Two-channel extrusion die for Mooney correction using pressure flow.

Abstract

Providing a two-channel extrusion die for Mooney correction having a novel structure. 【Solution means】A two-channel extrusion die for Mooney correction for obtaining the true shear viscosity of a resin, comprising a cylindrical body; and two channels, each of which is circular and has a constant cross-sectional area, and extends linearly over the entire length of the channel along the longitudinal direction of the cylindrical body. The large channel A has a longitudinal length L A and a cross-sectional diameter D A and the small channel B has a longitudinal length L along the longitudinal direction B and a cross-sectional diameter D B When it has, all of the three relational expressions (i) L A > L B , (ii) D A > D B and (iii) L A / D A = L B / D B are satisfied, whereby a two-channel extrusion die is disclosed in which each of the two channels is equally placed under a predetermined pressure head from the inlet to the outlet of the channel during the extrusion operation of the resin fluid.

Description

[Technical Field]

[0001] This invention relates to the field of Mooney correction, that is, correction of the wall-slip effect in the measurement of rheological properties using a rheometer. Specifically, this invention relates to a two-channel extrusion die using pressure flow, which is used to perform Mooney correction in the measurement of rheological properties using a rheometer. [Background technology]

[0002] The shear viscosity of a polymer molten material (in a flowing or viscoelastic state) is an essential physical property required for designing formulations, defining mold geometry, and setting processing details. To obtain true shear viscosity, Mooney correction is required for viscosity measurement. This correction requires two or more dies with identical L / D ratios, tested by a rheometer under the same pressure head. (Hereafter, the term "flowing state" encompasses the meaning of "viscoelastic state.")

[0003] Mooney correction has been commonly used to measure wall-slip viscosity for wall-slip materials such as HDPE and PVC resins. The Mooney correction model is based on the assumption that a material with a constant wall-slip viscosity Vs slips at the walls within the model. Typically, Mooney correction has been applied to the geometry of slit dies and rotational rheometers.

[0004] The following description of conventional methods focuses on the analysis of capillary die extrusion rheometry data for measuring slip velocity, as originally proposed by Mooney. In rheology theory, fluids are usually assumed to satisfy the "no-slip condition" (shear rate at the wall is zero) with respect to the wall. However, when the shear rate is large, the phenomenon that the polymer melt flows smoothly near the wall / the phenomenon that the shear rate at the wall changes greatly (the shear rate increases significantly because it was originally zero) is often observed. The term representing this phenomenon is "slip". That is, the term "slip" means a large shear rate change near the wall. This phenomenon is considered to occur either by the generation of a thin high-shear layer when the wall velocity is zero or by the wall velocity becoming non-zero. For example, when low-viscosity components accumulate near the wall, even if the no-slip condition is not broken / even if the shear rate at the wall is zero, a thin high-shear layer of low-viscosity components (high shear because of low viscosity and thin layer due to quantity relationship) is generated, and slip occurs. Alternatively, for example, when additives such as slip agents accumulate near the wall, the no-slip condition is broken / the shear rate at the wall becomes non-zero, and literally, slip occurs.

[0005] Slip flow can be modeled by adding the slip flow velocity to the velocity profile of shear flow, and this slip layer is assumed to be able to support the shear stress required to generate shear flow. The composite volume flow rate, shear volume flow rate, and slip volume flow rate of the fluid are denoted as Q T 、Q shear and Q slip respectively. Then the following relational expression holds. Q T = Q shear + Q slip Here, the fluid is assumed to be incompressible. For the flow in a capillary die with radius R, the slip flow rate Q slip is given by the following formula (where V s is the slip velocity). Q slip = V s πR 2

[0006] Shear viscosity η is defined as the ratio of shear stress τ to shear rate γ' and is given by the following equation. η = τ / γ' The power-law model for shear viscosity can be expressed as follows: η = Kγ' n-1 In the formula, K and n are predetermined constants.

[0007] For power-law fluids, the true wall shear velocity γ' for the flow in a cylindrical die. w According to the research by Brydson and Rabinowitsch, it is given by the following formula: γ' w = [(3n+1) / 4n]*(4Q / πR 3 )

[0008] Using these formulas, we can derive the following equation for the overall flow rate in the presence of slip. Q T = [nπR 3 / (3n+1)]*[τ w / K] 1 / n + V s πR 2 In the formula, τ w This is the wall shear stress. This equation is given by the slip velocity V s This means that the shape of the plot is determined by its dependence on the wall shear stress.

[0009] According to the work of Lupton and Register, the above equation can be rewritten as follows: 4th Quarter T / πR 3 = [4n / (3n+1)]*[τ w / K] 1 / n + 4V s / R Assuming that the wall shear stress is constant and that n and K do not change with the flow rate, the above equation can be simply rewritten as follows. 4th Quarter T / πR 3 = <predetermined constant> + 4V s / R This equation gives the apparent wall shear rate 4Q for a given wall stress. T / πR 3 The plot of 1 / R is 4V s This means that it has a slope, and that the slip velocity can be determined by it.

[0010] In conventional techniques, the fluid slip velocity can be determined according to the following steps: i) In accordance with ISO 11443, measure the behavior of the relationship between the shear stress and apparent shear rate of the material in question using a set of at least two dies having different diameters, thereby generating one flow curve for each diameter; ii) A step of determining multiple apparent shear rates corresponding to multiple shear stress values ​​selected for the diameter of each die by interpolation; iii) For each selected shear stress, plot the interpolated apparent shear rate against the reciprocal of the die radius, thereby determining the slope of the linear plot to the data; and iv) A step of calculating the slip velocity by dividing the slope in iii) above by 4. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 4-212042 [Patent Document 2] Special Publication No. 2015-522162 [Overview of the project] [Problems that the invention aims to solve]

[0012] The Mooney correction, traditionally used to determine the wall-slip rate of wall-slip materials, requires two or more dies with the same L / D ratio to be subjected to rheometer testing under the same pressure head. Testing with multiple dies in this manner requires not only multiple dies but also multiple test cycles. Disadvantageously, such traditional methods are also time-consuming processes. Furthermore, it is extremely difficult to maintain the same pressure head when operating two or more channels separately, making it challenging to keep two different flow channels under the same shear stress in a standard capillary rheometer. In other words, since most rheometers are shear-speed controlled, it is not possible to reliably perform multiple tests under exactly the same shear stress when using conventionally used capillary rheometers. In such cases, the shear rate value must be estimated for multiple points at the same shear stress using a flow curve or viscosity model. This process involves more test operations (at least two flow tests) and the associated data processing. Therefore, as mentioned above, another disadvantage exists: complex data processing is required to simulate the shear rate at a given shear stress. Furthermore, this requires an investment in an expensive rheometer and multiple dies. [Means for solving the problem]

[0013] The inventors have found that by using a two-channel extrusion die having a specific structure, the aforementioned drawbacks caused by conventional methods for Mooney correction (typically using a general capillary rheometer) can be overcome, and that it is possible to place two flow channels under exactly the same pressure head ΔP without separating and operating two or more channels, and without the need for complex data processing, thus completing the present invention. The two channels of the die are manufactured to have the same L / D value and can be placed under the same shear stress (i.e., under the conditions required by Mooney's theory). The two-channel extrusion die can significantly simplify the method of performing Mooney correction to obtain true shear viscosity.

[0014] A preferred embodiment of the present invention is as follows: A two-channel extrusion die for Mooney correction to determine the true shear viscosity of a resin, This two-channel extrusion die is - Cylindrical body; - There are two channels, Each of the two channels has a circular and constant cross-section, and extends linearly along the longitudinal direction of the cylindrical body throughout the entire channel. Two channels, both of which have inlets located in a plane perpendicular to the longitudinal direction of the cylindrical body; and, - Protrusions that fit into the extruder Includes, One of the two channels, the large channel A, has a longitudinal length L along the longitudinal direction of the cylindrical body. A , and the diameter D of the cross-section perpendicular to the longitudinal direction A The small channel B, which is one of the two channels, has a longitudinal length L along the longitudinal direction of the cylindrical body. B , and the diameter D of the cross-section perpendicular to the longitudinal direction BWhen this is the case, all three of the following relations (i), (ii), and (iii) are satisfied, so that each of the two channels is equally placed under a given pressure head from the channel inlet to the outlet during the fluid extrusion operation of the resin by the two-channel extrusion die. A two-channel extrusion die for Mooney correction. (i) L A > L B (ii) D A > D B (iii) L A / D A = L B / D B [Effects of the Invention]

[0015] By using the two-channel extrusion die of the present invention, the operator generates pressure flows in two channels under the same pressure head, thereby creating the same shear pressure for two channels with the same L / D ratio but different diameters. By using such a two-channel extrusion die setup, the operator can apply Mooney correction in a single extrusion operation without the need to change dies or perform complex data processing. Advantageously, by simply using this simple two-channel extrusion die, shear rate information under the same shear stress can be obtained directly, without performing any complex data simulations from multiple tests to find the same shear stress point. In other words, this two-channel extrusion die yields unexpected advantages, as shown below: 1) This provides an easy and quick method for applying Mooney correction to obtain true shear viscosity. 2) Since there is no need to use a conventional rheometer which involves performing multiple tests using multiple dies, the operating cost can be significantly reduced. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a plan view and a cross-sectional view taken along line A-A' of a preferred embodiment of a two-channel extrusion die. [Figure 2] Figure 2 is a perspective view of a preferred embodiment of a two-channel extrusion die. [Figure 3] Figure 3 is a plan view and a cross-sectional view along line A-A' of the two channels (large channel A and small channel B) formed in a preferred embodiment of a two-channel extrusion die. [Figure 4] Figure 4 is a plan view of another preferred embodiment of a two-channel extrusion die. [Figure 5] Figure 5 is a front perspective view of two types of 2-channel extrusion dies used in the embodiment, where one of these 2-channel extrusion dies (on the left in the figure) has a large channel and a small channel, each having a smaller diameter than the large channel and small channel diameters of the other 2-channel extrusion die (on the right in the figure). [Figure 6] Figure 6(a) is a bottom perspective view of each of the two types of 2-channel extrusion dies used in the embodiment. Figure 6(b) is a front view of each of the two types of 2-channel extrusion dies used in the embodiment. Figure 6(c) is a top view of each of the two types of 2-channel extrusion dies used in the embodiment. [Modes for carrying out the invention]

[0017] The following explanation is provided in conjunction with the drawings to aid in understanding the teachings described herein. The following discussion focuses on specific embodiments and examples of these teachings. However, this focus is provided to aid in explaining these teachings and should not be interpreted as limiting the scope or applicability of these teachings.

[0018] For the purposes of the following description, the embodiments provided by this disclosure should be understood, unless otherwise specified, to be capable of various alternative modifications and sequences of steps. Furthermore, except in the examples, and unless otherwise specified, all numerical values ​​expressing quantities of materials used in this specification and the claims should be understood, in all cases, to be modified by the term “approximately.” Although the ranges of numerical values ​​and parameters defining the broad scope of the invention are approximate, the numerical values ​​described in specific examples are reported as accurately as possible. However, any numerical value inherently contains some degree of error as a necessary consequence of the standard deviation found in their individual test measurements. In this application, the use of “or” should be understood to mean “and / or” unless otherwise specified (although there may be cases where “and / or” is used explicitly). When used herein, the term “including” or similar terms should be understood to mean “including, but not limited to,…” as intended to be an unrestricted, open scope.

[0019] A preferred embodiment of a two-channel extrusion die for Mooney correction according to the present invention is illustrated in Figures 1 and 2. This is merely an example, and the present invention should not be limited to the specific structure shown in these drawings. In particular, all dimensions described below can be appropriately adjusted and controlled depending on various factors, such as the size of the extruder and the type of polymer to be treated.

[0020] The upper part of Figure 1 is a plan view of the Mooney-corrected two-channel extrude die (10), and the lower part of Figure 1 is a cross-sectional view of the two-channel extrude die (10) along line A-A'. Figure 2 is a perspective view of the external appearance of the two-channel extrude die (10) illustrated in Figure 1. In Figure 1, the Mooney-corrected two-channel extrude die (10) comprises an elongated cylindrical body (1), a protrusion (2) that can be fitted into a resin fluid extruder, and a larger longitudinal length L A and larger diameter D AA large channel (3A) having a smaller longitudinal length L B and smaller diameter D B It includes a small channel (3B) having the following characteristics. Typically, the cylindrical body (1) has a substantially cylindrical contour in its entirety, as shown in Figures 1 and 2, but it may have a non-cylindrical contour in part.

[0021] Both the large channel A and the small channel B have substantially circular and substantially constant cross-sections and extend linearly along the longitudinal direction of the cylindrical body (1) throughout the channel. In other words, the large channel A has an inlet (3A i ) from the outlet (3A o It extends linearly to the inlet (3B), and small channel B is located at the inlet (3B i ) from the outlet (3B o It extends linearly to (see Figures 1 and 2). The longitudinal direction of the large channel (3A) and the longitudinal direction of the small channel (3B) are substantially parallel to each other. The inlet of the large channel (3A) (3A i ) and the inlet for the small channel (3B) (3B i Both of these are located in a plane substantially perpendicular to the longitudinal direction of the cylindrical body (1). Due to this structural feature, the inlet (3A) of the large channel (3A) of the resin fluid extruded from the extruder i The physical conditions at ) are the injection port (3B) of the resin fluid extruded from the extruder into the small channel (3B) i The physical conditions at the two inlet locations can be perfectly matched. This perfect match of physical conditions at the two inlet locations creates identical shear stresses, which can contribute to accurately performing Mooney correction and determining the slip velocity.

[0022] The reference numeral F shown in Figure 1 represents the flow direction of the resin fluid as it is extruded from the extruder into the large channel (3A) and the small channel (3B). The extruded resin flows through the large channel (3A) and the inlet (3A i ) from the outlet (3A o) to the inlet (3B) in the small channel (3B) i ) from the outlet (3B o ) can be advanced simultaneously.

[0023] The protrusion (2) provided around the upstream end of the cylindrical body (1) is not particularly limited as long as it can be adapted to the extruder and does not obstruct the extrusion operation. As illustrated in Figure 1, the protrusion (2) may have, for example, an annular projection, so that the outer circumference of the projection can adapt to the inner surface of the extruder. The protrusion (2) may further have an annular portion that protrudes outward from the periphery on the boundary with the cylindrical body (1). A device for measuring the temperature and / or pressure of the fluid extruded using a two-channel extrusion die may be connected to the cylindrical body (1) at a predetermined position (5). This measuring device can be installed at a position (5) where it can come into contact with the fluid (when the fluid is extruded and flows). The measuring device may have an indicator. A hole or space for mounting the measuring device may be formed at the position (5) where the measuring device is connected. The position (5) may be for mounting a pressure transducer. Such pressure transducers (if provided) are required to be located at the position of a common reservoir to apply the same pressure to both the large and small channels.

[0024] As illustrated in Figures 1 and 2, a semi-cylindrical protrusion (4) may be provided at the downstream end of the cylindrical body (1). When this is provided, the large channel (3A) passes through the semi-cylindrical protrusion (4) and the outlet (3A) of the large channel (3A) o ) will be located on the downstream surface of the semi-cylindrical protrusion (4).

[0025] The large channel (3A) and small channel (3B) of the 2-channel extrusion die (10) are required to satisfy all three of the following relationships (i), (ii), and (iii). (i) L A > L B (ii) D A > D B (iii) L A / D A = L B / D B Here, the large channel (3A) has a longitudinal length L along the longitudinal direction of the cylindrical body (1) A , and a diameter D of a cross-section perpendicular to the longitudinal direction A , and the small channel (3B) has a longitudinal length L along the longitudinal direction of the cylindrical body (1) B , and a diameter D of a cross-section perpendicular to the longitudinal direction B . Assume this is the case. The upper diagram in FIG. 3 is a plan view of the large channel (3A) and the small channel (3B). The lower diagram in FIG. 3 is a cross-sectional view taken along the line A-A' of the large channel (3A) and the small channel (3B). In the preferred embodiment shown in FIG. 3, the large channel (3A) has a longitudinal length L from the inlet 3A i to the outlet 3A O and a constant diameter D A and extends linearly. Similarly, the small channel (3B) has a longitudinal length L from the inlet 3B A to the outlet 3B i and a constant diameter D O and extends linearly. B and a constant diameter D B .

[0026] When all three relational expressions (i), (ii), and (iii) are satisfied, the two channels (3A, 3B) will each be equally placed under a given pressure head from the inlet (3A i or 3B i ) of the channel (3A or 3B) to the outlet (3A o or 3B o ). The two-channel extrusion die (10) has an equal L / D ratio (i.e., L A / D A =L B / D B ), but different diameters (D A , DB ) can create the same shear stress for two channels (3A, 3B) of different sizes, so that, without the need to replace the die and without any complex data processing, an operator can apply the Mooney correction by simply performing a single extrusion operation. As a result, there is no need to conduct multiple tests with multiple dies using an ordinary rheometer, thus providing an easy and rapid method for accurately applying the Mooney correction to obtain the true shear viscosity, and also achieving a great advantage of reducing the operation cost.

[0027] In the relationship between the longitudinal lengths of the two channels, although not particularly limited, L A is usually 1.1*L B or more and 2.0*L B or less. In a preferred embodiment, L A is 1.1*L B or more and 1.9*L B or less, 1.1*L B or more and 1.8*L B or less, 1.1*L B or more and 1.7*L B or less, 1.1*L B or more and 1.6*L B or less, 1.1*L B or more and 1.5*L B or less, 1.1*L B or more and 1.4*L B or less, 1.1*L B or more and 1.3*L B or less, or 1.1*L B or more and 1.2*L B or less.

[0028] In the relationship between the diameters of the two channels, although not particularly limited, D A is usually 1.1*D B or more and 2.0*D B or less. In a preferred embodiment, D A is 1.1*D B or more and 1.9*D B or less, 1.1*D B or more and 1.8*DB Below, 1.1*D B More than 1.7*D B Below, 1.1*D B More than 1.6*D B Below, 1.1*D B More than 1.5*D B Below, 1.1*D B More than 1.4*D B Below, 1.1*D B More than 1.3*D B The following, or 1.1*D B More than 1.2*D B The following is acceptable: One of these usual and preferred ranges in the relationship between the diameters of the two channels can be combined with one of the above usual and preferred ranges in the relationship between the longitudinal lengths of the two channels.

[0029] Regarding the ratio of the length to the diameter in each of the two channels, L A / D A and L B / D B Each of these may typically be between 5 and 50. In a preferred embodiment, L A / D A and L B / D B These may be 5 to 45, 5 to 40, 5 to 35, 5 to 30, 10 to 50, 10 to 45, 10 to 40, 10 to 35, 10 to 30, 15 to 50, 15 to 45, 15 to 40, 15 to 35, 15 to 30, 20 to 50, 20 to 45, 20 to 45, 20 to 35, or 20 to 30.

[0030] In the preferred embodiment shown in Figure 4, the endpoint (end point) of the center line C1 of the large channel (3A) extending along the longitudinal direction of the cylindrical body (1), i.e., the outlet (3A) of the large channel (3A) oThe center of the circle forming the small channel (3B), and the endpoint (end point) of the center line C2 of the small channel (3B) extending along the longitudinal direction of the cylindrical body (1), i.e., the outlet (3B) of the small channel (3B) o The centers of the circles forming the two channels are each located equidistant from the endpoint (end point) of the centerline of the cylindrical body (1) in a cross section perpendicular to the longitudinal direction of the cylindrical body (1) of the two-channel extrusion die (10). When each of the large channel (3A) and the small channel (3B) extends perfectly parallel and linearly along the longitudinal direction of the cylindrical body (1), the starting point of the centerline C1 of the large channel (3A) extending along the longitudinal direction of the cylindrical body (1), i.e., the inlet (3A) of the large channel (3A) i The center of the circle forming the small channel (3B), and the starting point of the center line C2 of the small channel (3B) extending along the longitudinal direction of the cylindrical body (1), i.e., the inlet (3B) of the small channel (3B) i The centers of the circles forming the two channels are each located equidistant from the endpoint (end point) of the centerline of the cylindrical body (1) in a cross section perpendicular to the longitudinal direction of the cylindrical body (1) of the two-channel extrusion die (10). This means that the distance S1 between the center of the large channel (3A) and the center of the cylindrical body (1) is equal to the distance S2 between the center of the small channel (3B) and the center of the cylindrical body (1). Due to these structural features, the inlet (3A) of the large channel (3A) i The physical conditions of the extruded resin flow at the small channel (3B) injection port (3B i This allows for a perfect match to the physical conditions of the extruded resin flow, creating identical shear stresses, which in turn enables more accurate Mooney correction and determination of the slip velocity.

[0031] The material forming the two-channel extrusion die is not particularly limited, as long as it has sufficient hardness to perform the extrusion operation of the resin fluid for Mooney correction. Any known material can be used to form the die. For example, the material may contain, in addition to iron (Fe), one or more elements selected from carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), copper (Cu), nickel (Ni), chromium (Cr), molybdenum (Mo), vanadium (V), nitrogen (N), oxygen (O), and aluminum (Al) in proportions adjusted as needed.

[0032] The type of resin extruded by the two-channel extrusion die (10) is not particularly limited, as long as the resin flow can maintain a fluid state when subjected to the extrusion operation by the die connected to the extruder. The extruded resin may be a thermoplastic resin, which is typically a crystalline thermoplastic resin or an amorphous thermoplastic resin. Examples of thermoplastic resins, though not limited to them, include: polyolefin resins such as polyethylene resin and polypropylene resin; polyamide resins (PA resins) such as polyamide 6, polyamide 66, and metaxylylenediamine polyamide (MXD6); polyoxymethylene (polyacetal, POM) resin; polyester resins such as polyethylene terephthalate (PET) resin and polybutylene terephthalate (PBT) resin; polyphenylene sulfide resin; styrene resins such as polystyrene resin, ABS resin, AES resin, and AS resin; methacrylic resin; polycarbonate resin (PC resin); modified polyphenylene ether (PPE) resin; polysulfone resin; polyethersulfone resin; polyarylate resin; polyetherimide resin; polyamideimide resin; polyimide resin; polyetherketone resin; polyetheretherketone resin; polyester carbonate resin; and liquid crystal polymers.

[0033] The type of extruder that can be connected to the 2-channel extrusion die (10) is not particularly limited. Any known extruder can be selected depending on the type of resin to be extruded and other extrusion conditions. The extruder may be a single-screw extruder or a twin-screw extruder. Two or more such extruders may be used in conjunction with each other.

[0034] Mooney correction can typically be performed by using a two-channel extrusion die (10) to determine the true shear viscosity of the resin by performing the following five steps: (1) The step of extruding the resin fluid from the large channel (3A) and the small channel (3B) through a two-channel extrusion die (10) connected to the extruder, thereby recovering the extruded material A from the large channel (3A) and the extruded material B from the small channel (3B); (2) A step of measuring the weight A of extruded A and the weight B of extruded B (where each weight is measured as weight per unit time); (3) A step of calculating the apparent shear rate A from weight A and the apparent shear rate B from weight B; (4) A step of applying Mooney corrections to apparent shear rates A and B, thereby determining the fluid slip rate; and (5) A step of calculating the true shear viscosity from the fluid slip velocity.

[0035] In a preferred additional embodiment, a two-channel extrusion die for Mooney correction includes an extrusion die having three or more channels with the same length-to-diameter ratio for Mooney correction that satisfy the following requirements: having three or more channels inevitably means including two channels among them. In other words, options with more than two channels, as well as two-channel extrusion dies, can fit perfectly into the concept of the present invention and can be covered by this patent application. Such an extrusion die having three or more channels for Mooney correction offers the significant advantage of obtaining multiple data points for the Mooney curve after a single extrusion operation.

[0036] <Extrusion die with 3 or more channels> An extrusion die having three or more channels for Mooney correction to determine the true shear viscosity of a resin, This extrusion die having three or more channels, - Cylindrical body; - Three or more channels, Each of the three or more channels has a circular and constant cross-section, and extends linearly along the longitudinal direction of the cylindrical body throughout the entire channel. Three or more channels, all of which have their inlets located in a plane perpendicular to the longitudinal direction of the cylindrical body; and, - Protrusions that fit into the extruder Includes, For any two channels selected from the three or more channels mentioned above, The large channel A, which is one of the two selected channels, has a longitudinal length L along the longitudinal direction of the cylindrical body. A , and the diameter D of the cross-section perpendicular to the longitudinal direction A The small channel B, which is one of the two selected channels, has a longitudinal length L along the longitudinal direction of the cylindrical body. B , and the diameter D of the cross-section perpendicular to the longitudinal direction B When this is the case, all three of the following relations (i), (ii), and (iii) are satisfied, so that each of the three or more channels is equally placed under a given pressure head from the channel inlet to the channel outlet during the fluid extrusion operation of the resin by the extrusion die having the three or more channels. An extrusion die having three or more channels for Mooney correction. (i) L A > L B (ii) D A > D B (iii) L A / D A = LB / D B

[0037] Unless otherwise deemed feasible from a technical standpoint, one or more of the embodiments described above for a two-channel extrusion die may also be applied to an extrusion die having three or more channels. For example, at the downstream end of the cylindrical body of an extrusion die having three or more channels, multiple partial cylindrical sections may be formed in a stepped manner. Also, for example, the largest channel may be inserted through the terminal partial cylindrical section of the multiple partial cylindrical sections, and the second largest channel may be inserted through a partial cylindrical section located at the second position from the terminal point. In a cross-section perpendicular to the longitudinal direction of the cylindrical body of an extrusion die having three or more channels, the centers of all three or more channels may be equidistant from the center of the cylindrical body. Alternatively, for at least two channels selected from the three or more channels, the centers of at least two channels may be equidistant from the center of the cylindrical body in a cross-section perpendicular to the longitudinal direction of the cylindrical body of the extrusion die having three or more channels. For any two channels selected from three or more channels, L A It is typically 1.1*L B More than 2.0*L B The following is acceptable: D A It is usually 1.1*D B More than 2.0*D B The following is acceptable. Also, for any two channels selected from three or more channels, L A / D A and L B / D B Each of these values ​​may be between 5 and 50. [Examples]

[0038] Two types of Mooney-correcting two-channel extrusion dies (#1 and #2), each having a large channel and a small channel with dimensions shown in Tables 1 and 2 below, were used. Two-channel extrusion die #1 was used in Example 1, and two-channel extrusion die #2 was used in Example 2. The schematic structure and appearance of these two extrusion dies are shown in Figures 5 and 6(a), (b), and (c). The reference numerals in Figures 5 and 6 are assigned in the same way as in the above embodiments. In Figure 5, the large channel and small channel of two-channel extrusion die #1 shown on the left have smaller diameters than the large channel and small channel of two-channel extrusion die #2 shown on the right in Figure 5.

[0039] [Table 1]

[0040] [Table 2]

[0041] Example 1 A 2-channel extrusion die #1 was mounted on an extruder with a screw diameter (extrusion diameter) of 19 mm. A flexible PVC compound (obtained from RIMTEC Corporation) was used as the extrusion fluid. Extrusion tests were conducted at a temperature of 170°C and a screw rotation speed of 3 revolutions per minute. The shear rate (i.e., apparent shear rate) was calculated from the weight per unit time of the extruded material from the large and small channels of the 2-channel extrusion die #1. The screw rotation speed (RPM: revolutions per minute), applied pressure, flow rate in the large and small channels, shear rate in the large and small channels, and apparent viscosity are shown in Table 3 below. The fluid slip rate and Mooney-corrected viscosity, determined based on the shear rate, are also shown in Table 3.

[0042] The Mooney-corrected viscosity in this example and subsequent examples was calculated as follows. As mentioned above, the apparent wall shear rate is 4Q T / πR 3 The slope of the plot relative to 1 / R is 4V. s Slip speed V S Based on the fact that (unit: mm / sec) can be determined, the slip velocity was calculated from the slope of the straight line connecting two points plotted from the results obtained from the large CH and small CH. Here, Q T is the combined volumetric flow rate (mm 3 The flow rate is ( / second), and R is the channel radius (unit: mm). In this example, the specific gravity of the extrusion fluid at the extrusion test temperature was 1.303, and the flow velocity (g / min) is calculated based on this specific gravity to determine the total volumetric flow rate Q. T (mm 3 It was converted to (per second). The two formulas mentioned above: Q T =Q shear +Q slip Q slip =V s πR 2 From the Mooney-corrected shear rate γ = 4(Q T -Q slip ) / πR 3 The value (in units of 1 / second) was calculated. Next, the shear stress σ = 2PR / 4L (unit: Pa) was calculated. Here, P represents pressure (in Pa) and L represents channel length (in mm). (A characteristic structure of the Mooney-corrected 2-channel extrusion die according to the present invention is that the shear stress σ of the large channel and the shear stress σ of the small channel are the same.) The Mooney-corrected viscosity η (unit: Pa·s (Pascal-seconds)) was calculated from η = σ / γ.

[0043] Example 2 A 2-channel extrusion die #2 was mounted on an extruder with a screw diameter (extrusion diameter) of 19 mm. A flexible PVC compound (obtained from RIMTEC Corporation) was used as the extrusion fluid. Extrusion tests were conducted under conditions of a temperature of 170°C and a screw rotation speed of 30 revolutions per minute. The shear rate (i.e., apparent shear rate) was calculated from the weight per unit time of the extruded material from the large and small channels of the 2-channel extrusion die #2. The screw rotation speed (RPM: revolutions per minute), applied pressure, flow rate in the large and small channels, shear rate in the large and small channels, and apparent viscosity are shown in Table 3 below. The fluid slip rate and Mooney-corrected viscosity, determined based on the shear rate, are also shown in Table 3. The specific gravity of the extrusion fluid at the extrusion test temperature in this example was 1.245.

[0044] [Table 3] [Explanation of symbols]

[0045] 1: Cylindrical body 2: Adapter to the extruder 3A: Big Channel 3A i Large channel inlet 3A o Large channel outlet 3B: Small Channel 3B i Small channel inlet 3B o : Small channel outlet 4: Semi-cylindrical protrusion 5: Connector to a device for measuring the temperature and / or pressure of a fluid. 10:2 channel extrusion die F: Flow direction of the resin fluid (when there is flow) D A : Diameter of large channel A L A : Longitudinal length of large channel A C1: Centerline of large channel A D B : Diameter of small channel B L B:Longest length of small channel B C2: Centerline of small channel B C p : The center line (center point) of the cylindrical body S1: Distance between the center of the large channel and the center of the cylindrical body S2: Distance between the center of the small channel and the center of the cylindrical body

Claims

1. A two-channel extrusion die for Mooney correction to determine the true shear viscosity of a resin, This two-channel extrusion die is - Cylindrical body; - There are two channels, Each of the two channels has a circular and constant cross-section, and extends linearly along the longitudinal direction of the cylindrical body throughout the entire channel. Two channels, both of which have inlets located in a plane perpendicular to the longitudinal direction of the cylindrical body; and, - Protrusions that fit into the extruder Includes, One of the two channels, the large channel A, has a longitudinal length L along the longitudinal direction of the cylindrical body. Ａ , and the diameter D of the cross-section perpendicular to the longitudinal direction Ａ The small channel B, which is one of the two channels, has a longitudinal length L along the longitudinal direction of the cylindrical body. Ｂ , and the diameter D of the cross-section perpendicular to the longitudinal direction Ｂ When this is the case, all three of the following relations (i), (ii), and (iii) are satisfied, so that each of the two channels is equally placed under a given pressure head from the channel inlet to the channel outlet during the fluid extrusion operation of the resin by the two-channel extrusion die. Mooney correction 2-channel extrusion die. (i) L Ａ > L Ｂ (ii) D Ａ > 0 Ｂ (iii) L Ａ / D Ａ = L Ｂ / D Ｂ

2. A two-channel extrusion die according to claim 1, wherein a semi-cylindrical protrusion is formed at the downstream end of the cylindrical body, and the large channel A is inserted through the semi-cylindrical protrusion.

3. The two-channel extrusion die according to claim 1, wherein in a cross section perpendicular to the longitudinal direction of the cylindrical body, the centers of the large channel A and the small channel B are each located at an equidistant distance from the center of the cylindrical body.

4. L Ａ However, 1.1 * L Ｂ More than 2.0*L Ｂ The following: D Ａ However, 1.1*D Ｂ More than 2.0*D Ｂ The following is: The two-channel extrusion die according to claim 1.

5. L Ａ / D Ａ and L Ｂ / D Ｂ However, each is between 5 and 50. The two-channel extrusion die according to claim 1.

6. The two-channel extrusion die according to claim 1, further comprising a member connected to an instrument for measuring the temperature and / or pressure of the resin fluid extruded using the two-channel extrusion die.

7. A system that performs Mooney correction to measure the true shear viscosity of a resin using a rheometer, A system comprising an extruder and a two-channel extrusion die according to claim 1 connected to the extruder.

8. A method for performing Mooney correction to measure the true shear viscosity of a resin using a two-channel extrusion die as described in claim 1, The steps include: extruding the resin fluid from the large channel A and the small channel B through the two-channel extrusion die connected to the extruder, thereby recovering the extruded material A from the large channel A and the extruded material B from the small channel B; A step of growing the weight A of the extruded product A and the weight B of the extruded product B, A step of calculating the apparent shear rate A from the weight A, and calculating the apparent shear rate B from the weight B, The steps include applying Mooney correction to the apparent shear rate A and the apparent shear rate B, thereby measuring the slip velocity of the fluid, and A step of calculating the true shear viscosity from the slip velocity of the fluid. A method that includes this.

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