JPH0278536A - Core for sandwich panel, only to edge face of which resin is adhered - Google Patents

Abstract

PURPOSE:To decrease the quantity of resin as adhesive by a method wherein the quantity of the fillet formable resin lying within the specified range per one side of a core is adhered only to the edge face at both the front and rear sides of the core. CONSTITUTION:Only to the edge face at both the front and rear sides of a sandwich core, 5-150g/m<2> per one side of fillet formable resin is adhered. The fillet formable resin is organic adhesive, which exhibits fillet forming power during the bonding between the core ad surface material and epoxy-based, unsaturated polyester-based, polyurethane-based, polyamide-based adhesives and the like are exampled for cold-setting adhesive and thermosetting adhesive and, further, ethylene-polyvinyl chloride copolymer-based, butadiene-based, polyamide-based, polysulfone-based adhesives and the like are exampled for thermoplastic adhesive. They are used singly or in the form of the mixture prepared by blending one or more of them with one another. As a result, in case that a sandwich panel is produced through the bonding between skin and the adhesive, favorable fillets can be formed at the bonded part between the core and the skin.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a core used in a sandwich panel, and more particularly to a core for a sandwich panel in which resin is adhered only to the end surfaces.

(Prior Art) In recent years, sandwich panels have been widely used as double building materials or aircraft materials. Because sandwich panels have a sandwich structure, they have desirable properties such as being light, having high rigidity, and having excellent sound insulation properties.Therefore, the structure of buildings can be diversified and the structure of buildings can be easily constructed. It has the advantage of being easy to prepare and prefabricate.

Conventionally, in the production of sandwich panels with these characteristics, the surface material (skin) and the core were bonded by inserting a film-like adhesive resin between the surface material and the core, or by bonding the entire back surface of the surface board. The method used was to apply a synthetic resin and adhere the surface plate to the core.

However, originally, only the adhesive resin near the end face of the core that comes into contact with the face plate is involved in adhesion between the core and the face plate, and most of the other resin is unnecessary, so both of the above It has been desired to improve the bonding method.

In recent years, as shown in Japanese Unexamined Patent Publication No. 5:1-134040, a means and method for applying an adhesive only to the cell edges of a honeycomb core has been developed.

Recently, in order to reduce the amount of adhesive used,
As shown in Publication No. 0-120045, etc., two types of resins are applied to both the front and back surfaces of the honeycomb core with a depth of 100 to 20%.
A technology has been developed that allows simultaneous coating with a coating amount of 0g/m2.
It has been reported that sandwich panels made using the honeycomb core have good adhesive properties.

(Problem to be solved by the invention) However, since the sandwich panel described above has an adhesive resin of 200 g/m2 or more on one side of the core, the amount of resin used is not necessarily economical. However, when the sandwich panel was subjected to a combustion test, a large amount of heat was generated and a large amount of toxic gas was generated.
The problem is that it is difficult to pass the standard test for noncombustible building materials set by the Ministry of Construction. Further, when the sandwich panel described above is used as a diaphragm of a speaker, etc., the amount of resin in the adhesive is too large, resulting in disadvantages such as a significant loss of vibration characteristics.

The present invention has been made based on the above-mentioned circumstances, and its purpose is to reduce the amount of resin in the adhesive while maintaining sufficient strength when creating a Santoy Antibanel. The object of the present invention is to provide a sandwich core that can make the panel nonflammable and improve its vibration characteristics.

(Means for Solving the Problems) In order to reduce the amount of resin used, the inventors of the present invention have carefully studied the relationship between adhesive strength, resin properties, and resin amount, and as a result of diligent efforts, they were able to create a good fillet. By attaching a high-performance fillet-forming resin only to the front and back end surfaces of the sandwich core in an amount of 5 to 150 g/m'' per side, there is no practical problem in terms of strength, etc., and it is also possible to test noncombustible materials. The present inventors have discovered that it is possible to make a sandwich panel that passes the test and has improved vibration characteristics, etc., and has completed the present invention.

That is, the sandwich core of the present invention is characterized in that a buttoforming resin is attached to the fiber only on the front and back end surfaces of the core in an amount of 5 to 150 g/m2 per side.

In the present invention, the fillet-forming resin refers to a fillet-forming resin that, when a sandwich panel is created using the core of the present invention, has a good fillet that enables effective adhesion between the core and the skin material at the joint between the core and the skin material. Refers to a resin that has the ability to form.

A good fillet means that in the cross-sectional view of FIG. 1 showing the vicinity of the resin fillet part of the sandwich panel after molding,
The ratio of the width a of the fillet to the height b of the fillet is 1:
The fillet l is 0.2 to 5. In particular, a fillet whose cross-sectional curve C is a bell-shaped curve as shown in the figure is more preferable for reasons such as economical efficiency.

Further, in order to have the ability to create a good fillet, the resin preferably has a viscosity, surface tension, thixotropy, etc. suitable for attaching the resin to the end face of the core. Moreover, it is more preferable that the material has a viscosity, surface tension, wetting angle, etc. that can be applied to the case where a sandwich panel is made using a core to which a resin is attached.

From this point of view, the fillet-forming resin used in the present invention is a resin whose viscosity is in the range of 3 to 3000 voids and the flowability fE product index is in the range of 2 to 60 at a predetermined fillet forming temperature. Or preferable.

If the viscosity of the resin is less than 3 voices, the resin will flow too much and hardly any fillets will be formed, and if the viscosity of the resin exceeds 3000 voices, the resin will flow extremely poorly and no good fillets will be formed.

In addition, if the flow performance index is less than 2, the resin will have difficulty flowing on the skin material or core, and a good fillet will not be formed.On the other hand, if the flow performance index is greater than 60, the sl
Too much fat flows out and good fillets cannot be formed.

Here, the flow performance index refers to viscosity, surface tension, wettability 1.
It refers to an index defined in the present invention that includes complex factors such as gender, and is specifically measured and calculated by the following method.

First, 0.5g of resin was molded into a tablet with a diameter of 13mm,
Next, the above tablet was placed on a board with the same material and turning surface as the adhesive surface of the skin material or the end surface of the core, which was set at the fillet forming temperature and inclined at 60 degrees, and after being left for 30 minutes, the tablet was melted. The flow distance fia and the tablet thickness h are measured, and the flow performance index is calculated according to the following formula.

In the present invention, it is more preferable to use a resin whose flow performance index determined on each surface of the two types of plate materials falls within the range of 2 to 60.

The resin that can be applied to the present invention is an organic adhesive that has good fission-forming performance when bonding the core and the surface material.

Examples of organic adhesives include room-temperature-curing adhesives, thermosetting adhesives, and thermoplastic adhesives, with structural adhesives that have traditionally been used for building exteriors being the most preferred. .

Room-temperature curing adhesives and thermosetting adhesives include, for example, epoxy adhesives, unsaturated polyester adhesives, polyurethane adhesives, phenolic adhesives, furan adhesives, silicone adhesives, and polyacid adhesives, each of which may be used alone or in combination with more than one type. Can be used as a mixture of

Examples of thermoplastic adhesives include ethylene-vinyl chloride copolymer adhesives, butadiene adhesives, polyamide adhesives, polyimide adhesives, polyethylene adhesives, polyester adhesives, polystyrene adhesives, and polysulfone adhesives, each of which may be used alone or in combination with more than one type. It can be used as a mixture of

Further, room temperature curable, thermosetting, and thermoplastic adhesives may be mixed together, and it is preferable to mix other additives such as flame retardants and inorganic fillers, modifiers, and the like.

As the flame retardant in the present invention, brominated resins such as brominated bisphenol A type, or halogenated compounds such as polychloro J14 paraffin and decabromodiphenyl ether can be used, and the amount added in the resin of the present invention is determined by By controlling the amount to 30% by weight or less, it is possible to create a resin that has good fillet-forming performance and a certain degree of strength.

Further, as the inorganic filler in the present invention, alumina, silica, talc, quartz powder, feldspar powder, mica, )1% calcium, thiolastonite, aluminum hydroxide, magnesium hydroxide, antimony dioxide, etc. can be used. The amount to be added is 1 while referring to the viscosity and flow performance index.
In the resin of the present invention, am
By doing so, it is possible to create a resin having sufficient strength and good fillet creation performance.

The particle size of the inorganic filler is adjusted so that the viscosity and flow performance index are each maintained within a certain range, and in order to prevent a decrease in resin strength, it is recommended to use particles with a major diameter of 2.0 pm or less. preferable.

Here, the long axis of one particle refers to the length of the longest diameter among the diameters of each part of the particle.

Further, by subjecting the particle surface of the inorganic filler to special processing such as silane treatment, a resin having good fillet forming performance and high strength can be produced.

As the core in the present invention, a metal foil such as an aluminum foil, a stainless steel foil, a thin inorganic sheet, a thin organic sheet (Nomex paper, etc.) is used, and a honeycomb structure (hexagonal cells, pseudo-hexagonal cells, square cells) is used. , roll cell, or circular cell), or formed into a hollow tubular structure, interlocking structure, network structure, hollow plate structure, wavy structure, uneven structure, rod-shaped structure, etc., or lightweight aerated concrete. , light stone, ceramic foam, a lightweight core material combined with glass balloons, etc. can be used.

In the case of a core with a honeycomb structure, the thickness of the core foil is between 5JL and 100. The cell size (distance between facing sides) is preferably in the range of 3.175■-45.
00 m5 range can be used.

In addition, there is no limit to the thickness of the entire core, and a thickness of 2.0 mm to 0.0 mm is usually used.

Further, it is preferable to use a core whose end surface is subjected to polishing treatment of #80 to 2000 or chemical treatment, since this improves the adhesive strength.

In the present invention, the end face of the core means, in the case of a honeycomb core,
It refers to the outer surface perpendicular to the through hole, and the surface area of the honeycomb core extending from that surface to about 10 cm into the through hole.

The amount of resin used in the present invention is preferably 5 to 150 g/m'' per side on both the front and back end surfaces of the core.

If the resin coverage is less than 5 g/m2, the adhesive strength between the core and the skin will decrease rapidly when molded into a panel, and if the resin coverage is greater than 150 g/m2, the formed panel will Although the adhesion strength between the core and the skin is good, it is not only uneconomical, but also the vibration characteristics, nonflammability, etc. are significantly deteriorated.

(Function) The core of the present invention uses a fillet-forming resin, that is, a resin with a viscosity of 3 to 30 mouths and 0 voids at the fillet forming temperature and a flow performance index of 2 to 60, so that it adheres to the skin. When forming a sandwich panel using this method, a good fillet can be created at the bond between the core and the skin.

This good fillet provides sufficient adhesion between the core and the skin, and therefore provides sufficient mechanical properties such as compressive strength and tensile strength when formed into a panel.

In addition, since the core of the present invention has resin attached only to the end face, the amount of resin used can be significantly reduced when molded into a panel, thus contributing to improved flame resistance and vibration characteristics. .

(Example) The present invention will be explained in detail below.

As a resin for adhesion, an epoxy resin that is liquid at room temperature (Araldite" 260 (manufactured by Nippon Ciba Geigy)),
Epoxy resin (Araldite" 7072) that is solid at room temperature
(manufactured by Nippon Ciba Geigy)), ethylene-vinyl acetate copolymer, and aluminum hydroxide (average particle size: 4) were mixed in varying proportions to produce resins with different viscosities and flow performance indexes as shown in Table 1 below. were prepared and used for each test specimen. Note that the flow performance index was measured by the method described above.

In addition, in order to thermally cure the epoxy resin, the above resin contains 4 parts of dicyanacyate and 3-(:1.4-dichlorophenyl)-1,1-N per 100 parts by weight of epoxy in the mixture. - each mixed with 5 parts of dimethylurea.

In addition, the core has an aluminum honeycomb core (300:
1 alloy, foil thickness 76IL, cell size 1/4 inch,
A thickness of 18 iv) was used.

Moreover, an aluminum plate (made of 300:1 alloy, thickness 0.5 mm) was used as the skin material.

The test specimen was prepared by applying the resin to both the front and back end surfaces of the aluminum honeycomb core using a roll coating method, then sandwiching both sides of the core between the skin materials, and applying the resin at 130°C and 3 kg/cm.
It was made by pressing under the conditions of 1 hour.

A FWT strength test was conducted on each specimen, and the results are shown in Table 1 below. FWT strength test is MIL-S
The test method according to TD-401B was followed.

In the evaluation, when the FWT strength was 15 Kg/CJ2 or more, it was given a pass (0), and when the FWT strength was the same or less than 15 Kg/cm2, it was given a fail (X).

Table 1 Table 1 (Continued) When the cores of Examples 1 to 3 were made into sandwich panels, good fillets were formed, and as can be seen from this table, the panels had sufficient strength and It has also been possible to reduce the amount of resin used. In addition, Example 1
was the interface failure between adhesive and skin, but in Example 2
In Example 3, the entire core was destroyed.

On the other hand, when the cores of Comparative Examples 1 to 13 were molded into panels, good fillets were not formed, and as shown in Table 1, the adhesive strength was insufficient for panels.

(Effects of the Invention) As explained above, when the sandwich panel core of the present invention is bonded to the skin to form the sandwich panel 1, a good fillet can be created at the bonded portion between the core and the skin. .

In particular, although the core of the present invention has resin attached only to the end face of the core and the amount of resin used is significantly reduced, compared to conventional products, there is no rapid decrease in adhesive strength and the core has a low basis weight. It is possible to exhibit sufficient adhesive strength even if the material is

Furthermore, when a panel made from the core of the present invention is subjected to a combustion test, the calorific value, the amount of smoke produced, and the amount of toxic gas are significantly reduced, and as a result, the non-combustibility is improved, and it is sufficient for the test of non-combustible building materials. It will be possible to pass the exam.

Furthermore, due to the reduction in the amount of resin, when a sandwich panel using the core of the present invention is used as a diaphragm for a speaker or the like, the influence on vibration characteristics is reduced.

At the same time, it goes without saying that economic efficiency has been greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the vicinity of a resin fillet portion of a sandwich panel molded using a honeycomb core. In the figure a-- Width of the bottom of the fillet b-- Height of the fillet C-- Cross-sectional curve of the fillet d-- Core e-- Skin material

Claims (1)

[Claims] Fillet-forming resin is applied only to the front and back end surfaces of the core.
Core for sandwich panels deposited in an amount of 5 to 150 g/m^2 per side.