM WALLACE ROWE, OF CINCINNATI, OHIO, ASSIGNOR TO THE PAPER SERVICE COMPANY, OF LOCKLANI), OHIO, A CORPORATION OF OHIO CREPING WEBS OF PAPER ANIS'THE LIKE Application filed December 81, 1980. Serial No. 505,881.

My invention is directed to improvements Patent No. 17,633, dated April 1, 1930, I

have described the process of creping material in which a web of paper or the like is led to a creping cylinder with the interposition of a film of ther'mo-plastic adhesive substance between the web and the cylinder, and is removed from the cylinder by a doctor or a knife, thereby being creped.- My present invention is applicable to this process in gen- The drawing illustrates semi-diagrammab ically and in elevation, an apparatus adapted for the practice of my invention. It will be understood from the ensuing description that my invention is not limited to this apparatus alone, but that modifications may be made in 1t by those skilled in the art without departing from the spirit of my invention. 1

Throughout this specification I shall refer to asphalt as an example of a thermo-plastic adhesive substance; but it will be understood that my invention is not limited in this respect but is equally applicable to other thereral and to modifications thereof and will be g mo-plastic substances among which may be found particularly valuable where it is desired to crepe paper or other webs coated upon bothsides with a thermo-plastic adhesivesubstance.

The primary object of my invention is to attain better control of the creping process and the product produced thereby. Control may be efiected in creping processes of this character through a number of variables, such for example as the character of web being creped, the nature,'thickness and temperature of the filmsof thermo-plastic adhesive substance employed in the creping, the angle, conformation and position of the creping knife, and the like. The specific elements of control toward which my present application is directed have to do primarily with the nature and quality of the coating or film of thermoplastic substance employed in the process, somewhat with the character of the web being creped, and quite importantly with the relationship of the thermo-plastic coating substance or other coating substance present to the various instrumentalities employed. Another object of my invention is the attainment of control by the use of water in a process of this character. These and the more specific objects of my invention which will be set had to the drawing which forms a part hereof.

[single coated mentioned as exemplary but without limitaand adhesive under commercially. feasible temperatures to serve as a positive adhesive medium for binding aweb to a creping cyl- 'inder. The only limitation upon the range of materials available for use in my present process is that they be of such character as to be substantially water insoluble, since I do not contemplate in my process any solvent actionof water upon the various thermo-plastif adihesive substances which may be emp o e shall describe my invention with respect. to the creping of webs which have been coated on both sides with a substance or substances which need not necessarily be the same on both sides. Mygrocess is applicable also to we s; but its'usefulness there apparently lies rimarily in a chan e in the characteristics 0 the webitself-rat er than in the various additional elements of control upon which I shall dwell primarily in this specification.

In accordance with the teachings of a'copending application for Letters Patent Serial no. 344,311, filed Mar. 5, 1929-, it is m practice to crepe paper by first coating t e said paper either upon one side by means of a roll coating apparatus, or upon both sides (by dipping the paper into a bath,) with bitumen such as asphalt, then tempering the coating thereon usually by cooling it, and usually also either by leading the coated web through an air gap in which it may be cooled or around a cooling cylinder. Then it is conducted to a creping cylinder and caused to adhere to the surface thereof by means of the coating of semiplastic substance. In my preferred apparatus I have means for controlling the temperature of the creping cylinder so that the temperature of this cylinder determines the temperature of the film of adhesive, or at least of the part thereof 1ying next the cylinder when very thick coatings are employed, at the creping point. The web is brought down into positive contact with the creping cylinder by means of a back up or pressure roll.

I have discovered that it is possible to control the creping process advantageously by means of the use of water and among the advantageous actions which I have noted are the following: First, the water insofar as it penetrates to the web itself modifies the characteristics thereof in accordance with its amount.

In general the effect of water is to soften a web so that it may be deformed more easily, possibly to soften the size therein so that when it has been creped it will reset in the new form, and under certain circumstances where the amount of moisture is very slight, possibly to increase the bursting strength of the paper initially, while at the same time rendering the paper somewhat easier to deform. All of these actions may be advantageous in a creping process of this character. In the second place, the application of water to a coated web and particularly to a web which has been coated upon both sides may be made use of to temper or control the temperature of the film of thermo-plastic adhesive substance upon the surface or surfaces thereof, thus eliminating in the process described, the necessity for a large air gap for cooling, or a cooling drum, air blast or other cooling means. The function of the water in this respect is however, not restricted to cooling since the temperature of the water may be quite carefully controlled and it may even be used for heating where desired. Additionally the water may advantageously afiect the nature of the union between the web and the film of adhesive substance, to the extent either of inhibiting or promoting a penetration of the web by the the thermo-plastic substance, dependent upon the temperature of the treatment. In the third place, the water is very useful in reducing the tendency of a double coated Web to adhere to instrumentalities in the creping apparatus to which it is not desirable to have the web adhere.

This latter advantage becomes of very considerable importance when creping double coated paper. With a very thin coating of thermo-plastic adhesive, it is usually necessary to operate at a relatively high temperature in order to secure the necessary adhesion of the web to creping cylinder. Where the flOll to facilitate the creping.

In the drawing I have shown a source of material to be creped which may be a roll 1; thence the web of paper or other fabric 2 is led over a suitable idler roll 3 down beneath the surface of a bath of bitumen or other thermo-plastic adhesive substance 4 in a container 5. It is passed through doctor rolls or otherwise treated as with scrapers 6 to remove an excess of the coating and, passing over such other idler rolls 7 as may be necessary, is next dipped beneath the surface of a body of water 8 in a container 9. It' is then led to a creping cylinder 10, the temperature of which will be controlled, as ex-' plained, to give the desired amount of adhesion between the film of adhesive substance underlying the web and the roll itself. A back up or pressure roller 11 presses the web into intimate contact with the creping roll 10; and the web follows the roll to a point where a doctor 12 removes it in creped form as shown at 2a.

I have found when using apparatus of this character or when otherwise following my process, that'I gain the advantages hereinabove noted. Even where the paper as shown is double coated, i. e. coated on both sides with the thermo-plastic adhesive substance, there may under certain conditions, be some penetration of the water through the coatings. This is ordinarily unimportant although in many instances it appears advantageously to affect the character of the web as the creping is being carried on, thereby enabling me to crepe to somewhat better advantage. A little water is also picked up by the surface of the web in spite of its water repellent characteristics, and this water seems completely effective in preventing any sticking of the web to the back up roll 11'. On the other hand it does not prevent the sticking of the web to the creping cylinder 10, partly, no doubt, because the web follows the creping roll and there is a much greater surface for adhesion. I have not experienced any difiiculty in this direction, and have uniformly secured the proper adhesion to the roll 10. If the creping machine is stopped and an effort made to pull the paper from the creping cylinder by hand it will be found that the adhesion between the paper and the creping cylinder is very noticeably greater than when no asphalt is present, in spite of the presence of the water. Again, the creping roll 10 will be held at such a temperature as to bring the film of thermo-plastic adhesive beneath the web to a proper adhesive-consistency for creping. Additionally, I am en'abled more carefully to control the temperature of the coatings upon the web as the web reaches the creping cylinder, by controlling the temperature of the water 8 in the 'watenbath. I need. not, of course, dip my paper into water as shown, but I may spray the surfaces thereof, and more particularly I can spray the upper surface thereof without at all wetting the lower surface and gain an equivalent non-sticking result. I do not usually however, gain by i,

spraying, an equivalent temperature control. I need not coat my paper by the mechanism shown, but instead of dipping it beneath the surface of a bath of the thermoplastic substance, I may roll coat it upon one or both sides. As indicated, I may moisten a web which has been coated upon only one side and crepe it in a moistened condition, if desired, with the coated side next the creping cylinder. The back up roll 11 becomes wetted with water in the practice of my process and the,film of adhesive substance upon the web does notstick to it. A very little water only. however, is required for this. The moisture on the roll 11 is, of course, continually being renewed by the smgll quantity of water carried up by the we Having thus described my invention, What I claim as new and desire to secure by Letters Patent, is:

1. A creping process comprising coating a web with a thermo-plastic adhesive substance, moistening said web, binding it to a creping roll by means of said adhesive substance and creping it by removing it from said roll with a creping knife.

2. A process of creping a web which comprises double coating said web with a thermoplastic adhesive substance, moistening said web, binding said web to a creping roll by means of said substance, and creping said web by removing it from said roll with a crep ing hife.

3. A process of creping a web which comprises dipping said web into a body of thermo-plastic adhesive substance so as to coat thesame, afterward dipping said web into a body of water, thereafter leading said Web to a creping cylinder and binding it to said cylinder by means of said thermo-plastic adhesive substance, and creping said web by removing it from said cylinder with a creping doctor.

4. Inc creping process involving the use of a thermoplastic adhesive substance as a binding agent, a method of preventing the sticking of a web to the back up roll which comprises kee ing said back up roll moist by water carried ysaid web.

5. A process of creping paper which comprises double coating said paper with asphalt, moistening said coated paper, bindin said paper with said asphalt to a creping cy inder and creping it thereon.

6. In a creping process, the step of treating a web coated with thermo-plastic adhesive substance so as to temper the same, by wetting the surface of said coated web with water at a different temperature.

7. In a creping process the step of coating a web upon both sides with a thermo-plastic adhesive substance and subsequently controlling the temperature of residual films of .such substance on' said web by passing said web through a bath of water maintained at a desired temperature different from the temperature of the thermo-plastic adhesive substance in said coating step.

8. In a creping process the steps of passing a web coated with a thermo-plastic adhesive substance through a water bath maintained at a temperature suflicient to develop adhesive characteristics in said coating, conducting said coated web to a creping cylinder with a coated surface against said cylinder and creping said web'by removal therefrom with a doctor.

9. In a creping process the steps of treating. a web coated with thermo-plastic adhesive substances with water so as to moisten a coated side thereof, leading said coated side against a crepin cylinder and creping said web by removal t erefrom with a doctor.

WILLIAM WALLACE ROWE.

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