JP2003262579A - Viscosity measuring apparatus and method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the viscosity of a mixture of a resin in a molten state and gases pressurized more than atmospheric pressure within a share rate range conceivable in normal injection molding and thus to provide viscosity data capable of simulating the flow pattern of the molten resin mixed with the gases. <P>SOLUTION: A measuring device 6 comprises a channel 9 for making the molten resin mixed with the gases, extruded out of an injection machine 14 having a gas supply part at a midpoint in a heating tube, flow to a discharge opening 8, an orifice 10 interposed in the channel 9, and a pressure detector 11 for detecting the pressure of the molten metal mixed with the gases in the channel 9 on the upstream side from the orifice 10, and the measuring device 6 is connected to the injection machine 14. A valving element 12 is provided for either the upstream side or downstream side of the orifice 10 of the measuring device 6. By closihg the valving element 12, the molten resin mixed with the gases in a pressurized state is accumulated and stored in a measuring part of the injection machine 14 in the viscosity measuring apparatus. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viscosity measuring device capable of measuring the viscosity of a mixture of a resin in a molten state and a gas pressurized above atmospheric pressure, and a viscosity measuring method using the same.

[0002]

2. Description of the Related Art Conventionally, as a method for measuring the viscosity of a resin, JIS K7210: 1999 (ISO1133:
1997), "Test method for melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastics", JIS K7.
199: 1999 (ISO 1443: 1995), "Method for testing plastic flow characteristics by capillary rheometer and slit die rheometer".
Is generally done.

The above-mentioned melt mass flow rate (hereinafter referred to as "MF
R) and melt volume flow rate (hereinafter abbreviated as “MVR”) test methods are viscosity test methods under specific temperature and specific load conditions. Specifically, the resin is kept at a specific temperature in a vertically arranged cylinder, and after a certain period of time, the weight or volume of the resin extruded from the orifice arranged at the bottom of the cylinder is adjusted by a piston loaded with a load. It is something to measure.

The viscosity of the resin is closely related to the shear rate (shear rate), but the shear rate under the test conditions of MFR and MVR is lower than the shear rate used under normal processing conditions. Since it is a region, the viscosity data obtained by this method may not be correlated with the behavior under actual processing conditions.

On the other hand, the viscosity measuring method using a capillary rheometer and a slit die rheometer is
This is a viscosity measurement method in which rate (shear rate) and shear stress (shear stress) are taken into consideration. The shear rate is in the range of 1 to 10 ⁶ (/ sec). It covers the low speed range of the share rate range.

[0006]

By the way, Japanese Unexamined Patent Publication No.
In Japanese Patent No. 318541, WO98 / 52734, etc., a method for obtaining a resin molded article after lowering the viscosity of the resin by including a gas such as carbon dioxide or nitrogen in the resin is shown. Has been done.

In these patent publications, the fluidity of the resin is improved by decreasing the viscosity of the resin, the reproducibility of the mold surface is improved, the glossiness is improved, and the sharp edge reproducibility of the mold surface is improved. Although it is described that it is effective in making the weld line inconspicuous as well as improving the reproducibility of fine irregularities on the mold surface, the viscosity data of the mixture of resin and gas has been digitized and converted into data. Absent. For this reason, it is not possible to simulate the flow pattern using a computer, which is generalized and put into practical use in resins, and it is difficult to design a mold for molding with a mixture of resin and gas that has different flow characteristics from the resin alone. There is a situation.

Since the viscosity measuring method using the capillary rheometer and the slit die rheometer covers the low speed range of the share rate range at the time of injection molding which is usually performed as described above, it is used for the above resin. It is conceivable to obtain the viscosity data of the mixture of gas and gas.

However, the capillary rheometer,
Since the viscosity measuring device using the slit die rheometer does not have the function of mixing the resin and the gas, there is a problem that the viscosity of this mixture cannot be measured. In particular, a molten resin mixed with a gas is likely to release the gas, and an ordinary viscosity measuring device causes the gas to be released during the measurement, which makes accurate measurement difficult. In addition, in order to apply molding with a mixture of resin and gas to molding of molded products that meet recent market demands such as thin-walled molded products and precision molded products, further specialization of mold structure such as gate diameter reduction In order to cope with this, a viscosity measuring device capable of measuring the viscosity of the molten resin mixed with the gas to a higher shear rate range is required.

The present invention has been made in view of the above-mentioned conventional problems, and a viscosity measuring device capable of measuring the viscosity of a mixture of a resin in a molten state and a gas (particularly gas) pressurized above atmospheric pressure. Another object of the present invention is to provide a viscosity measuring method using the same.

Specifically, a viscosity measuring device capable of measuring the viscosity of a mixture of a resin in a molten state and a gas pressurized above atmospheric pressure in a shear rate range considered in ordinary injection molding, and It is an object of the present invention to provide a viscosity measurement method using the above, and to provide viscosity data that enables simulation of a flow pattern of a molten resin mixed with gas.

[0012]

A first object of the present invention is, for the above-mentioned purpose, a mixing section for mixing and transferring a molten resin and another gas, and a gas-mixed molten resin transferred from this mixing section. Mixing extrusion that has a screw or a plunger that stores and stores the gas-mixed molten resin stored in the storage part at the time of forward movement, and a storage part that is prepared for extrusion from the extrusion port and that can advance and retreat in the axial direction. The device, a flow path connected to the extrusion port of the mixing extrusion device, for flowing the gas-mixed molten resin extruded from the extrusion port of the mixing extrusion device to the discharge port, an orifice interposed in the flow channel, and A measuring device having a pressure detector for detecting the gas-mixed molten resin pressure in the flow path upstream of the orifice, and further, between the reservoir of the mixing extruding device and the orifice of the measuring device, and between the orifice of the measuring device and the discharge of the measuring device. A valve element is provided in at least one of the openings, and by closing this valve element, it is possible to accumulate and store the gas-mixed molten resin under pressure in the reservoir of the mixing extruder. A characteristic viscosity measuring device is provided.

The first aspect of the present invention is that the valve body is a flow rate adjusting valve whose opening can be adjusted, and pressure detection for detecting the gas-mixed molten resin pressure in the flow path downstream of the orifice of the measuring device. Has a vessel, a backflow prevention mechanism is provided between the mixing section and the storage section of the mixing extruder, and moreover, the accumulation of the gas-mixed molten resin in the storage section is due to the gas-mixed fusion stored in the storage section. It is carried out while the screw or plunger is retracted against the advancing force applied to the screw or plunger that pushes the resin out of the extrusion port, and the mixing section of the mixing and extruding device is an extruder having a gas supply section in the middle of the heating cylinder. Alternatively, the mixing / extruding apparatus has a valve element at the injection port as a valve element between the reservoir of the mixing / extruding apparatus and the orifice of the measuring device, and the gas supply section is provided in the middle of the heating cylinder. Have inline Be composed of Cru type or screw preplasticization injection machine, orifice, equal capillary diameter, it capillary length can be replaced with a different orifice, it is intended to include the preferred embodiments thereof with.

The second aspect of the present invention is the first aspect of the present invention.
The viscosity of the capillary is d (m
m), for the orifice having a capillary length of L (mm), the gas-mixed molten resin stored in the storage portion is mixed under a predetermined shear rate γ (sec ⁻¹ ) calculated by the following formula 1 in the mixing extruder. The gas mixture molten resin pressure in the flow passage on the upstream side of the orifice is measured by a pressure detector, and the apparent shear stress τ (Pa) is calculated by the following formula 2 and the following formula is calculated. Apparent viscosity η (P
The present invention provides a method for measuring viscosity, which comprises determining a.s).

However, P is the gas-mixed molten resin pressure (Pa) in the flow passage on the upstream side of the orifice, D is the screw or plunger diameter (mm), S is the advancing speed of the screw or plunger (mm / sec), Q is the volumetric flow rate ratio (mm ³ /
sec), Q = (π × D ² ÷ 4) × S.

Γ = (4 × Q) ÷ (π × d ³ ÷ 8) Equation 1 τ = (P × d) ÷ (4 × L) Equation 2 η = τ ÷ γ Equation 3

In the second aspect of the present invention, the apparent viscosities η (Pa.multidot.Pa) are obtained under a plurality of share rates .gamma. (Sec.sup.- ¹ ).
Obtaining s) includes obtaining an apparent viscosity curve in a constant shear rate range as a preferred embodiment.

A third aspect of the present invention is the viscosity measuring apparatus according to the first aspect of the present invention, in which the orifices having the same capillary diameter and different capillary lengths are replaceable, and the capillary diameter d ( mm) and the capillary lengths L ₁ and L ₂ (where L ₁ <L ₂ ) (m
For each of the two orifices of m), the gas-mixed molten resin stored in the storage section is extruded from the extrusion port of the mixing extrusion device under the same share rate γ (sec ⁻¹ ) calculated by the following formula 1. The gas-mixed molten resin pressures P ₁ , P ₂ (P
a) is measured with a pressure detector, and the capillary lengths L ₁ and L ₂ (mm) of each orifice and the gas-mixed molten resin pressures P ₁ and P ₂ (Pa) on the upstream side of the orifice are used to determine the orifice. The pressure loss value P ₀ (Pa) when the capillary length is 0 is obtained by P ₀ = (P ₁ × L ₂ −P ₂ × L ₁ ), and the shear stress τ _c (P
a), the viscosity η _c (Pa
The present invention provides a method for measuring viscosity, which comprises determining s).

However, L _x is the capillary length (mm) of any orifice, P _x is the gas-mixed molten resin pressure (Pa) on the upstream side of the orifice having a capillary length of L _x , and D is the screw or plunger diameter (mm). ), S is the forward speed (mm / sec) of the screw or plunger, Q is the volumetric flow rate ratio (mm ³ / sec), and Q = (π × D ² ÷ 4) × S.

Γ = (4 × Q) ÷ (π × d ³ ÷ 8) Equation 1 τ _c = (P _x −P ₀ ) × d ÷ (4 × L _x ) Equation 4 η _c = τ _c ÷ γ Equation 5

Further, a fourth aspect of the present invention relates to the first aspect of the present invention.
In the viscosity measuring device, the orifice is the capillary diameter.
Can be replaced with orifices of the same size but different capillary lengths
Capillary diameter d (mm) is
The same and the capillary length is L ₁, L₂, ... L_n(However, L₁
<L₂<... <L_n) (Mm) to three or more orifices
And the gas-mixed molten resin stored in the storage section, respectively.
To the same share rate γ (s
ec^-1) Below and extrude through the extrusion port of the mixing extruder.
Gas flow in the upstream flow path for each orifice.
Combined molten resin pressure P ₁, P₂,… P_n(Pa) is the pressure
Capillary of each orifice as well as measurement by detector
Long L₁, L₂, ... L_n(Mm) and upstream of the orifice
Side mixed molten resin pressure P₁, P₂,… P_nFrom (Pa),
Pressure loss value P when the capillary length of the orifice is 0₀
(Pa) was obtained by linear regression and corrected by the following equation 4.
Share stress τ_c(Pa) is calculated and corrected by the following formula 5.
Viscosity η_cCharacterized by obtaining (Pa · s)
A method for measuring viscosity is provided.

However, L _x is a capillary length (mm) of any orifice, P _x is a gas mixture molten resin pressure (Pa) by a pressure detector immediately upstream of the orifice having a capillary length L _x , and D is a screw. Or plunger diameter (m
m), S is the forward speed of the screw or plunger (mm /
sec), Q is the volumetric flow rate ratio (mm ³ / sec), Q
= (Π × D ² ÷ 4) × S.

Γ = (4 × Q) ÷ (π × d ³ ÷ 8) Equation 1 τ _c = (P _x −P ₀ ) × d ÷ (4 × L _x ) Equation 4 η _c = τ _c ÷ γ Equation 5

In the third and fourth aspects of the present invention described above, the viscosity η _c (Pa · s) corrected under a plurality of share rates γ (sec ⁻¹ ) is obtained to obtain a constant shear rate range. Obtaining a corrected viscosity curve is included as a preferred embodiment.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below.

The resin to be measured in the present invention refers to a thermoplastic resin characterized by softening and plasticity when heated and solidification when cooled, and a thermoplastic resin composition containing the thermoplastic resin as a main component. . Further, the thermoplastic resin may be either a crystalline resin or an amorphous resin.

Specific examples of the resin include polyacetal, polyoxymethylene (hereinafter abbreviated as "POM"),
Polyamide (hereinafter abbreviated as "PA"), polyethylene terephthalate (hereinafter abbreviated as "PET"), polybutylene terephthalate (hereinafter abbreviated as "PBT"), high density polyethylene (hereinafter abbreviated as "HDPE"), low density polyethylene (hereinafter "LDPE"), linear low-density polyethylene (hereinafter "LLDPE"), polyetheretherketone (hereinafter "PEEK"), polypropylene (hereinafter "PP"), polystyrene (hereinafter "P").
S) resin, polyphenylene ether (hereinafter abbreviated as "PPE") resin, and modified PP obtained by blending or graft polymerizing a PPE resin with another resin.
E-based resin, acrylonitrile-butadiene-styrene copolymer (hereinafter abbreviated as "ABS-based resin"), acrylonitrile-styrene copolymer (hereinafter abbreviated as "AS-based resin"), polycarbonate (hereinafter abbreviated as "PC")-based Examples thereof include resins and polymethylmethacrylate (hereinafter abbreviated as "PMMA") resins.

The resin to be measured in the present invention is a mixture of resin components having the same molecular structure but different molecular weights or different molecular weight distributions, or two or more kinds of resin components are physically or chemically mixed. It may be a polymer alloy which is a composite resin material.

The resin component having different characteristics which can be used by mixing with the resin component as the main component constituting the polymer alloy is not particularly limited as long as it is compatible with the resin component as the main component. For example, POM, PP, PA, PE
T, PBT, PEEK, polyethylene, PS, ABS resin, polyvinyl chloride, PC, modified PPE, polyphenylene sulfide (hereinafter abbreviated as "PPS"), polyimide,
Polyamideimide, polyetherimide, polyarylate, polysulfone, polyethersulfone, liquid crystal polymer (hereinafter abbreviated as “LCP”), polytetrafluoroethylene, thermoplastic elastomer, polytetrafluoroethylene, polyvinyl alcohol, etc. it can.

Examples of polymer alloys are "PA / PPE polymer alloys" made of PA resin and PPE resin, and "PP / PP made of PP resin and PPE resin".
"E polymer alloy", "PC / ABS polymer alloy" made of PC resin and ABS resin, "PA / ABS polymer alloy" made of PA resin and ABS resin, PC resin and PET resin By "PC / PET
Examples include "polymer-based alloys", "LCP / PPE-based polymer alloys" composed of LCP-based resins and PPE-based resins, and "PPS / PPE-based polymer alloys" composed of PPS-based resins and PPE-based resins.

The resin to be measured in the present invention may be a resin to which an inorganic or organic filler is added for the purpose of imparting specific gravity and strength, improving dimensional accuracy and heat resistance. Good. The type and shape of these inorganic or organic fillers are not limited, and fibrous,
A plate shape or a spherical shape can be arbitrarily selected. Examples of the specific gravity-imparting agent include barium sulfate, red iron oxide, tungsten powder, and other inorganic salts, oxides, and metal powder. As the strength-imparting agent, glass fiber, carbon fiber, metal fiber, aramid fiber, potassium titanate, asbestos,
Silicon carbide, ceramic, silicon nitride, barium sulfate,
Calcium sulfate, kaolin, clay, pyrophyllite, bentonite, sericite, zeolite, mica,
Mica, nepheline sinite, talc, attarpulgite, wollastonite, slag fiber, ferrite, silicon, calcium, calcium carbonate, magnesium carbonate,
Dolomite, zinc oxide, gypsum, glass beads, glass powder, glass balloons, quartz, quartz glass, alumina and the like can be mentioned.

The above-mentioned inorganic or organic filler is 2
It is also possible to use more than one type together. If necessary, it can be used after being pretreated with a coupling agent such as a silane-based or titanium-based coupling agent.

When the resin to be measured in the present invention has an inorganic or organic filler added, the addition amount may be selected according to the function required of the molded product to be molded. However, it is generally preferably 5% by weight or more, and more preferably 10% by weight or more.

The resin to be measured in the present invention contains additives usually used for the purpose of improving its function, for example, antioxidants, flame retardants, mold release agents, lubricants, heat stabilizers, and weather resistance. One or more kinds of stabilizers, rust preventives, fillers, colorants, antibacterial agents, antifungal agents and the like may be added as required. Further, in order to reduce the electric resistance, carbon fiber, metal fiber, graphite or the like may be added. A molded product made of a resin whose electric resistance is reduced by adding these substances can easily prevent dust from adhering to it due to static electricity.

The viscosity measuring device according to the present invention comprises a mixing extrusion device, a measuring device, and a valve element provided on at least one of the mixing extrusion device and the measuring device.

The mixing and extruding device comprises at least a mixing section and
With a reservoir and a screw or plunger,
Usually, a melting part is provided on the upstream side of the mixing part in the moving direction of the resin to be measured.

The melting portion is a portion for heating and melting a resin which is usually supplied as pellets, and is a state in which a thermoplastic resin constituting the resin to be measured in the present invention can be subjected to general injection molding, that is, It refers to a portion that is heated until it is plasticized and undergoes a phase transition to a liquid state. Specifically, when the thermoplastic resin constituting the resin to be measured in the present invention is a crystalline resin, the temperature exceeds its melting point, and when it is an amorphous resin, the temperature exceeds its glass transition point. The part that is heated up to.

The melting part in the present invention can be heated to an arbitrarily set temperature, can be maintained at a constant temperature, and can be heated to a uniform temperature by melting the supplied solid resin and then heating the temperature. It is preferable to have a transfer function as well as a mixing and stirring function so that it can be transferred to the next process part (mixing part) while maintaining the above. Further, in order to measure the viscosity in the high shear rate region with high accuracy, it is preferable that a large amount of the resin can be used for the measurement as compared with the measurement in the low shear rate region. It is preferable that the heating capacity is large so that it can be melted. Considering these things,
The melting part preferably has a structure similar to or similar to the heating part of an injection machine or an extruder. Specifically, a heating cylinder for heating and melting the resin and a screw for stirring and mixing the resin and transferring the resin. It is preferable to be composed of

The mixing section in the viscosity measuring device of the present invention is
In the portion that mixes the gas while maintaining the temperature of the molten resin to form the gas-mixed molten resin, normally, supplying pressurized gas while continuing to heat the molten resin sent from the melting section,
This is a part for mixing the both with stirring and transferring the obtained gas-mixed molten resin to the storage part which is the next step. Considering the heating of the molten resin, the sufficient mixing of the molten resin and the gas, the transfer of the gas-mixed molten resin, etc., this mixing section has a structure similar to that of the heating section of the injection machine or the extruder, like the melting section. An equivalent structure is preferable, and specifically, it is preferable that the melting unit, a series of heating cylinders, the melting section, a series of screws, a gas supply unit provided in the heating cylinder, and the like.

The melting section and the mixing section in the viscosity measuring apparatus of the present invention can be constructed in series using an injector or an extruder having a gas supply section in the middle of the heating cylinder. Any gas supply unit may be used as long as it can supply a gas to the molten resin moving in the heating cylinder, and a vent portion provided in the middle portion of the heating cylinder can be used. The gas can be supplied to the molten resin by press-fitting the gas from the vent portion into the heating cylinder.

When an injector or an extruder is used, the screw shape in the mixing section is such that the depth of the screw groove in the vicinity of the gas supply section is deepened like the vent section of the vent type screw to obtain a molten resin. It is preferable to make the gas injection easy by making the transfer of the resin into a starvation state and lowering the molten resin pressure in the heating cylinder. Further, in order to allow the supplied gas and the molten resin to be uniformly mixed, it is preferable to provide the screw with a mixing mechanism such as a dullage or a kneading pin, or to provide a static mixer in the resin flow path. The injection machine can be used without distinction between an in-line screw type and a screw pre-plastic type.

In the present invention, the gas to be mixed with the molten resin is not particularly limited as long as it is a substance that is a gas under normal temperature and pressure, and various gases can be used as a simple substance or a mixture. By mixing with a molten resin, a gas having an effect of extending the characteristics of the resin or a gas having an effect of compensating for the defects of the resin is used. For example, a gas having the effect of reducing the viscosity of the molten resin,
A gas having an effect of foaming the inside of the molten resin filled in the mold cavity is usually used. Specific examples thereof include carbon dioxide and nitrogen.

The above gas is usually pressurized to atmospheric pressure or higher and supplied to the molten resin in order to facilitate supply and mixing into the molten resin. In order to easily mix the gas and the molten resin uniformly in a short time, it is preferable to supply the gas at a pressure higher than the pressure of the molten resin in the heating cylinder.

The gas-mixed molten resin mixed with the gas in the mixing section is sent to the storage section. The storage section is a section for accumulating a predetermined amount of the gas-mixed molten resin transferred from the mixing section and storing it in preparation for extrusion from the extrusion port, and a gas sent from the mixing section with the valve body to be described later closed. The mixed molten resin can be accumulated and stored under pressure. By storing the gas-mixed molten resin under pressure in the storage portion, it is possible to prevent a measurement failure due to gas being released from the gas-mixed molten resin and foaming.

Further, the storage portion has an extrusion port connected to the flow path of the measuring device described later, and is capable of advancing and retreating in the axial direction. At the time of forward movement, the gas-mixed molten resin stored in the storage portion is extruded from the extrusion port. It has a screw or plunger that pushes out of it.

The storage part having the screw or the plunger can be constructed in series with the melting part and the mixing part by using an in-line screw type injection machine or a screw pre-plastic type injection machine. That is, the measuring unit of the injector is used as a storage unit, and the storage unit is connected to the flow path of the measuring device described later, whereby the melting unit and the mixing unit can be configured in series. Further, the storage part having the plunger has a plunger that advances and retreats toward the extrusion port, and by separately providing a cylinder that sequentially receives and stores the gas-mixed molten resin sent from the mixing part on the forward end side of the plunger. Can be configured. In this case, it is preferable that an extruder is used as the mixing section for supplying the gas-mixed molten resin to the cylinder.

Between the mixing section and the storage section, in order to prevent the gas-mixed molten resin supplied to the storage section from flowing back to the mixing section, it is easy to maintain the pressurized state of the gas-mixed molten resin in the storage section. It is preferable that a backflow prevention mechanism is provided.
This backflow prevention mechanism is interposed between the mixing section and the storage section to close the valve element described later, and also to apply a forward force to the screw or plunger, and to retract the screw or plunger against this forward force, and to store the storage section. By accumulating the gas-mixed molten resin in the reservoir, it is possible to reliably maintain the pressurization of the gas-mixed molten resin in the storage portion. In particular, it is preferable to use an injection machine and configure the storage section in series with the melting section and the mixing section because the check valve provided at the tip of the screw of the injection machine can be used as the backflow prevention mechanism. This is the same regardless of whether the injector is an in-line screw type or a screw pre-plastic type.

The viscosity measuring device of the present invention has a measuring device connected to the mixing and extruding device.

The measuring device is connected to the extrusion port of the mixing extrusion device, and has a flow passage through which the gas-mixed molten resin extruded from the extrusion port of the mixing extrusion device flows to the discharge port, and an orifice interposed in this flow passage. And a pressure detector for detecting the pressure of the gas-mixed molten resin in the flow path upstream of the orifice.

The gas-mixed molten resin measured and stored in the storage section of the mixing extrusion apparatus is pushed out into the flow path of the measuring apparatus by the advance of the screw or the plunger in the storage section, and flows out from the discharge port through the orifice. It is preferable that the forward speed of the screw or the plunger can be arbitrarily set so that the share rate can be adjusted.

Extrusion of the gas-mixed molten resin from the mixing and extruding device to the measuring device is carried out when the melting part, the mixing part, and the storage part are made up of a series of injection machines, and when the injection machine is an in-line screw type, it is built in. It is carried out by advancing the screw, and when the injector is of the screw pre-plastic type, it is carried out by advancing the plunger. In addition, the melting section and the mixing section are configured in series with an extruder, and a cylinder having a plunger that advances and retracts toward the extrusion port is separately provided as a storage section, and the extrusion side of the extruder is connected to the plunger forward end side of the cylinder. In that case, it is performed by advancing a plunger provided in the cylinder. In particular, if the melting section, mixing section and storage section are configured in series with an injection machine and the gas-mixed molten resin is extruded by advancing the built-in screw or plunger, the extrusion capacity can be adjusted easily and large extrusion can be performed. Since the capacity can be secured, viscosity can be measured over a wide range from the low share rate range to the high share rate range.

In the viscosity measuring device of the present invention, while the gas-mixed molten resin extruded from the mixing extrusion device is discharged to the outside through the discharge port through the flow passage and the orifice, the upstream side of the orifice, that is, the storage part. A pressure detector provided between the orifice and the orifice measures the gas-mixed molten resin pressure on the upstream side of the orifice. Then, the viscosity of the gas-mixed molten resin can be calculated from the function of the measured value of the gas-mixed molten resin pressure and the shear rate.

In order to measure the viscosity with higher accuracy,
It is preferable that the pressure detector is set so as not to obstruct the flow of the gas-mixed molten resin, and that the pressure detector is installed close to the orifice.

The viscosity measuring device of the present invention has a valve element between at least one of the reservoir and the orifice and between the orifice and the discharge port. This valve body is closed when the gas-mixed molten resin is accumulated and stored in the reservoir of the mixing / extruding device, and is opened when the gas-mixed molten resin is pushed out of the reservoir of the mixing / extruding device to the measuring device. In particular, the viscosity measuring device of the present invention accumulates and stores the gas-mixed molten resin under pressure in the storage portion in order to suppress the release of gas from the gas-mixed molten resin. By closing the valve body when accumulating and accumulating in the portion, it is possible to prevent the pressurized gas-mixed molten resin from flowing out of the discharge port through the flow path and the orifice. That is, by closing the valve body, the pressure of the gas-mixed molten resin in the reservoir can be kept constant. When using an in-line screw type or screw pre-plastic type injection machine having a gas supply part in the middle part of the heating cylinder and a valve body at the injection port as a mixing extrusion device, at least one of the orifice and the discharge port is used. The valve element provided at the injection port of the injection machine can be used as the valve element provided in, and the equipment newly prepared for the viscosity measurement can be simplified.

The valve body need only be provided between the reservoir and the orifice and / or between the orifice and the discharge port, and may be a simple on-off valve, but it is a flow rate adjusting valve whose opening can be adjusted. It is preferable. By using the flow rate adjusting valve as the valve body, it is possible to reproduce the pressure rise and the temperature rise when the gas-mixed molten resin is filled into the closed space assuming the mold cavity instead of the open system. At this time, it is preferable to provide a pressure detector not only between the reservoir and the orifice but also between the orifice and the discharge port so that the gas-mixed molten resin pressure before and after passing through the orifice can be measured.

In the present invention, the capillary refers to a narrow channel provided in the orifice, and the sectional shape of the channel is not limited, but usually a circular section is often used. When the channel has a circular cross section, this diameter is the capillary diameter d (mm), and the channel length is the capillary length L (mm).

Although the capillary diameter and the capillary length of the orifice used in the viscosity measuring apparatus of the present invention are not limited, the orifices have the same capillary diameter and can be replaced with orifices having different capillary lengths. Is preferred. This is because the same capillary diameter is used, and a plurality of orifices with different capillary lengths are reattached, and measurement is performed for each orifice, which makes it possible to correct bagelie.
The pressure loss value at the entrance and exit of the orifice can be calculated. As a result, viscosity data with a smaller error can be obtained.

In the measurement using the viscosity measuring apparatus according to the present invention, the prepared resin is melted in the melting section, the molten resin and the pressurized gas are mixed in the mixing section, and a predetermined amount of gas is mixed in the storage section. The molten resin is accumulated and stored, and the gas-mixed molten resin pressure P before passing through the orifice is measured while discharging the gas-mixed molten resin stored in the storage section through the orifice at an arbitrarily set share rate γ (sec ^-1 ). By doing. The calculation method of the apparent viscosity η (Pa · s) at the share rate γ (sec ⁻¹ ) and the orifice length L (mm) is as follows.

The share rate (sec ^-1 ) is also called shear rate and shear rate, and is calculated by the following equation ( ¹ ).

Γ = (4 × Q) ÷ (π × d ³ ÷ 8) Equation 1

Here, Q is the volumetric flow rate ratio (mm ³ / se
c), which is a value calculated by Q = (π × D ² ÷ 4) × S. Also, d is the diameter of the capillary of the orifice (mm), D is the diameter of the screw or plunger (m
m) and S are advancing speeds (mm / sec) of the screw or plunger set arbitrarily.

On the other hand, the shear stress τ (Pa), which is also called shear stress, is calculated by the equation 2 shown below.

Τ = (P × d) ÷ (4 × L) Equation 2

Here, P is the gas-mixed molten resin pressure (Pa) before passing through the orifice, d is the diameter of the capillary of the orifice (mm), and L is the length of the capillary of the orifice (m).
m).

The apparent viscosity (Pa · s) at the shear rate γ (sec ⁻¹ ) and the orifice length L (mm) is expressed by the following equation using the shear stress τ (Pa) calculated by the above equation 2. It can be obtained by 3.

Η = τ ÷ γ Equation 3

By obtaining the apparent viscosities η under a plurality of share rate γ (sec ⁻¹ ) conditions,
Share rate γ (sec ^-1 ) and apparent viscosity η (Pa
The correlation graph of s) can be obtained. An example of a correlation graph of the share rate γ (sec ⁻¹ ) and the apparent viscosity η (Pa · s) is shown in FIG.

On the other hand, the method of calculating the corrected viscosity ηc (Pa · s) at the share rate γ (sec ⁻¹ ) is as follows.

A plurality of orifices having the same capillary diameter d (mm) and different capillary lengths L (mm) are used by using a viscosity measuring device in which the orifices can be exchanged, and the same temperature and the same share rate γ are obtained. (Sec
^-1 ) Measure the gas mixture molten resin pressure P (Pa) on the upstream side of each orifice under the conditions. Here, the capillary length is L ₁ , L ₂ , ... Ln (mm) (where L ₁ <L ₂ <...
<L _n ) n orifices are used, and the gas mixture resin pressures on the upstream side of the respective orifices are P ₁ , P ₂ , ... P _n .

Capillary lengths L ₁ , L ₂ ... L _n (mm)
And the measured values of the gas-mixed molten resin pressure P ₁ , P ₂ , ... P _n (P
The pressure loss value P ₀ (Pa) when the capillary length L is 0 (mm) is calculated by linear regression obtained from each value of a). FIG. 2 shows an example in which P ₀ (Pa) is calculated by linear regression from a plurality of capillary lengths and the gas-mixed molten resin pressure on the upstream side of each orifice. The gas-mixed molten resin pressure when the capillary length in FIG. 2 is 0 is P ₀ (Pa).

Capillary lengths L ₁ (mm) and L ₂ (m
m) using two orifices, the gas mixture molten resin pressures by the pressure detectors on the upstream side are P ₁ (Pa) and P _{2 respectively.}
If (Pa), the calculation of P ₀ (Pa) is P ₀ = (P
₁ × L ₂ −P ₂ × L ₁ ) ÷ (L ₂ −L ₁ ).

Corrected shear stress τ _c (Pa)
Can be calculated by the following equation 4 using the calculated P ₀ (Pa).

Τ _c = (P _x −P ₀ ) × d ÷ (4 × L _x ) ... Formula 4

Here, L _x is the capillary length (mm) of any of the orifices used for the measurement, and P _x is the gas-mixed molten resin pressure (Pa) measured by the pressure detector immediately upstream of the orifice.

The corrected viscosity η _c (Pa · s) can be calculated by the following equation 5 using the shear rate γ (sec ⁻¹ ) and the corrected shear stress τ _c (Pa).

Η _c = τ _c ÷ γ Equation 5

Same as the apparent viscosity η (Pa · s) described above
, Multiple share rates γ (sec ^-1) Under conditions
Corrected viscosity η_cBy finding
Air rate γ (sec^-1) And the corrected viscosity η_c(P
The correlation graph of a · s) can be obtained. Share
Gamma (sec^-1) And the corrected viscosity η_c(Pa · s)
An example of the correlation graph of is shown in FIG.

With respect to the viscosity obtained by the above method, the characteristics of the resin can be known as data at one temperature level, and by measuring the data at a plurality of temperature levels, CAE (Computer aided e)
It can be used as the data of the flow analysis simulation by ngineering computer aided engineering).

An example of the viscosity measuring device according to the present invention will be described with reference to FIG.

FIG. 4 shows an example of a viscosity measuring apparatus according to the present invention using an extruder. In the figure, 1 is a mixing and extruding apparatus, and a gas supply section (not shown) is provided in the middle of the heating cylinder.
Extruder 2 having a cylinder and cylinder 4 having a plunger 3
It is composed by. The extruder 2 constitutes a melting section and a mixing section connected in series, the cylinder 4 with the plunger 3 constitutes a storage section, and the tip of the cylinder 4 is an extrusion port 5.

Reference numeral 6 denotes a measuring device, which is a supply path 7 for sending the gas-mixed molten resin supplied from the extruder 2 to the cylinder 4.
And a channel 9 connected to the extrusion port 5 for allowing the gas-mixed molten resin extruded from the cylinder 4 to pass through and to flow out from the discharge port 8 at the tip. In the channel 9, the orifice 1
0 is interposed, and pressure detectors 11 for measuring the pressure of the gas-mixed molten resin in the flow path 9 are provided on the upstream side and the downstream side of the orifice 10, respectively. A valve body 12 is provided near the discharge port 8.

Reference numeral 13 is a drive device for moving the plunger 3 forward and backward.

The extruder 1 heats and melts the supplied resin, mixes the gas supplied from the gas supply section in the middle into the heating cylinder, and mixes the mixed gas-mixed molten resin through the supply path 7. And sends it into the cylinder 4. At this time, the valve body 12 is closed, the plunger 3 is placed in the forward position, and the forward force is applied.

Cylinder 4 from extruder 1 via feed passage 7
The gas-mixed molten resin fed inside is filled in the flow path 9 closed by the valve body 12, and is accumulated in the cylinder 4 while gradually retracting the plunger 3 against the advancing force of the plunger 3. It will be. Therefore, the gas-mixed molten resin accumulated in the cylinder 4 is pressurized by the force corresponding to the advancing force applied to the plunger 3, and the release of gas is suppressed.

After accumulating and storing a predetermined amount of the gas-mixed molten resin in the cylinder 4, the valve body 12 is opened, and the retracted plunger is advanced at a set speed.
The gas-mixed molten resin inside is extruded from the extrusion port into the flow path 9. Measured values by the pressure detector 11 at this time, known orifice 10 and dimensions of the plunger 3, and the plunger 3
The apparent viscosity can be obtained from the advancing speed of Eq. In addition, a plurality of orifices 10 are provided,
By providing the pressure detector 11 also between the orifices, the corrected viscosity can be obtained by using the above equations 1, 4, and 5.

Next, another example of the viscosity measuring device according to the present invention will be described with reference to FIG.

FIG. 5 shows an example of a viscosity measuring apparatus according to the present invention using an injection machine. In the figure, 1 is a mixing and extruding apparatus, and a gas supply section (not shown) is provided in the middle of the heating cylinder.
It is constituted by the injection machine 14 having. Injection machine 14
Comprises a melting section, a mixing section and a storage section which are connected in series. The measuring unit of the injection machine 14 constitutes a storage unit,
The tip of the injection machine 14 is the extrusion port 5.

The measuring device 6 is attached in place of the injection nozzle of the injection machine 14, is connected to the extrusion port 5, allows the gas-mixed molten resin extruded from the injection device 14 to pass therethrough, and the discharge port 8 at the tip. It has a flow path 9 for flowing out from. An orifice 10 is interposed in the flow path 9,
A pressure detector 11 for measuring the gas-mixed molten resin pressure in the flow path 9 is provided on the upstream side of the orifice 10. A valve body 12 is provided near the discharge port 8.

The injector 14 heats and melts the supplied resin, mixes the gas supplied from the gas supply unit in the middle into the heating cylinder, and measures the mixed gas-mixed molten resin in the storage unit. Accumulate in the department. At this time, the valve body 12 is closed, and a forward force (back pressure) is applied to a screw (not shown) built in the injector 14.

A part of the gas-mixed molten resin transferred to the metering section (reservoir section) of the injector 14 is part of the valve body 1 of the measuring device 6.
The flow path 9 closed by 2 is filled, and the screw is gradually retracted against the advancing force applied to the screw, and is accumulated in the measuring unit (reserving unit) of the injector 14. . Therefore, the gas-mixed molten resin accumulated in the metering section (reservoir section) of the injector 14 is pressurized by the force corresponding to the advancing force applied to the screw, and the release of gas is suppressed.

After accumulating and storing a predetermined amount of gas-mixed molten resin in the measuring section (reservoir section) of the injector 14, the valve body 12 is opened, and the retreated screw is set as in the normal injection operation. By advancing at a speed, the gas-mixed molten resin in the measuring unit (reservoir) is pushed out from the extrusion port to the flow path 9.
From the measured values by the pressure detector 11 at this time, the dimensions of the known orifice 10 and screw, and the advancing speed of the screw, the apparent viscosity can be obtained by using the above equations 1 to 3. Further, by providing a plurality of orifices 10 and providing a pressure detector 11 between each orifice,
4, 5 can be used to obtain a corrected viscosity.

[0092]

[Examples] Viscosity was measured by a viscosity measuring device using an injection machine as shown in FIG.

As the pressure detector, a pressure sensor "NP465XL-1 / 2-200 MPa" manufactured by Dynisco Corporation was used. The output value from the pressure sensor is output as a voltage value and a current value through a pressure sensor amplifier "N600D-64" manufactured by the same company. The current signal was displayed by reading a numerical value by inputting it to a digital indicator "1400-4-3" manufactured by the same company. Moreover, the waveform data was displayed by inputting the voltage signal into the digital scope "DL708E" manufactured by Yokogawa Electric Corporation, and this was read as pressure data.

The resins used for the measurement were modified PPE resin ("Zylon 540Z" manufactured by Asahi Kasei), POM resin ("TENAC 4010" manufactured by the same company), PA66 resin ("Leona 1300G" manufactured by the same company), PBT system. Resin (Wintec Polymer's "Duranex 733L"
D)), PC resin ("Multilon TN" manufactured by Teijin Chemicals Ltd.
-3813BW "), and each has a pellet shape before viscosity measurement.

Examples 1 to 3 Modified PPE resin heated to 300 ° C. by an injector having a gas supply part in the middle part and carbon dioxide adjusted to a pressure in the range of 4 to 12 MPa were mixed, and the gas was mixed. The apparent viscosity of the mixed molten resin was measured.

Capillary diameter 2 mm, capillary length 2
Using a 0 mm orifice, the share rate (γ) is
The range was 7.84 × 10 ² to 1.18 × 10 ⁵ (sec ⁻¹ ).

The measurement results are shown in Table 1 and FIG.

Reference Example 1 The apparent viscosity of the modified PPE resin was measured in the same manner as in Examples 1 to 3 except that carbon dioxide was not mixed.

The measurement results are shown in Table 1 and FIG.

[0100]

[Table 1]

Examples 4 and 5 POM resin heated to 190 ° C. by an injection machine having a gas supply part in the middle and carbon dioxide adjusted to 6 MPa were mixed to give an apparent viscosity of the gas-mixed molten resin. The measurement was performed.

Capillary diameter 1 mm, capillary length 1
A 0 mm orifice is used and the share rate is 6.2.
The range was from 7 × 10 ³ to 9.41 × 10 ⁵ (sec ⁻¹ ).

The measurement results are shown in Table 2 and FIG.

Reference Example 2 The apparent viscosity of the POM resin was measured in the same manner as in Examples 4 and 5 except that carbon dioxide was not mixed.

The measurement results are shown in Table 2 and FIG.

[0106]

[Table 2]

Examples 6 to 8 PBT resin heated to 265 ° C. by an injector having a gas supply section in the middle and carbon dioxide adjusted to a pressure in the range of 4 to 12 MPa were mixed, and the gas was mixed. The apparent viscosity of the molten resin was measured.

Capillary diameter 1 mm, capillary length 1
Using a 0 mm orifice, the share rate (γ) is
The range was 6.27 × 10 ³ to 9.41 × 10 ⁵ (sec ⁻¹ ).

The measurement results are shown in Table 3 and FIG.

Reference Example 3 The apparent viscosity of the PBT resin was measured in the same manner as in Examples 6 to 8 except that carbon dioxide was not mixed.

The measurement results are shown in Table 3 and FIG.

[0112]

[Table 3]

Examples 9 to 11 PC resin heated to 280 ° C. by an injector having a gas supply part in the middle part and carbon dioxide adjusted to a pressure in the range of 4 to 12 MPa are mixed, and the gas is mixed. The apparent viscosity of the molten resin was measured.

Capillary diameter 1 mm, capillary length 1
Using a 0 mm orifice, the share rate (γ) is
The range was 6.27 × 10 ³ to 9.41 × 10 ⁵ (sec ⁻¹ ).

The measurement results are shown in Table 4 and FIG.

Reference Example 4 The apparent viscosity of PC resin was measured in the same manner as in Examples 9 to 11 except that carbon dioxide was not mixed.

The measurement results are shown in Table 4 and FIG.

[0118]

[Table 4]

Examples 12 and 13 PA66 resin heated to 280 ° C. by an injector having a gas supply section in the middle and carbon dioxide adjusted to a pressure in the range of 4 and 8 MPa were mixed, and the gas was mixed. The apparent viscosity of the molten resin was measured.

Capillary diameter 1 mm, capillary length 5
Using the mm orifice, the share rate (γ) is
The range was 6.27 × 10 ³ to 9.41 × 10 ⁵ (sec ⁻¹ ).

The measurement results are shown in Table 5 and FIG.

Reference Example 5 Examples 12 and 13 except that carbon dioxide was not mixed.
In the same manner as above, the apparent viscosity of PA66 resin was measured.

The measurement results are shown in Table 5 and FIG.

[0124]

[Table 5]

Examples 14 and 15 PA66 resin heated to 280 ° C. by an injector having a gas supply section in the middle and carbon dioxide adjusted to a pressure in the range of 4 and 8 MPa are mixed, and the gas is mixed. The apparent viscosity of the molten resin was measured.

Capillary diameter 1 mm, capillary length 1
Using a 0 mm orifice, the share rate (γ) is
The range was 6.27 × 10 ³ to 9.41 × 10 ⁵ (sec ⁻¹ ).

The measurement results are shown in Table 6 and FIG.

Reference Example 6 Examples 14 and 15 except that carbon dioxide was not mixed.
In the same manner as above, the apparent viscosity of PA66 resin was measured.

The measurement results are shown in Table 6 and FIG.

[0130]

[Table 6]

Examples 16 and 17 Pressure measurement results obtained using the orifices having a capillary diameter of 1 mm and a capillary length of 5 mm obtained in Examples 12 and 13 and the capillary diameter of 1 m obtained in Examples 14 and 15.
m and a pressure measurement result using an orifice having a capillary length of 10 mm, the baggley correction was performed, and the corrected viscosity was calculated.

The calculation results of the corrected resin viscosity are shown in Table 7 and FIG.

Reference Example 7 By the same method as in Examples 16 and 17, baggley correction was performed from the pressure measurement results of Comparative Examples 5 and 6, and the corrected viscosity was calculated.

The calculation results of the corrected resin viscosity are shown in Table 7 and FIG.

[0135]

[Table 7]

[0136]

The present invention is as described above, and can provide the viscosity data of the gas-mixed molten resin, so that the simulation of the flow pattern using a computer can be easily performed. Therefore, it becomes easy to design a mold for molding with the gas-mixed molten resin, and it becomes possible to obtain an injection molded product having high mold transferability, dimensional accuracy, and dimensional stability.

[Brief description of drawings]

FIG. 1 is an example of a correlation diagram between a share rate and an apparent viscosity.

FIG. 2 is a theoretical diagram for calculating a P ₀ value required for Bagley correction.

FIG. 3 is an example of a correlation diagram between a share rate and a corrected viscosity.

FIG. 4 is a diagram showing an example of a viscosity measuring device according to the present invention.

FIG. 5 is a diagram showing another example of the viscosity measuring device according to the present invention.

FIG. 6 is a correlation diagram of shear rates and apparent viscosities obtained in Examples 1 to 3 and Reference Example 1.

FIG. 7 is a correlation diagram of shear rates and apparent viscosities obtained in Examples 4 and 5 and Reference Example 2.

8 is a correlation diagram of shear rates and apparent viscosities obtained in Examples 6 to 8 and Reference Example 3. FIG.

9 is a correlation diagram of the shear rate and the apparent viscosity obtained in Examples 9 to 11 and Reference 4. FIG.

FIG. 10 is a correlation diagram of shear rate and apparent viscosity obtained in Examples 12 and 13 and Reference 5.

11 is a correlation diagram of shear rates and apparent viscosities obtained in Examples 14 and 15 and Reference Example 6. FIG.

FIG. 12 is a correlation diagram of shear rates and corrected viscosities obtained in Examples 16 and 17 and Reference Example 7.

[Explanation of symbols]

1 Extruder 2 extruder 3 Plunger 4 cylinders 5 Extrusion port 6 Measuring device 7 supply route 8 outlets 9 channels 10 Orifice 11 Pressure detector 12 valve bodies 13 Drive 14 injection machine

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F206 AB16 AP03 AP16 JA07 JF02                       JF21 JF41 JM01 JN01 JN03                       JP11

Claims (12)

[Claims] 1. A mixing section for mixing and transferring a molten resin and a gas, a storage section for accumulating and storing the gas-mixed molten resin transferred from the mixing section and preparing for extrusion from an extrusion port, and a shaft. It is possible to move back and forth in the direction, and at the time of forward movement, a mixing / extruding device having a screw or a plunger that pushes out the gas-mixed molten resin stored in the storage portion from the extrusion port, and the extrusion port of this mixing extrusion device, A flow path for flowing the gas-mixed molten resin extruded from the outlet to the discharge port, and an orifice interposed in this flow path,
And a measuring device having a pressure detector for detecting the pressure of the gas-mixed molten resin in the flow path on the upstream side of the orifice, and between the reservoir of the mixing-extruding device and the orifice of the measuring device and the orifice of the measuring device. A valve element is provided on at least one of the discharge ports, and by closing this valve element, the gas-mixed molten resin can be accumulated and stored under pressure in the storage section of the mixing extruder. Viscometer. 2. The viscosity measuring device according to claim 1, wherein the valve body is a flow rate adjusting valve whose opening can be adjusted. 3. The viscosity measuring device according to claim 1, further comprising a pressure detector for detecting the pressure of the gas-mixed molten resin in the flow passage downstream of the orifice of the measuring device. 4. A backflow prevention mechanism is provided between the mixing section and the storage section of the mixing and extrusion apparatus, and further, the accumulation of the gas-mixed molten resin in the storage section is caused by the gas-mixed fusion stored in the storage section. The viscosity measuring device according to any one of claims 1 to 3, which is performed while the screw or the plunger is pushed backward against the forward force applied to the screw or the plunger that pushes out the resin from the extrusion port. 5. The viscosity measuring apparatus according to claim 4, wherein the mixing section of the mixing extrusion apparatus is constituted by an extruder or an injection machine having a gas supply section in the middle of the heating cylinder. 6. The in-line screw type in which the mixing and extruding device has a valve body at the injection port as a valve body between the reservoir of the mixing and extruding device and the orifice of the measuring device, and has a gas supply part in the middle of the heating cylinder. The viscosity measuring apparatus according to claim 4, wherein the viscosity measuring apparatus is configured by a screw pre-plastic injection machine. 7. The viscosity measuring device according to claim 1, wherein the orifices can be replaced with orifices having the same capillary diameter and different capillary lengths. 8. The viscosity measuring device according to claim 1, wherein the orifice having a capillary diameter of d (mm) and a capillary length of L (mm) is stored in a storage portion. The gas-mixed molten resin is extruded from the extrusion port of the mixing-extrusion device under the predetermined shear rate γ (sec ^-1 ) obtained by the following formula 1 and allowed to flow through, and the gas-mixed molten resin in the flow path on the upstream side of the orifice Measure the resin pressure with a pressure detector, and calculate the apparent shear stress τ using the following formula 2.
(Pa) is calculated and the apparent viscosity η (Pa · s) is calculated by the following formula 3.
A method for measuring viscosity, which comprises: Here, P is the gas-mixed molten resin pressure (Pa) in the flow path on the upstream side of the orifice, D is the screw or plunger diameter (mm), S
Is the forward speed of the screw or plunger (mm / se
c) and Q are volumetric flow rate ratios (mm ³ / sec), and Q =
(Π × D ² ÷ 4) × S. γ = (4 × Q) ÷ (π × d ³ ÷ 8) Equation 1 τ = (P × d) ÷ (4 × L) Equation 2 η = τ ÷ γ Equation 3 9. An apparent viscosity curve in a constant shear rate range is obtained by obtaining an apparent viscosity η (Pa · s) under a plurality of share rates γ (sec ⁻¹ ) respectively. Item 7. The method for measuring resin viscosity according to Item 7. 10. The viscosity measuring device according to claim 7, wherein the capillary diameter d (mm) is the same and the capillary lengths are L ₁ and L ₂ (provided that L ₁ <L ₂ ) (mm). With respect to the orifices, the gas-mixed molten resin stored in the storage section is extruded from the extrusion port of the mixing-extrusion device under the same share rate γ (sec ^-1 ) obtained by the following formula 1 to flow through each of the orifices. The gas-mixed molten resin pressures P ₁ and P ₂ (Pa) in the flow passages on the upstream side of the orifices are measured by pressure detectors, respectively, and the capillary lengths L ₁ and L ₂ (mm) of the orifices and the orifices concerned are measured. The pressure loss value P ₀ (Pa) when the capillary length of the orifice is 0 is P ₀ = (P ₁ × L ₂ −P ₂ ) from the gas mixture molten resin pressures P ₁ and P ₂ (Pa) on the upstream side of X L ₁ ) and corrected by the following equation 4. And a shear stress τ _c (Pa), and a viscosity η _c (Pa · s) corrected by the following equation 5 is calculated. Here, L _x is the capillary length (mm) of any orifice, P _x is the gas-mixed molten resin pressure (Pa) on the upstream side of the orifice having a capillary length of L _x , D is the screw or plunger diameter (mm), S
Is the forward speed of the screw or plunger (mm / se
c) and Q are volumetric flow rate ratios (mm ³ / sec), and Q =
(Π × D ² ÷ 4) × S. γ = (4 × Q) ÷ (π × d ³ ÷ 8) Equation 1 τ _c = (P _x −P ₀ ) × d ÷ (4 × L _x ) ... Equation 4 η _c = τ _c ÷ γ 5 11. Use of the viscosity measuring device according to claim 7.
Capillary with the same diameter d (mm)
Length is L₁, L₂, ... L_n(However, L₁<L₂<... <L_n) (M
m) three or more orifices, respectively, storage
The gas-mixed molten resin stored in the
Same share rate γ (sec ^-1) Under mixed extrusion
Extrude from the extrusion port of the device and let it flow through,
About the gas mixture molten resin pressure P in the upstream flow path₁，
P₂,… P_nWhen each (Pa) is measured with a pressure detector,
Capillary length L of each orifice₁, L₂, ... L_n
(Mm) and mixed molten resin pressure on the upstream side of the orifice
P₁, P₂,… P_nFrom (Pa), the capacity of the orifice
Pressure loss value P when rally length is 0₀(Pa) linear regression
And the shear stress τ corrected by the following equation 4
_c(Pa) is calculated and the viscosity η corrected by the following equation 5_c(Pa
-A method for measuring viscosity, which comprises determining s). However,
L_xIs the capillary length of either orifice (m
m), P_xHas a capillary length of L_xUpstream of the orifice
Gas mixed molten resin pressure (Pa) by the latest pressure detector,
D is screw or plunger diameter (mm), S is screw
Or plunger forward speed (mm / sec), Q is volume
Flow rate (mm³/ Sec), Q = (π × D²÷ 4) ×
It is S. γ = (4 × Q) ÷ (π × d³÷ 8) ... Equation 1 τ_c= (P_x-P₀) × d ÷ (4 × L_x)… Equation 4 η_c= Τ_c÷ γ ... Equation 5 12. A plurality of share rates γ (sec ^-1 )
The method for measuring resin viscosity according to claim 10 or 11, wherein a corrected viscosity curve in a constant shear rate range is obtained by obtaining the corrected viscosity η _c (Pa · s) below.