JPH04500933A - Method for producing biaxially oriented polymer sheet and sheet produced by the method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Method for producing biaxially stretched polymer products and products produced by the method] Honkaidan Koyogetsu The present invention provides a method for manufacturing biaxially oriented polymer products and the method for manufacturing biaxially oriented polymer products. Regarding products. More specifically, the present invention relates to a feedstock of polymers. by continuous forging, in which the bar is advanced between a pair of opposing belts. It provides instructions on how to manufacture such products.

Biaxially oriented polypropylene polymers, such as those sold under the trade name BEXOR. The polymer has higher strength and improved stiffness compared to unstretched polymers. It has many advantages, including increased toughness and better thermoplasticity.

Biaxially oriented polymers are a technique disclosed by U.S. Pat. No. 4,282,277. It has been successfully manufactured by. This patent is owned by the inventor of this invention. , the disclosure of which is incorporated herein by reference. According to this patent For example, a tube is first formed by hydraulic extrusion using a mandrel in combination with a conical die. A shaped product is produced. This tubular product is then cut, flattened, and molded. Heat treated. Therefore, expensive equipment for flattening and heat treatment is used. . In the method using a mandrel-conical die, a good biaxially stretched structure can be obtained. However, in order to remove the residual curvature after the final sheet is formed, a considerable surface area is required. Transforming an extruded tube into a flat sheet that must survive tipping Even if the curvature is removed by Equilibrium stresses and strains tend to appear later, so when using sheets cause difficulty.

Still further, manufactured according to the teachings of U.S. Pat. No. 4,282,277, The cost of biaxially oriented sheets is relatively high because one billet at a time can only be extruded, and as it is intermittent production, there is no loss in production. This is because there are many. Furthermore, by properly aligning the mandrel within the die, Producing uniform sheets during the extrusion process is costly and I have come to realize that it is difficult.

Forming the tube first and then cutting and flattening the tube In order to avoid the trouble of biaxially oriented sheets, the inventors of the present invention We considered extruding the polymer in solid form using a die with protrusions on the . No. 806.994, filed December 9, 1985. is shown inside. By using the protrusions inside the flat die, the flat Non-uniformity in the die that would normally occur due to friction between the workpiece and the die is overcome. This method involves cutting and flattening to form sheets. This process also produces products one sheet at a time. It is an intermittent process and is not a continuous process. Even more so , 10,000 psi (703 kg/cm requires a very large machine that can withstand the required extrusion pressure of the order of ’) or more. shall be. As a result of actual experiments, a flat die with protrusions has a pressure of 7.000 psi. (492 kg/am”) pressure was required.In contrast, twin belt type machine The machine required only 1.200 psi (84.4 kg/am") pressure.

Flat die type machines have higher extrusion pressure than twin belt type machines, so Requires a larger initial investment.

Biaxially stretched sheets are processed by platen forging or cross rolling. However, both of these processes are batch processes and continuous processes. However, it has the disadvantage of not being a cesspool, and therefore has limitations both dimensionally and economically. approx. is large, therefore it is difficult to produce long sheet-like materials on the one hand, Furthermore, when forging sheets between mutually parallel platens, uniform biaxial stretching is achieved. In order to obtain elongation, the sheet must be manufactured from a circular blank, and Since the blank has to be trimmed, an additional step is added, Material waste occurs. Sheets manufactured by cross rolling are almost rectangular, but As a result of uneven elastic springback of the sheet emerging from the gap between the rolls and This results in a wavy surface and is therefore not necessarily suitable for subsequent processing and molding. stomach.

In addition, cross rolling has less time to deform, so the resulting elastic spring Backing will reduce desirable properties such as stiffness.

The inventors of the present invention pursued the idea of opposing belts to bind wood particles and fibers. For manufacturing something like particle board that is compressed together with a mixture and made into a sheet. We tested the use of a commonly used twin-belt heat treatment press. I discussed it. This type of process requires lower pressures than required for biaxially oriented polymers. The results of the test were unsatisfactory because the test was carried out using force. The inventors also A twin-belt type used to produce metal sheets and slabs by continuous casting. The machine was investigated. However, in continuous casting machines, the molten metal processed by it Only enough pressure is required to hold the object. this type of machine In this case, the molten material is placed in a pair of tapered arrangements. ) between the belts, spread horizontally and vertically between them, and continuously becomes a sheet metal product. Since the above methods are unsuitable, two-axis stretching To impart biaxial stretching to the feedstock to produce sheets of stretched polymer It is thought that there is no prospect of using the existing opposing belt.

Kien Mamebe I Biaxially oriented polymer products are produced by a continuous process rather than an open process. Because of the difficulties mentioned above, one of the objects of the present invention is to solve the problem. Provides a method for producing products such as by continuous forging and the products themselves. It is to be.

The present invention comprises a solid workpiece of polymeric feedstock with opposite ends. By introducing it in the axial direction between a pair of movable endless surfaces in a tapered arrangement, two The company envisions ways to produce polymer products such as axially oriented polymer sheets.

The angle between the surfaces of the polymer, which may be in the form of a belt, brings them closer together composition, surface friction, workpiece width and thickness, and workpiece temperature. Depending on many factors, the range is approximately greater than Oo and less than 6°. Ru. In this tapered zone, due to the belt surface, polymer feet Sufficient support is provided to overcome the compression deformation resistance of the stock. Fi The hard stock expands laterally and at the same time axially while its thickness is reduced. stretched in the direction. Such processes involve frictional engagement between both surfaces and the workpiece. The material is forced to advance between these surfaces and form a deformation zone as a biaxially oriented sheet. emerges from the edge at the same speed as both surfaces.

The temperature of the workpiece is determined by its glass transition temperature and viscosity while being deformed. maintained between flow temperatures, both surfaces resist the effects of surface friction and compressive flow of the polymer. is maintained under conditions that balance the internal resistances that occur. The thickness of the workpiece As soon as the workpiece has been The form is stabilized by crystallization or cross-linking so that it remains stable. is held at a temperature for a period of time long enough to

The temperature at which viscous flow occurs is higher than the glass transition temperature of the polymer. While the workpiece is being deformed and heated to a temperature level lower than During the constraint step it is desirable to maintain within that temperature range. the product is cooled or undergoes structural stabilization by crystallization or cross-linking. It is heated to make it cool.

The polymer is polypropylene, polyethylene, ultra-high molecular weight polyethylene, Acetal, polyamide, polyethylene terephthalate and polybutylene terephthalate Preferably selected from the group of semi-grade materials containing phthalates. but , polymers include poly and nyl chloride, polystyrene, polymethyl methacrylate Glue of amorphous materials including carbonate, polycarbonate and polyethylene terephthalate. It can also be selected from loops. The above polymers may also contain up to 60% by weight of carbon. Fillers such as calcium oxide, talc, mica, or alumina trihydrate Even if it is stretched, it can be biaxially stretched. Filling that makes the sheet fireproof or flame retardant Fillers containing materials, e.g. aluminum trihydrate, can be used in structural panels, e.g. For example, it is used to make aircraft interiors. Traditionally, such filled polymers Sheets made from was insufficient.

The device for carrying out the method according to the invention is a continuous one in the form of a twin belt press. 7 osing machines, which include a pair of temperature-controlled belts, and the belts are biaxially attached to the polymer in the first region. Tapered to provide elongation. This first region supports the belt and It includes a pair of opposing platens that maintain accurate belt-to-belt spacing. direction The fitted belts are then subjected to biaxial stretching by continuous forging. a second region where the belt is restrained between and stabilized between the belts; It may extend through.

Also, to produce biaxially oriented sheets, a pair of tapered belts are used in a convex shape. Supported by rollers or platen sections to impart biaxial stretching to the feedstock It has been proposed to expand feedstock continuously. child In such systems, the support system imparts a convex surface to the belt. , which reduces the effect of surface friction on the workpiece and spreads it across its width. A sheet with uniform biaxial orientation is produced.

Selecting and using profiled or flat belts is not enough In order to obtain uniform biaxial stretching in Metals, such as plastic polyesters, polyamides and polymethyl methacrylate This is a problem for polymers that have a relatively high coefficient of friction between them. In such a case, Lubrication between polymer and belt to ensure uniform spreading and biaxial stretching It is proposed to use a film. How many ways can you make such a lubricating film? For example, flow additives may be included in the polymer feedstock. In addition, a surface film of a low-friction polymer such as polyethylene is 4-500933 (5 frames) It can also be interposed between the feedstock of the mer and the belt. Possible before deformation Brush or otherwise apply a high-temperature and chemically resistant lubricant to the surface of the rimmer. May be granted.

This novel polymer sheet has a flat, semi-crystalline or amorphous surface. has a density equal to or greater than that of the original unstretched polymer from which it was made. ing. This sheet consists of uniformly distributed deformations within a matrix of deformed amorphous molecules. with deformed crystalline aggregates or with only deformed amorphous molecules. This is true across the thickness of the sheet, and the strain is virtually uniform across the sheet. Distributed throughout.

Further objects and advantages of the present invention will become apparent to those skilled in the art from reading this specification and the appended claims. If you examine the surroundings, it will become clear.

11 animals 1 kouhuang bean dumplings Various other objects, features and attendant advantages of the present invention will be apparent from the accompanying drawings. It will be better understood and at the same time appreciated if it can be considered with reference to In the drawings, the same or similar parts may be designated as the same in several views. The reference number is given by Mr. and, FIG. 1A shows a new and improved apparatus for carrying out the method according to the invention. FIG. 1B is a side view of an apparatus used to produce a biaxially oriented sheet with a textured structure. is a continuation of Figure 1A, and the sheet made with the apparatus of Figure 1A is further heat treated and FIG. 1C is a diagram showing a state in which the device is restrained while being cooled and/or cooled. FIG. 3 is a top view of the apparatus shown in FIG. A diagram showing the platen oil seal used when restraining the sheet with broken lines, FIG. 2 is a top view of a portion of FIG. A diagram showing the process of turning into a stable biaxially oriented sheet given axial stretching, Figure 3 is a cross-sectional view of Figure 1, showing the dimensions of the feedstock entering the apparatus of Figure 1. Figure 4 is a cross-sectional view of Figure 1, with the thickness exaggerated; The thickness is exaggerated to show that the film has been subjected to biaxial stretching by the apparatus shown in Figure 1. figure, Figure 5 is a cross-sectional view of Figure 1, showing the appearance of the feedstock after being subjected to biaxial stretching. A diagram showing the thickness exaggerated, FIG. 6 is a cross-sectional view of FIG. 1, in which the sheet is cooled and/or Figure 7 is a diagram showing the state of being restrained during heat treatment with exaggerated thickness. comes out of the apparatus of Figure 1 and still has the heat treatment and A sheet that has been subjected to biaxial stretching prior to cooling and/or cooling is exaggerated in thickness. The figure shown in FIG. 8 is a cross-sectional view of another embodiment of the invention, in which the belt is giving at least one belt a convex profile where it widens A diagram showing a case where a convex platen is used, as shown in FIG. FIG. 9 shows a semi-crystalline, unstretched polymer square cube before being subjected to biaxial stretching. FIG. 10 is a perspective view of the coupon of FIG. 9 after being subjected to biaxial stretching; FIG. 3 is a diagram showing that the spherical head has changed to a flat, plate-like structure.

“day” If we now turn to FIG. 1A, there is a twin A belt-type press is indicated generally by the reference numeral 10. Twin belt type At its upstream end 12, the resin 10 has a polygon generally designated by the reference numeral 11. A biaxially stretched sheet 13 is placed at the downstream end 14. Discharge. The twin belt press 10 applies biaxial stretching to the feedstock 11. The processing area 16 where the feedstock is subjected to biaxial stretching is heat treated. to restrain the sheet 13 until it is processed and/or cooled into a flat and stable sheet 13. It has a constraint area 17.

Ideally, the workpiece 11 would be placed directly in the twin-belt machine 10 of FIG. Produced upstream.

In other words, a pellet of workpiece material (not shown) is fed into an extruder (not shown). , extrude the workpiece, cool the workpiece (not shown), and cool the workpiece. () directly into a continuous twin-belt machine. As an alternative, Immediately before feeding the workpiece into the twin-belt machine, the workpiece in the form of several billets is The arc pieces 11 may be made continuous by thermally welding the ends.

The twin belt type brace 10 includes two upper rollers 21 and 23 and their upper rollers. It includes two lower rollers 24 and 26 opposite the rollers. Upper roller 2 A metal belt 28 is bent around 1 and 23, while a lower roller 24 and A belt 29 is placed around 26. Belts 28 and 29 are chrome plated Preferably made of steel, seamless, and with a hardness of at least Rotwell C45. stomach. As seen in FIG. 1A, between rollers 21 and 24 in the area of machining 16. The upper and lower platens 41 (δ1 , 42(a), the foot stock 11 is engaged with the foot stock 11 in a uniform manner.

Special Table Sen4-500933 (7) The angle a between the belts 28 and 29 in the first region 16 is approximately within the range Larger than Oo and smaller than 6″.

The optimal angle α to produce balanced biaxial stretching is determined by the feed speed of the polymer. It is a function of the thickness and width of the tok 11, the composition of the polymer, and the desired draw ratio.

0.5 inch (12.7 mm) thick, 6 inch (15.2 cm) wide polypropylene In the case of pyrene feedstock, a balanced biaxial stretching ratio of 2.2 to 2.5 is required. The angle α typically ranges from 248° to 314°. for specific materials The specific angle α to be can be obtained by an experimental program that allows the

By conventional means, rollers 21 and 24 adjust the glass transition temperature and temperature of the polymer. It is heated to a temperature between the viscous flow temperature of the dostock 11. Feedstock 1 1 also has a viscosity above the glass transition temperature before it is passed through the first region 16. It is desirable to heat the film to a temperature lower than the fluid flow temperature. If the feedstock 11 to be obtained is polypropylene, it is generally is heated to about 140-160°C, platens 41(a), 42(a) and rollers 2+ and 24 will be heated in the same way. When processing feedstock 11 The temperature increase exceeds the viscous flow temperature of polypropylene.

Relative temperatures of both surfaces and feedstock within the overall temperature range as described above. The key to controlling the temperature is to balance the surface friction and flow resistance of the polymer. One essential parameter for achieving substantially uniform biaxial stretching through the thickness is It is a meter. For example, in the case of polypropylene, both surfaces are heated to approximately 160°C and the workpiece is Substantially uniform biaxial stretching can be achieved when the base is heated to about 146°C. It is shown.

In a twin-belt machine 10, the speed of the belt is constant from the inlet end 12 to the outlet end 14. It is fixed. Therefore, the twin-belt machine 10 is capable of handling deformation of the workpiece 11. This reduces the axial sliding friction that occurs. Axial sliding friction A straight or conical die is used to force the feedstock through the die. Occurs when The frictional force occurring between the belt 28, 29 and the feedstock 11 is It is caused by spreading the feedstock polymer. this kind of friction The force is applied to the solid state by passing the foot stock 11 through a stationary die. is substantially smaller than the sliding friction that occurs when extruding at

If we now look at Figures 2-7 in relation to Figures 1A, IB and IC, there , feedstock 11 while the footstock is processed into sheet 13. The relative dimensions of are shown. As seen in Figure 3, feedstock 11 The rollers 21 and 2 have a relatively thick vertical dimension Y and a relatively narrow width X. Enter the roll gap between 4.

As the feedstock 11 advances through the region of processing 16 (Fig. 4), the dimension Y decreases. As dimension 2 increases, the backflow for both belt surfaces increases slightly. (see Fig. 2), the feedstock II increases in the processing area 16. At the end, the width of the foot stock in the X direction is 28°29. The quality is sufficient to extend completely across.

As can be seen in FIGS. 5 and 6, the feedstock 11 passes through the area of restraint 17. Do not change its dimensions while proceeding. The constraint area 17 is located in the processing area 16. Thermal treatment of the workpiece 11 after spreading in the lateral direction and reducing the vertical dimension In order to ), and the pair 41(c) and 42(cl), which are in the constraint area 17. In this case, the pair of platens 41(b), 42(b) are used for heat treating the workpiece 11. may be heated to fix the tissue in the workpiece or cooled to fix the tissue in the workpiece. . If the workpiece is a cross-linked polymer such as polypropylene, the pressure The pair of plates 41(a) and 42fa) are heated and heated to heat treat the workpiece. The Latin 41(c) and 42(c) pairs are used to stabilize the structure of the workpiece. Allow to cool. As seen in Figure 7, the feedstock 11 is a twin bell From the downstream end 14 of the press 10, a finished sheet 1 with a stable and flat shape is produced. It comes out as 3.

Biaxially oriented polymers cool relatively slowly in twin-belt machines; 6. Machines with extremely long cooling zones have limited mechanical aspects that limit the speed of production. In some cases, one unit may be replaced with a lot change because it is unfavorable from both a cost and cost perspective. Machines for shaping, heat treating and to some extent cooling, the second one is further It is better to have two machines that are low-pressure machines for long-term cooling. Probably.

Particularly, if you look at Figure B and IC diagram, there are additional heat treatments and A cooling/cooling arrangement is generally designated by the reference numeral 39. This device Immediately after leaving the twin-belt machine 10 of FIG. or other heat-treated dark roller pairs 45 and 46. and that of 47 and 48 It is restrained between belts 43 and 44 that go around each. 1 of the present invention In one preferred embodiment, belts 43 and 44 are under pressure facing each other. It is engaged with the sheet 13 by the plates 49 and 50 and the special table 14-500933 ( 8) and the platens may be heated or cooled. The platens 49 and 50 are bell oil contained within dynamic peripheral seals 54 and 55. It is supported with equal pressure on the film. The device 13 in FIG. 1B and IC diagram can be used in various cases. For example, amorphous polymers provide a flexible system that can be adapted. products may require relatively long heat treatment times; For this purpose, the platens 49 and 50 of the device 39 can be heated.

In a further embodiment of the invention, a metal foil is placed on the final sheet 13. such a putter to highlight a pattern that corresponds to the pattern above. Loop 8o of metal foil 81 with a If desired, additional belts may be inserted between the belt 29 and the feedstock.

The flat sheet 13 produced by this process and the equipment shown in Figures 1-7 is , a substantially biaxially oriented semi-crystalline or amorphous thermoplastic polymer sheet which, unlike the sheet according to U.S. Pat. No. 4,282,277, It has a substantially uniform strain throughout its thickness.

U.S. Patent Application No. 933.951, filed November 24, 1986, and Nos. 806 and 944, received on December 9, 1985, are for reference only. These patent applications are incorporated herein by reference to workpiece 11. Expanding in the X direction while pushing in the Y direction is more effective in the inner region than in the outer region. It discloses the concept of "doing more with more." The main engine shown in Figure 8 In the specific embodiment, the twin belt machine 10 has at least an upper platen 41. fa) has a convex cross-sectional shape during part of its length, and the degree of convexity gradually decreases It is deformed so that it becomes flat at the downstream end of the processing area 16. Ru. The shape of the upper platen 41(a)' in each case is It is determined by a row of distributed hydraulic jacks 51°. Lower platen 42 (a)' is preferably flat and supported by a rigid frame 75 , an endless belt 28, 29 and respective dependent platens 41(a)° and 42 During (a)', the belt should move freely on the platen (to ensure that Closely spaced rows of roller supports 96 and 97 are provided.

The final product exemplified by sheet 13, when made from a semi-crystalline polymer, A spherical knot compressed perpendicularly to the plane of the product and stretched biaxially within the plane of the product. It is characterized by having a microstructure containing aggregates of crystals. This product has a small This product does not inherently contain any process that generates grains or microfibers. possesses at least the same density as unoriented polymers, and Less permeable than products made with the solid-state stretching process.

The product represented by biaxially oriented thermoplastic sheet 13 contains up to about 60% filler by weight. I can see it. Before the advent of hydraulically extruded BEXOR, there was a significant amount of charge. It is not impossible to produce expanded thermoplastic materials containing fillers on a commercial scale. However, it was extremely difficult. a semi-crystalline thermoplastic polymer containing a filler; When processed in accordance with the present invention, the thermoplastic polymer can be used successfully as described above. The structure is different from previous products, with no micro-gap and no micro-fibers. Virtually the base is first compressed in a thermoplastic polymer in a direction perpendicular to the plane of the product. Discrete, stopper-shaped, spherical-head-shaped crystals are biaxially stretched in the plane of the sheet 13. It has crystalline aggregates.

The sheet-like product 13 may be used in its original form for construction or similar purposes or for other purposes. Although it can be used for many purposes, it is often used to create final products, e.g. solid molded products. It is used as a blank for Many solid molded products are subject to so-called stress. molded products, in which the thermoplastic polymer is exposed to sufficient heat in a die. A solid thermoplastic polymer that is shaped to deform under pressure. . The properties of the solid, stretch-formed final product depend primarily on the degree of deformation. do. However, a solid string made from a biaxially oriented sheet blank according to the present invention Retch molded products have properties that compare favorably with similar products made from unoriented thermoplastic polymers. For example, the biaxially oriented thermoplastic polymer according to the present invention has excellent properties. Stretch-molded products made from sheet blanks have a more uniform cross-sectional shape That will happen. This is because the excellent properties of oriented thermoplastic polymers This is because "necking" of the rimmer is considerably prevented. Therefore The resulting product has a more uniform stiffness than would otherwise be the case. Become. The actual properties of stretch-molded products depend on the processing applied to each location of the product. In other words, the amount of deformation varies from place to place within the product. If the product has a flange In other words, it is virtually unprocessed but has the same excellent properties as the original biaxially stretched blank. will have the following. This is extremely important for certain products. Because This is because flanges require structural strength and toughness. refrigerator freezer door liners, freezer food containers, lips around the edges of pots or transport containers In other words, flanges are a typical example of this in products. Similarly, stress in products Any area stretched during stretch forming will be higher than in the original stretched blank material. It will have certain characteristics. Therefore, the biaxial stretching plan special table according to the present invention 1,400-50,093; He (9) Products manufactured from superior to products made from unoriented thermoplastic polymers of the same composition regardless of This means that it has certain characteristics.

By way of example only, as also noted in U.S. Pat. No. 4,282,277, Isotactic used as the first polymer to form the hard stock 11 A typical structure of a polymer, polypropylene, is illustrated pictorially in FIG.

The structure of the biaxially oriented sheet is illustrated pictorially in FIG.

In the unstretched feedstock 11 shown in FIG. 9, the crystal growth is at nucleus +00 The crystal 101 with a folded chain structure moves in the radial direction until it combines with the adjacent crystal. It can be seen that they grew in the opposite direction, forming rows in a rosette-like pattern. Biaxial stretching sheet In step 13, the crystals are flattened, overlapped 1 and interlocked. are stacked together to form a layered structure.

If the polymer feedstock is polypropylene, its initial thickness is e.g. For example, if it is 0.5 inch (12.7 mm) and becomes a biaxially stretched sheet 13, the thickness will be The height will be approximately 1/10 inch (2.54 mm).

The polypropylene used has a crystallinity of about 65-70%. Feeds There is little or no change in crystallinity from Tok 11 to Sheet 13; Density measurements show that only the morphology changes.

PPMΔ, 2 for amorphous polymers such as pvc and polycarbonate Axial stretching increases impact strength by absorbing impact energy through delamination. Improved. This is because in unstretched polymers, impact energy can cause fractures or cracks. It is contrasted with being absorbed.

The immediate field of use of the products produced by the device and method according to the invention is for the production of bullets. molded products requiring excellent physical or mechanical properties, and for the electronics industry. Bunched strips for making terminal boards.

Essentially, the present invention, in its preferred embodiment, has a thickness of 0.03 inches (0.03 inches). , 76 mm) to 0.5 inch (2°7 mm), and the thickness is approximately uniform. A rectangular, relatively rigid thermoplastic sheet with a length-to-width ratio of less than about 0.04. The process is directed to the continuous production of sheets 13. The sheet is compressed It consists of composite fibers that are biaxially stretched, and the stretching ratio is essentially constant in all planes of the sheet. uniformly. Sheet 13 has high strength, stiffness, low (NA impact value and uniform thermal Essentially, the sheet 13 is a rectangular slab having extensibility properties. The tock 11 is placed between two belts 28 and 29 that are flat and tapered. The product is continuously wedge-formed in a solid state, substantially immediately after which the desired structure of the product is achieved. Both belts 28 and 29 are parallel to each other so as to have a stable biaxial stretching ratio. It is created by post-processing in the area 17. slab stock may contain up to 60% filler by weight, and the slabstock may contain up to 60% filler by weight; 28 and 29, it expands simultaneously in the transverse and longitudinal directions A structure of a biaxially oriented sheet is created in which the elongation is at least 100%.

This process can produce continuous sheets of any length. However, the flight Provides individual sheets that can be handled conveniently and, if necessary, placed for individual purposes. The sheets are cut to shorter lengths as desired, with each sheet 13 The length can be made into discrete pieces longer than 20 feet (6.1 m). The device IO is When producing discontinuous sheets 13, continue operation while billet insertion is interrupted. , maintain temperature and pressure parameters.

Sheets 13 made by the process of the invention are typically rectangular in cross-section. Yes, made of a semi-crystalline thermoplastic polymer that has been biaxially stretched in the plane of the sheet. The sheet 13 has a density equal to or greater than that of the unstretched polymer. It also has virtually no microcavities or microfibers due to the process.

As can be seen in FIG. It includes a crystalline aggregate 101 that is elongated and compressed, like a plug sphere, and its deformed crystalline aggregate 101 is The crystalline aggregates extend across the length and width of the sheet and through its thickness. It is distributed virtually uniformly throughout the country.

The sheet according to the invention is a continuous rectangular polymer sheet of substantially uniform thickness. Each sheet is made of biaxially oriented semi-crystalline thermoplastic polymer; Desirably, the density is at least equal to the density of the polymer in the unstretched state, each The sheet is virtually free of micro-cavities and microfibers caused by the process; discrete plate-like crystals formed from compressed, originally spherical aggregates The crystalline aggregates are biaxially stretched in the plane of the elongation of the sheet. ing. Each sheet is substantially uniform over its length and width and through its thickness. has a crystalline aggregate deformed to , so that the sheet is thermally stable and It has substantially constant mechanical and physical properties in all planes.

Each sheet is approximately 0.03 inches (0.76 mm) to approximately 0.5 inches (0.76 mm) thick. 12,7 mm), for example 0,05 inches (1,27 mm) to 03 inches ( 7.62 mm) is preferable, and it is preferable that it is and the ratio of thickness to width is less than about 004, e.g. 0.001 to 0.01. are desirable; these sheets are not optional except for certain desired end purposes. be made at least 20 feet (s, + m) long as a section.

The sheet may contain a filler in an amount up to 60% by weight of the sheet. Ru.

In one aspect of the invention, a rectangular, biaxially oriented sheet is formed from a thermoplastic amorphous polymer. sheets of unstretched amorphous thermoplastic polymer This amorphous sheet has a density at least equal to that of has a substantially uniform distribution of strain across its width and through its thickness, and It has virtually constant mechanical and physical properties in all planes.

For materials such as polypropylene, it is generally in the range of 1.5 to 4.0. It is believed that the stretch ratio is the most desirable. To achieve such a draw ratio, 1 Ability to maintain pressures on the order of 000 ps i (70,3 kg/cm") It is necessary to use a certain machine. Germany as a twin-belt machine By urt He1d and Edward Kusters of the Federal Republic of Although such machines on the market are capable of maintaining such pressures, , which must be modified to incorporate a high-pressure, fixed-angle inlet zone. tyrene, ultra-high molecular weight polyethylene, polypropylene, and amorphous polyvinyl Materials such as luchloride are Successfully at pressures between +000 psi (70,3 kg/cm”), the draw ratio was approximately A biaxial stretch of 2.0 is given. Under such pressure, the material is amorphous Materials like polymethyl methacrylate and polyaceter, which is a semi-crystalline material The homopolymers are also subjected to biaxial orientation.

Without further elaboration, one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. It is thought that you can get it. Accordingly, the preferred specific embodiments described below are merely examples. and in no way limit other parts of this disclosure. stomach.

In the above explanation and in the following examples, all temperatures are compensated unless otherwise noted. Uncorrected Celsius ring, all parts and percentages are given by weight.

The following is a method for forging polypropylene using a twin belt method according to the present invention. This is an example of making a biaxially stretched sheet.

Him is a slab of isotactic polypropylene produced by melt extrusion. ont 1 (cut E6023, width 13.2 cm (5.2 inches), length It was made into a 30 cm (11.8 inch) strip. The thickness of the strip is 1 ．． The strip, which was 27 cm (0,50 inches), had a density of 0.903 , crystallinity 67.8%, peaks measured by differential scanning calorimetry (D, S, C) was machined from a slab whose crystalline melting temperature was 169°C (336”F). A melt flow index value of 0.4 dgm/min was measured for the material.

Lightly scratch a 1 cm (0,39 inch) square grid pattern onto the surface of the strip. I drew Place the gridded strips in a circulating air oven for 60 minutes at the indicated temperature. Heat to 146' degrees (295 degrees Fahrenheit) and place on the lower belt of a twin-belt machine. The longitudinal centerline of the strip runs along the length of the belt and is parallel to the machine centerline. I positioned it so that The dimensions of this machine were as follows. In other words, strange The length of the shape area is 19.5cm (7, Twift), the angle of deformation is 3.14°, flat The running area is 31.0 cm (12.2 inches), the width of the belt is 66.0 cm ( 26,0 inches), the belt spacing on the supply roll is 5,8 cm (2,3 inches) ), the spacing at the exit (downstream) roll of the belt is 0.2 cm (0.08 inch). This machine has the first advantage that the parallel areas are not supported by platens. The machine was different from the one shown in the diagram.

The two strips, butted end to end, are passed through the twin belt machine described above. The belt speed at that time was 1.2 m/min (3.9 ft/m1n). The first strip comes out of the downstream roll of the machine and the second strip 0 machine that stopped the machine when the pool had been accommodated within the area parallel to the machine's deformation. When a cooled strip is removed from a machine that has been forced air cooled to room temperature, The strip is substantially uniformly biaxially stretched at the ends of the region of deformation. It was known that

As a result of measuring the grid described above, the length of the grid in the machine direction is 2.31 cm (0, 91 inches), the length of the horizontal grid was 2,00 cm (0,79 inches). Therefore, the stretch ratio in the machine direction and in the transverse direction was 1.16:1.

In this test, there was no support in the parallel region, so A relaxation of the draw ratio was observed. Have adequate belt support in parallel areas and other areas If the above example is carried out using a device similar to that described above, for example the device shown in FIG. , since this relaxation is prevented, a cooled product with the above draw ratio can be made. Ru.

Gal Same as described in Example 1 above by reducing the deformation angle from 314° to 2.48°. An experiment was conducted. As a result of measuring the grid after deformation, the grid length in the machine direction is 2.00. cm (0.79 inch), horizontal grid length is 2.33 cm (0.92 inch) h). Therefore, the machine direction and transverse stretching ratio table 1,4-50,093 3 (1j) was 086 vs. l.

From the above experiment, one of the polypropylene strips under the conditions as described. It is clear that the angle of deformation for biaxial stretching is between 314° and 248°. That's it.

After conducting the above example tests, high density polyethylene, ultra high molecular weight polyethylene, Sheets were made from polyacetal, PVc and polymethyl methacrylate.

(Fillers may also be filled with sheets of polymer, e.g. mica flakes or talc, by weight) 30 parts, or 40 parts of calcium carbonate, or flame retardant alumina trihydrate It could be made from polypropylene containing 60 parts of. ) From the above description, a person skilled in the art will easily know what are the essential characteristics of the present invention. However, the present invention may be used for various purposes and purposes without departing from the spirit and scope of the invention. Various modifications and variations may be made to suit the circumstances.

In theory, the process and equipment described above could produce sheets of any width that are flat. 9 48-inch wide sheets are versatile for transportation, storage, construction and processing machinery. This can be useful in many current situations. A 48 inch seat is 18 inches wide. They can be conveniently made from inch, 1/2 inch thick billets or blanks.

The width of the seat is limited only by mechanical constraints in belt-type equipment.

In a twin-belt type construction, the friction between the opposing belt and workpiece is wide. It exists only in the direction of the edge. This is because the workpiece is twin in the vertical direction. This is because it is being carried at the same speed as the belt. This spread, or lateral friction Reducing component forces can be accomplished in many ways. Teflon or polypro A low-friction polymeric film made of a material like pyrene is attached to both belts and the workpiece. It is inserted between the two pieces located at the entrance of the twin belt type machine. Simply feeding the films from the roll between the belts and the workpiece achieved by Dispense lubricant onto the belt and/or workpiece surface. lubricating additives can be added to the polymer itself. Ru.

The process described above proposes an equation to describe the deformation behavior of a polymer, and can be mathematically modeled by incorporating a finite element analysis method for lateral flow. is being processed. Biaxial stretching of polymers in the region of deformation of twin-belt machines It is known that the stretch ratio (B, O, R) is expressed as a function of the following parameters. There is.

B, O, R = g (W, , t, θ, λ, V,, T) where W0 = supplied Width of slab stock, λ1 = reduction in thickness after deformation, θ = wedge angle in the region of deformation, μ = coefficient of friction between belt and polymer, Vb = belt speed, T=temperature of belt and polymer.

From the above description, a person skilled in the art will easily know what are the essential characteristics of the present invention. However, the present invention may be used for various purposes and purposes without departing from the spirit and scope of the invention. Various modifications and variations may be made to suit the circumstances.

FI6.10 FI6.9 international search report

Claims (41)

[Claims] 1. A method for producing a biaxially oriented polymer product, the method comprising: They face each other, taper toward the downstream, and move endlessly. axially introducing a solid polymer feedstock between the pair of surfaces; The thickness of the material is increased by advancing the material with the surfaces as they move. By reducing the the material, thereby imparting a biaxial stretch to the material, and the feedstock imparting a biaxial stretch. While the temperature is increasing, the temperature of the feedstock and both surfaces are maintained at a temperature between the glass transition temperature of the rimmer and the viscous flow temperature; After the feedstock thickness has been reduced to the thickness of the polymer product, A step that keeps the dostock restrained for a sufficient period of time to stabilize its form and shape. A method of manufacturing a biaxially oriented polymer product comprising 2. the moving surfaces are arranged at an angle that tapers close to each other, and the angle is greater than 0°; 2. The method of claim 1, wherein the method is within an approximate range of less than 6 degrees. 3. Before starting the process, both materials are tested at the glass transition temperature and viscous flow temperature of the polymer. 2. The method of claim 1, wherein the method is heated to a temperature level between temperatures. 4. Before starting the process, both moving surfaces are tested to determine the glass transition temperature and viscosity of the polymer. 3. The method of claim 2, wherein the method is heated to a temperature level between the flow temperature. 5. 2. The method of claim 1, wherein the material is cooled during the constraining step. 6. 2. The method of claim 1, wherein the material is heated during the constraining step. 7. 2. The method of claim 1, wherein the polymer is a semi-crystalline polymer. 8. Polymers such as polypropylene, polyethylene, ultra-high molecular weight polyethylene, Liacetal, polyamide, polyethylene terephthalate and polybutylene terephthalate 8. The method of claim 7, wherein the method is selected from the group comprising phthalate. 9. 2. The method of claim 1, wherein the polymer is an amorphous material. 10. Amorphous materials include polyvinyl chloride, polymethyl methacrylate, poly selected from the group including carbonate and polyethylene terephthalate , the method according to claim 9. 11. Immediately after the step of deforming the material, the step of constraining the feedstock 2. The method of claim 1, wherein the steps are sequential. 12. For manufacturing biaxially oriented polymer sheets from polymer feedstock laws that are mutually opposite, continuous, and in at least one area This reduces the thickness of the feedstock between a pair of tapered belts. the feedstock while its thickness is reduced to that of the sheet by During the step of imparting biaxial stretching to the material and reducing the thickness of the feedstock, The feedstock temperature is determined by the glass transition temperature of the feedstock material and the viscous flow. between both belts, where the feedstock is maintained between dynamic temperatures and advances it. both bases so that the feedstock stabilizes after its thickness has been reduced. constrains the feedstock while keeping the feedstock substantially equidistant from each other, thereby , the feedstock is a sheet with a stable flat shape from the restraint step The biaxially oriented polymer sheet contains the steps of: How to manufacture. 13. The feedstock and both belts are below the glass transition temperature of the feedstock. 13. The method of claim 12, wherein the method is heated to a temperature above and below the viscous flow temperature. 14. 14. The method of claim 13, wherein the sheet is cooled while being restrained. 15. 14. The method of claim 13, wherein the sheet is heated while being restrained. 16. 14. The polymer feedstock is a semi-crystalline material according to claim 13. the method of. 17. Polycrystalline materials include polypropylene, polyethylene, and ultra-high molecular weight polyester. tyrene, polyacetal, polyamide, polyethylene terephthalate and poly 17. The person according to claim 16, selected from the group comprising butylene terephthalate. Law. 18. 14. The method of claim 13, wherein the polymer is an amorphous material. 19. Amorphous materials include polyvinyl chloride, polymethyl methacrylate, poly selected from the group including carbonate and polyethylene terephthalate 19. The method of claim 18. 20. While the feedstock moves forward, the flow between the feedstock and both belts The feedstock is as claimed, further comprising the step of controlling the temperature of the rack and both belts. 12. The method described in 12. 21. While the sheet of feedstock moves forward, both belts 13. The support according to claim 12, wherein the Method. 22. A sheet continuously produced by the process of claim 12, , rectangular in cross-section and sheet plane, made of semi-crystalline thermoplastic polymer and biaxially oriented, having a density equal to or greater than the density of the unoriented polymer; It has a microstructure that is virtually free of process-induced microcavities and microfibers. , a compressed, plug-like, crystalline collection that is biaxially stretched in the plane of the sheet's elongation. including coalescence, where the deformed crystalline aggregates extend over the length and width of the sheet. and is substantially uniformly distributed throughout the thickness of the sheet. 23. The thickness of the sheet is greater than approximately 0.0762 cm and less than approximately 1.27 cm. the thickness to width ratio is less than about 0.04 and the length is at least 6.0 m; The sheet according to claim 22. 24. containing fillers, the amount of which is up to 60% by weight of the sheet; The sheet according to claim 23. 25. 13. A sheet continuously produced by the method of claim 12, comprising: It is made of a plastic amorphous polymer, has a rectangular shape, and is biaxially stretched. It has a density at least equal to that of the crystalline thermoplastic polymer, and the sheet length and The strain is distributed substantially uniformly across the width and thickness, and sheet whose mechanical and physical properties are substantially constant in all planes. 26. The thickness of the sheet is greater than approximately 0.0762 cm and less than approximately 1.27 cm. the thickness to width ratio is less than about 0.04 and the length is at least 6.0 m; The sheet according to claim 25. 27. containing fillers, the amount of which is up to 60% by weight of the sheet; The sheet according to claim 25. 28. A method for producing biaxially oriented polymer sheets from unoriented feedstock. There it is, A pair of continuous belts facing each other and having inner and outer surfaces form a flap. It has a region for stretching the feedstock and a region for stabilizing the feedstock. The stretching region is supported upstream of the stabilizing region and is They taper in the region and become parallel to each other in the region of stabilization. The feedstock is passed between the pair of belts, and both belts are supported by a pair of platens facing each other and tapering in the area of While the feedstock is in the drawing area, a pair of opposing platens are Fix the positional relationship, While applying biaxial stretching to the feedstock, the gap between the feedstock and the belt must be In addition to controlling friction, the temperature of the feedstock Both belts and feeds are maintained between the glass transition temperature and the viscous flow temperature. Control the temperature of the tok, In order to stabilize the shaped, biaxially oriented sheet in the region of stretching, controlling the temperature of both belts in the region of A method of manufacturing a biaxially oriented polymer sheet. 29. Polymer sheets manufactured continuously, rectangular in shape, and of substantially uniform thickness. comprising a semi-crystalline thermoplastic polymer with biaxial orientation, and in an unstretched state. has a density at least equivalent to that of the polymer at It has a microstructure that is virtually free of fibers and microfibers, and has a compressed original structure. It contains dissociated, plate-like crystalline aggregates formed from spheroidal aggregates. , these crystalline aggregates are biaxially stretched in the plane of sheet elongation, and The crystalline aggregates form substantially throughout the length and width of the sheet and through its thickness. mechanical and physical properties in all planes by being uniformly deformed to A sheet of thermally stable polymer that has a substantially constant value. 30. The thickness is within the range of 0.0762 to 1.27 cm, with the minimum thickness to width ratio. 29. within a range of about 0.04 and has a length of at least 6.0 m. Sheet listed in. 31. containing fillers, the amount of which is up to 60% by weight of the sheet; The sheet according to claim 29. 32. Contains a thermoplastic amorphous polymer produced continuously and rectangular in shape A polymer sheet that is biaxially oriented and has a density equal to or less than that of an unoriented thermoplastic polymer. of similar density across the length and width of the sheet and through its thickness. Virtually uniform strain distribution and mechanical and physical A polymer sheet with substantially constant physical properties. 33. The thickness is greater than approximately 0.762 cm, but less than approximately 1.27 cm, and the thickness and width is about 0.04, and the length is at least 6.0 m. The sheet according to item 32. 34. containing fillers, the amount of which is up to 60% by weight of the sheet; The sheet according to claim 32. 35. Each discrete sheet produced in a continuous process has a length greater than about 6.0 m. has a substantially uniform thickness, is rectangular on each side, is biaxially stretched, and is semi-solid. Contains a crystalline thermoplastic polymer with a density at least equivalent to that of the unoriented polymer. microfibers and contains virtually no process-induced microcavities or microfibers. Discrete and plate-like structures that have a black tissue and that arise from compressed condylar aggregates. The crystalline aggregates have two axes in the plane of the elongation of the sheet. The crystalline aggregates are stretched over the length and width of the sheet. Also, by being deformed and distributed substantially uniformly throughout the thickness, all A thermally stable sheet with constant mechanical and physical properties in the plane of 36. The thickness is within the range of 0.0762 to 1.27 cm, and the width is approximately 36.5 cm. 152.4 cm, with a minimum thickness-to-width ratio of approximately 0.04. The sheet according to claim 35. 37. containing fillers, the amount of which is up to 60% by weight of the sheet; The sheet according to claim 36. 38. Each discrete sheet produced in a continuous process has a length greater than about 6.0 m. a biaxially oriented thermoplastic material having a substantially uniform thickness and a rectangular surface. containing an amorphous polymer, the density of the unstretched amorphous thermoplastic polymer and at least It has comparable density and is substantially The strain is uniformly distributed in the plane, and the mechanical and physical properties are realized in all planes. A sheet that is qualitatively constant. 39. In each sheet, the thickness is greater than 0.0762 cm and approximately 1.27 cm. 39. The sheet of claim 38, wherein the minimum thickness to width ratio is about 0.04. To. 40. Each sheet contains filler, the amount of which is up to 60% of the sheet by weight. The sheet according to claim 39. 41. From a solid workpiece made of semi-crystalline polymer material, biaxially oriented poly A method for producing a mersheet, the method having an inner portion and an outer portion, the method comprising: The workpiece has a first lateral dimension extending in a first lateral direction and a first inspection direction. dimension is a second lateral dimension extending in a second lateral direction in a perpendicular direction; a longitudinal dimension extending longitudinally perpendicular to both the first and second transverse dimensions; and the method has the following steps: Two machining surfaces that are continuous, i.e. straight, from an upstream location to a downward tapering closer to each other as they go to the downstream locations, and between them However, when the workpiece passes through it, the inner part is more sensitive than the outer part. The workpiece is then It involves machining a workpiece while passing it through a As the base is advanced, the material of the workpiece changes in a first lateral dimension. The material flows vertically while simultaneously decreasing and expanding the second lateral dimension, making the material continuous. Generally, the inner part is pushed in more than the outer part, so the half Friction between the crystalline polymer material and the working surface is reduced, thereby reducing the The base is stretched in two directions to produce a biaxially oriented polymer sheet. Law.