MEMBRANOUS BODY

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2024-001478 filed on Jan. 9, 2024, incorporated herein by reference in its entirety.

BACKGROUND
1. Technical Field

The present disclosure relates to a technical field of a membranous body.

2. Description of Related Art

Membranous bodies configured with super fiber have been proposed as this type of membranous bodies (see Japanese Unexamined Patent Application Publication No. 2007-063710 and Japanese Unexamined Patent Application Publication No. 2021-070788).

SUMMARY

There is room for improvement in the techniques described in JP-2007-063710 A and JP-2021-070788 A.

The present disclosure provides a membranous body having high strength.

An aspect of the present disclosure is a membranous body. The membranous body includes a super fiber layer configured with super fiber, and resin solvent layers that are in contact with the super fiber layer and formed so as to interpose the super fiber layer therebetween. The super fiber layer has been subjected to at least one of a deoiling treatment and a hydrophilic treatment.

In the membranous body according to the aspect of the present disclosure, resin solvent constituting the resin solvent layers may be coated on the super fiber layer.

In the membranous body according to the aspect of the present disclosure, the resin solvent may include a super engineering plastic.

In the membranous body according to the aspect of the present disclosure, the super fiber layer may have at least two threads out of a first thread, a second thread, and a third thread. The first thread may be a thread that extends in a first direction and is formed to include the super fiber. The second thread may be a thread that extends in a second direction different from the first direction and is formed to include the super fiber. The third thread may be a thread that extends in a third direction different from the first direction and the second direction and is formed to include the super fiber. The at least two threads may be intertwined with each other such that fluctuation of relative positions between the at least two threads is restrained, or the at least two threads may be bound by at least one of a machine sewing thread and a melt thread such that the fluctuation of the relative positions between the at least two threads is restrained.

In the membranous body according to the aspect of the present disclosure, the super fiber layer may include a plurality of threads that are formed to include the super fiber and extend in one direction. Two adjacent threads out of the plurality of threads may be intertwined with each other such that fluctuation of the relative positions between the two adjacent threads is restrained.

The membranous body according to the aspect of the present disclosure may have a tensile strength of 51 to 64 N/mm and a mass of 45 to 55 g/m².

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like signs denote like elements, and wherein:

FIG. 1 is a diagram schematically showing a configuration of a membranous body according to an embodiment;

FIG. 2 is a sectional view taken along a line II-II in FIG. 1;

FIG. 3 is a flowchart showing a main part of a method for manufacturing a membranous body according to the embodiment;

FIG. 4 is a diagram showing an example of an inflatable kite;

FIG. 5A is a diagram schematically showing a configuration of a membranous body according to a comparative example;

FIG. 5B is a diagram schematically showing a configuration of a membranous body according to a comparative example;

FIG. 6 is a diagram showing a creep test;

FIG. 7 is a diagram showing an example of a result of the creep test;

FIG. 8 is a diagram showing a sewing slippage test;

FIG. 9 is a diagram showing an example of a result of the sewing slippage test;

FIG. 10 is a diagram showing a tear test;

FIG. 11 is a diagram showing an example of a result of the tear test;

FIG. 12 is a diagram showing an example of a result of a puncture test; and

FIG. 13 is a diagram showing the relation between the mass and tensile strength of the membranous body.

DETAILED DESCRIPTION OF EMBODIMENTS

An embodiment of a membranous body will be described with reference to FIG. 1 to FIG. 13. In FIG. 1, a membranous body 10 includes a super fiber layer 11 configured with super fiber, and resin solvent layers 12 and 13 that are in contact with the super fiber layer 11 and are formed so as to interpose the super fiber layer 11 therebetween.

Configuration of Membranous Body 10

Examples of the super fiber include ultra-high strength polyethylene (ultra-high molecular weight polyethylene fiber), para aramid fiber, polyarylate fiber, polyparaphenylene benzobisoxazole (PBO) fiber, carbon fiber, glass fiber, metal fiber, and ceramic fiber.

As shown in FIG. 2, the super fiber layer 11 has a plurality of threads 11a extending in a first direction, and a plurality of threads 11b extending in a second direction different from the first direction. The plurality of threads 11a and 11b are threads that are formed to include super fiber. As shown in FIG. 2, the threads 11a and 11b are intertwined with each other such that fluctuation of the relative positions between the threads 11a and 11b is restrained. A woven fabric using super fiber threads may be formed by intertwining the threads 11a and 11b. In other words, the super fiber layer 11 may be configured by a woven fabric using the super fiber threads. Examples of the woven fabric include plain weave, twill weave, and satin weave.

Note that in addition to the plurality of threads 11a extending in the first direction and the plurality of threads 11b extending in the second direction, the super fiber layer 11 may have threads each including one or more super fibers extending in a third direction different from the first direction and the second direction. In this case, the threads 11a, 11b, and the threads extending in the third direction may be intertwined with one another such that the relative positions of the threads 11a, 11b, and the threads extending in the third direction are restrained from fluctuating. In this case, the super fiber layer 11 may be configured by a woven fabric woven by the threads 11a, 11b, and the threads extending in the third direction.

Note that the thread 11a and the thread 11b may be bound by at least one of a machine sewing thread and a melt thread such that fluctuation of the relative positions between the thread 11a and the thread 11b is restrained. In this case, the thread 11a and the thread 11b do not have to be intertwined with each other. For example, the super fiber layer 11 may have a first layer including a plurality of threads 11a and a second layer including a plurality of threads 11b. At least one thread 11a included in the first layer and at least one thread 11b included in the second layer may be bound by at least one of a machine sewing thread and a melt thread. In other words, the super fiber layer 11 may be formed by binding the first layer and the second layer with at least one of a machine sewing thread and a melt thread.

Note that when the super fiber layer 11 includes the threads extending in the third direction in addition to the threads 11a and the threads 11b, at least two of the thread 11a, the thread 11b, and the thread extending in the third direction may be bound by at least one of a machine sewing thread and a melt thread. In this case, the thread 11a, the thread 11b, and the thread extending in the third direction do not have to be intertwined with one another. For example, the super fiber layer 11 may have a first layer including a plurality of threads 11a, a second layer including a plurality of threads 11b, and a third layer including a plurality of threads extending in the third direction. Here, at least two threads of at least one thread 11a included in the first layer, at least one thread 11b included in the second layer, and at least one thread included in the third layer may be bound by at least one of a machine sewing thread and a melt thread. In other words, the super fiber layer 11 may be formed by binding the first layer, the second layer, and the third layer with at least one of a machine sewing thread and a melt thread.

Note that the super fiber layer 11 may have a plurality of threads extending in one direction instead of the threads 11a and 11b. The plurality of threads are threads containing super fiber. The one direction may be the same direction as any of the first direction, the second direction, and the third direction described above, or may be a direction different from the first direction, the second direction, and the third direction. Two adjacent threads out of the plurality of threads extending in the one direction may be intertwined with each other such that fluctuation of the relative positions between the two threads is restrained. A knitted fabric using super fiber threads may be formed by intertwining two adjacent threads out of the plurality of threads extending in the one direction. In other words, the super fiber layer 11 may be configured by a knitted fabric using super fiber threads. Examples of the knitted fabric include plain stitch, rib stitch, purl stitch, Denbigh stitch, cord stitch, and atlas stitch.

The resin solvent layers 12 and 13 are formed by coating a resin solvent on the super fiber layer 11. In other words, the super fiber layer 11 is coated with the resin solvent. For this reason, the resin solvent layers 12 and 13 may be referred to as resin coating layers. The resin solvent constituting the resin solvent layers 12 and 13 may contain a super engineering plastic. Note that examples of the super engineering plastic include polyamide-imide, polyimide, polyphenylene sulfide, polysulfone, polyphenylene sulfone, polyether sulfone, polyarylate, polyetherimide, polyether ether ketone, polyether ketone, polyether ketone ketone, polytetrafluoroethylene, perfluoroalkoxy alkane polymer, and liquid crystal polymer.

Method of Manufacturing Membranous Body 10

A method of manufacturing the membranous body 10 will be described with reference to the flowchart in FIG. 3. The method of manufacturing the membranous body 10 includes a weaving step (step S101), a refining step (step S102), and a resin processing step (step S103). Note that FIG. 3 is a flowchart showing a main part of the method of manufacturing the membranous body 10. Therefore, one or more other steps may be present before the weaving step. Similarly, one or more other steps may be present after the resin processing step.

In the weaving step of step S101, the super fiber layer 11 is formed by using super fiber threads. As described above, the super fiber layer 11 may be a woven fabric or a knitted fabric using super fiber threads. Alternatively, the super fiber layer 11 may be formed by binding at least two super fiber threads with at least one of a machine sewing thread and a melt thread. Note that the super fiber thread may be a twisted thread or may not be a twisted thread.

In the refining step of step S102, the super fiber layer 11 formed in the weaving step is subjected to a deoiling treatment. The deoiling treatment may be selected as appropriate according to the super fiber to be used in the weaving step. Note that various existing methods can be applied as the deoiling treatment, and thus detailed description thereon will be omitted.

In the resin processing step of step S103, a resin solvent is coated on the surface of the super fiber layer 11 from which oil agent has been washed away (i.e., deoiled) in the refining step. The resin solvent layers 12 and 13 are formed by the resin solvent coated on the surface of the super fiber layer 11.

In the resin processing step, the super fiber layer 11 may be subjected to at least one of a hydrophilic treatment and surface preparation before the surface of the super fiber layer 11 is coated with the resin solvent. In other words, the resin processing step may include at least one of the hydrophilic treatment and the surface preparation step, and the resin solvent coating step. Since various existing methods can be applied as the hydrophilic treatment and the surface preparation, detailed description thereon will be omitted. Note that the surface preparation may be referred to as pretreatment.

Note that the method of manufacturing the membranous body 10 may not include either the refining step or the hydrophilic treatment step. In other words, the super fiber layer 11 may not be subjected to either the deoiling treatment or the hydrophilic treatment.

Example of Use of Membranous Body 10

The membranous body 10 described above may be used, for example, for the inflatable kite 1 shown in FIG. 4. The inflatable kite 1 may be used, for example, in a tethered wind power generation system. For example, an inflatable tube 1a of the inflatable kite 1 is manufactured by gluing the membranous body 10 with an adhesive or sewing the membranous body 10 with threads.

For example, the inside of the inflatable tube 1a may be filled with air. At this time, the internal pressure of the inflatable tube 1a is higher than atmospheric pressure.

As a result, a relatively strong force is applied to at least one of the adhered portion and sewn portion of the inflatable tube 1a. For this reason, the membranous body 10 is required to be relatively high, for example, in creep resistance and slippage resistance. Furthermore, the inflatable kite 1 may crash. The membranous body 10 is required to have a relatively high puncture strength such that the inflatable kite 1 is prevented from being damaged when the inflatable kite 1 crashes.

Evaluation of Membranous Body 10

An evaluation result of test pieces of the membranous body 10 (hereinafter referred to as “examples” as appropriate) manufactured by the above-mentioned manufacturing method will be described. The membranous body 10 as examples has a super fiber layer 11 as a woven fabric using super fiber threads. The resin solvent layers 12 and 13 are formed to contain polyamide-imide. The mass of the membranous body 10 as the examples is 45 to 55 g/m². Note that the mass of the membranous body 10 as the examples takes into account the variation in mass of a plurality of examples.

A membranous body 210 as a comparative example 1 to be compared with the membranous body 10 and a membranous body 220 as a comparative example 2 will be described with reference to FIG. 5A and FIG. 5B. In FIG. 5A, the membranous body 210 includes a fiber layer 211 formed by laminating one layer including a plurality of threads extending in one direction and another layer including a plurality of threads extending in another direction different from the one direction, and resin film layers 212 and 213 that interpose the fiber layer 211 therebetween. Note that the fiber layer 211 is formed by using super fiber threads. The resin film layers 212 and 213 are formed to contain PET (polyethylene terephthalate). The mass of the membranous body 210 as the comparative example 1 is 73 g/m².

In FIG. 5B, the membranous body 220 includes a fiber layer 221 as a woven fabric that is woven using threads extending in one direction and threads extending in another direction different from the one direction, and resin film layers 222 and 223 that interpose the fiber layer 221 therebetween. Note that the fiber layer 221 is formed by using super fiber threads. The resin film layers 222 and 223 are formed to contain PET. The mass of the membranous body 210 as the comparative example 2 is 82 g/m².

(1) Creep Test

There was conducted a creep test in which two test pieces bonded to each other with an adhesive were pulled in a direction of arrows under a load of 800 N as shown in FIG. 6. The distance (length) in a longitudinal direction between the test piece after bonding was 200 mm, and the distance (width) in a lateral direction was 30 mm.

An example of a creep test result is shown in FIG. 7. The membranous body 210 as the comparative example 1 stretched a little over 15 mm in about 8.7 hours, and then broke. The membranous body 220 as the comparative example 2 stretched a little over 40 mm in about 35 hours, and then broke. In contrast, the membranous body 10 as the example stretched about 45 mm in about 110 hours, and then broke. From this result, it can be said that the membranous body 10 has higher creep resistance than the membranous bodies 210 and 220.

(2) Sewing Slippage Test

There was conducted a sewing slippage test in which two test pieces sewn together with a thread were pulled in a direction (see arrows) crossing a direction in which the sewing thread penetrates the two test pieces as shown in FIG. 8. An example of a sewing slippage test result is shown in FIG. 9. Note that when the thickness of the membranous body increases or the amount of fiber constituting the membranous body increases, the strength of the membranous body is enhanced, and the mass of the membranous body increases. The sewing strength shown in FIG. 9 is a value obtained by dividing the strength measured in the test by the square meter mass (g/m²) of the membranous body. In other words, the sewing strength shown in FIG. 9 indicates the strength per unit mass.

From the result related to the membranous body 10 as the example 1 and the result related to the membranous body 10 as the example 2, it can be said that the membranous body 10 has a sewing strength of 30 to 44 N/gsm when the tensile stroke is 7.5 to 12.5 mm. Comparing the maximum sewing strength values of the membranous body 10 as the example, the membranous body 210 as the comparative example 1, and the membranous body 220 as the comparative example 2, it can be said that the membranous body 10 is about 3 times the strength of the membranous body 210, and the membranous body 10 is about 1.7 times the strength of the membranous body 220. From this result, it can be said that the membranous body 10 has higher slippage resistance than the membranous bodies 210 and 220. Note that the sewing strength may be referred to as a tensile load. Note that the unit [gsm] means [g/m^2].

(3) Tear Test

There was conducted a tear test in which two test pieces sewn together with a thread were pulled in a direction in which the sewing threads penetrated the two test pieces (see arrows) as shown in FIG. 10. An example of a tear test result is shown in FIG. 11. The sewing tear strength shown in FIG. 11 is a value obtained by dividing the strength measured in the test by the square meter mass (g/m²) of the membranous body like the sewing strength shown in FIG. 9. In other words, the sewing tear strength shown in FIG. 11 indicates the strength per unit mass.

From the result related to the membranous body 10 as the example 1 and the result of the membranous body 10 as the example 2, it can be said that the membranous body 10 has a sewing tear strength of 20 to 35 N/gsm when the tensile stroke is 3 to 6 mm. Comparing the maximum sewing tear strength values of the membranous body 10 as the example, the membranous body 210 as the comparative example 1, and the membranous body 220 as the comparative example 2, it can be said that the membranous body 10 is about 2.5 times the strength of the membranous bodies 210 and 220. Note that the sewing tear strength may also be referred to as tensile load.

(4) Puncture Test

There was conducted a puncture test in which a pin having a diameter of 1 mm was stuck into the test piece at a speed of 20 inches/min. An example of a puncture test result is shown in FIG. 12. The puncture strength shown in FIG. 12 is a value obtained by dividing the strength measured in the test by the square meter mass (g/m²) of the membranous body like the sewing strength shown in FIG. 9. In other words, the puncture strength shown in FIG. 12 indicates the strength per unit mass.

From the result related to the membranous body 10 as the example 1, the result related to the membranous body 10 as the example 2, the result related to the membranous body 10 as the example 3, and the result related to the membranous body 10 as the example 4, it can be said that the membranous body 10 has a puncture strength of 0.6 to 0.8 N/gsm when the puncture stroke is 2 to 3 mm. The average value of the puncture strength of the membranous body 10 as the example is 0.73 N/gsm. The average value of the puncture strength of the membranous body 210 as the comparative example 1 is 0.44 N/gsm. From this result, it can be said that the membranous body 10 has a higher puncture strength than the membranous body 210. Note that the puncture strength may also be referred to as a puncture load.

(5) Fiber Pull-Out Test

There was conducted a fiber pull-out test in which a test piece having one end bonded to metal (for example, stainless steel) was pulled in the longitudinal direction of the test piece under a load of 130 N. Here, when the test piece breaks with fracture, cracks occur in the resin layer (for example, the resin solvent layers 12 and 13), and the resin layer and the fiber layer (for example, the super fiber layer 11) peel off, or broken fibers are pulled out. The fiber pull-out test is a test to measure the time until the broken fibers are pulled out. In the membranous body 10 as the example, no fibers were pulled out even after 10 hours had passed since the start of the test.

(6) Tensile Strength Measurement

A tensile strength measurement was conducted on a plurality of membranous bodies 10 as the example. In the tensile strength measurement, each test piece was measured three times, and an average value was taken as the tensile strength. A measurement result is shown below. Note that the tensile strength indicates the strength per unit width.

TABLE 1

EXAMPLE
EXAMPLE
EXAMPLE
EXAMPLE
EXAMPLE
EXAMPLE

1
2
3
4
5
6

TENSILE
60
54
57
53
55
56

STRENGTH

[N/mm]

Here, the variation in the results of the three measurements for each test piece was +6.4% to −3.9%. When the variation is taken into consideration, it can be said that the tensile strength of the membranous body 10 as the example was 51 to 64 N/mm. The tensile strength of the membranous body 210 as the comparative example 1 was 44.6 N/mm, and the tensile strength of the membranous body 220 as the comparative example 2 was 50.0 N/mm.

As described above, when the thickness of the membranous body increases or the amount of fibers constituting the membranous body increases, the strength of the membranous body is enhanced, and the mass of the membranous body increases. Therefore, a membranous body having a relatively heavy mass has a relatively high strength. Therefore, in consideration of the mass of the membranous body, the tensile strengths of the membranous body 10 as the example, the membranous body 210 as the comparative example 1, and the membranous body 220 as the comparative example 2 are compared with one another.

As described above, the mass of the membranous body 10 as the example is 45 to 55 g/m². The mass of the membranous body 210 of the comparative example 1 is 73 g/m². The mass of the membranous body 210 as the comparative example 2 is 82 g/m². When the mass is taken into consideration, it can be said that the tensile strength of the membranous body as the example is about twice as high as the tensile strength of the membranous body 210 as the comparative example 1 and the membranous body 220 as the comparative example 2.

Further description will be made with reference to FIG. 13 showing the relation between the mass and tensile strength of the membranous body. In FIG. 13, the tensile strength when the mass of the membranous body is taken into consideration is indicated by gradients of a solid line, a dashed line, and a dotted line shown in FIG. 13. As is clear from the solid line and dashed line shown in FIG. 13, the membranous body 10 as the example has a lighter mass and a higher tensile strength than the membranous body 210 as the comparative example 1 and the membranous body 220 as the comparative example 2. In other words, it can be said that the membranous body 10 is a light and strong membranous body.

For example, when the fiber density of the super fiber layer 11 of the membranous body 10 is increased, the mass of the membranous body 10 increases, and the tensile strength of the membranous body 10 is enhanced. On the other hand, when the fiber density of the super fiber layer 11 is decreased, the mass of the membranous body 10 decreases, and the tensile strength of the membranous body 10 deteriorates. In such a case, the mass and tensile strength of the membranous body 10 change along the solid line shown in FIG. 13. Therefore, the membranous body 10 is not limited to membranous bodies having a tensile strength of 51 to 64 N/mm and a mass of 45 to 55 g/m².

Technical Effect

The super fiber has a relatively low affinity for water. Therefore, when the resin solvent is coated on the super fiber layer 11 without taking any measure, the adhesive strength between the super fiber layer 11 and the resin solvent becomes relatively low. In contrast, in the present embodiment, the super fiber layer 11 is subjected to at least one of a deoiling treatment and a hydrophilic treatment. Therefore, according to the present embodiment, the adhesive strength between the super fiber layer 11 and the resin solvent can be enhanced. As a result, the super fiber layer 11 and the resin are restrained from peeling off each other, so that it is possible to enhance the strength of the membranous body 10. In other words, according to the present embodiment, it is possible to provide a membranous body 10 having high strength.

When the resin solvent is coated on the super fiber layer 11, the contact area between the surface of the super fiber layer 11 and the resin can be increased as compared with a case where the super fiber layer 11 is interposed between resin films. In other words, according to the present embodiment, the adhesive strength between the surface of the super fiber layer 11 and the resin can be enhanced as compared with the case where the super fiber layer 11 is interposed between the resin films. As a result, the super fiber layer 11 and the resin can be restrained from peeling off each other, so that it is possible to enhance the strength of the membranous body 10.

The resin solvent makes it difficult for the relative positional relation between the threads constituting the super fiber layer 11 to change. For example, it is possible to restrain occurrence of fiber slippage of the super fiber layer 11 caused by the sewing threads. Therefore, according to the present embodiment, the sewing strength of the membranous body 10 can be enhanced.

The super fiber layer 11 may be a woven or knitted fabric of super fiber threads. Alternatively, the super fiber layer 11 may be formed by binding a plurality of fiber layers with at least one of sewing thread and melt thread. Such a configuration makes it difficult for the relative positional relation between the threads constituting the super fiber layer 11 to change. In this case, the sewing strength of the membranous body 10 can be enhanced, for example.

As described above, the membranous body 10 is relatively high, for example, in creep resistance, slippage resistance, and puncture strength. Therefore, it can be said that the membranous body 10 is suitable as a material for the inflatable kite 1. In particular, the membranous body 10 is lighter than other membranous bodies having equivalent strength (for example, the membranous bodies 210 and 220). Therefore, when the membranous body 10 is used to manufacture the inflatable kite 1, it can make enhancement in strength and reduction in weight compatible with each other for the inflatable kite 1.

Aspects of the present disclosure which are derived from the above-described embodiment will be described below.

A membranous body according to an aspect of the present disclosure includes a super fiber layer configured with super fiber, and resin solvent layers that are in contact with the super fiber layer and formed so as to interpose the super fiber layer therebetween, wherein the super fiber layer has been subjected to at least one of a deoiling treatment and a hydrophilic treatment.

In the above membranous body, resin solvent constituting the resin solvent layers may be coated on the super fiber layer. Here, the resin solvent may include a super engineering plastic.

In the above membranous body, the super fiber layer may have at least two threads out of a thread that extends in a first direction and is formed to include the super fiber, a second thread that extends in a second direction different from the first direction and is formed to include the super fiber, and a third thread that extends in a third direction different from the first direction and the second direction and is formed to include the super fiber. The at least two threads may be intertwined with each other such that fluctuation of relative positions between the at least two threads is restrained, or the at least two threads may be bound by at least one of a machine sewing thread and a melt thread such that the fluctuation of the relative positions between the at least two threads is restrained.

Alternatively, in the membranous body, the super fiber layer may include a plurality of threads that are formed to include the super fiber and extend in one direction. Two adjacent threads out of the plurality of threads may be intertwined with each other such that fluctuation of the relative positions between the two adjacent threads is restrained.

The membranous body may have a tensile strength of 51 to 64 N/mm and a mass of 45 to 55 g/m².

The present disclosure is not limited to the above-described embodiment, but may be modified as appropriate within the scope that does not contradict the gist or concept of the present disclosure readable from the claims and the entire specification, and membranous bodies having such modifications are also included in the technical scope of the present disclosure.

MEMBRANOUS BODY

Information

Publication Number

Date Filed

Date Published

Inventors

Original Assignees

CPC

International Classifications

Abstract

Description

Claims

Priority Claims (1)