KR101243992B1 - Laminated Structure for Infrared Camouflage - Google Patents

Abstract

In the present invention, the inner layer of the woven fabric using a polymer fiber comprising an infrared absorbing component; A knitted intermediate layer laminated on one surface of the inner layer of the fabric; And a fabric outer layer laminated on the knitted intermediate layer, the fabric outer layer including a fabric outer layer having a color coating layer formed on one side of the fabric layer in a direction opposite to the fabric inner layer direction.
Since the present invention is manufactured by the method of complexing the fiber material, the strength is lower and more flexible than the method by the conventional metal thin film coating. Therefore, it is easy to use even in equipment with bends, and light weight can be usefully applied to equipment requiring mobility. In addition, since the knitted intermediate layer can be variously changed according to the type of heat source, there is an advantage that it can be adapted to suit the purpose.

Description

Laminated Structure for Infrared Camouflage

The present invention relates to a fiber composite structure for thermal imaging, and more particularly, a fabric inner layer woven using a polymer fiber containing an infrared absorbing component; A knitted intermediate layer laminated on one surface of the inner layer of the fabric; And a fabric outer layer having a color coating layer formed on the opposite side of the fabric layer in one side of the fabric layer as a fabric layer laminated on the knitted intermediate layer, and having a low heat reflectance value in the infrared region, and having a flexible and light thermal image. It relates to a fiber composite structure for camouflage.

Thermal infrared detection is a method of illuminating and detecting a specific area by using near-infrared light which is invisible to the naked eye, and the level of thermal infrared camouflage (thermocamel) is determined by the detection capability of thermal imaging equipment. It is divided into two types (3 ~ 5㎛, 8 ~ 14㎛) according to the wavelength range used in the thermal imaging equipment. To cope with this, the material design technology and the raw material for heat cut / modulation related to the material technology are used. One of the key factors is the processing technology and the fiber composite material technology that can absorb heat energy sufficiently. There are many difficulties in the development of technology because there are few technologies known for thermal imaging, and many other industrial technologies must be combined with fibers.

All thermal infrared sensors determine the presence of a target by contrasting the infrared radiation between the target and the background. Therefore, for thermal infrared camouflage, a technique is needed to adjust and control the thermal infrared signals radiated from the weapon system as closely as possible to the radiation of the surrounding background. To this end, developed countries have developed and operated sophisticated analysis programs that can accurately interpret the complex infrared radiation patterns of each weapon system.

The first method used to adjust and control the infrared radiation pattern is to keep the surface temperature as low as possible. This is because the infrared radiation intensity is proportional to the square of the temperature. For this purpose, in order to lower the surface temperature of the inorganic system, a technique of preventing heat from spreading to the surface by wrapping a heat generating portion such as an engine with an appropriate insulating material is used.

Second, in order to lower the exhaust gas temperature, the exhaust pipe is cooled with cold air or water, and a large amount of cold air is also mixed with the exhaust gas. In addition, the curved intake and exhaust pipe structure prevents direct thermal radiation from being radiated to the outside.

A third method for controlling thermal infrared radiation intensity is to coat an infrared absorbing material on the surface of the inorganic system. Currently, infrared absorbing material coating technology has been developed to reduce the intensity of radiated infrared rays by 1/10 without increasing weight. The infrared absorber coating is designed to reduce infrared radiation from the surface of the inorganic system while reducing infrared reflections from sunlight.

For example, Patent Literature 1 discloses a thermoset material in which a patch layer, a polyethylene film, a metal layer, an adhesive layer, and a support layer of a fiber material are laminated in this order. In the thermally superposed material, the basic support layer of the fibrous material and a metal layer capable of reflecting thermal infrared rays and a plastic layer having different emissivity from each other are formed in a thin sheet form. The backing layer consists of a fibrous material, such as polyester or polyamide in woven form. The reflective layer is a conductive material such as aluminum foil, the thickness of which is effective at more than 5nm, the most ideal thickness is 50nm. This layer serves to maintain the thermal radiation equilibrium by giving a thermal insulation effect from the interior of the target to be camouflaged. On the other hand, a film such as polyethylene or polyvinyl chloride, which is represented as a material having a low emissivity, is used for the plastic layer. The plastic layer may vary the emissivity according to the thickness. The surface of the plastic layer is colored for camouflage of the visible area, and a colored dye is used for materials with low thermal energy absorption, and the surface is matte.

However, in the conventional technology as described above, since the metal layer is used, there is a problem in that it is insufficient to be easily applied to equipment having a bend, such as a mobile weapon system, and there is a problem of a complicated configuration composed of five or more multilayered structures. Therefore, there is a continuing need to develop a fiber composite structure that is flexible and lightweight, having thermal infrared blocking properties by improving this.

Accordingly, the present inventors employ a fabric using a yarn containing a metal oxide as an inner layer, and on the inner layer, a knitted fabric forming an air layer to prevent the infrared rays absorbed from the camouflage material and the inner layer from being released into the atmosphere, In the case of laminating the camouflage coating layer on the intermediate layer, it was confirmed that the camouflage performance for visual observation as well as thermal imaging equipment can be implemented as a relatively simple structure and completed the present invention.

U.S. Patent 4,529,633

SUMMARY OF THE INVENTION An object of the present invention is to provide a fiber composite structure for thermal phase shifting having a low heat reflectance value in the infrared region, being flexible and light, and further applicable to a variety of heat sources.

The fiber composite structure for thermal imaging of the present invention for achieving the above object is a textile inner layer woven using polymer fibers containing metal oxide particles; A knitted intermediate layer laminated on one surface of the inner layer of the fabric; And a fabric outer layer in which a color coating layer is formed on one side of the fabric layer opposite to the fabric inner layer direction of the fabric layer stacked on the knitted intermediate layer.

The metal oxide particles are preferably at least one selected from the group consisting of ATO, ITO and AZO.

The content of the metal oxide is preferably 1.0 to 4.0% by weight of the total weight of the polymer fiber.

It is preferable that the polymer fiber containing the metal oxide particles is a composite fiber.

The composite fiber may be a sheath-type composite fiber in which metal oxide particles are included in a sheath portion, and a quencher is further included in the core portion.

6. The fiber composite structure according to claim 5, wherein the cardiac composite fiber comprises metal oxide particles in a sheath portion and a quencher is further included in the core portion.

The matting agent is preferably at least one selected from the group consisting of titanium dioxide (TiO ₂ ), zincation (ZnO), lithopone (ZnS, BaSO ₄ ), lead white (2PbCO ₃ ) and antimony oxide (Sb ₂ O ₃ ). .

The content of the matting agent is preferably 1.5 to 5.0% by weight relative to the weight of the yarn.

A color coating layer may be further formed on the inner layer of the fabric.

It is preferable that the knitted fabric is a warp knitted fabric.

The space volume ratio of the knitted fabric is preferably 30 to 60%.

It is preferable to adhere | attach with urethane resin.

The color coating is preferably a coating of 4 degrees color.

The fiber composite structure for thermal phase shifting of the present invention has a reflectance value of 0.7 or less at a wavelength of 3 to 5 µm and 8 to 14 µm at a temperature of 70 to 100 ° C.

Since the present invention is manufactured by the method of complexing the fiber material, the strength is lower and flexible than the conventional method by the metal thin film coating. Therefore, it is easy to use even in equipment with bends, and light weight can be usefully applied to equipment requiring mobility. In addition, since the knitted intermediate layer can be variously changed according to the type of heat source, there is an advantage that it can be adapted to suit the purpose.

1 is a schematic cross-sectional view of a fiber composite structure for thermal imaging of the present invention.
Figure 2 is a cross-sectional picture of the sheath type polyester composite fiber yarn used in the inner layer of the fabric in the embodiment of the present invention.
3A is a thermal image of a fabric inner layer,
3B is a thermal image photograph of a laminate of the inner layer of the fabric and a knitted intermediate layer laminated on one surface thereof;
Figure 3c is a thermal image photograph of the fiber composite structure for thermal imaging of the present invention is further laminated on the laminate fabric outer layer.
4A and 4B are thermal image photographs of the fiber composite of Comparative Example 1 and Comparative Example 2. FIG.

Hereinafter, a fiber composite structure for thermal phase shifting of the present invention will be described with reference to the drawings. 1 is a schematic cross-sectional view of a fiber composite structure 1 for thermal imaging of the present invention. In Figure 1, the fiber composite structure (1) for thermal imaging of the present invention is a fabric inner layer (10) woven using a polymer fiber comprising an infrared absorbing component; A knitted intermediate layer 20 laminated on one surface of the inner layer of the fabric; And a fabric outer layer 30 having a color coating layer 31 formed on an opposite side of the fabric layer 10 in one direction of the fabric layer as a fabric layer laminated on the knitted intermediate layer 20.

< Fabric inner layer 10>

The fiber composite structure (1) for thermal thermosetting of the present invention is composed of three layers, the first fabric inner layer 10 is woven using a polymer fiber containing an infrared absorbing component.

The inner layer 10 serves as a support layer of the fiber composite of the three-layer structure of the present invention. Therefore, the fabric is used to have a compact structure in order to prevent deformation due to external force.

At this time, the polymer fibers used need not be particularly limited, and fibers prepared using polymers such as polyester, polyamide, polyethylene, polyethylene, polypropylene, polyvinyl alcohol, polyimide, and molybamideimide may be used. Among these, polyester fibers are preferable as fibers having a high fiber strength and a relatively low price.

The polymer fiber contains an infrared absorbing material having a capability of absorbing thermal infrared rays. As the infrared absorber used for this purpose, at least one metal oxide selected from the group consisting of aluminum doped tin oxide (ATO), aluminum doped zinc oxide (AZO) and indium doped tin oxide (ITO) is used. Among them, the use of ATO is preferred because it is not only excellent in conductivity and transmittance, but also advantageous in terms of cost.

The metal oxide is uniformly dispersed in the polymer fiber in a ratio of 1.5 to 4.0% by weight based on the total weight of the fiber in the fiber manufacturing process. If the metal oxide is less than 1.5% by weight, the thermal infrared absorption performance is deteriorated, which is not preferable. If the metal oxide is more than 4.0% by weight, problems such as trimming (cutting) occur during the fiber polymerization process are not preferable.

On the other hand, there is no particular limitation on the method of dispersion, and any conventional method of dispersing an infrared absorber in a polymer fiber is sufficient in the art. Usually, a master chip is first prepared for smooth spinning in a state in which a polymer material is melted so as to achieve a uniform dispersion state, and the filament is formed with a thickness of about 100 to 160 deniers by melt spinning the master chip. After the fabrication, the filament is used as a yarn, and the fabric is supplied to warp and weft yarns at a constant density. Also in the method of weaving, possible weaving methods such as plain weave, twill weave and runner weave can be used as necessary.

On the other hand, the form of the fiber is not only a normal fiber, but also a form of a composite fiber including a sheath type, an island-in-sea type, a split type, and the like. Among them, a structure that maximizes the density of infrared absorbing materials as a method for enhancing the effect of the thermal infrared stealth is a vinegar type, and a lot of infrared absorbing materials including metal oxides are distributed in the initial part (outer layer) of the yarn. It is particularly desirable to have.

On the other hand, when the cardiac sheath composite fiber is used as the yarn of the inner fabric layer, a matting agent may be added to the core portion. The matting agent added to the core portion is somewhat inferior to that of metal oxide (ATO), but because it has a property of blocking thermal infrared rays, in order to maximize thermal infrared ray shielding characteristics during the manufacturing of a deep sheath type composite fiber. To serve as an adjunct in combination with ATO. As the quencher used for this purpose, TiO ₂ is generally used, but in addition, zinc oxide (ZnO), lithopone (ZnS, BaSO ₄ ), lead white (2PbCO ₃ ), antimony oxide (Sb ₂ O ₃ ), etc. There is this. The content of the matting agent is preferably 1.5 to 5.0% by weight relative to the weight of the yarn. If the content of the matting agent does not reach 1.5% by weight, it is not preferable as an inadequate content to serve as an auxiliary role of the thermal infrared blocking effect, and if the content of the matting agent exceeds 5.0% by weight, the yarn is broken in the process of spinning the yarn. There is a problem of envoys.

If necessary, the fabric may be subjected to pretreatment for removing foreign matters such as foils or emulsions attached during the weaving process.

The fiber material of the fabric inner layer 10 may increase the camouflage effect by further processing the appearance state if necessary. To this end, color coating may be additionally performed on the surface of the pretreated material. The color coating is the same as the color coating method of the outer layer to be described later.

< Knitting Interlayer 20>

In the fiber composite structure (1) for thermal phase shifting of the present invention, the knitted intermediate layer (20) is supported in the porous intermediate layer as much as possible before releasing the thermal infrared energy generated from the heat source of the equipment to the outside, and is similar to the ambient air temperature. To release slowly. For this purpose, as the material of the intermediate layer, a knitted fabric is used to form a myriad of porous air layers. Among them, warp knitted fabrics are particularly preferable because they are porous and have similar shape stability as fabrics.

As the material used for the knitted interlayer, fibers prepared using polymers such as polyester, polyamide, polyethylene, polyethylene, polypropylene, polyvinyl alcohol, polyimide, and polyamideimide may be used.

The knitted intermediate layer preferably has a space volume ratio of 30 to 60%, more preferably 35 to 50%. The space volume ratio refers to the ratio of the space excluding the fibers constituting the knitted fabric, that is, the space occupied by the air layer, in the volume of the entire interlayer of the knitted fabric. If the space volume ratio does not reach 30%, there is a problem that it is not possible to carry the heat source emitted for a long time and is easily detected outside, and when the space volume ratio exceeds 60%, the shape stability of the tissue is poor and deformation of the appearance occurs. There is a problem and is undesirable.

The same is true for the inner fabric of the fabric, except that the polymeric fibrous material for obtaining the knitted fabric does not contain an infrared absorber. The thickness of the knitted intermediate layer 20 may be variously adjusted according to a specific use, but, since the knitted fabric lacks texture in a rough shape, the thickness of the knitted intermediate layer 20 is improved, thereby providing a dense texture and being attached in the manufacturing process of the knitted fabric. The pretreatment process may be carried out as necessary for the removal of the emulsion or emulsion.

< Fabric outer layer 30>

In the fiber composite structure (1) for thermal thermosetting of the present invention, the outer fabric layer 30, the color coating layer 31 is formed on the knitted intermediate layer 20 is laminated. The direction in which the color coating layer 31 is formed in the fabric outer layer 30 is the opposite side of the fabric inner layer 10 in one direction of the fabric outer layer 30. The role of the fabric outer layer 30 serves to slowly release the thermal energy contained in the intermediate layer 20 in a state similar to the temperature of the outside atmosphere.

The polymer fibers for use in the fabric outer layer 30 are the same as in the fabric inner layer 10 in the kind, weaving method, pretreatment, and the like. However, there is no need to absorb extra thermal infrared rays. Therefore, the metal oxide is not included in the polymer fiber.

In addition, the outer layer 30 has the performance of the naked gastrointestinal and near-infrared (Near Infra-Red) camouflage at night, it is necessary to play a role to protect the thermal infrared camouflage network as a whole. To this end, unlike the color coating used for the inner layer 10, a color coating of 4 degree color is required for the naked eye and near-infrared camouflage.

<Interlayer Adhesion>

When the above-described inner layer, middle layer and outer layer are each separately present, the thermal infrared ray shielding performance cannot be sufficiently exhibited, and thus, adhesion between the layers is required as a method for combining these layers. The bonding method may be a conventional bonding method such as a method using an adhesive, a quilting (adhesion by sewing) method. Among these, in order to prevent separation between layers as much as possible and not to impair the appearance of the composite material, a method using an adhesive is preferred. In particular, the disadvantage of using a metal layer as in the prior art was the lack of flexibility of the material, for the purpose of improving this as much as possible for the purpose of improving the maximum flexibility without the adhesive is applied to the front surface in the roll (roll) method for bonding each layer between It is desirable to.

On the other hand, when making the said interlayer adhesion | attachment an adhesive agent, it is preferable to use a polyurethane resin for this purpose. Polyurethane resin is a general term for a polymerized compound having a large number of chemically structural urethane bonds (-NHCOO-). Urethane bonds are formed by the addition reaction of highly reactive isocyanate groups (-NCO-) with alcohols with active hydrogen (-0H). Among the compounds with active hydrogens, amines (-NH _2- ), water, etc. It is commonly used to produce urea bonds (-NHCONH-). Here, the segment made by the reaction of the diisocyanate with the polymeric polyol becomes a soft segment, and the segment made by the reaction of the diisocyanate with the chain extender becomes a hard segment and exists simultaneously in one molecule.

The polyurethane resin (adhesive) is divided into one-component and two-component, and usually has the advantage that one-component can be used alone as a self-crosslinking resin, the two-component is an additive in order to have an adhesive performance There is a disadvantage that must be given separately.

Hereinafter, the present invention will be described in more detail with reference to Examples. This embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

Example

(1) fabric inner layer:

Flat thickness of 0.25mm to 0.3mm using 160D / 48F sheath / core type polyester composite fiber manufactured by uniformly dispersing ATO (metal oxide), an infrared absorber, by 2.0% by weight of the total weight of the fiber The fabric was prepared. Figure 2 is an enlarged photograph of the cross section of the sheath type polyester composite fiber yarn used in the inner layer of the fabric in this embodiment. The strength of the yarn was 3.7 g / d and the elongation was 37.8%. In Fig. 2, the outer portion containing ATO, which is represented by black spots, is the outer portion, and the inner bright portion is a core portion made of polyester yarn containing 4% by weight of TiO ₂ .

The color coating of the inner layer fabric was made in defense color out of four colors based on defense standards. First, 17.5% by weight of polyurethane resin (Cytec, UCECOAT-775) and 43.8% by weight of inorganic inorganic pigments (Chromium Oxide Green GN, Bayer, Germany) were dissolved in 38.7% by weight of DMF solvent in the outer layer of the fabric, and then the coating The solution was coated on the polyester fabric with a thickness of 50-100 μm. Next, drying and heat treatment (Drying & Curing) was carried out at 130 ℃ × 180 seconds conditions to remove the solvent color and resin was left on the surface color coating was performed .

(2) knitted interlayer:

The material used as the intermediate layer was woven from 15D polyester (PET) fibers into a knit fabric, and the knit fabric was designed to have a thickness of 7-8 mm and a space volume ratio of 38.5-42.0% per 1M ³ .

(3) fabric outer layer:

The polyester fiber used in the outer layer of the fabric was a plain weave fabric composed of warp 75D / 36F and weft 150D / 36F, and a thickness of 0.25-0.3 mm was used.

Color coating on the fabric outer layer was carried out in the following manner. First, 17.5% by weight of polyurethane resin (Cytec, UCECOAT-775) and 43.8% by weight of inorganic inorganic pigments (Chromium Oxide Green GN, Bayer, Germany) were dissolved in 38.7% by weight of DMF solvent in the outer layer of the fabric, and then the coating The solution was coated on the polyester fabric with a thickness of 50-100 μm. Next, drying and heat treatment (Drying & Curing) was carried out at 130 ℃ × 180 seconds conditions to remove the solvent color and resin was left on the surface color coating was performed .

(4) interlayer adhesion

Each layer was bonded in a gravure roll method. Polyurethane resin (FULLER, HL-9588X; viscosity 8,000CPS) was used as the adhesive, and the inner and outer layers were applied to the intermediate layer under the conditions of applying a temperature of 105 to 110 ° C, a winding speed of 20 to 25 M / min, and a tension of 4 bar. Bonding was in turn to prepare a fiber composite structure for thermal imaging.

Comparative example  One

Fiber composite for thermal imaging in the same manner as in Example 1, except that a general polyester (PET) plain fabric (inclined: 75D / 36F, weft: 150D / 48F) containing no infrared absorbing component was used as the inner layer of the fabric. The structure was prepared.

Comparative example  2

Fiber composite for thermal superposition by bonding the inner and outer layers of the fabric to the same layer using ordinary polyester (PET) plain weave fabric (inclined: 75D / 36F, weft: 150D / 48F) without using the intermediate fabric. The structure was prepared.

evaluation

Using the black body thermostat for the manufactured fiber composite structure, the temperature was set at 70 ° C. and 100 ° C., respectively, through a thermal imaging camera (FLUKE, Thermal Imagers, Ti25) for detecting thermal infrared rays. The performance was confirmed. The test conditions were measured using a black body thermostat and a sample of 2 cm and a distance between the sample and the thermal imaging camera as 1 M. At the time of measurement, the atmospheric temperature was measured at 26 to 27 ° C. and the humidity at 70% RH. Summarized in

3 ~ 5um emissivity 8 ~ 14um emissivity 70 ℃ 100 ℃ 70 ℃ 100 ℃ Example 0.66 0.51 0.59 0.52 Comparative Example 1 0.86 0.89 0.89 0.90 Comparative Example 2 0.98 0.97 0.95 0.93

In the above table, emissivity refers to the rate at which an object absorbs, transmits, and reflects infrared energy. In theory, an object that only absorbs external energy but does not reflect it is called a black-body, and the emissivity value is "1." Is defined as ". However, ordinary objects vary the amount of energy they absorb and reflect, depending on their surface conditions (gloss, roughness, oxidation, etc.). That is, when the ratio of absorbed and reflected energy is based on a black body, the value is actually smaller than "1". The emissivity value of a material that can be used as a thermal infrared camouflage network is 0.7 or less. The result of Table 1 is the emissivity value of the fiber composite structure of the present invention having a three-layer structure, showing a value of 0.51 ~ 0.66 lower than the above standard was confirmed that the level can be used for thermal imaging.

On the other hand, as in Comparative Examples 1 and 2 do not include an infrared absorbing material in the inner layer, or when only the fabric is laminated without a knitted intermediate layer to form a fiber composite structure there is a thermal infrared blocking effect, but the emissivity value is somewhat All of them can be confirmed to be inadequate to be used for stealth applications in excess of 0.7.

Figure 3a is a thermal image photograph of the inner layer of the fabric, Figure 3b is a thermal image photograph of a laminate of the intermediate layer of the fabric and the inner layer laminated on one side, Figure 3c is further laminated fabric outer layer on the laminate It is a thermal image photograph of the fiber composite structure for thermal imaging of the present invention. 3A to 3C, it can be seen that the temperature range measured in the thermal image when the outer layer, the middle layer, and the inner layer are bonded to each other is almost similar to the outside temperature. From this, it can be seen that it can be used as a low-infrared radiation shielding material only when three layers are combined, not as a single material.

4A and 4B are thermal image photographs of the fiber composite of Comparative Example 1 and Comparative Example 2. FIG. When Comparative Examples 1 and 2 do not include an infrared absorbing material in the inner layer of the fabric, or when only the fabric is laminated without a knitted intermediate layer to form a fiber composite structure, the thermal infrared blocking effect is somewhat, but in Example 3c Compared with the red part, there are many shortcomings suitable for stealth use.

Therefore, the technology of the present invention not only protects expensive mobile weapon systems (eg armored vehicles) but also has a great ripple effect such as energy saving effect by the development of a material that can express excellent thermal insulation effect in daily life. Can be.

1 ... fiber composite structure
10 ... fabric inner layer
20 ... knitted interlayer
30 ... fabric outer layer
31 ... color coated

Claims (15)

A textile inner layer woven using polymer fibers containing metal oxide particles;
A knitted intermediate layer laminated on one surface of the inner layer of the fabric; And
And a fabric outer layer having a color coating layer formed on an opposite side of the fabric layer in one direction of the fabric layer as a fabric layer laminated on the knitted intermediate layer. The fiber composite structure of claim 1, wherein the metal oxide particles are at least one selected from the group consisting of ATO, ITO, and AZO. According to claim 1, wherein the content of the metal oxide is a fiber composite structure for the thermal phase shifting, characterized in that 1.5 to 4.0% by weight of the total weight of the polymer fiber. The fiber composite structure of claim 1, wherein the polymer fiber including the metal oxide particles is a composite fiber. According to claim 4, The composite fiber is a fiber composite structure for the thermostomosis, characterized in that the cardiac composite fiber. 6. The fiber composite structure according to claim 5, wherein the cardiac composite fiber comprises metal oxide particles in a sheath portion and a quencher is further included in the core portion. The method of claim 6, wherein the quencher is selected from the group consisting of titanium dioxide (TiO ₂ ), zincation (ZnO), lithopone (ZnS, BaSO ₄ ), lead white (2PbCO ₃ ) and antimony oxide (Sb ₂ O ₃ ). Fiber composite structure for the thermostage, characterized in that at least one. The fiber composite structure according to claim 6, wherein the content of the quencher is 1.5 to 5.0% by weight based on the weight of the yarn. The fiber composite structure of claim 1, wherein a color coating layer is further formed on the inner layer of the fabric. delete The fiber composite structure of claim 1, wherein the knitted fabric is a warp knitted fabric. According to claim 1, wherein the space volume ratio (the ratio of the space occupied by the air layer, ie the space excluding the fibers constituting the knitted fabric in the total volume of the intermediate layer of the knitted fabric) is 30 to 60% Fiber composite structure for. The fiber composite structure according to claim 1, wherein each layer is bonded by urethane resin. 5. The fiber composite structure according to claim 1, wherein the color coating is a coating of 4 degrees color. 6. 10. The fiber for thermal imaging according to any one of claims 1 to 9, wherein a reflectance value for light having a wavelength of 3 to 5 µm and 8 to 14 µm at a temperature of 70 to 100 ° C is 0.7 or less. Complex structure.

Images