JP2000226443A - Conductive fiber reinforced shape memory resin molded product and its production and use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable uniform and quick heating of a shape memory resin molded product up to its restorable temperature when the shape memory resin molded article is restored to the memorized shape or when flexibility is imparted to a molded product to effect postforming change of shape to a desired shape, and also to increase the mechanical strengths of the shape memory resin molded product. SOLUTION: Molded products are constituted of a conductive continuous fiber 1 as the electrically conductive medium and the reinforcing material and a shape memory resin 2 as the matrix, and at least two electrodes 3 are conductively connected to the conductive continuous fiber 1 so as to apply a current to the conductive continuous fiber 1 through these electrodes 3. The shape memory resin 2 is a norbornene type polymer, and the norbornene type polymer is a polydicylopentadiene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive fiber-reinforced shape memory resin molded product, a method for producing the same and a method for using the same.

[0002]

2. Description of the Related Art A shape memory resin is a material in which an arbitrary shape is stored in advance and is deformed in a low temperature region, but is restored to the stored original shape when the temperature becomes high. That is, the shape memory resin is a resin having a property that a molded article having a certain shape is plastically deformed into another shape, the shape can be fixed by cooling, and the original shape can be restored when heated.

As the shape memory resin, styrene-butadiene-styrene block copolymer (SBS), trans polyisoprene (TPI), polynorbornene resin,
Polyurethane resin, high styrene resin and the like can be mentioned.

[0004] The characteristics required of such a shape memory resin are excellent mechanical strength, good repetition of shape recovery, high recovery speed, and no shape collapse. The norbornene-type resin is most excellent in such characteristics.

As means for restoring a shape memory resin from a deformed or deformed shape to a memorized shape, conventionally, as disclosed in JP-A-2-225518, heating in a heating liquid, Examples of the method include air heating using an oven, a hot blaster, and a heat gun, and steam heating. Examples of the electric heating means include a method of heating with an electric heating tube and an electric ribbon, and a method of embedding an electric heating element in a resin.

[0006]

By the way, heating by air or water vapor can be only partially performed, and it is necessary to separately prepare a heating means. Furthermore, there is a problem that it is not suitable for work outdoors, particularly in winter. In addition, when heating in a heated liquid, it is necessary to prepare a heated liquid tank, and it is necessary to remove the liquid after deforming or restoring the shape memory resin, which is troublesome.

On the other hand, when using an electric heating means, it takes time and effort to set the electric heating tube or the electric heating ribbon on the shape memory resin. In addition, when embedding an electric heating element in resin, if the interfacial adhesion is poor, the mechanical strength is reduced.If it is necessary to uniformly heat the entire molded body, a large number of heating elements are embedded. There must be.
Furthermore, when the heating element is in the form of particles such as conductive particles, or fibrous such as conductive short fibers, it is difficult to uniformly disperse the heating element. However, there is a problem that the heat generation is extremely reduced and the heat generation is reduced, or no heat is generated.

[0008] The present invention has been made in view of such circumstances, and is used when a molded article is restored to a memorized shape or when a primary molded article is given flexibility to undergo secondary deformation to a desired shape. A conductive fiber reinforced shape memory resin molded article capable of uniformly and quickly raising the temperature of a molded article to a recoverable temperature and having high mechanical strength, and a conductive fiber reinforced shape memory resin having such properties An object of the present invention is to provide a method for manufacturing and using a molded article.

[0009]

As shown in FIG. 1, the shape-resin molded article of the present invention comprises a conductive medium 1 as a current-carrying medium and a reinforcing material, and a shape-memory resin 2 as a matrix. And at least two electrodes 3 are electrically connected to the conductive continuous fiber 1.

According to the shape memory resin molded article of the present invention, the molded article can be rapidly heated by supplying electricity to the conductive continuous fiber through the electrode, so that it can be quickly restored to the memorized shape. Can be. In addition, the primary molded body can be given flexibility to be deformed into a desired shape.
As described above, in the memory resin molded body of the present invention, the conductive continuous fibers can also exert an electric heating effect in addition to the reinforcing effect of the molded body.

The shape memory resin used in the shape memory resin molded article of the present invention is preferably a polynorbornene-based polymer, particularly preferably polydicyclopentadiene.

In the shape memory resin molded article of the present invention, the conductive continuous fibers are preferably present inside the shape memory resin. If the conductive continuous fibers are exposed from the surface of the molded article, there is a possibility that a danger such as electric shock may occur during energization.

The number of laminated conductive continuous fibers and the basis weight may be appropriately determined according to the strength and elastic modulus required for the molded article. When it is desired to partially generate heat in the conductive fiber reinforced shape memory resin molded body, conductive continuous fibers having at least two electrodes conductively connected may be present only in a place where heat is to be generated.

In the shape memory resin molded article of the present invention, the electrode may be integrated with the molded article at the time of manufacture or may be formed afterwards, but it is necessary to make conductive connection with the conductive continuous fiber. It is preferable to integrate with the molded body during the production. The reason is that, in the case of retrofitting, there is a risk of short circuit due to poor adhesion between the conductive continuous fiber and the electrode, and since the electrode is separated from the conductive fiber, the electrical resistance value increases and the molded body cannot be heated. , Because of the problem. When the electrodes are embedded in the molded body, it is preferable to embed the entire conductor (lead wire).

In the shape memory resin molded article of the present invention, as a method of electrically connecting the electrode and the conductive continuous fiber, there is a method such as pressure bonding of the electrode to the conductive continuous fiber. In addition, the conductive connection method of the electrode is not limited to the crimping method, and any conductive connection method can be adopted as long as the storage resin molded article of the present invention can be efficiently and uniformly heated. In general, it is sufficient to provide two electrodes, but three or more electrodes may be provided when it is desired to heat quickly or to partially heat two or more places.

The manufacturing method of the present invention is a method for manufacturing a conductive fiber reinforced shape memory resin molded article having the above-mentioned properties, wherein conductive continuous fibers formed by conductively connecting at least two electrodes are placed in a mold. In the set state, a polymerizable reaction solution containing a norbornene-type monomer and its polymerization catalyst is supplied into the molding die to perform bulk ring-opening polymerization.

More specifically, as shown in FIG. 2, a conductive continuous fiber 1 in which two electrodes 3 including lead wires are conductively connected in advance is cut into a predetermined size, and placed in a molding die 4. (FIG. 2 (A)). Next, the mold is closed, and the polymerizable reaction liquid 5 containing the norbornene-type monomer and its polymerization catalyst is injected into the mold 4 (FIG. 2B). During a lapse of a predetermined time from the injection, the polymerization of the polymerizable reaction liquid 5 and the impregnation of the conductive continuous fiber 1 are completed.
By performing mold opening, a conductive continuous fiber reinforced shape memory resin (norbornene-type polymer) molded article can be obtained.

Here, as the shape memory resin used in the present invention, styrene-butadiene-styrene block copolymer (SBS), trans polyisoprene (TPI),
Polynorbornene-type resin, polyurethane resin, high styrene resin and the like can be mentioned.

Among them, a polynorbornene-type resin having high mechanical strength and heat resistance, good repetition of shape repetition, high recovery speed, and no collapse of shape is most suitable.
The polynorbornene-type resin can be obtained by bulk polymerization of a norbornene-type monomer in the presence of a polymerization catalyst.

Examples of the norbornene-type monomer to be polymerized include bicyclic norbornene monomers such as norbornene and norbornene, tricyclics such as dicyclopentadiene and dihydrodicyclopentadiene, tetracyclics such as tetracyclododecene, and tricyclohexane. Pentacycles such as pentadiene, heptacycles such as tetracyclopentadiene, and alkyl-substituted products thereof (for example, methyl, ethyl, propyl,
Butyl-substituted), alkylidene-substituted (eg, ethylidene-substituted), aryl-substituted (eg, phenyl-, tolyl-substituted) and the like.

In order to impart strength and heat resistance to a molded article, crosslinking may be performed using a crosslinking monomer. Examples thereof include polycyclic norbornene monomers having a reactive double bond, and specifically, dicyclopentadiene,
And tetracyclopentadiene. here,
When the norbornene-type monomer and the crosslinkable monomer are the same, it is not particularly necessary to use another crosslinkable monomer.

Dicyclopentadiene is expensive, reactive,
It can be said that among the norbornene-type monomers, they are preferable in terms of physical properties and availability.

These norbornene-type monomers may be used alone or as a mixture of two or more.
Further, a monocyclic cycloolefin such as cyclobutene and cyclopentadiene which can be ring-opening copolymerized with the norbornene-type monomer may be used within a range not to impair the object of the present invention.

Examples of the polymerization catalyst for bulk-opening polymerization of the norbornene-type monomer include a metathesis catalyst.
For the metathesis catalyst, first, a combination system of a catalyst and a cocatalyst is used. Examples of the catalyst include halides such as tungsten, molybdenum, and tantalum, oxyhalides, oxides, and organic ammonium salts. In addition, examples of the activator that is a cocatalyst include an alkylaluminum halide, an alkoxyalkylaluminum halide, an aryloxyalkylaluminum halide, and an organotin compound.

In addition, there is a catalyst capable of subjecting a norbornene-type monomer to metathesis polymerization by itself without using a cocatalyst. Examples of the catalyst include ruthenium such as bis (tricyclohexylphosphine) benzylidene ruthenium chloride. -Carbene complexes.

Various additives such as an antioxidant, a filler, a colorant, a polymer modifier, and a flame retardant may be blended with the above shape memory resin.

Examples of the type of conductive continuous fibers include conductive fibers such as carbon fibers, metal fibers, and metal-coated glass fibers.

Examples of the form of the conductive continuous fiber include roving, roving cloth, chopped strand mat, continuous mat, and nonwoven fabric. These may be used alone or in combination of two or more.

Next, the method of using the conductive fiber reinforced shape memory resin molded article of the present invention will be described in detail below.

First, when the conductive fiber reinforced shape memory resin molded article is deformed by external stress such as impact, the molded article is energized through the current applying means and the conductive continuous fiber. Due to this energization, the temperature of the shape memory resin molded body rises, and when the temperature exceeds the shape recovery temperature, the shape is restored to the original shape. Therefore, when such a shape-memory resin molded product is used for a certain purpose, and when deformation due to impact or the like occurs, the shape can be easily restored to the stored shape by immediately energizing at the site. Also, no large-scale equipment is required.

Here, a point to be noted when energizing is to prevent the temperature from rising above the thermal decomposition temperature of the shape memory resin constituting the molded body. In addition, there is a problem if the specific resistance of the shape memory resin molded product is too large or too small, and a range of 2 to 900Ω is preferable. If it is less than 2 Ω, the electric resistance may be too small to generate heat uniformly. If it is more than 900 Ω, the power consumption increases, which is not practical.

As another method of use, first, a primary molded body (shape memory resin molded body) is molded using a mold having a certain shape, and then the primary molded body is energized through conductive continuous fibers. In addition, there is a method in which heating is performed at a temperature equal to or higher than the heat deformation temperature to impart flexibility, thereby deforming the secondary molded body. Body) can be obtained.

An advantage of this method is that a primary molded body is manufactured by a simple and inexpensive mold without using a complicated mold and mechanism, and is subjected to secondary deformation by heat generation. Because a product having a complicated shape can be obtained, the process and equipment can be simplified.
Furthermore, as another specific example, if a product used in one shape is to be transformed into another shape for some reason, it can be quickly transformed into another desired shape. Become.

[0034] As a method of shaping the secondary molded body, manual or a specific jig / apparatus may be used.

[0035]

<Example 1> Monomer 1 (Solution A): A solution comprising a catalyst and dicyclopentadiene (trade name: Meton: manufactured by Teijin Meton Co., Ltd.) Monomer 2 (Solution B): Activator, activity regulator and dimer Solution consisting of cyclopentadiene (trade name: Meton: manufactured by Teijin Meton Co., Ltd.) Fiber reinforcing material: carbon fiber cloth (count: 317 g / m ² ) First, a flat mold for reaction injection molding controlled at 70 ° C. (volume: 3 mm ×) 400 mm x 400 mm), a carbon fiber cloth in which electrodes including lead wires were pressure-bonded to
After ply setting and closing the mold with the lead wire protruding outside the mold, nitrogen purge was performed in the mold for 30 seconds.

Next, a dicyclopentadiene A solution containing a metathesis catalyst and a dicyclopentadiene B containing an activator
RIM (Reaction injection Mol) so that the mixing ratio with the liquid (catalyst and activator compound names are unknown) becomes 1/1.
ding) It was injected into the mold by a molding machine. After 4 minutes from the end of the injection, the mold was opened to obtain a flat plate (molded product) made of carbon fiber reinforced polydicyclopentadiene.

The two lead wires protruding from the molded product obtained by the above molding were connected to a power source, heated to 120 ° C. by applying a current of 20 V, and immediately bent at a 90 ° angle. The lead wire was removed from the power supply and cooled. Next, the two lead wires were connected to the power supply again, and heated to 160 ° C. or more by applying a current of 20 V. As a result, it was confirmed that the original shape (flat plate) was restored from the 90-degree bent state. . At this time, the time required to restore from the bent state to the original flat plate shape was 2 minutes. <Example 2> A urethane-based shape memory resin (glass transition temperature: 55 ° C) was used.

Monomer 1 (Liquid A): Polyol (trade name Diary: manufactured by Mitsubishi Heavy Industries, Ltd.) Monomer 2 (Liquid B: isocyanate (trade name Diary: manufactured by Mitsubishi Heavy Industries, Ltd.) Fiber reinforcing material: carbon fiber cloth (counter 317 g / m ² ) First, a carbon fiber cloth in which electrodes including lead wires were pressure-bonded to two end portions was placed in a flat plate for reaction injection molding (volume: 3 mm × 400 mm × 400 mm) controlled at 80 ° C.
After ply setting and closing the mold, the mixing ratio of the liquid A and the liquid B of the urethane-based shape memory resin is 2/3.
It was injected into a mold by a RIM molding machine. Four hours after the end of the injection, the mold was opened to obtain a flat plate (molded product) made of carbon fiber reinforced polyurethane resin.

Next, two lead wires protruding from the obtained flat plate made of carbon fiber reinforced polyurethane resin were connected to a power source, heated to 55 ° C. by applying a current of 20 V, and immediately heated to 90 ° C. After bending at an angle, the lead wire was removed from the power supply and cooled. Next, the two lead wires were connected to the power supply again, and heated to 55 ° C. or more by applying a current of 20 V. As a result, it was confirmed that the original shape (flat plate) was restored from the 90-degree bent state. At this time, the time required to restore from the bent state to the original flat plate shape was 1 minute. <Comparative Example 1> Monomer 1 (Solution A): solution comprising catalyst and dicyclopentadiene (trade name: Meton: manufactured by Teijin Meton Co., Ltd.) Monomer 2 (Solution B): composed of activator, activity regulator and dicyclopentadiene Solution (trade name: Meton: manufactured by Teijin Meton Co., Ltd.) A flat plate mold for reaction injection molding controlled at 70 ° C. (volume: 3 m)
The mixing ratio of the dicyclopentadiene A liquid containing the metathesis catalyst and the dicyclopentadiene B liquid containing the activator (the names of the compounds of the catalyst and the activator are unknown) within mx 400 mm x 400 mm) As in the above, using a RIM molding machine. After 3 minutes from the end of the injection, the mold was opened to obtain a flat plate made of polydicyclopentadiene.

First, the molded product was placed in a heating oven, heated to 120 ° C., immediately bent at an angle of 90 °, and cooled. Next, place the oven with an internal temperature of 25 ° C
Heating to 60 ° C. took 15 minutes to raise the temperature. It was confirmed that the molded body bent at 90 ° C. was placed in the oven, and the original shape (flat plate) was restored from the bent state at 90 degrees. At this time, the time required to restore from the bent state to the original flat plate shape was 3 minutes. The time required to restore the shape was a total of 18 minutes. <Comparative Example 2> Monomer 1 (Solution A): solution comprising catalyst and dicyclopentadiene (trade name: Meton: manufactured by Teijin Meton Co., Ltd.) Monomer 2 (Solution B): consisting of activator, activity regulator and dicyclopentadiene Solution (trade name: Meton: manufactured by Teijin Meton Co., Ltd.) Fiber reinforcing material: carbon fiber cloth (count: 317 g / m ² ) First, a flat mold for reaction injection molding controlled at 70 ° C. (volume: 3 mm × 400 mm × 400 mm) Inside, 2 ply of carbon fiber cloth is set and the mold is closed.
A nitrogen purge was performed for seconds.

Next, a dicyclopentadiene A solution containing a metathesis catalyst and a dicyclopentadiene B containing an activator
The liquid (the names of the compounds of the catalyst and the activator are unknown) was injected into the mold by a RIM molding machine so that the mixing ratio became 1/1. Four minutes after the completion of the injection, the mold was opened to obtain a flat plate made of carbon fiber reinforced polydicyclopentadiene.

Next, the obtained molded article was placed in a heating oven, heated to 120 ° C., immediately bent at an angle of 90 °, and cooled. Next, the oil bath having a liquid temperature of 25 ° C. was heated to 160 ° C. This temperature increase required 10 minutes. Then, the molded body bent at 90 ° C. was put in an oil bath, and it was confirmed that the original shape (flat plate) was restored from the bent state at 90 degrees. The time required to restore the original flat shape from the bent state was 3 minutes. The time required to restore the shape was a total of 13 minutes.

Example 1 and Comparative Examples 1 and 2
The bending strength (according to JIS K 7055) and the flexural modulus (JIS)
K7055). The evaluation results are shown in Table 1 below.

[0044]

[Table 1]

From the above results, by using the conductive fibers not only as a reinforcing material but also as an energizing medium and energizing the shape memory resin molded body, a heating device or the like is used more quickly than other heating methods. It was confirmed that it was possible to restore the deformed shape without deforming, and to make it possible to deform the shape memory resin molded body to a desired shape by applying an external force to the state in which the shape memory resin molded article was flexible due to electric heating. .

[0046]

As described above, according to the present invention,
It is possible to quickly restore the deformed shape by using the conductive continuous fiber as a reinforcing material, as well as conducting electricity through a conductively connected electrode and using it as an energizing medium. In addition, the primary molded body can be flexibly formed into a desired shape by giving flexibility by energizing.

Further, there is an advantage that equipment such as a heating tank and an oven is not required unlike the case where the shape memory resin molded body is heated by other means. Moreover, since the deformed shape can be easily restored with a power supply, even if the shape memory resin molded article of the present invention is used in various places, it can be installed without being affected by the environment (outdoor, winter, etc.) of the place. It can be restored as it is.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of a conductive fiber reinforced shape memory resin molded product of the present invention.

FIG. 2 is an explanatory view of one example of a method for producing a conductive fiber reinforced shape memory resin molded product of the present invention.

[Description of Signs] 1 Conductive continuous fiber 2 Shape memory resin 3 Electrode 4 Mold 5 Polymerizable reaction liquid

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Claims (6)

[Claims] 1. A conductive material comprising conductive fibers as a current-carrying medium and a reinforcing material, and a shape memory resin as a matrix, wherein at least two electrodes are conductively connected to the conductive fibers. Shaped fiber reinforced shape memory resin molding. 2. The conductive fiber reinforced shape memory resin molded product according to claim 1, wherein the shape memory resin is a norbornene type polymer. 3. The conductive fiber-reinforced shape memory resin molded product according to claim 2, wherein the norbornene-type polymer is polydicyclopentadiene. 4. A polymerizable reaction solution containing a norbornene-type monomer and a polymerization catalyst is placed in a mold with conductive continuous fibers formed by conductively connecting at least two electrodes in the mold. A method for producing a conductive fiber reinforced shape memory resin molded product, comprising supplying and performing bulk ring-opening polymerization. 5. When the conductive fiber reinforced shape memory resin molded product according to claim 1, 2 or 3 is deformed by external stress, electricity is supplied to the conductive continuous fiber of the molded product via an electrode, A method for using a conductive fiber-reinforced shape memory resin molded product, which recovers the shape of the molded product. 6. The conductive fiber of the conductive fiber reinforced shape memory resin molded article according to claim 1, 2 or 3 is energized through an electrode to give flexibility to the molded article, and molded in this state. A method for using a conductive fiber reinforced shape memory resin molded article, wherein an external force is applied to the body to shape the body into a predetermined shape.