DE1779458A1 - Material web with thin, opaque and longitudinally extending blind-like elements and manufacturing processes - Google Patents

Description

M 2455

Minnesota Mining and Manufacturing Company, Saint Paul

Minnesota 55101 (V.St «v.Ao)

material web with thin, opaque and in the Blind-like elements running longitudinally and manufacturing process

The invention relates to paper sheet-like materials, with which optical effects can be achieved, and which are used in particular where there are limited angles of visibility are desired so that the optical aperture is restricted. The invention also relates to a method for Manufacture of such materials. Examples of how such a material can be used are: Traffic signs, prevention of reflection and mirroring

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for surfaces on instruments, one-way glasses and similar purposes ο The invention also includes various procedural steps » i

An older process involved the production of such plastic films in such a way that blocks were cut into films which consisted of alternating translucent and opaque and glued together oils. One commercial use of such products has not yet become known, probably because of the very considerable difficulty ^ with which polymeric materials can be cut in the intended way o

Another method of cutting a polymeric material, such as polytetrafluoroethylene, has been made from plywood borrowed from the processing industry, namely the splitting It is well known that polytetrafluoroethylene has such unusual properties that there is a special position among the polymers

does not take and compared with other polymers and their use /

can be. Z »B * can use this material from most others Materials are not wetted or wet them so that) this material does not stick to a paring knife and in in this respect resembles wood or leather, which likewise does not adhere to the metal.

It has now been shown that, with certain modifications, the splitting or peeling process for cutting up polymer webs can be applied which polymers adhere to metals can «Although the process is probably common with thermoplastic Plastics can be applied, so it is of particular use for the manufacture of sheets from thermoplastic Polymers with structures that can be produced with the use of extrusion

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or semolina processes can only be produced with difficulty.

Such a structure is, for "B ₀ of relatively wide and clear strip and with this alternating relatively narrow opaque stripes, both types of strips extend across the web and through, so that a limited optical aperture is present.

These webs of material can more or less easily be wound up on supply rolls from which the desired pieces can be cut. The ease of take-up depends M on the thickness, stiffness and other characteristics of the peeled i? Olie from "Since much larger dimensions are available than was previously possible, as well as new uses can be provided, and, larger areas covered become ₀ ZeB. Large windows can be covered in such a way that the view is essentially not obstructed, while an almost vertical sun cannot shine through the window. Such a shielding effect can be of particular use in those latitudes where the sun is always almost vertical. The material therefore acts like a blind, the slats of which are "closely spaced from one another".

It is a special feature of the sheets of material produced by splitting or peeling off that one surface is linearly shorter than the other surface, although both surfaces encompass the same circular arc. If cooling takes place immediately after peeling, this difference remains in the plastic as a curvature, and when the material web is stretched in the longitudinal direction, this curvature is converted into a transverse curvature. This curvature is removed in the manner described below.

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It has been shown that the peeling of thermoplastic materials is best performed on a block of round material with a rigid shaft around which the polymer is formed into a "block, and that the surface of the round block is heated to a temperature at which the Polymer is softened at least to a depth to which the paring knife penetrates the round block before contact with the paring knife occurs. The methods for heating the round block will be described later. For the round block, a steel shaft, which is attached to the one End captured by a jig

™ will.

In order to produce a polymeric material web with a restricted optical opening, in the manner described above a round block shaped around a shaft. Made from a primary laminate made from a clear and contrasting polymeric material disks are cut out, the center holes of which are about 0.1 to 0.5 mm larger than the shaft, which disks then molded around the shaft. Some thermoplastics contain small amounts of volatiles, such as moisture, so

t the slices should be dried thoroughly beforehand they are used to make the round block. Conical or concave disks can also be used, with the opaque layers are inclined at an angle.

The primary laminate can be produced in any suitable manner or discs made of a clear and a contrasting material alternately can be used exist. In the latter case it is possible to change the order of the two types of discs and, for example, several

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to arrange clear slices on top of each other. The primary laminate can be made from an extruded thermoplastic plastic material be produced, which is provided with a covering made of a covering made of a contrasting material, which covering by a Gravure printing or another printing process, by vapor deposition, etc. «can be generated.

The contrasting layer may also consist of a polymer which has been colored with dyes or pigments dissolved "By way of example, a layer Zobe contains 5 wt. $> Carbon black as a pigment. According to the invention can JE μ but a two-color contrast layer are also provided, one of which is adjacent to the clear layer a color, and the outside may have a different color, or the clear polymer may be on opposite sides with a multi-colored base are provided. It could, for ₀ B _e a web of material are produced which saw except the limited optical aperture from the front, from the side to a green and bon the other side looks red "Regardless of the chosen method clear and

pigmented juagen provided, and the discs are on a " Shaft secured using suitable retaining means. Avoid getting particles of foreign matter or the layer material be included. As many slices are put together until the stack has the desired width of the material track slightly exceeds the entire arrangement is then entered into a chamber, the diameter of which is only so much larger that thermal effects can be compensated, and the stack is then gradually heated and pressurized until the

Eundblock on the shaft up to the diameter of the chamber completely

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has been shaped and cured »At the same time, a vacuum can be applied. The heating process and the required temperature depends upon the particular thermoplastic material from ₀ Suitably, a double-walled housing is provided, can be inserted into the completely cured, the cooling water, so that the round billet rapidly cools ,, Kormalerweise is the round billet immediately after cooling to Peel ready, but can be used some time later after the block has cooled enough to be handled «

The thermoplastic material is quite limp, like ZoB * polyvinyl butyral, peeling off the round block is difficult perform. In such a case, the round block is cooled down to a temperature at which the polymer is sufficiently rigid for what purpose e.g. solid carbon dioxide can be used.

The invention will now be described in detail. In the accompanying single drawing is

Pigot a drawn as a sectional view, position the manufacturer W a round block shows

Figo2 is a diagrammatic representation of a round block, the

Peeling knife, the heating lamp and the material web in the Location on the bed of a conventional large metalworking lathe,

Iig.3, 4-, 5 each have a cross section through a web of material without additional Covering, with transparent coverings on both sides of the same thermoplastic material and with a glass covering on both sides of the material web. The Pig.T is a somewhat schematic and not to scale

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Faithful representation showing the manufacture of a round block 10 on the shaft 12 from disks 14, the ones represented by lines Alternate impermeable areas with clear parts. One end of the shaft 16 is designed as a square, which is inserted into the Chuck of a lathe, not shown, can be clamped, and furthermore the shaft is in the middle with a bore 20 for admitting steam or cooling water. The bore 20 is provided with an internal thread, by means of which a screw connection can be made with an arrangement that permits alignment of shaft 16 with respect to disks 14 during Formens made possible. A pipe 11 is attached to a fitting 13, which sits in the bore 20 and holds a sealing ring 15, which tube is provided by a provided on a top plate 46 Sliding seal 19 and a sealing ring 21 is passed and at the point of use against the effects of gravity is held by a clamping ring 23 which is provided with a gap on one side and is tightened by means of a screw can be, as a result of which the shaft 16 is prevented from sinking down into a recess on a pressure plate 54.

Steam can escape from the bore 20 of the shaft 16 and from the plate 46 through an outlet 22 is 7 / arine from the outside during molding by means of a steam housing jacket 26 supplied, the inlets and outlets of which are not shown. The round block shape 28 is lined with a polytetrafluoroethylene 30 »The round block shape 28 is attached to a base plate 40 by means of tie rods 42 and the upper plate 46 attached, which in turn is attached by means of tie rods 45 to the base of a pressing device, not shown, which has a piston 60 has. The stack consisting of the disks 14 is

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kept separated from the upper plate 46 by an insulation 48 and an upper pressure plate 50. The pressure is from below exercised by the lower pressure plate 52, which is kept separated from the stacking plate 54 by a further insulation 49, which Stamp plate 54 is also separated from the piston 60, which passes through an opening 44 on the base plate 40 via an insulating Insert 58 works. The pressure plates encircle the shaft 16 and a pin 18 prevents the lower pressure plate 52 from moving lower end of the shaft 16 slides. As part of the bottom plate 40, around the piston 60 (not shown) can be gas-tight

M means are provided »Passages can be provided on the upper plate 46 and on the lower wall of the round block mold 20, through which a vacuum can be generated and maintained during the production of a round block, if desired.

From the above it can be seen that under the action of temperatures at which the polymer of the panes 14 becomes thermoplastic, and under the action of the pressure exerted by the piston 60, the disks 14 around the shaft 12 become one Round block can be formed. The lining of the cylinder 2ö is from

™ thermoplastic polymer not wetted, so the round block can be pulled out of the cylinder as a result of the shrinkage of the polymer as it cools.

As shown in Fig.2, the in the above-described Way manufactured round block 10 in the middle of a shaft 12, which at one end with a square and a bore is provided, and which is rotated clockwise (jt'feil) by the chuck of a lathe, not shown. The other The end of the shaft is the tailstock, not shown, on the dom

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ORIGINAL INSPECTED

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Lathe mounted »The one attached to the cross slide of the support 116 Paring knife 114 is driven by the cross feed device with constant Speed horizontally in the direction of the shaft 12, so that the knife after it hits the outside of the Round block has come into contact, peel off a web with the desired thickness from the round block, which web becomes a not shown Holle is wound up · The cutting edge of the paring knife 114 must be parallel to the axis of the dog block 10 and in the same horizontal plane like this one.

An important feature of this device is the heating Λ housing 120, on the Jjänge of the round block of years and about t to 10/4 whose circumference extends to 1/2. With the aid of the heating housing 120, the outer skin of the dog block 10 may be to a temperature of about to be heated 120 to 18O ⁰ G when the block consists of cellulose acetate butyrate, can be such that the peeling-resistant and uniformly carried out without a large force is required, and without major irregularities occurring · The heating device can be regulated so that the heat can be generated that is required for a particular polymer or for a certain depth of cut. During the course of the peeling process, the heating device can be adjusted manually or automatically in such a way that a temperature that is too high or too low is counteracted. Temperatures that are too high can lead to excessive thinning of the material immediately after peeling, before the material web has cooled down or wound into a roll On the other hand, too low temperatures may cause chattering of the paring knife and uneven peeling, so that more power is required, and further, the paring knife becomes likely

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quick blunt

The heating device shown consists of an arrangement of individually adjustable heating lamps 122, of which each lamp emits 1200 watts per 30 cm length. However, other suitable heating methods can also be used. As the peeling proceeds, the distance of the round block from the heater increases, but this does not pose a problem since the heat flow is usually more than sufficient to soften the collar block on the outside to the desired degree. The heater housing 120 extends beyond the ends of the round block. There is therefore a risk that the ends and the center of the round block will be overheated. This risk is counteracted by the fact that less heat-absorbing coatings are applied to the ends of the round block, ζ radiating heat is returned. These measures equalize the temperature along the round block, so that it is heated more evenly and better material webs are produced. "Other devices can also be used for heating " provided by vapors.

Although the paring knife 114 and its holder 116 in Direction to the shaft 112 are advanced, however, that Housing 120 initially set with respect to d π round block and not moved.

The material web 130 produced by the peeling off consists

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ORlQiNAL mP

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from the alternating clear strips 132 and the opaque strips 134. The one that receives the material web The device is only intended to prevent the occurrence of slack in the web of material, with only a small amount of tension being exerted on it will. Cooling or polishing rollers or also a winding roller may be desired, with an insert film being included at the same time which prevents the still relatively hot and soft material web from sticking to itself.

The adjustment of the regulating devices can be done manually or automatically.

If a web of material 130 is produced in the manner described from a round block consisting of thin black and relatively thick clear layers, the web of material has essentially the cross-section shown in FIG black parts 134 are separated. The optical opening is represented by the angle 150 (Pig _o 3). The size of this angle can obviously be determined in such a way that either the clear parts 132 are dimensioned differently, or the thickness of the peeled-off material web is changed. The inclination of the opaque parts also influences the optical opening and the light transmission angle. With a suitable programming of a peeling machine, e.g. a powerful lathe, material webs with a changing numerical opening can be produced, ZeBo could determine the depth of the cut with the help of coolants that are arranged directly above the cutting line and change it as required »

The material web produced has depending on the used thermoplastic material and because of the fact that the

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Peeling with a knife does not produce a completely clear surface can only be used in a limited way. Except for the lengthways and small irregularities The lines generated by the cutting edge of the paring knife consist of larger or smaller irregularities because of the paring knife Complete smoothness cannot be produced * Both types of irregularities were present in those produced in this way Materials such as veneers, split leather and plastic foils, presumably always existed, but were overlooked as meaningless »

I ^{1 For} most purposes and to achieve the best optical effects, the removal of irregularities on the surface is highly desirable and necessary. If the material web or a part of the web is glued between two glass plates HO, the cross-section shown in FIG. 5 is produced. In this way, a safety glass can be produced with polyvinyl butyral as the thermoplastic of the material web. According to another method for achieving smooth surfaces, the material web is provided on both sides with a layer of the same clear thermoplastic material, so that the material has the cross-section shown in FIG having"

Another method of achieving clarity is to keep the surfaces in contact with the softening point To heat an extremely smooth and non-adhesive surface, e.g. a polyester film, which is removed again after cooling will. This process also removes a large part of the material's inherent curvature.

The following describes the manufacture of a layered sheet using cellulose acetate butyrate as the

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ORIGINAL INSPECTED

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thermoplastic material described

The primary laminate is manufactured in such a way that a film of butyrate is extruded into the in a Banbury mixer or other suitable facility 3 Grewo # carbon black is mixed in. This starting film with a thickness of 0.004 mm is then extruded with a layer of clear butyrate with a thickness of 0.25 mm.

The forming of the collar block is done with the help of a cylinder carried out, which is provided with a lining made of polytetra- ^ fluoroethylene and an inner diameter of 255.47 mm which Eundblock is molded on a shaft with an outer diameter of 63.5 mm. The primary laminate becomes Punched out discs with an outside diameter of 254.96 mm and an opening in the middle and 63.65 mm wide, so that there is a clearance of 0.51 mm at the outer edge and a clearance of 0.15 mm at the central opening. Usually be three discs punched out at once. It is important to have sufficient clearance so that the slices reach the The walls of the facility do not get stuck and tilt. I The discs stretch excessively under the action of heat strong, discs with a smaller outer diameter and larger holes in the center must be used. The at Waste that arises from punching out the panes can be processed into a new black film with the addition of carbon black.

After a sufficient supply of slices has been punched out, these are heated in stacks of about 80 to 200 pieces in an oven with a draft for four or more hours to a temperature of about 65 ⁰ O to remove moisture and other volatile substances

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Expelling substances, also eliminating the weak curvature which is a consequence of keeping the primary laminate in the form of rolls < >

The 92 cm long shaft consists of a hollow shaft. This wave can also be designed so that in this steam or Cooling water can be admitted, as shown in Fig.1. The shaft is attached to the lower plates in a vertical position « The disks that have been taken out of the drying oven and are still hot are placed on the shaft and by hand or through A set a stream of air in rapid rotation to Prendetoffe and to remove the punching residue, especially at the center holes. The discs are placed on the shaft as flat as possible. Irregularities in the panes are also compensated for, z «B · strips of greater or lesser thickness running in the longitudinal direction of the lumps of the primary laminate get lost. In the device according to Figure 1, the discs starting from the weight of the sci.oiben 14 itself and the top plate 46 compressed, which presses against the lower pressure plate 52 and the pin 18. Here, the shaft 16 is pushed through the stack of disks lifted through as high as possible and held in this position with the help of the clamping ring 23

As already described, the round block shape is cylindrical designed and with an inner lining made of polytetrafluoroethylene Mistake. The end of the mold is provided with means that keep the pressure exerted on the shaft low, and also aluminum disks are provided, which are supported by the Caps provided with recesses are thermally insulated, through which the pressure is transmitted to the round block. If desired, can the mold closed and pressed to a pressure of about 10 em Hg evacuated while the round block is being formed.

109842/1752 original hispegted

With the aid of a hydraulic press, ^{a mechanical pressure of approximately 2 atm is exerted on the stack of discs at a temperature of approximately 50 °} C. (the remaining temperature of the discs after drying) and is maintained during the subsequent processing until the shaped round block finally extends so far has cooled down so that it can be removed from the mold. "At the same time as the hydraulic pressure is exerted, a pressure steam (95 G) is let into the heating jacket and the shaft." This temperature of 95 ° C is maintained for 6 hours, after which the ^{Temperature is increased to HO 0} G for a further 6 hours, until the individual discs have fused together. The heating is now stopped so that the round block can cool down for 16 hours when the hydraulic pressure is applied, at which time the temperature is about 35 -4O ⁰ O is. The round block has shrunk away from the polytetrafluoroethylene lining and can be removed from the mold. External cooling can also be provided in order to shorten the cooling time. The round block formed around the shaft is now ready to be peeled off.

The round block is in a large lathe with sufficient ä the scope for the handling of such a large workpiece used, wherein the stored one end of the shaft in the chuck and the other end in the tailstock. The holder for the peeling knife consists essentially of a steel block with the dimensions of approximately 20 cm 80 cm, which is provided on one side with a recess receiving the peeling knife, in which the knife is attached. This arrangement is stored on the lathe bed and aligned so that the peeling knife runs parallel to the axis of the lathe. Forms the top of the knife

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with the horizontal an angle of 20 °, while the front inclined back from the vertical by 8 ° · Deviations from this angle from 0 ° up to at least 50 # higher values are absolutely permissible · The cutting edge of the blade therefore encompasses an angle of approximately 50 ° to 90 °. At angles less than 45 ° the risk of damage is slightly greater. The heating housing with eight 85 cm long heating pipes (3 KVA each) is above the Round block attached and initially has a distance from this about 3 -7 cm. A winding roller is arranged parallel to the axis of the lathe and is driven with a constant torque will. >

The lathe is put into operation with a rotation of 12 rpm, while the cross feed for the peeling knife is set to 1.1 mm per rotation, but is not put into operation «. Approximately half of the heat lamps are turned on and the temperature on the outside of the round block is tracked using commercially available feeler pens which indicate temperatures by whether or not they are melting. The heating is continued without feed of Abschälmessers until the Pühlstifte a temperature of 150 ° - 160 ⁰ C show at the surface of the round block. This temperature is maintained by switching the lamps on and off, and the feed for the peeling knife is switched on. Peeling begins with the removal of high places, after which the entire width of the web of material is peeled off very quickly from the round block. The end of the web is quickly attached to the take-up roll. Peeling continues, with the cross stroke being switched off before the knife edge has approached the metallic shaft enough to damage it.

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ORIGINAL

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If the temperature of the Sundblock appears to be too high or too low, the necessary settings are made on the heating device during the peeling process. Too low temperatures lead to a rough surface and are particularly disadvantageous when very thick material webs are made, for "B ₀ with a thickness of 1 - 2 mm and more. Material webs with a thickness of about 0.05 mm are so thin that there is little interest in narrowing the optical aperture, although such webs are quite suitable for some purposes.

Small irregularities on the knife edge cause parallel longitudinal grooves on the peeled film and make the film along with other surface imperfections translucent rather than clear. As a result of peeling there is also there is a slight curvature in the material web, since with each subsequent turn of the peeled material web a slightly shorter one is linear Piece is peeled off. Although the curvature is generated in the longitudinal direction of the material web, in an attempt, this To eliminate curvature, tension is generated in the web of material, which leads to a transverse curvature of the web of material. In other words, a peeled sheet of polymeric material inherently has a curvature.

These surface effects are corrected in that the material spell is pressed between polished flat plates under a pressure of approximately 3 »5 at une at a temperature of more than approximately 130 ^° C., the softening temperature of the polymer, and is cooled in contact with the polished surface. Other methods can be used to achieve a smooth surface, and the surface can be coated with smooth clear sheets of the same polymer or with glass, with flat sheets or

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Plates with the cross-sections shown in FIGS. 4 and 5 be generated"

In producing a web of polyvinyl butyral resin is substantially the same method with some modifications applied in the manner described above using lower temperatures during extrusion and laminating together at 93 ⁰ O primary laminates and discs are made. The polyvinyl butyral disks do not need to be dried. The round block is formed around the shaft at slightly lower temperatures using the process described.

When peeling off the round block made of polyvinyl butyral, it must first be cooled to a temperature at which this material is solid. Cooling in solid carbon dioxide for about 16 hours is more than sufficient, although such a low temperature is not absolutely necessary. The peeling is carried out in the manner described above, wherein a lower surface temperature is applied from about ⁰ 95-11O C. This sheet of material is laminated with glass by the methods generally used in the manufacture of safety glass from a polyvinyl butyral film.

Claims

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ORIGINAL INSPECTED

Claims (1)

Claims Method for producing a material web from a substantially transparent film material with an optical opening that is restricted in a linear direction and relatively has narrow opaque elements which are distributed at regular intervals across the web and do not form more than a quarter of the material web, characterized in that Ι · a one-piece cylindrical end block made of a thermoplastic Polymer is made from in the longitudinal direction regularly alternating with each other proportionally consists of thin clear and relatively thin contrasting discs, which are produced by mechanical pressure are united with each other at an elevated temperature around a shaft located in the middle, that II. The round block is rotated with the aid of the shaft mentioned, during Ä A. A knife is advanced parallel to the shaft in the direction of the hand block along the entire length at one speed which is kept essentially constant with respect to the radial speed of the round block will, and that Β · the surface of the round block in front of the contact line is heated to a temperature with the mentioned knife at the same time sufficient to soften the outer part of the round block to at least the depth in 109842/1752 that the cut will be made. ^ · * ^ Ο 2ο method according to claim 1, characterized in that the thermoplastic polymer is cellulose acetate butyrate, and that the area in front of the knife on a! Heating temperature of about 150 ° to 160 ⁰ G. 3. The method according to claim 1, characterized in that the thermoplastic polymer consists of polyvinyl butyral, and that the surface in front of the knife is ^{heated to a temperature of approximately t 95 0 0} to 100 ° g. 4ο product, characterized in that it is according to the procedure of claim 1 is made. 5ο plastic film material that is essentially transparent whose optical aperture is restricted in a linear direction, and whose face is at least from scratches thereby What is exempted is that a synthetic marriage is required to promote transparency polymeric matrix is polished, characterized by relatively narrow, opaque elements that are distributed at regular intervals across the material web and do not form more than a quarter of the width of the material web and which is continuous through at least a quarter of the thickness extend through the material web, and characterized in that, that the distance is not more than twice the distance over which the said elements extend through the material web O Ί098Α2 / 1752 Plastic film which is essentially transparent, the optical opening of which is restricted along a first linear direction in the general plane, and which is not restricted along a second linear direction which is essentially perpendicular to the said first linear direction, which film is essentially smooth ! Has surfaces that are sufficiently free of scratches and irregularities to achieve transparency, characterized by relatively narrow, parallel, opaque, blind-like elements that are arranged at regular intervals and on the surface of the mentioned % material at an angle of approximately 75 - 90 ° and are separated from one another by a transparent matrix material of at least three times the width, and characterized in that said elements extend through the sheet material over a distance which is at least equal to half the distance between bena elements is 7 # plastic film according to claim 6, characterized in that the film consists essentially of cellulose acetate butyrate. G 8 # plastic film according to claim 6, characterized in that that the film consists essentially of polyvinyl butyral. 109842/1752 Blank page