KR20020062108A - Honeycomb core for sandwich-structure material and the preparation method thereof - Google Patents

Abstract

PURPOSE: Light weight honeycomb core of sandwich structured composites is provided, which has improved physical and mechanical properties, and nonflammability compared with conventional honeycomb core made of aramid or aluminum by impregnating fibrous reinforcing materials with inorganic fillers. CONSTITUTION: The honeycomb core is prepared by impregnating fibrous reinforcing material such as paper, wood, natural fiber or synthetic fiber with inorganic filler such as sodium silicate(Na2O.nSiO2.xH2O), sodium aluminate(Na2O.Al2O3.xH2O) or lithium polysilicate(Li2O.nSiO2.xH2O) through spray or immersion method, followed by drying under the foaming temperature of inorganic filler, 60-130deg.C, for 1-30min. The prepared honey comb has good compression strength and nonflammability.

Description

Honeycomb core for sandwich-structure material and the preparation method

The present invention relates to a honeycomb core material of a sandwich composite structure material and a method of manufacturing the same, and more particularly, to impregnating inorganic fillers with lightweight fibrous combustible materials such as paper, natural and synthetic fibers, or wood, so that their strength and flame retardancy are increased. To reinforce and to use it as a honeycomb core of sandwich composite materials.

The sandwich composite material is composed of two thin, high-strength surface materials (skin layer) and a honeycomb core layer in the shape of a honeycomb using a relatively light material, and an adhesive layer for bonding them. Consists of. Looking at the physical properties of the materials used in these skin layers and core layers, the skin layer material should be relatively rigid and excellent in strength to exhibit strong stresses in tension and compression, and the core layer material should be relatively flexible and regular honeycomb. It should be in the form of a back and have a strong and light jungle stress. When these two layers are glued together to form a single structure, they have a compressive strength of up to 30 times or more than a sandwich panel consisting of a skin layer alone.

Since the core layer of the sandwich composite material generally has a honeycomb structure, it is also called a honeycomb core or honeycomb core. In general, the honeycomb refers to the shape of the original honeycomb, but in the present invention, the honeycomb is not limited to a honeycomb shape, but is used in a concept including all of a lattice shape, a wave shape, a convex shape, or a concave shape. When honeycomb cores are used in sandwich composite materials, the overall weight is light and the compressive strength is excellent. The sandwich composite structure using honeycomb core materials has been used as part of aircraft and transportation structural materials since 1940, and is currently used for lightweight construction in building interior materials, ship or vehicle interior materials, bulkhead materials and leisure, and sports fields. It is widely used.

Although the light metal may be used as the honeycomb core material of the sandwich composite structure material, since the light metal is considerable in weight and expensive, such a light metal core material is not widely used except in special cases. In addition, a material made of carbon fiber, glass fiber or polymer fiber may be used as a honeycomb core material, but it has an advantage of significantly increasing the strength and durability of physical properties of such material, but the workability and adhesion are poor, and the price is also high. Due to the high price, this situation is not widely used.

In recent years, honeycomb core materials made of paper are widely used in doors, partitions, and lightweight panels. Since paper cores are lighter, cheaper than other materials, and are easy to form and adhere to in a honeycomb form, many of the composite composite materials used in real life use these paper cores. However, since the paper is highly flammable, when the paper is used as a honeycomb core material for furniture products such as panels, doors and partitions made of combustible materials, there is a risk of rapidly spreading a flame in a fire. In addition, since the honeycomb core made of paper is difficult to ensure sufficient strength, its use is very limited.

On the other hand, in the light weight sandwich composite structure material, an organic polymer resin is filled into an inorganic or organic fiber reinforcement material and used as a honeycomb core material. Filling the fibrous reinforcement with the organic polymer resin can significantly improve the compressive and tensile strengths. However, fillers made of such organic polymer resins are not only flammable in general, but also have a problem of generating toxic gases in case of fire.

The present invention was devised to solve the problems of the conventional honeycomb cores used in sandwich composite structure material, the object is light, excellent workability and adhesion, low manufacturing cost, compression resistance, tensile resistance, wear resistance It is to provide honeycomb core material of sandwich composite structure material which has excellent physical and mechanical properties such as bendability, weather resistance and moisture resistance.

Another object of the present invention is to provide a core material of a flame retardant sandwich composite structure material which improves the flammability or detrimental disadvantages of a honeycomb core made of lightweight fiber such as paper, fabric or wood by using an inorganic material as a filler. .

1 is a table of measurements of embodiments of the present invention.

2 is a compressive strength of the honeycomb core material according to the concentration change of the coating liquid

3 is the shear bond strength of the honeycomb core material according to the concentration change of the coating liquid

Figure 4 is a photograph taken of the specimen before the flame retardant test

Figure 5 is a picture taken to apply a flame

Figure 6 is a photograph showing the state after removing the flame

Figure 7 is a photograph showing the foamed state after the test

Figure 8 is a DSC result showing the foaming range and heat capacity of sodium silicate.

The present invention is used as a honeycomb core material of a sandwich composite structure material by impregnating an inorganic filler with a flammable material made of light fiber such as paper, natural or synthetic fibers, wood, and the like. The core material has a honeycomb, that is, a honeycomb shape, which is advantageous in terms of compressive strength, but a lattice type may be used depending on the requirements of strength, and a corrugated or convex / concave type may also be used, such as cardboard.

Inorganic fillers used in the present invention include alkali silicates such as sodium silicate (Na ₂ O.nSiO ₂ .xH ₂ O) and lithium polysilicate (Li ₂ O.nSiO ₂ .xH ₂ O), and sodium aluminate (Na _2). Alkaline alumina, such as O.Al ₂ O ₃ .xH ₂ O), silica sol (nSiO ₂ .xH ₂ O, colloid type) or complex magnesium-aluminum sulfonate soda (Na ₂ O.Mg/Al-SO ₄ .xH ₂ O), and preferably sodium silicate _{(Na 2 O · nSiO 2 ·} xH 2 O), aluminate soda _{(Na 2 O · Al 2 O} 3 · xH 2 O), lithium polysilicate (Li ₂ O · nSiO ₂ · xH it is better to use the ₂ O). In the present invention, in order to impregnate such an inorganic filler into the reinforcing material, a method of spraying an aqueous solution of the filler into the reinforcing material or immersing the reinforcing material into the aqueous solution of the inorganic filler may be used. The concentration of the filler aqueous solution, drying time, drying temperature and the like affect the strength and flame retardancy of the core material.

In the present invention, a method for manufacturing a honeycomb core material is sprayed with an injector or an aqueous solution of an inorganic filler having a concentration of 10% by weight to 70% by weight to a lightweight fibrous reinforcement such as paper, natural or synthetic fibers, wood, or the like. After immersing in a water tank of the above aqueous solution of filler, the filler aqueous solution is sufficiently impregnated into the reinforcing material, and then at a temperature and time in the state that the inorganic filler does not foam, that is, from 1 minute to a hot air dryer of about 60 ℃ to 130 ℃ To dry for 30 minutes. This is because when the inorganic filler is foamed, its physical properties decrease.

Sodium silicate used in the present invention is a so-called water glass, which is an alkali silicate obtained by melting silicon dioxide and an alkali in a concentrated aqueous solution, and is a liquid substance containing _{2 to} 4 mol SiO ₂ per mol of Na ₂ O. Colorless, odorless, highly viscous liquid. When dried in air, it forms a solid glass form. It is marketed in various forms according to the molar ratio of Na ₂ O and SiO ₂ , which are water glass components, and when the ratio of Na ₂ O: SiO ₂ is 1: 1, it is meta-sodium silicate, 1.5: 1 In the case of ortho-sodium silicate, it is called ortho-sodium silicate, and usually 1: 2 is No. 1 sodium silicate, 1: 2.5 is No. 2, 1: 3 is No. 3, 1: 4 is No. 4 Called soda. In addition, liquid alumina soda, lithium polysilicate, silica sol, and composite magnesium / aluminum sulfonate soda used in the present invention are commercially available in various forms according to the molar ratio of the constituents thereof. Sodium silicate fillers can be used regardless of the molar ratio of the components.

Liquid sodium silicate according to the invention _{(Na 2 O · nSiO 2 ·} xH 2 O), aluminate soda _{(Na 2 O · Al 2 O} 3 · xH 2 O), lithium polysilicate (Li ₂ O · nSiO ₂ · The concentrations of the aqueous solutions of xH ₂ O), silica sol (nSiO ₂ · xH ₂ O, colloid type) and composite magnesium / aluminum sulfonate soda (Na ₂ O.Mg/Al-SO ₄ · xH ₂ O) range from 10% by weight to It is preferable to set it as 70 weight%. This means that when the concentration of the aqueous solution is less than 10% by weight, the core manufactured by the drying process after spraying or dipping into the core does not have sufficient compressive strength, and the mechanical and chemical properties of the core are sufficiently expressed by moisture absorption. If it is more than 70% by weight, it is difficult to maintain the basic physical properties by deforming the core structure itself, and the additional cost may increase due to the consumption of a large amount of time and calories during the drying process.

In the coating of the inorganic filler on the surface of the fibrous reinforcement according to the present invention, the drying temperature is preferably in the range of 60 ° C to 130 ° C. The reason is that when the drying temperature is less than 60 ° C, sufficient drying is not achieved. The weight of the core structure is heavy, it is difficult to manufacture the reinforcement sandwich structure after drying, and if the drying temperature exceeds 130 ℃, the structural properties of the coated water glass may decrease due to the boiling phenomenon on the surface due to the high temperature foaming phenomenon. Because it can.

The drying time in the present invention is preferably 1 minute to 30 minutes. If the drying time is less than 1 minute, the honeycomb core structure is heavy due to insufficient drying, and it is difficult to manufacture the reinforced sandwich structure after drying. If the drying time is more than 30 minutes, The peeling phenomenon of the honeycomb core material and the water glass component occurs and the surface is not smooth, and it is disadvantageous in the manufacturing process as the sandwich structure material.

According to the present invention, the mechanical properties such as the compressive strength and the tensile strength of the honeycomb core coated with the inorganic filler on the surface of the reinforcement are about 2 to 5 times the compressive strength, and the shear bond strength is about It is increased by 2 to 4 times or more. Therefore, this invention enables manufacture of the ultralight honeycomb core material which is excellent in compression resistance and excellent in flame retardancy.

Hereinafter, the present invention will be described based on Examples. However, the scope of the present invention is not limited to the embodiment.

Example 1

In this embodiment, the honeycomb core material of the sandwich composite structure material is cut into a length of 600 mm, a width of 600 mm, and a thickness of 25 mm using a paper commonly used as a reinforcement material. The inorganic filler is liquid silicon silica having a concentration of about 10 wt%. the _{2 O · nSiO 2 · xH 2} O) was used. The spray method was adopted to coat the filler on the reinforcement. After impregnating the filler in the reinforcing material by spraying method sufficiently, it was dried in a hot air drying furnace at about 60 ° C. for about 1 minute, and the surface of the reinforcing material was coated with the filler, and then a honeycomb core material was manufactured.

For honeycomb cores obtained through this process, the weight and structure changes, compressive strength and shear bond strength before and after the filler coating treatment were measured, and are shown in <Table 1>. According to the measurement results, there were almost no deformations in weight and appearance, and the honeycomb core material obtained through the sodium silicate coating treatment increased the compressive strength by 2.2 times and the shear bond strength by 1.8 times as compared with before treatment. From this result, it was confirmed that the mechanical properties of the honeycomb core material using the paper as a reinforcing material by the present invention, significantly improved by the water glass coating process without changing its weight or structure.

Example 2

Embodiments use paper, such as from 1 to reinforcing material, and as the inorganic filler uses aluminate soda _{(Na 2 O · Al 2 O} 3 · xH 2 O) aqueous solution of about 50% by weight, and coat the filler in the reinforcing materials The spray method was adopted. After impregnating the filler in the reinforcement by the spray method sufficiently and dried in a hot air drying furnace of about 80 ℃ for about 5 minutes to coat the reinforcement surface with the filler, a honeycomb core material was produced.

For the core material obtained by this process, changes in weight and structure, compressive strength and shear bond strength before and after the filler coating treatment were measured and shown in Table 1. According to the measurement results, there were almost no deformations in weight and appearance, and the honeycomb cores obtained through the alumina soda coating were increased 4.5 times in compressive strength and 3.2 times in shear bond strength, respectively. From this result, it was confirmed that the mechanical properties of the honeycomb core material using paper as a reinforcing material were remarkably improved by the water glass coating process without any change in weight or structure.

Example 3

The same paper as in Example 1 was used as the reinforcing material, and an aqueous lithium polysilicate (Li ₂ O.nSiO ₂ xH ₂ O) solution of about 30% by weight was used as the inorganic filler. The spray method is adopted. After impregnating the filler in the reinforcing material by spraying method sufficiently, it was dried in a hot air drying furnace at 100 ° C. for about 10 minutes to coat the surface of the reinforcing material with an inorganic filler, and then a honeycomb core material was manufactured.

For the core material obtained by this process, the weight and structure change, the compressive strength and the shear bond strength before and after the filler coating treatment were measured and shown in Table 1. According to the measurement results, there was almost no deformation in weight and appearance, and the honeycomb core material obtained through the lithium polysilicate coating treatment increased the compressive strength by 3.4 times and the shear bond strength by 2.7 times, respectively. From this result, it was confirmed that the mechanical properties of the honeycomb core material using paper as a reinforcing material were remarkably improved by the water glass coating process without any change in weight or structure.

Example 4

The same paper as in Example 1 was used as the reinforcing material, and about 70 wt% of silica sol (nSiO ₂ · xH ₂ O, colloid type) aqueous solution was used as the inorganic filler, and the spraying method was used to coat the filler on the reinforcing material. Was adopted. After impregnating the filler in the reinforcing material by spraying method sufficiently, it was dried in a hot air drying furnace at 130 ° C. for about 20 minutes, and the surface of the reinforcing material was coated with the filler, and then a honeycomb core material was manufactured.

For honeycomb cores obtained through this process, changes in weight and structure, compressive strength, and shear bond strength before and after inorganic filler coating were measured and are shown in Table 1. According to the measurement results, there was almost no deformation in weight and appearance, and the honeycomb core material obtained through the silica sol coating treatment increased the compressive strength 5.3 times and the shear bond strength 3.8 times, respectively, compared with the pretreatment. From this result, it was confirmed that the mechanical properties of the honeycomb core material using paper as a reinforcing material were remarkably improved by the water glass coating process without any change in weight or structure.

Example 5

The same paper as in Example 1 was used as a reinforcing material, and as an inorganic filler, an aqueous solution of composite magnesium-aluminum sulfonate (Na ₂ O.Mg/Al-SO ₄ .xH ₂ O) at a concentration of about 40% by weight was used. In coating the inorganic filler with the reinforcing material, a method of dipping the reinforcing material in the filler aqueous solution was adopted. After sufficiently impregnating the filler in the reinforcing material, and dried for about 30 minutes in a hot air drying oven of about 110 ℃ after the surface of the reinforcing material coated with the filler, a honeycomb core material was produced.

For honeycomb cores obtained through this process, changes in weight and structure, compressive strength, and shear bond strength before and after inorganic filler coating were measured and are shown in Table 1. According to the measurement results, there was almost no deformation in weight and appearance, and the honeycomb core material obtained through the composite magnesium-aluminum sulfonate soda coating treatment increased the compressive strength by 4.8 times and the shear adhesive strength by 3.2 times, respectively. From this result, it was confirmed that the mechanical properties of the core material using the paper as a reinforcing material were remarkably improved by the water glass coating process without any change in weight or structure.

Example 6

The same paper as in Example 1 was used as the reinforcing material, and about 60% by weight aqueous solution of sodium silicate (Na ₂ O.nSiO ₂ · xH ₂ O) was used as the inorganic filler, and the inorganic filler was coated on the reinforcing material. The method of immersing the reinforcing material in the filler aqueous solution was adopted. After sufficiently impregnating the filler in the reinforcing material, and dried for about 15 minutes in a hot air drying oven of about 90 ℃ after the surface of the reinforcing material coated with the filler, a honeycomb core material was produced.

For honeycomb cores obtained through this process, changes in weight and structure, compressive strength, and shear bond strength before and after inorganic filler coating were measured and are shown in Table 1. According to the measurement results, there were almost no deformations in weight and appearance, and the honeycomb core material obtained through the sodium silicate coating treatment increased the compressive strength by 5.1 times and the shear bond strength by 3.4 times as compared with before treatment. From this result, it was confirmed that the mechanical properties of the core material using the paper as a reinforcing material were remarkably improved by the water glass coating process without any change in weight or structure.

Example 7

Embodiments use paper, such as from 1 to reinforcing material, and as the inorganic filler uses aluminate soda _{(Na 2 O · Al 2 O} 3 · xH 2 O) aqueous solution of about 20% by weight, and coat the filler in the reinforcing materials In the case, a method of immersing the reinforcing material in the filler aqueous solution was adopted. After sufficiently impregnating the filler in the reinforcing material, and dried for about 25 minutes in a hot air drying oven of about 70 ℃ after the coating surface of the reinforcing material with the filler, a honeycomb core material was produced.

For honeycomb cores obtained through this process, changes in weight and structure, compressive strength, and shear bond strength before and after inorganic filler coating were measured and are shown in Table 1. According to the measurement results, there were almost no deformations in weight and appearance, and the core obtained through the alumina soda coating treatment had 3.5 times higher compressive strength and 2.4 times higher shear bond strength than before treatment. From this result, it was confirmed that the mechanical properties of the honeycomb core material using paper as a reinforcing material were remarkably improved by the water glass coating process without any change in weight or structure.

Example 8

In this embodiment, general wood is used as a reinforcement material for the sandwich composite structure, an aqueous solution of sodium silicate (Na ₂ O · nSiO ₂ · xH ₂ O) at a concentration of about 20% by weight is used as the inorganic filler, and the filler is coated on the reinforcement material. The spray method was adopted. After impregnating the filler with the reinforcing material by the spray method sufficiently, it was dried in a hot air drying furnace at about 80 ° C. for about 20 minutes, and the surface of the reinforcing material was coated with the filler, and then a honeycomb core material was manufactured.

For honeycomb cores obtained through this process, changes in weight and structure, compressive strength, and shear bond strength before and after inorganic filler coating were measured and are shown in Table 1. According to the measurement results, there was almost no deformation in weight and appearance, and the core obtained through the coating of sodium silicate increased 2.6 times in compressive strength and 1.8 times in shear bond strength, respectively. From this result, it was confirmed that the mechanical properties of the honeycomb core made of wood as a reinforcing material were remarkably improved by the water glass coating process without any change in weight or structure.

Example 9

The same wood as in Example 8 is used as the reinforcing material, and about 40 wt% of silica sol (nSiO ₂ · xH ₂ O, colloid type) aqueous solution is used as the inorganic filler, and the reinforcing material is coated when the inorganic filler is coated on the reinforcing material. The method was immersed in a filler aqueous solution. After sufficiently impregnating the filler in the reinforcing material, and dried for about 10 minutes in a hot air drying oven of about 100 ℃ after coating the surface of the reinforcing material with the filler, a honeycomb core material was produced.

For honeycomb cores obtained through this process, changes in weight and structure, compressive strength, and shear bond strength before and after inorganic filler coating were measured and are shown in Table 1. According to the measurement results, there were almost no deformations in weight and appearance, and the honeycomb core obtained through the silica sol coating treatment increased the compressive strength by 3.4 times and the shear bond strength by 2.3 times as compared to before treatment. From this result, it was confirmed that the mechanical properties of the core made of wood as a reinforcing material were remarkably improved by the water glass coating process without any change in weight or structure.

Example 10

In this embodiment, natural and synthetic fibers are used as a reinforcing material, and about 30% by weight of polysilicate (LiO · nSiO ₂ · xH ₂ O) aqueous solution is used as the inorganic filler, and the spray method is used to coat the filler on the reinforcing material. Was adopted. After fully impregnating the filler in the reinforcing material was dried for about 30 minutes in a hot air drying oven of about 70 ℃ after the surface of the reinforcing material was coated with the filler to produce a honeycomb core material.

For honeycomb cores obtained through this process, the weight and structure changes, compressive strength and shear bond strength before and after the filler coating treatment were measured, and are shown in <Table 1>. According to the measurement results, there was almost no deformation in weight and appearance, and the honeycomb core material obtained through the polysilicate coating treatment increased the compressive strength by 7.8 times and the shear adhesive strength by 1.7 times, respectively, compared with the previous treatment. From this result, it was confirmed that the mechanical properties of the honeycomb core material using the fiber as a reinforcement material were remarkably improved by the water glass coating process without any change in its weight or structure.

Example 11

Artificial and synthetic fibers as in Example 10 were used as reinforcing materials, and as an inorganic filler, aqueous solution of composite magnesium-aluminum sulfonate (Na ₂ O.Mg/Al-SO ₄ .xH ₂ O) at a concentration of about 50% by weight. In the case of coating the inorganic filler on the reinforcing material, a method of immersing the reinforcing material in the filler aqueous solution was adopted. The inorganic filler was sufficiently impregnated into the reinforcing material, and then dried in a hot air drying furnace at about 90 ° C. for about 15 minutes to coat the reinforcing material with the filler, and then a honeycomb core material was manufactured.

For honeycomb cores obtained through this process, changes in weight and structure, compressive strength, and shear bond strength before and after inorganic filler coating were measured and are shown in Table 1. According to the measurement results, there was almost no deformation in weight and appearance, and the honeycomb core material obtained through the composite magnesium-aluminum sulfonate soda coating treatment increased the compressive strength 3.4 times and the shear adhesive strength 2.3 times as compared with the previous treatment. From this result, it was confirmed that the mechanical properties of the honeycomb core material with fiber as a reinforcing material were remarkably improved by the water glass coating process without any change in weight or structure.

Example 12

Flame retardancy tests were performed on specimens of core material prepared according to each of the above examples. The equipment used for the flame retardant test included a tube with a burner length of 100 ± 10mm and an inner diameter of 9.5 ± 0.3mm and was manufactured according to the standard ASTM D5025, and the feed gas was constant with methane gas of the required grade (minimum purity 98%). There is a regulator and indicator for flow control.

The smoke evacuation facility had a fan with a minimum internal area of 0.5 m 3 so that it could naturally release toxic fumes under test so that the fan was not running during the test. The temperature of the test site was 23 ℃, relative humidity 45% and the flame was observed after adding a blue flame of 20mm height for 30 seconds. The flame incline was made from the central axis of the burner tube at the same vertical plane as the vertical bottom of the sample and inclined about 45 ° toward the end of the sample. Experimental results showed that the specimens had a combustion length of 0 mm and a linear combustion rate of 0 (V = 60 L / t, mm / min) and no ignition on the flame retardant paper core.

In Examples 1 to 11, the appearance and deformation of the appearance structure of the water glass surface coated and dried core material was visually observed, the compressive strength and shear bond strength in the measurement of mechanical properties according to each embodiment is in accordance with KS F3517 It measured accordingly. Two types of specimens were measured, corrugated or hexagonal honeycomb, depending on the shape of the cell. Each cell size was 10 mm. The specimen size was 50 mm in length, 50 mm in width and 25 mm in thickness for compressive strength, and the shear bond strength test was cut to 200 mm in length, 75 mm in width and 25 mm in thickness. At this time, in the compressive strength test, the load surface treatment of the test piece was reinforced with epoxy resin, and the shear bond strength test was performed by adhesively bonding both ends of the test piece with an epoxy resin using an aluminum plate having the same size as the specimen (thickness of 0.8 mm). It was. Each specimen was tested after being completely dried in a drying oven at 90 ° C. for about 12 hours, and the compressive and shear bond strengths were measured at a loading speed of 1 mm / min. The results were treated with uncoated specimens. It is shown in Table 1 by comparing the specimens. The measured value of <Table 1> shows the five measured value in the average in each Example.

4, 5, 6 and 7 are photographs of the experimental procedure. The test result was found to be suitable for the 94HB classification condition, and the sample did not ignite, and thus the average linear combustion rate was 0 (mm / min), indicating excellent flame retardancy. This excellent flame retardancy is because the coated inorganic ceramic, water glass (or sodium silicate), is foamed by heat and has an excellent thermal insulation effect between heat and paper, thereby protecting the product from heat.

8 is a diagram showing the results of differential scanning calorimetry (DSC) measurement of the expandable ceramic (water glass). During the temperature change from room temperature to 270 ° C., the temperature range of foaming ceramic foaming in response to heat was about 125 ° C. to 200 ° C., and it was found to absorb about 116 to 162 J of heat per gram.

On the other hand, Figures 2 and 3 show the changes in the compressive strength and shear bond strength of the honeycomb core material according to the concentration change of the inorganic filler aqueous solution (coating solution), respectively.

The core material of the sandwich composite structure according to the present invention is to significantly improve the physical and mechanical properties such as compression resistance, tensile resistance, wear resistance, bending resistance, weather resistance, moisture resistance, etc. while maintaining lightness through the inorganic filler impregnation treatment. That is, as shown in the above embodiment, the core material produced by the surface coating treatment method according to the present invention, despite the almost no change in weight or appearance structure before and after coating, mechanical properties such as compressive strength and tensile strength Compared with the existing core material without coating, it is improved significantly, and it is possible to manufacture the ultralight honeycomb core material with excellent compression resistance.

In addition, the core material according to the present invention is cheaper than the existing expensive aramid or aluminum honeycomb core material, and its mechanical properties have almost no difference, so the replacement effect is large, and there is no need for a separate mechanical device or facility according to the coating treatment. The continuous process is possible and economically advantageous.

In addition, the present invention solves the disadvantages of low strength and flammability of lightweight fiber core material, thereby opening up the possibility that such a core material can be widely used as a reinforcement material of products to which flame retardant standards such as construction materials and ships are applied. Do.

Claims (8)

The lightweight, fibrous reinforcing material is either alkali silicate, alkali alumina, silica sol (nSiO ₂ xH ₂ O, colloid type) or composite magnesium / aluminum sulfonate soda (Na ₂ O.Mg/Al-SO ₄ xH ₂ O). A honeycomb core material of a sandwich composite material, characterized in that one inorganic filler is impregnated. The honeycomb core material of claim 1, wherein the fibrous lightweight reinforcement material is one of paper, wood, natural fiber or synthetic fiber. The method of claim 1, wherein the inorganic filler is sodium silicate (Na ₂ O · nSiO ₂ · xH ₂ O), sodium aluminate (Na ₂ O. Al ₂ O ₃ · xH ₂ O) or lithium polysilicate (Li ₂ O Honeycomb core of sandwich composite material with nSiO ₂ xH ₂ O). The honeycomb core material of the sandwich composite structural material as described in any one of Claims 1-3 whose shape is honeycomb, a lattice shape, a wave shape, a convex shape, or a concave shape. The lightweight, fibrous reinforcing material is either alkali silicate, alkali alumina, silica sol (nSiO ₂ · xH ₂ O, colloid type) or composite magnesium / aluminum sulfonate soda (Na ₂ O.Mg/Al-SO ₄ · xH ₂ O). A method of manufacturing a honeycomb core material of a sandwich composite structure material comprising impregnating a single inorganic filler and drying it for a temperature and a time under the condition that the inorganic filler foams. The method of claim 5, wherein the drying of the inorganic filler is a honeycomb core material manufacturing method of the sandwich composite structure material is made for 1 to 30 minutes at 60 ℃ to 130 ℃. 6. The method of claim 5, wherein the fibrous reinforcement material is one of paper, wood, natural fiber or synthetic fiber. The method of claim 5, wherein the inorganic filler is sodium silicate _{(Na 2 O · nSiO 2 ·} xH 2 O), aluminate soda _{(Na 2 O · Al 2 O} 3 · xH 2 O) , or lithium polysilicate (Li ₂ O · Honeycomb core material manufacturing method of sandwich composite structure material of nSiO ₂ · xH ₂ O).