JPH02223434A - Sandwich panel using core, only edge face of which resin adheres to - Google Patents

Abstract

PURPOSE:To reduce a resin quantity of an adhesive agent by maintaining strength, by a method wherein a honeycomb sandwich panel for which a honeycomb core is used is formed by sticking fillet-formable resin to end faces of both sides of the core. CONSTITUTION:A sandwich panel is formed by making use of a honeycomb core (d) by sticking fillet-formable resin to only end faces of both sides of the honeycomb core, suitably at a quantity of 20-120g/m<2> per one side. A fillet 1 where a, length ratio between a width (a) and teight (b) of the base is 1 versus 0.2-5 is favorable one. Especially the fillet 1 whose sectional curve (c) becomes a temple-bell-like curve is far suitable from an economical point of view. Resin whose viscosity and flow capacity index are respectively 3-3000 poises and 2-60 at a fixed fillet making temperature is suitable for fillet forming resin.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a sandwich panel using a special honeycomb core, and more particularly to a sandwich panel using the core with resin adhered only to the end faces. It is.

(Prior Art) In recent years, sandwich panels have been widely used as building materials and 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, they have diversified the configurations of buildings, and have also facilitated the construction of buildings. It has the advantage of being easy to prepare and prefabricate.

Conventionally, in the production of sandwich panels with such 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. 53-134040, a means and method for applying 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 Japanese Patent No. 0-120045, two types of resins are applied to both the front and back surfaces of the honeycomb core at 100 to 20% each.
A technique for simultaneous coating with a coating amount of 0 g/l112 has been developed, and it has been reported that sandwich panels made using the honeycomb core have good adhesion.

(Invention or problem to be solved) However, the honeycomb sandwich panel as described above,
Since one side of the core has an adhesive resin of 200 g/m2 or more, the amount of resin used cannot necessarily be said to be economical, and furthermore, when the sandwich panel was subjected to a combustion test, a large amount The problem is that they generate heat and a large amount of toxic gas, making it 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 drawbacks such as a significant loss of vibration characteristics.

The present invention has been made based on the above circumstances, and its purpose is to reduce the amount of resin in the adhesive while maintaining sufficient strength as a sandwich panel, thereby making the panel nonflammable and vibration-resistant. An object of the present invention is to provide a honeycomb sandwich panel whose characteristics can be improved.

(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. A fillet-forming resin with high performance is applied only to the front and back end surfaces of the honeycomb core of the sandwich panel, at a rate of 20 to 120 per side.
It was discovered that by depositing the adhesive in an amount of g/m2, it was possible to make a honeycomb sandwich panel that did not pose any practical problems in terms of strength, passed the test for noncombustible materials, and had improved vibration characteristics, etc., and developed the present invention. It was completed.

That is, the sandwich panel of the present invention is characterized by using a core in which fillet-forming resin is adhered only to both the front and back end surfaces of the honeycomb core, preferably in an amount of 20 to 120 g/m'' per side. It is.

In the present invention, the fillet-forming resin means that when the sandwich panel of the present invention is produced, a good fillet is formed at the contact area between the honeycomb core and the skin to make the adhesion between the core and the skin effective. A resin that has the ability to do certain things.

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 1 has a diameter of 0.2 to 5. In particular, a fillet in which the cross-sectional curve C of the fillet 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 viscosity, surface tension, thixotropy, etc. that can be applied to the case where the resin is attached to the end face of the core. Moreover, it is more preferable to have a viscosity, surface tension, wetting angle, etc. that is suitable for making a sandwich panel 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 that has a viscosity in the range of 3 to 3000 voids and a flow performance index in the range of 2 to 60 at a predetermined fillet forming temperature. preferable.

If the viscosity of the resin is less than 3 poise, the resin will flow and hardly any fillets will be formed.
If the number exceeds 000 voices, the flow of the resin is extremely poor and a good fillet cannot be formed.

In addition, if the flow performance index is less than 2, the resin will not flow over the skin or core, and a good fillet will not be formed. Fillet or not formed.

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

First, 0.5g of resin was molded into a tablet with a diameter of 13mm,
Next, the tablet was placed on a plate made of the same material and surface condition as the adhesive surface of the skin or the end surface of the core, which was set at the fillet forming temperature and inclined at 60°, and left for 30 minutes. The distance a melted and flowed and the thickness h of the tablet were measured, and the flow performance index was calculated according to the following formula 8, %.

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 fillet forming performance when bonding the core and the skin.

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. It can be used as a mixture of

Examples of thermoplastic adhesives include ethylene-vinyl chloride copolymer adhesives, phthadiene 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, etc.

As the flame retardant in the present invention, brominated resins such as brominated bisphenol A type, or halogenated compounds such as polychloroparaffin 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.

In addition, as the inorganic filler in the present invention, alumina, silica, talc, quartz powder, feldspar powder, mica, calcium carbonate, thiolastonite, aluminum hydroxide, magnesium hydroxide, antimony trioxide, etc. are used. By adjusting the amount within the range of 50% by weight or less in the resin of the present invention while referring to the viscosity and flow performance index, it is possible to create a resin with sufficient strength and good fillet-forming 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 preferable to use particles with a major axis of 2.0 JLm or less. .

Here, the long axis of the 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 alloy foil or a stainless steel foil, a thin inorganic sheet, or a thin organic sheet such as Nomex paper is used,
Those formed into a honeycomb structure (hexagonal cells or pseudo-hexagonal cells) can be used.

The thickness of the core foil of the honeycomb structure core is 5iL or more.
A range of 100 IL is preferable, and the cell size (distance between opposing sides) is between 3.175 am and 45 am.
．． 00 mm range can be used.

There is no limit to the thickness of the entire core, but a thickness of 2.0 mm to 100.0 am is usually used.

Further, it is preferable to use a core whose end surface is subjected to #80 to #20 polishing treatment or chemical treatment, since this improves adhesive strength.

In the present invention, the end face of the honeycomb core refers to the outer surface of the honeycomb core perpendicular to the through hole, and the surface portion of the honeycomb core extending from that surface to about 10 mm into the through hole.

The skin in the present invention includes metal materials, inorganic materials,
Alternatively, organic materials can be used alone or in combination.

Examples of metal material skins include aluminum, iron,
Alternatively, a thin plate or a processed product made of titanium steel or alloy steel thereof, such as stainless steel, may be used.

As the organic material skin, a hard synthetic resin board or a processed product thereof, such as an acrylic resin board or a melamine resin board, can be used.

As the skin of inorganic material, it is possible to use thin sheets or manufactured products thereof, such as lightweight cellular concrete, ceramic foam, marble, granite, etc.

Furthermore, a fiber-reinforced plastic (FRP) board, which is a composite of organic and inorganic materials, or a processed product thereof can be used.

Preferred skins are those of metallic materials such as aluminum alloys, stainless steel and titanium alloys, inorganic materials such as glass, marble and granite, or fiber reinforced plastics.

Although it is preferable that the surface of these skins be flat, a perforated plate with holes partially formed therein may be used as long as it does not impede the effects of the present invention.

Furthermore, on the skin surface on the side of contact with the honeycomb core, #
A skin that has been subjected to an abrasive treatment or a chemical treatment of 80 to 2000 dollars is more preferable for use because it greatly improves the adhesive strength.

The amount of fillet-forming resin used in the present invention is 20 to 12
Preferably, the coating weight is 0 g/m''.

If the resin adhesion amount is less than 20g/m2, the adhesive strength between the core and the skin will decrease rapidly when molded into a panel.
If the amount of resin deposited is more than 120 g/m2, the adhesion strength between the core and the skin in the molded panel will be good, but it will not be economical, but the vibration characteristics, nonflammability, etc. will be significantly deteriorated.

(Function) The sander belt panel of the present invention uses a fillet-forming resin, that is, a resin having a viscosity of 3 to 3000 voids and a flow performance index of 2 to 60 at the fillet forming temperature, on the end face of the honeycomb core. Therefore, a good fillet is created at the bond between the honeycomb core and the skin during sandwich panel molding.

This good fillet provides sufficient adhesion between the core and the skin, so that the formed sandwich panel can exhibit sufficient mechanical properties such as compressive strength and tensile strength.

In addition, since the sandwich panel of the present invention is molded by adhering resin only to the end face of the honeycomb core, the amount of resin used in panel molding can be significantly reduced, and therefore the non-combustibility performance is improved and the vibration characteristics etc. It also improves.

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

As a resin for adhesion, epoxy resin (liquid at room temperature) is used.
Arartite R2fiO (manufactured by Nippon Ciba Geigy)),
Epoxy resin (Araltai) R7072 (solid at room temperature)
(manufactured by Nippon Ciba Geigy)), ethylene-vinyl acetate copolymer, and aluminum hydroxide (average particle size: 4k) were mixed in varying proportions to create 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 dicyandiazide and 3-(3,4-dichlorophenyl)-1,1-N- per 100 parts by weight of epoxy in the mixture. 5 parts of dimethyl urea are mixed together.

In addition, the core is an aluminum honeycomb core (300
3 alloy, foil thickness 76 mm, cell size 1/4 inch, thickness 18 cm) was used.

Moreover, a stainless steel plate (made of SUS 430, thickness 0.15 am) was used for the skin.

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 skins, and applying the resin at 130°C and 3 kg/cI.
112. It was created by pressing under 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 MI L-
The test method according to 3TD-401B was followed.

In the evaluation, when the FWT strength was 30 kg/cm2 or more, it was evaluated as a pass (○), and when the same strength was less than 30 kg/cm2, it was evaluated as a fail (X).

Table 1 Table 1 (Continued) The sandwich panels of Examples to Example 3 had good fillets on the core end faces, and as can be seen from this table, the panels had sufficient strength. , and was able to reduce the amount of resin used. In Example 1, there was an interface failure between the adhesive and the skin, but in Examples 2 and 3, there was a total core failure.

On the other hand, the sandwich panels of Comparative Example 1 to Comparative Example 13 did not have good fillets on the core end face, and as shown in Table 1, the adhesive strength was insufficient for sandwich panels. Ta.

(Effects of the Invention) As explained above, the sandwich panel of the present invention has
Because the adhesive area between the honeycomb core and skin has a good fillet, there is no sudden drop in adhesive strength compared to conventional products, even though the amount of resin used is significantly reduced. Even with low basis weight, it can exhibit sufficient adhesive strength.

Moreover, when the sandwich panel of the present invention is subjected to a combustion test, its calorific value, smoke emission, and amount of toxic gas are significantly reduced, and as a result, it is rendered non-combustible or improved, and it satisfactorily passes the test for non-combustible building materials. Become something.

Further, since the sandwich panel of the present invention has a reduced amount of resin, when it is used as a diaphragm for a speaker or the like, the effect on vibration characteristics is reduced.

At the same time, it goes without saying that the economy 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 and skin

Claims (4)

[Claims] (1) A honeycomb sandwich panel using a core in which fillet-forming resin is attached to both front and back end surfaces of the honeycomb core. (2) The honeycomb sandwich panel according to claim 1, wherein the fillet-forming resin is used in an amount of 20 to 120 g/m^2 per side on both the front and back end surfaces of the core. (3) The honeycomb core is formed by using metal foil such as aluminum alloy foil or stainless steel foil or thin organic sheet such as Nomex paper to form a honeycomb structure consisting of hexagonal cells or pseudo-hexagonal cells. Claim 2
Honeycomb sandwich panel as described. 4. The honeycomb sandwich panel of claim 2, wherein the skin is made of metallic materials such as aluminum alloys, stainless steel and titanium alloys, inorganic materials such as glass, marble and granite, or fiber reinforced plastics.