Method and apparatus for producing textured
US RE23910 E
Description (OCR text may contain errors)
Dec. i4, 1954 METHOD AND APPARATUS FUR RDUC1'NG TEXTUHED FLMF E Shasta-.Sheet l Original Filed Nov.
.una EV ,mw H STF ORNEY Dec. 14, 1954 fm, sin fwmfx AL @ma g METHGD AND APPARATUS FUR FRQDUGING T'LLiTURED ZLMS Original Filed Nov. 2, 1950 "D INVENTORS @www //ATTORNEY Re. 23,910 Reiasued Dec. 14, 1954 METHOD AND APPARATUS FOR PRODUCING TEXTURED FILMS Leland H. Smith and Frank M. Smith, Grenville, N. Y., assignors to Decora Corporation, Ft. Edward, N. Y., a corporation of New York Original No. 2,660,757, dated December 1, 1953, Serial No. 193,639, November 2, 1950. Application for rcissue July 14, 1954, Serial No. 443,452
11 Claims. (Cl. 18--19) `lt is the object of this invention to provide a method and apparatus for forming an initially smooth, homogeneous plastic lilm or web having a three-dimensional, twosided, textured finish of any desired caliper, and to do this without substantial shrinkage of overall dimensions and without substantial decrease of strength.
As is well known, plastic films now are used for a great many purposes as a substitute for textiles, as in ramcoats, shower curtains, drapes, etc., and such films have many advantages for such purposes. The industry has long sought for some means of giving plastic tilms a texture comparable to that of textiles. Until the present invention, all of such eiorts have involved one form or another of embossing operation, in which the embossing is secured primarily by pressure. The resultshave been extremely limited in eect, have been impractical except for very light impressions on high or heavy caliper tilms, and all prior art treatments for the purpose of producing tex ture have resulted in an extreme loss of strength.
A further disadvantage in the prior art methods is that there is a considerable investment tied up in etched or knurled rolls and in order to secure a change of pattern, it has been necessary to etch or ltnurl a new roll. The present invention provides an infinite variety of patterns at very low'cost and the change from one pattern to another may be made easily and quickly.
Another feature of the present invention is that while all manner of textured effects may be had, the caliper of the sheet remains substantially unchanged and, moreover, one side of the sheet is distinctly complementary of the other, so that both sides look substantially alike. As used herein the word textured" means not only similar to textiles but includes any three-dimensional pattern.
The invention in all its aspects will be better understood from the following detailed description taken in connection with the annexed drawings, in which:
Figure l is a schematic elevation view of the apparatus used to practice the invention;
Figure 2 is a section on the line 2 2 of Figure l;
Figure 3 is a section on the line 3 3 of Figure 1;
Figure 4 is a sr hematic section illustrating how a variety of different etiect; may be secured;
Figure 5 is a plan view in perspective of a sheet of the finished material;
Figure 6 represents a section taken on either of the lines 6 6 of Figure 5;
Figure 7 is a cross-sectional view illustrating another form of apparatus for carrying out the improved method;
Figure 8 is a section on the line 8 8 of Figure 7; and
Figure 9 is a diagrammatic view illustrating the pneumatic circuit of the machine.
Referring now to Figure 1 there is shown a foraminous, endless belt 10 preferably formed of wire mesh. At the leading end it passes over a roll 12, then over a guide roll 14 and then over a suction box 16, having a suction connection 18. Table rolls are mounted within the box 16 to support the belt 10 against the eliect of the suction. At the handling end of the suction box and outside the box are a few more table rolls 22. The belt then passes over a guide roll 24 and around a roll 26 whence it returns to the roll 12. A web of plastic material 30 is lill fed from a supply roll 32y and` passes under a guide roll 34 into contact with the belt lil. At the opposite end of the machine the web 30 passes under a guide roll 36 and is wound up or otherwisedisposcd of in reel 3B. A radiant heating member 40 mounted so as to be raised or lowered and having its temperature thermostat controlled is mounted above approximately the leading half of the suction box 16. A pair offbelts 42 having side beads 44 are mounted at each margin of the belt 10. The beads 44 pass through grooves 46 in the rolls 12, 14, 24 and Z6 and at the sides of suction box 16 bear on rods 45S. The belts 42 have flanges 50 which 'bear on the margins ofthe belt 10 and act as vacuum seals.
Considered as endless belts, the upper surface of the deckle straps is higher than the surface of the belt 10 and accordingly, if driven with the belt 10, there would be a certain amount of creep between the deckle straps and the belt 10. To overcome this, the deckle straps at each end of the machine are separated from the belt 10 and pass over guide rolls 29, 27 and 33. A Reeves drive (not shown) drives the roll 33 from the roll 26 and permits an adjustment to be made to equalize the actual surface speeds of the deckle straps and the belt 10.
As the plastic web 30 passes over the suction box 16 it is drawn into perfect conformity with the belt 10. The heater member 4u is regulated as to temperature and the lineal speed of the belt 10 so as to soften the plastic. As the web 39 passes out from under the heater 40 it is still held in shape, that is, in wnformity with the belt 10 by the prolongation of the suction box 16 and during its passage over the remainder of the suction box it cools below its temperature of plasticity. A plurality of air jets 2l are mounted above vthe trailing end of the belt 10 and are supplied with refrigerated air by means of the pneumatic circuit illustrated in Figure 9. The cooling of the iim while rrnly held in conformity with the belt (and whether air jets are used or not)` has the effect of destroying plastic memory, particularly since the heating has been carried out almost to molten condition.
Assuming, as will usually be the case, that belt 10 is a woven wire mesh, the web 30 as it leaves the machine will retain a perfect impression of the surface of the belt 1l). if other patterns are desired, a second, specially patterned belt may be superimposed on the belt 10. Such an arrangement is shown in Figure 4 in which a specially patterned belt 60 is superimposed on the belt 10 and underlies the plastic web 30 which will take an impression from the member 60.
inevitably there will have to be a joint of some sort joining the ends of the belt 10 and this will leave equally spaced marks on the finished web. These finished webs are sold in lengths of fifty to seventy-tive yards. Accordingly it is desirable to be able to produce such lengths without any intermediate occurrence of the joint marks but it is not always practical to provide a wire of any such length. To meet this problem, the requisite length of patterned fabric is set up in a supply roll 31 and fed between the film 30 and the wire 10 and is rewound on a roll 2S at the opposite end. The roll 31 is replenished by moving roll 25 back to that position whenever it is desired to start` a new length.
In Figure 5 and Figure 6. the web 30 is shown as having multiple projections 62 which are formed approximately equal on both sides of a medium line. It is further to be noted that the caliper of the web on any line normal to the surface of the sheet is substantially uniform. It is this characteristic which maintains the strength of the textured web substantially unimpaired over the strength of the original, untextured web. This is what is meant by threedimensional, two-sided, textured finish.
Referring now to Figures 7 and 8. there is shown a drum which by means of spiders 102 is rotatably mounted on the xed hollow shaft 104. The drum has a foraminous surface 106 supported on ribs 108 and annuli 110. This construction is conventional in pulp washers. An arcuate suction box 112 underlies most of the drum surface. A web 114 is fed over a guide roll 116 at the leading end of the suction box 112 and is removed over a guide roll 118 at the opposite end of the suction box 112. A duct 120 connects the suction box 112 with the interior of the hollow shaft 104 through which a vacuum is drawn. An arcuate heating element 1122 is provided to overlie the leading portion of the suction box while cooling nozzles 124 are provided at intervals around the remaining surface of the drum.
The action in principle is precisely similar to that of the apparatus illustrated in Figure 1 except that decide straps are not necessary. Clearly enough, in order to avoid joint marks an arrangement similar to the rolls dil and 25 may be used if desired. Surprisingly enough, even when formed on a cylindrical surface such as the foraminous surface 106 of the drum 100, the resultant textured web has no more tendency to curl than when formed on the flat surface defined by the belt 10 of Figure l.
In Figure 9 there is shown a suction boit 200 corresponding either to the arcuate box M2 of Figures 7 and 8 or the rectangular box 16 of Figure l. A line 202 unects ,the box 200 to the suction side of a compressor 204. There is always substantial leakage at thesides and ends of the suction area so that a substantial quantity of air must be handled. From the discharge side of the compressor 204 a line 206 takes the compressed air to a cooler 208 whence a line 210 takes the compressed air to nozzles 212 which correspond either to the nozzles 2i of Figure l or the nozzles 124 of Figure 7. The air expanding as it leaves the nozzles has a distinct refrigerating fect and greatly accelerates the cooling of the plastic Very special effects can be obtained by feeding piastic scrap onto the surface of the belt 10 as it moves under the heater 40. lt has been found that at the temperatures involved such scrap will make a weld to the him 30 so that effects in the nature of pile fabric can be secured.
The article produced by this invention is disclosed and claimed in our copending application Serial No. 193,640, filed of even date herewith and entitled: Three-Dimensional, Two-Sided, Textured Film.
While certain specic embodiments have been disclosed herein, it is not intended to limit this invention to the precise details disclosed but only as set forth in the subjoined claims which are to be broadly construed.
l. A method of providing continuous smooth,7 homogeneous plastic lms with a three-dimensional, twosided textured nish comprising: advancing a length of smooth lm over a. forarninous, patterned surface; ad-
vancing said surface at the same rate as said tilrn, applying vacuum to the underside of said surface to draw the film into conformity therewith while simultaneously heating said lm to the temperature of plasticity; then cooling the lm to well below the temperature of plasticity While 7 retaining said vacuun'u'then releasing said vacuum and separating the textured film from said surface.
2. Apparatus for providing continuous smooth, homogeneous, plastic lm with a :mee-dimensional, two sided, textured finish comprising: an endless, foraminous member having a textured surface; means for advancing said member with a hlm of plastic in contact therewith; vacuum means to draw said hlm into conformity with the texture of said surface; means to heat the film to the `temperature of plasticity while thus conformed; means to cool the lm while still thus conformed and means to separate the` iilm from said member.
3. Apparatus according to claim 2 in which the endless foraminous member is a belt.
4. Apparatus according to claim 2 in which the endless foraminous member is a drum.
5. Apparatus for providing a continuous smooth, homogeneous, plastic iilm with rubros-dimensional, twosided, textured iinish comprising: an endless, foraminous beit; a suction holt underiying said belt; table rolls supporting said belt over said suction box; n radiant heater overlying the leading portion only ci said belt and said suction box; and means for advancing said belt over said suction boit.
6. Apparatus as set forth in claim fi, including a foreminous belt having a textured pattern; said patterned belt overiying said iorarninous beit.
7. Appmatus according to claim 5, including grooves at. each side oi said suction box and a decide strap overiying and in contact with each side oi said belt; each such strap having a bead entering one of said grooves, a part, at ieast, oi the portion of said straps overlying said belt underlying the iilm to he treated on said machine.
S.' Apparatus for producing a textured iinish in plastic films comprising: a rotatable drum having a foraminous, patterned surface; means for applying vacuum over a. porM tion ony of the surface of the drum; and heating means adjacent a portion only ot' that part of the drum subjected to vacuum.
9. Apparatus for providing smooth, homogeneous plastic film with a three-dimensional, two-sided nish' comprising: an endless forni-nitrous member, means for advancing said member, vacuum means underlying a p0rtion ot' said endless foramincus member, means for feeding a ferai-nitrous patterned belt over said member9 means for feeding a. continuous web of smooth, homogeneous plastic material over said foraminons patterned belt whereby said suction means witl draw said plastic web into conformity with said patterned belt, heating means covering the ieading portion of said means and terminating short of the end of said suction means.
10. .A method ef providing continuous smooth, hoxrttrgeneousy plastic films with a three-dimensional, twosided, textured Finish comprising: advancing a length of smooth hlm over a foraminousfpatterned surface; advancing said surface at the same rate as said film; applying vacuum to the under side of said surface to draw the r'ilm into conformity therewith While simultaneously heating said iiirn to the temperature of plasticity; then cooling the hlm to weli below the temperature of plasticity while retaining said vacuum; then releasing said vacuum.
Il. A method of providing continuous, smooth, homogeneous, plastic fims with a three-dimensional, twosided, textured )nsiz comprising: advancing a length of smooth film; .heating sain' film to the temperature of piasticz'ty daring auch advance; advancing a oramnous patterned surface at the same rate as said film; bringing .mid film into Contact with .said surface; applying vacuum to the wider side of scid surface to draw the fim into conformity therewith, cooling the film to wel! below the tempemtme of ptnsticity whiie retaining said vacuum; and than stripping said film from said surface.
lieiiereneea @iisd in the le of this patent or the originati patent UNITED STA'IZES PATENTS Number Name Date 2,i52,i0i Scherer Mar. 23, 1939 2,354,916 Hurt Aug. 1, 1944 2,493,439 Braund Ian. 3, 1950 45,915 Chavannes Feb. 19, 1952