JP7665371B2 - ACTUATOR AND METHOD FOR MANUFACTURING ACTUATOR - Google Patents

Description

The present invention relates to an actuator and a method for manufacturing an actuator.

Due to the advent of aging societies in developed countries, advances in robotics, and the shift towards intellectual activities among humans, there is a demand for powering a variety of items, and various actuators have been proposed.
For example, Patent Document 1 discloses an actuator including a polymer fiber into which twist has been introduced in a coiled or non-coiled form.

An actuator containing a polymer fiber with non-coiled twist is formed by selecting a single filament or multifilament precursor polymer fiber (hereinafter also referred to as a fibrous polymer material) that is high strength and highly chain-oriented, and introducing twist into the fibrous polymer material to a level that does not produce coiling.

An actuator including a polymer fiber with coiled twist is formed by introducing twist into the fibrous polymer material to the extent that coiling occurs or to a level that does not produce coiling, and then introducing coiling in the same or opposite direction to the twist introduced initially.

Patent Document 1 discloses a non-electrochemical actuator in which an electronic conductor (hereinafter also referred to as conductive yarn) such as a multi-walled carbon nanotube (MWNT) is spirally wound around a nanofiber twist-spun yarn segment, which is the fibrous polymer material, to enable electrothermal operation.

JP 2016-42783 A

When a conductive thread is wound spirally around a fibrous polymer material, the conductive thread may not be sufficiently fixed to the fibrous polymer material and may come off, preventing the desired actuator performance from being obtained.

The present invention was made in consideration of the above circumstances, and aims to provide an actuator that includes a fibrous polymer material and a conductive thread, and that is highly effective in fixing the conductive thread to the fibrous polymer material, and a method for manufacturing the actuator.

The present invention has the following aspects.
[1] A fibrous polymer material;
A composite elongated body including a thermoplastic resin and a conductive thread,
the composite long body is wound in a spiral shape around the fibrous polymer material,
An actuator which satisfies the following formula 1, where V1 is the total volume of the thermoplastic resin contained per 1 m of the composite long body, and A1 is the total surface area of the conductive yarn contained per 1 m of the composite long body.
5 [μm ³ /μm ² ]≦V1/A1≦60 [μm ³ /μm ² ] Formula 1
[2] A step of spirally winding a composite yarn obtained by combining a fusion yarn containing a thermoplastic resin and a conductive yarn around a fibrous polymer material;
heating the composite yarn to fuse it to a surface of the fibrous polymeric material;
A method for manufacturing an actuator comprising:
A method for manufacturing an actuator, which satisfies the following formula 2 when the total volume of the fusion yarns contained per 1 m of the composite yarn is V2 and the total surface area of the conductive yarns contained per 1 m of the composite yarn is A2.
5 [μm ³ /μm ² ]≦V2/A2≦60 [μm ³ /μm ² ] Formula 2
[3] The method for manufacturing an actuator according to [2], wherein the composite yarn is a composite yarn obtained by combining the fusion yarn and the conductive yarn through twisting.

The actuator of the present invention comprises a fibrous polymer material and a conductive thread, and can provide an actuator that is highly effective in fixing the conductive thread to the fibrous polymer material, as well as a method for manufacturing the actuator.

FIG. 1 is a schematic diagram illustrating an actuator according to an embodiment of the present invention. 5 is a manufacturing flow diagram of an actuator according to an embodiment of the present invention. FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate.
In addition, the figures used in the following explanation may show key parts enlarged for convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not necessarily be the same as the actual ones.

<Actuator>
FIG. 1 is a schematic diagram showing an actuator 1 according to a first embodiment of the present invention.
The actuator 1 comprises a fibrous polymer material 10 that is deformed by heating, and a composite elongated body 20 including a thermoplastic resin and a conductive thread, the composite elongated body 20 being spirally wound around the fibrous polymer material 10. When the total volume of the thermoplastic resin contained per meter of the composite elongated body 20 is V1 and the total surface area of the conductive thread contained per meter of the composite elongated body 20 is A1, the following formula 1 is satisfied.
5 [μm ³ /μm ² ]≦V1/A1≦60 [μm ³ /μm ² ] Formula 1

In the actuator 1 of this embodiment, the composite elongated body 20 containing the conductive thread contains a thermoplastic resin, so the conductive thread is fixed to the fibrous polymer material 10 effectively, and the desired actuator operating performance can be stably obtained.

[Fibrous polymeric material]
The fibrous polymer material for obtaining an actuator that is driven by heating may be twisted in a coiled shape so as to wind a spiral, or may be twisted in a non-coiled shape while maintaining a linear shape without winding a spiral. In addition, the fibrous polymer material may be twisted in a non-coiled shape and then formed into a coiled shape by a method other than the twist introduction. A coiled or non-coiled twisted fibrous polymer material can be obtained, for example, by the method described in JP 2016-42783 A.

Let us take nylon 6,6 as an example of a polymer that constitutes a fibrous polymer material. When a nylon 6,6 monofilament with a diameter of 250 μm is twisted in an environment of 25°C with an appropriate tensile stress applied so as not to cause coiling, it can be rotated up to about 850 to 1150 times per meter. If the nylon 6,6 monofilament is twisted beyond this number of rotations, it will coil or break.

When a nylon 6,6 monofilament with a diameter of 500 μm is twisted at 25°C with an appropriate tensile stress applied without causing coiling, it can rotate up to about 400 to 600 times per meter.

In this manner, a fiber made of a polymer having a glass transition temperature higher than 25° C. can be twisted to the point of just before coiling by applying an appropriate tensile stress in a temperature environment below the glass transition temperature of the polymer (e.g., 25° C.). The appropriate tensile stress is approximately 4.5×10 ⁻³ times the tensile modulus of the fiber, with a value in the vicinity of that, for example, 1×10 ⁻³ to 1×10 ⁻² times the tensile modulus of the fiber.

When manufacturing a fibrous polymer material to obtain an actuator that is driven by heat, the temperature environment in the fiber twisting process may be an environment at a temperature higher than the glass transition temperature of the polymer, preferably an environment at a temperature 10°C or more higher than the glass transition temperature of the polymer, and more preferably an environment at a temperature 20°C or more higher than the glass transition temperature of the polymer. An environment at a temperature 40°C or more higher than the glass transition temperature of the polymer is particularly preferable. By setting the temperature environment in the fiber twisting process at a higher temperature, the torque required to twist the fiber can be reduced, and it is also useful in that thick or rigid fibers that previously required a very large torque can be easily twisted.

In a fibrous polymer material that has been twisted in a temperature environment close to the glass transition temperature of the polymer, it is preferable to carry out a residual stress relaxation process, such as storing the material in an environment above the glass transition temperature of the polymer for a certain period of time, in order to suppress the return of the twist to its original state.

In the actuator of the present invention, the glass transition temperature (Tg) of the polymer constituting the fibrous polymer material may be higher than 25°C or higher than 45°C. For example, types of polymers include nylons such as nylon 6 (Tg: 45°C) and nylon 6,6 (Tg: 47°C), acrylic resins such as polymethyl methacrylate (Tg: 100°C), polyester resins such as polyethylene terephthalate (Tg: 80°C), polyvinyl chloride (Tg: 82°C), polycarbonate (Tg: 150°C), etc. In addition, types of polymers with a glass transition temperature (Tg) lower than 25°C include polyethylene (Tg: -120°C), polypropylene (Tg: -20°C), etc.

The polymers constituting the fibrous polymer material are preferably crystalline. The degree of crystallinity of the polymers in the fibrous polymer material is preferably 50% or more, and more preferably 55% to 90%. With a degree of crystallinity in this range, it becomes easy to obtain a material with high anisotropy of molecular orientation and excellent effectiveness as an actuator.

In the actuator of the present invention, the fibrous polymer material may be a monofilament fiber or may be made of a multifilament fiber.

[Composite long body]
The composite elongated body 20 includes a thermoplastic resin and a conductive thread.

Examples of thermoplastic resins include polyolefins such as polyethylene and polypropylene; polyamides such as nylon 6, nylon 6,6 and nylon 6,10; polyethylene terephthalate; polyesters; and fluoropolymers such as polyvinylidene fluoride, with polyamides being preferred.
The thermoplastic resin may be used alone or in combination of two or more kinds.

The melting temperature of the thermoplastic resin is preferably 60 to 180°C, more preferably 70 to 170°C, and even more preferably 80 to 160°C. If the melting temperature is equal to or higher than the lower limit of the range, the thermoplastic resin will not melt due to the heat generated when driving the actuator, and the effect of fixing the conductive thread to the fibrous polymer material 10 will be sustained, making it easier to stably obtain the desired actuator operating performance. If the melting temperature is equal to or lower than the upper limit of the range, the step of heating the composite thread in the actuator manufacturing method described below can be performed at a heating temperature that does not damage the fibrous polymer material 10.

Examples of the conductive thread include metal wires, carbon nanotube conductive threads, conductive threads with metal-plated cores, etc., and conductive threads with metal-plated cores are preferred from the viewpoint of flexibility and light weight. Examples of the metal wire include stainless steel wires such as SUS302 and SUS304, tungsten wires, silver wires, gold wires, and wires made of two or more of these metals (for example, wires in which the surface of a metal is plated with another metal).
In the conductive thread having a metal-plated core, any plating method known in the art can be used without restriction to plate the core with a metal.

Examples of the core material include those made of polymers exemplified as the polymers constituting the fibrous polymer material, such as nylons (nylon 6, nylon 6,6, nylon 6,10, etc.), polyether ether ketone, and polyvinylidene fluoride.
The polymers may be used alone or in combination of two or more.

The melting temperature of the core material is preferably at least 50°C higher than the melting temperature of the thermoplastic resin, more preferably at least 60°C higher, and even more preferably at least 70°C higher.

The metal to be plated is not particularly limited as long as the effects of the present invention can be obtained, but examples include gold, silver, copper, nickel, etc., with silver being preferred.
The above metals may be used alone or in combination of two or more.

The diameter of the conductive thread is preferably 1 to 1000 μm, more preferably 5 to 500 μm, and even more preferably 10 to 100 μm. When the diameter of the conductive thread is equal to or greater than the lower limit of the above range, conductivity is ensured and disconnection due to wear and the like can be suppressed. When the diameter of the conductive thread is equal to or less than the upper limit of the above range, flexibility and handleability are improved. In addition, inhibition of actuator movement is suppressed.
In the above description, the conductive thread is assumed to be substantially circular, but it may be substantially elliptical. In this case, the diameter of the conductive thread is determined to be the average of the major axis and the minor axis of the substantially elliptical shape.

The number of conductive threads contained in the composite elongated body 20 is preferably 1 to 10, more preferably 1 to 7, and even more preferably 1 to 5. When the number of conductive threads is equal to or greater than the lower limit of the range, the decrease in the conductivity of the actuator is suppressed. When the number of conductive threads is equal to or less than the upper limit of the range, the fixing effect of the conductive threads to the fibrous polymer material is enhanced. In addition, the rigidity is within an appropriate range. In addition, the proportion of thermoplastic resin contained in the composite elongated body 20 is not too small, improving adhesion.
It is preferable that a portion of the conductive thread is exposed on the surface of the composite elongated body 20. By having a portion of the conductive thread exposed on the surface of the composite elongated body 20, poor contact is less likely to occur when the conductive thread is connected to an external power source.

When the total volume of the thermoplastic resin contained per meter of the composite long body 20 is V1 and the total surface area of the conductive yarn contained per meter of the composite long body is A1, the following formula 1 is satisfied.
5 [μm ³ /μm ² ]≦V1/A1≦60 [μm ³ /μm ² ] Formula 1

V1/A1 is 5 to 60 ^μm3 / ^μm2 , preferably 7 to 55 ^μm3 / ^μm2 , and more preferably 10 to 30 ^μm3 /μm2. When V1/A1 is equal to or ^greater than the lower limit of the aforementioned range, the effect of fixing the conductive thread to the fibrous polymer material is enhanced. When V1/A1 is equal to or less than the upper limit of the aforementioned range, the conductivity of the conductive thread in the actuator is enhanced.

[Method of measuring V1/A1]
When the composite elongated body 20 is pulled while the actuator 1 is heated with a hair dryer or a heat gun, the composite elongated body 20 can be peeled off from the fibrous polymer material 10. The mass per unit length (l ₁ [m]) of the obtained composite elongated body 20 is measured. The conductive thread is isolated from the composite elongated body 20, and the mass of the conductive thread contained per unit length (l ₁ [m]) of the composite elongated body 20 is measured. The difference between the mass per unit length (l ₁ [m]) of the composite elongated body 20 and the mass of the conductive thread contained per unit length (l ₁ [m]) of the composite elongated body 20 is calculated, and the mass of the thermoplastic resin contained per unit length (l ₁ [m]) of the composite elongated body 20 is calculated. From the obtained mass and the density of the thermoplastic resin, the volume (V1' [μm ³ ]) of the thermoplastic resin contained per unit length (l ₁ [m]) of the composite elongated body 20 is calculated. The total volume V1 of the thermoplastic resin contained per meter of the composite elongated body 20 can be obtained from V1' x 1/ _l1 .
The diameter _r2 [μm] of the conductive thread contained per unit length ( _l1 [m]) of the composite elongated body 20 isolated by the above-mentioned method is measured by optical observation. The surface area of the conductive thread contained per meter of the composite elongated body 20 is _r2 ×π×1× ¹⁰⁶ [ ^μm2 ]. When multiple conductive threads are contained in the composite elongated body, the surface area of all the conductive threads can be calculated and the total value can be taken as A2 ( ^μm2 ). The number of conductive threads can be confirmed by optical observation.
In the above description, the conductive thread is assumed to be substantially circular, but it may be substantially elliptical. In this case, the average of the major axis and the minor axis of the substantially elliptical shape is set as the diameter _r2 [μm] of the conductive thread.

In addition, when the actuator 1 is manufactured by the actuator manufacturing method described below, V2/A2 obtained by the method described below as the method for measuring V2/A2 can be used as V1/A1.

As shown in FIG. 1, the actuator 1 has a substantially cylindrical fibrous polymer material 10 having a diameter D ₁₀ and a composite long body 20 having a diameter D ₂₀ wound helically with a predetermined gap I ₂₀ therebetween.

As shown in FIG. 1, when the angle formed between the composite long body 20 and the fibrous polymeric material 10 is θ, the pitch of the composite long body 20 can be expressed as [I ₂₀ +(D ₂₀ /sin θ)].
From the viewpoint of reducing the variation in pitch [ _I20 + ( _D20 /sin θ)], the cross section of the fibrous polymeric material 10 is preferably approximately circular, and although the description is given assuming that the cross section is approximately circular, the cross section may also be approximately elliptical. In this case, the average of the major axis and minor axis of the ellipse can be understood as the diameter _D10 .

The diameter _D10 of the fibrous polymeric material 10 may be 0.01 mm< _D10 ≦40 mm, 0.05 mm< _D10 ≦10 mm, or 0.1 mm< _D10 ≦1 mm. When _D10 is equal to or greater than the lower limit of the range, mechanical damage such as breakage is unlikely to occur during processing, after processing, or during operation, and the quality of the actuator is maintained. When _D10 is equal to or less than the upper limit of the range, the motion that can be obtained from the unit length of the actuator can be sufficiently large.
In this specification, D ₁₀ can be determined by measuring the diameter D ₁₀ of the approximately cylindrical fibrous polymer material 10 in the actuator at 5 to 10 randomly selected points and averaging the measurements.

The diameter _D20 of the composite elongated body 20 may be 0.04 mm< _D20 ≦1.6 mm, 0.1 mm< _D20 ≦1.5 mm, or 0.2 mm< _D20 ≦1.4 mm. When _D20 is equal to or greater than the lower limit of the range, the possibility of a handling error such as the composite elongated body 20 being cut during the manufacture of the actuator 1 is reduced. When _D20 is equal to or less than the upper limit of the range, the risk of impeding the operation of the actuator 1 is reduced.
The cross section of the composite elongated body 20 is described below on the assumption that it is substantially circular, but it may be substantially elliptical or flat. The major axis of the elliptical or flat shape can be understood as the diameter _D20 .
In this specification, _D20 can be determined by measuring the width direction length ( _D20 in FIG. 1) of the composite elongated body 20 in a planar view when observing the actuator 1 with an optical microscope at 5 to 10 randomly selected points, and taking the average of these measurements.

The relationship between the diameter _D10 of the fibrous polymer material 10 and the diameter _D20 of the composite elongated body 20 is preferably 0.1≦ _D20 / _D10 <1.0, more preferably 0.2≦ _D20 / _D10 ≦0.8, and particularly preferably 0.4≦ _D20 / _D10 ≦0.7. When _D20 / _D10 is within the above range, the conductive yarn can be fixed to the fibrous polymer material without impeding the drive of the actuator.

The pitch [ _I20 +( _D20 /sin θ)] of the composite elongated body 20 is preferably 0.01 mm≦[ _I20 +( _D20 /sin θ)]≦5.0 mm, more preferably 0.05 mm≦[ _I20 +( _D20 /sin θ)]≦1.0 mm, and even more preferably 0.1 mm≦[ _I20 +( _D20 /sin θ)]≦0.5 mm. When [ _I20 +( _D20 /sin θ)] is within the above range, the actuator can be driven without being hindered and heat can be transmitted uniformly.

The diameter D20 of the composite elongated body ₂₀ and the gap interval _I20 of the composite elongated body 20 are preferably 0.5≦ _I20 / _D20 ≦20, more preferably 1≦ _I20 / _D20 ≦10, and particularly preferably 2≦ _I20 / _D20 ≦5. When _I20 / _D20 is within the above range, the conductive yarn can be fixed to the fibrous polymer material without impeding the drive of the actuator.
In this specification, _I20 can be determined by measuring the gap spacing ( _I20 in FIG. 1) of the composite elongated body 20 in a planar view when observing the actuator 1 with an optical microscope at 5 to 10 randomly selected points and averaging them.

The angle θ between the composite elongated body 20 and the fibrous polymer material 10 is 0°<θ<90°, preferably 20°≦θ≦70°, and more preferably 30°≦θ≦60°. When θ is within the above range, heat can be transferred uniformly over the entire length of the actuator without uneven heating.
In this specification, θ can be determined by measuring the angle (θ in Figure 1) between the composite elongated body 20 and the fibrous polymer material 10 in a planar view when observing the actuator 1 with an optical microscope at 5 to 10 randomly selected points and taking the average of these angles.

In the actuator 1, the coverage of the composite elongated body 20 with respect to the outer surface area of the actuator 1 in a plan view when observed with an optical microscope is preferably 10 to 60%, more preferably 20 to 50%, and even more preferably 30 to 40%. When the coverage is equal to or greater than the lower limit of the range, the effect of fixing the conductive thread to the fibrous polymer material 10 is enhanced, and the effect of preventing the conductive thread from falling off is enhanced. As a result, it becomes easier to stably obtain the desired actuator operation performance. When the coverage is equal to or less than the upper limit of the range, the adverse effect of the coverage on the actuator operation can be reduced. In addition, the amount of thermoplastic resin used can be reduced, which is economical.
In this specification, the coverage can be determined by the following method.
When the actuator 1 is observed under an optical microscope in a plan view, the length (L1i) occupied by the composite elongated body 20 and the length (L2i) of the portion not covered by the composite elongated body 20 in any straight line in the axial direction of the actuator 1 (axial direction of the fibrous polymeric material 10) are measured ( FIG. 1 ). The sum of the measured L1i is defined as L1, the sum of the measured L2i is defined as L2, and the coverage rate can be determined as L1/(L1+L2)×100.

A method for fixing a conductive thread to a fibrous polymer material has been known to use a liquid adhesive containing an organic solvent. Specifically, a liquid adhesive is applied to a fibrous polymer material around which a conductive thread is wound in a spiral shape, and then the adhesive is dried to form an adhesive layer. However, when a liquid adhesive containing an organic solvent is used, an additional step of drying the organic solvent is required, which complicates the manufacturing process of the actuator. In addition, since the liquid adhesive is applied to the entire surface of the fibrous polymer material around which the conductive thread is wound in a spiral shape, the conductive thread is completely covered by the adhesive layer, making it difficult to connect external power.
Forming an adhesive layer so as not to cover a portion of the conductive yarn makes the process more complicated and makes quality control difficult. On the other hand, in the manufacturing method of the actuator of this embodiment, as described below, the composite yarn containing the conductive yarn is wound around a fibrous polymer material and then heated, so that it is not necessary to use an organic solvent, the manufacturing process is simple, and it is advantageous in that the above-mentioned coverage rate can be easily controlled to a constant level.

<Actuator Manufacturing Method>
The method for manufacturing the actuator of this embodiment includes a step of spirally winding a composite yarn 20', which is a composite of a fusion yarn containing a thermoplastic resin and a conductive yarn, around a fibrous polymer material 10 (hereinafter also referred to as "step 1"), and a step of heating the composite yarn to fuse it to the surface of the fibrous polymer material (hereinafter also referred to as "step 2") (Fig. 2). When the total volume of the fusion yarns contained per meter of the composite yarn is V2 and the total surface area of the conductive yarns contained per meter of the composite yarn is A2, the following formula 2 is satisfied.
5 [μm ³ /μm ² ]≦V2/A2≦60 [μm ³ /μm ² ] Formula 2

According to the method for manufacturing the actuator of this embodiment, the fusion yarn contained in the composite yarn 20' is melted, so that the composite yarn 20' becomes a composite long body 20, and the actuator 1 described above can be manufactured.
Each step will be described below.

[Step 1]
The fibrous polymer material 10 used in step 1 can be the same as the fibrous polymer material described in the actuator 1 above. In step 1, a composite thread 20' obtained by combining a fusion thread containing a thermoplastic resin and a conductive thread is spirally wound around the fibrous polymer material 10. The winding density, which is expressed by the number of windings of the composite thread per meter of the fibrous polymer material, may be set so that the pitch [I ₂₀ + (D ₂₀ /sin θ)] of the composite elongated body 20 in the actuator 1 above, the angle θ between the composite elongated body 20 and the fibrous polymer material 10, and the like, fall within a predetermined range, and is preferably 500 to 10,000 turns/m, more preferably 1,000 to 8,000 turns/m, and even more preferably 2,000 to 6,000 turns/m. The predetermined angle θ is the preferred range of θ described in the actuator 1 above.

The composite yarn 20' used in step 1 is a composite yarn made by combining a fusion yarn containing a thermoplastic resin and a conductive yarn. The conductive yarn used in the composite yarn can be the same as the conductive yarn described in the actuator 1 above. The fusion yarn used in the composite yarn can be, for example, a thread of the thermoplastic resin described in the actuator 1 above. The diameter of the fusion yarn may be 0.05 to 0.6 mm, 0.1 to 0.5 mm, or 0.2 to 0.4 mm. If the diameter of the fusion yarn is equal to or greater than the lower limit of the range, the fixing effect of the conductive yarn to the fibrous polymer material is enhanced. If the diameter of the fusion yarn is equal to or less than the upper limit of the range, the decrease in the conductivity of the actuator is suppressed.

The method of compounding is not particularly limited as long as the effects of the present invention can be obtained, but twisting is preferred.
When the composite yarn is composited by twisting the yarn, the number of twists per meter is preferably 100 to 10,000 T/m, more preferably 500 to 5,000 T/m, and even more preferably 1,000 to 3,000 T/m. When the number of twists per meter is within the above range, the unraveling of the twisted yarn is suppressed in the step of spirally winding the composite yarn around the fibrous polymer material, and after the fusion step, the fixing effect of the conductive yarn to the fibrous polymer material is enhanced, and the heat transfer of the actuator is improved.

The number of fused yarns contained in the composite yarn is preferably 1 to 10, more preferably 1 to 7, and even more preferably 1 to 5. If the number of fused yarns is equal to or greater than the lower limit of the range, the effect of fixing the conductive yarn to the fibrous polymer material is enhanced. If the number of fused yarns is equal to or less than the upper limit of the range, the decrease in the conductivity of the actuator is suppressed.

The number of conductive threads contained in the composite thread is preferably 1 to 10, more preferably 1 to 7, and even more preferably 1 to 5.

The ratio of the number of fused yarns to the number of conductive yarns contained in the composite yarn, i.e., the number of fused yarns:the number of conductive yarns, is preferably 1:2 to 4:1, and more preferably 1:1 to 2:1.

[Step 2]
In step 2, the composite yarn is heated to fuse to the surface of the fibrous polymer material 10. The heating temperature is not particularly limited as long as it is a temperature at which the thermoplastic resin contained in the fusion yarn can be melted, and may be, for example, the melting temperature of the thermoplastic resin to the melting temperature + 60°C, preferably the melting temperature + 10°C to the melting temperature + 50°C, and more preferably the melting temperature + 20°C to the melting temperature + 40°C.
When the heating temperature is equal to or higher than the lower limit of the above range, the thermoplastic resin melts and bonds the fibrous polymer material 10 to the conductive thread, thereby improving the effect of fixing the conductive thread to the fibrous polymer material, and making it easier to stably obtain the desired actuator operation performance. When the heating temperature is equal to or lower than the upper limit of the above range, the fibrous polymer material is less likely to be damaged.

When the total volume of the fusion yarn contained per meter of the composite yarn is V2 and the total surface area of the conductive yarn contained per meter of the composite yarn is A2, the following formula 2 is satisfied.
5 [μm ³ /μm ² ]≦V2/A2≦60 [μm ³ /μm ² ] Formula 2

V2/A2 is 5 to 60 ^μm3 / ^μm2 , preferably 7 to 55 ^μm3 / ^μm2 , and more preferably 10 to 30 ^μm3 /μm2. When V2/A2 is equal to or ^greater than the lower limit of the above range, the effect of fixing the conductive thread to the fibrous polymer material is enhanced. When V2/A2 is equal to or less than the upper limit of the above range, the decrease in the conductivity of the actuator is suppressed.
In addition, since the total volume of the fused yarns and the total surface area of the conductive yarns do not substantially change before and after fusion, V2/A2 will be the same value as V1/A1 in the manufactured actuator.

[Method of measuring V2/A2]
If the diameter of the fusion yarn is r1 _' [μm], the volume per meter of the fusion yarn is (r1 _' /2) ² ×π×1× ¹⁰⁶ [ ^μm3 ]. When multiple fusion yarns are used, the volumes of all the fusion yarns are calculated, and the total value can be taken as V2 [ ^μm3 ].
If the diameter of the conductive thread is r2 _' [μm], then the surface area of the conductive thread is r2 _' × π × 1 × ¹⁰⁶ [ ^μm2 ]. When multiple conductive threads are used, the surface areas of all the conductive threads can be calculated and the total value can be taken as A2 [ ^μm2 ].
In the above description, the fusion yarn and the conductive yarn are assumed to be substantially circular, but they may be substantially elliptical. In this case, the average of the major axis and the minor axis of the substantially ellipse is set as the diameter r1 _' [μm] of the fusion yarn and the diameter r2 _' [μm] of the conductive yarn.

The above describes the embodiments of the present invention in detail with reference to the drawings. However, each configuration and their combination in the embodiments is merely an example, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to each embodiment, but is limited only by the scope of the claims.

The present invention will be described in more detail below with reference to specific examples. However, the present invention is not limited to the examples shown below.

[Measurement of V1/A1]
The diameter of the fusion yarn was defined as r1 _' [μm], and the volume per meter of the fusion yarn was calculated as ( _r1 /2) ² ×π×1× ¹⁰⁶ [ ^μm3 ]. When multiple fusion yarns were used, the volumes of all the fusion yarns were calculated, and the total value was defined as V2 (V1) [ ^μm3 ].
The diameter of the conductive thread was defined as r2 _' [μm], and the surface area of the conductive thread was calculated as r2 _' × π × 1 × ¹⁰⁶ [ ^μm2 ]. When multiple conductive threads were used, the surface areas of all the conductive threads were calculated, and the total value was defined as A2 (A1) [ ^μm2 ].

[Evaluation of adhesiveness of conductive yarn]
The actuators made by the method described below were cut with scissors in the short direction to 10 pieces of 1 cm each, and the ends were observed under a microscope. Those in which no gaps were found between the fibrous polymer material and the composite long body were judged to have good adhesion, and those in which gaps were found were judged to have poor adhesion. The number of measurement points was 20 points in total (10 pieces x both ends), and the percentage of those with good adhesion was calculated and judged as follows:
・Rate of good adhesion is over 85%...A
The percentage of good adhesion is over 50% and 85% or less...B
The percentage of good adhesion is 50% or less...C

[Conductivity evaluation]
The electrical resistance was measured by the four-terminal method under the following conditions over the entire length of the actuator (1 m) created by the method described below, and the connection of the conductive yarn to the outside was evaluated. A resistance of less than 10 kΩ was considered good, and a resistance of 10 kΩ or more was considered bad. The proportion of good points out of all measurement points was calculated and judged as follows:
Conditions Actuator feed speed: 10 mm/s
Measurement interval: 0.2 s
Distance between terminals: 40mm
Terminal diameter: 10mm
Measurement points: Approximately 500 points. The percentage of good conductivity is over 98%.
The percentage of good conductivity is over 70% and 98% or less...B
The percentage of good electrical conductivity is 70% or less...C

[comprehensive evaluation]
In the above evaluation results, when both the adhesiveness evaluation and the electrical conductivity evaluation were "A", the overall evaluation was judged to be "A". When the adhesiveness evaluation and the electrical conductivity evaluation were "A" or "B" and there was one or less "A", the overall evaluation was judged to be "B". When either or both of the adhesiveness evaluation and the electrical conductivity evaluation were "C", the overall evaluation was judged to be "C".
The overall evaluations of A and B were considered to be pass, and C was considered to be fail.

[Ingredients used]
Nylon filament (Toray Monofilament Co., Ltd., nylon 66, diameter: 0.5 mm)
- Copolymer nylon fusion yarn (manufactured by Unitika Ltd., product name: Flor M, diameter: 100 denier, melting temperature: 130°C)
Conductive thread (manufactured by Osaka Electric Industry Co., Ltd., product name: ODEX30d, thread with silver-plated core, diameter: 30 denier)

[Example 1]
Nylon filaments were twisted at 600 T/m and heat-treated at 180°C for 40 minutes to obtain a fibrous polymer material. One conductive yarn and one fusion yarn were twisted at 1000 T/m to obtain a composite yarn. The composite yarn was spirally wound around the fibrous polymer material at 1000 T/m and heat-treated at 130°C for 5 minutes to adhere the composite yarn to obtain actuator 1. The V1/A1 of actuator 1 was 14 ^μm3 / ^μm2 . The results of the adhesiveness evaluation and conductivity evaluation of the conductive yarn are shown in Table 1.

[Example 2]
Actuator 2 was obtained in the same manner as in Example 1, except that two conductive yarns and one fused yarn were used to prepare the composite yarn. V1/A1 of actuator 2 was 7 μm ³ /μm ^2. The results of the adhesiveness evaluation and conductivity evaluation of the conductive yarn are shown in Table 1.

[Example 3]
Actuator 3 was obtained in the same manner as in Example 1, except that one conductive yarn and two fused yarns were used to prepare the composite yarn. V1/A1 of actuator 3 was 27 μm ³ /μm ^2. The results of the adhesiveness evaluation and conductivity evaluation of the conductive yarn are shown in Table 1.

[Example 4]
Actuator 4 was obtained in the same manner as in Example 1, except that one conductive yarn and four fused yarns were used when preparing the composite yarn. V1/A1 of actuator 4 was 55 μm ³ /μm ^2. The results of the adhesiveness evaluation and conductivity evaluation of the conductive yarn are shown in Table 1.

[Comparative Example 1]
Actuator 5 was obtained in the same manner as in Example 1, except that one conductive yarn was used instead of the composite yarn. Since no fusion yarn was included, V1/A1 of actuator 5 was 0 μm ³ /μm ^2. The results of the adhesiveness evaluation and conductivity evaluation of the conductive yarn are shown in Table 1.

[Comparative Example 2]
Actuator 6 was obtained in the same manner as in Example 1, except that four conductive yarns and one fused yarn were used to prepare the composite yarn. V1/A1 of actuator 6 was 3 μm ³ /μm ^2. The results of the adhesiveness evaluation and conductivity evaluation of the conductive yarn are shown in Table 1.

[Comparative Example 3]
Actuator 7 was obtained in the same manner as in Example 1, except that one conductive yarn and eight fused yarns were used when preparing the composite yarn. The V1/A1 of actuator 7 was 110 μm ³ /μm ^2. The results of the adhesiveness evaluation and conductivity evaluation of the conductive yarn are shown in Table 1.

The actuators of Examples 1 to 4 were evaluated as having good adhesiveness and conductivity. Comparative Example 1, which did not use fusible yarn, and Comparative Example 2, in which V1/A1 was 3 μm ³ /μm ² , showed poor adhesiveness. Comparative Example 3, in which V1/A1 was 110 μm ³ /μm ² , showed poor conductivity.

The actuator of the present invention can be used as an actuator that changes shape when heated, in applications for powering a variety of items.

1: actuator, 10: fibrous polymer material, 20: composite elongated body, 20': composite yarn, _I20 : gap between adjacent composite elongated bodies in the spiral structure of the composite elongated body, _D10 : diameter of the fibrous polymer material, _D20 : diameter of the composite elongated body, θ: angle between the composite elongated body and the fibrous polymer material, L1i: length occupied by the composite elongated body, L2i: length of the portion not covered by the composite elongated body

Claims (3)

A fibrous polymer material;
and a composite long body including a conductive thread and a thermoplastic resin (however, in a case where the fibrous polymer material includes a thermoplastic resin, the thermoplastic resin included in the fibrous polymer material is excluded; and in a case where the conductive thread includes a thermoplastic resin, the thermoplastic resin included in the conductive thread is excluded) ,
The polymer constituting the fibrous polymer material is nylon 6, nylon 6,6, polymethyl methacrylate, polyethylene terephthalate, polyvinyl chloride, or polycarbonate;
The thermoplastic resin has a melting temperature of 60 to 180° C.
the composite long body is wound in a spiral shape around the fibrous polymer material,
An actuator which satisfies the following formula 1, where V1 is the total volume of the thermoplastic resin contained per 1 m of the composite long body, and A1 is the total surface area of the conductive yarn contained per 1 m of the composite long body.
5 [μm ³ /μm ² ]≦V1/A1≦60 [μm ³ /μm ² ] Formula 1 A step of spirally winding a composite yarn obtained by combining a fusion yarn containing a thermoplastic resin and a conductive yarn around a fibrous polymer material;
heating the composite yarn to fuse it to a surface of the fibrous polymeric material;
A method for manufacturing an actuator comprising:
The polymer constituting the fibrous polymer material is nylon 6, nylon 6,6, polymethyl methacrylate, polyethylene terephthalate, polyvinyl chloride, or polycarbonate;
The thermoplastic resin has a melting temperature of 60 to 180° C.
A method for manufacturing an actuator, which satisfies the following formula 2 when the total volume of the fusion yarns contained per 1 m of the composite yarn is V2 and the total surface area of the conductive yarns contained per 1 m of the composite yarn is A2.
5 [μm ³ /μm ² ]≦V2/A2≦60 [μm ³ /μm ² ] Formula 2 The method for manufacturing an actuator according to claim 2, wherein the composite yarn is a composite yarn obtained by combining the fusion yarn and the conductive yarn through twisting.

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