JPH0381447A - composite stone panel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention uses a high-quality stone as a surface material, and has excellent workability,
This invention relates to composite stone panels with excellent flame retardancy, heat insulation and sound insulation properties.

[Conventional technology]

BACKGROUND OF THE INVENTION In recent years, stone panels, which use natural stone as a surface material, have become a structural material with excellent aesthetics and durability, and have thus become widely used as interior materials for large buildings.

However, if this natural stone is to be used as a single board, it is necessary to use a board with a certain thickness due to problems with the strength of natural stone, which increases the weight considerably and causes difficulties in construction. In order to compensate for this drawback, that is, to reduce the weight while maintaining sufficient strength, organic materials such as plastic are used for reinforcement on the back side of natural stone sheets, and lightweight, high-quality materials such as honeycomb cores are used. Stone panels combined with rigid compositions have been developed.

Many proposals regarding such technology have already been made, for example, Japanese Patent Application Laid-Open No. 63-42.857, Japanese Patent Application Laid-Open No. 63-42.863, or Japanese Patent Application Laid-Open No. 63-42.
Publication No. 851 and the like are known.

That is, such a composite panel has a structure in which thin stones are attached to both or one side of a core material such as a fiber-reinforced plastic plate, lightweight foam sheet, or honeycomb core. This core material can be made of fiber-reinforced plastic made by impregnating reinforcing fibers such as glass fiber with resin, elastomer, etc., lightweight foam sheets such as polyurethane, vinyl chloride, phenolic resin, paper, metal, etc. Honeycomb core etc. are used. This core material acts as a reinforcing material by adhering to the back side of the surface material, and also contributes to improving strength and rigidity as the core material of sandwich panels. Furthermore, since it includes an air layer, heat insulation and sound insulation properties are improved.

Conventionally, when manufacturing these sandwich panels, a method using a sheet-like film adhesive is generally used to bond the skin material and the core material. However, if the adhesive strength between the skin material and the core material is not sufficient, the strength of the skin material will not be fully utilized when a bending load is applied to the sandwich panel, and sufficient load capacity will not be exhibited. Therefore, the film adhesive used is required to have sufficient adhesive strength, and when using honeycomb material or foam material as the core material, it is not possible to secure a sufficient adhesive area, so the flow of the resin is controlled and the skin material is It is necessary to create a resin pool called a fillet at the contact area between the core material and the core material. For this reason, in conventional film adhesives, epoxy resins have been widely used because they have excellent adhesive strength and have a large degree of freedom in modification.

However, the plastic sheets used for lining and the adhesives such as epoxy resins used for adhesion to the honeycomb core are flammable and also produce toxic gases when burned, so this is not a problem when testing the board. This has created the possibility of causing serious problems in terms of safety in the event of a fire.

On the other hand, in recent years, from the perspective of safety in the event of a fire, flame-retardant regulations have been tightened for materials used for interior decoration in places where large numbers of people gather. Or it is spreading to the interior wall materials of buildings. For this reason, skin materials or film adhesives made of flame-retardant epoxy resins, which have been widely used until now, have become difficult to use for aircraft interior materials due to the smoke and heat generated when they are burned. A replacement has become necessary. As a result, studies have begun to consider the use of phenolic resins, which have long been known for their good flame retardant properties.

However, although this phenolic resin certainly surpasses epoxy resin in flame retardant properties and has the best properties as a thermosetting resin, it does not match epoxy resin in mechanical properties, making it a so-called brittle resin. Therefore, there is a problem that the strength of reinforcing fibers cannot be fully expressed in skin materials, and that the adhesive strength is low even when used as an adhesive. In other words, when phenolic resin is used, its flame retardant properties are good, but its strength is low, and extra reinforcing material is required to obtain the same strength as epoxy resin. There was a problem that the effect was not sufficiently exhibited. Furthermore, since phenolic resin contains a solvent, it is difficult to process into a film adhesive, and there are problems in that it is difficult to process into a film adhesive, and has a low degree of freedom in modification for flow control.

[Problem to be solved by the invention]

The object of the present invention is to provide a composite stone panel manufactured by using a thin plate of stone as a surface material and laminating this to a core material,
An object of the present invention is to provide a composite stone panel that has excellent flame retardant properties, generates little smoke during combustion, and has sufficient weight and strength.

[Means to solve the problem]

That is, the present invention is a composite stone panel formed by pasting thin stones on both sides or one side of a core material such as a fiber-reinforced plastic plate, lightweight foam sheet, or honeycomb core. Composite stone panels bonded with a phenolic adhesive layer. In the present invention, the materials for forming the phenolic adhesive layer include (1) a phenolic adhesive containing as an essential component a phenolic resin and a thermoplastic resin that is compatible with the phenolic resin; / or (2
) Phenol resin prepreg obtained by impregnating organic fibers such as glass fibers, carbon fibers, and aramid fibers with phenol resin is used.

The present invention will be explained in detail below.

First, the composite stone panel referred to in the present invention, as mentioned earlier, has a structure in which thin stones are attached to both or one side of a core material such as a fiber-reinforced plastic plate, lightweight foam sheet, or honeycomb core. It is something. Such core materials include fiber-reinforced plastics made by impregnating reinforcing fibers such as glass fibers with resins, elastomers, etc., lightweight foam sheets such as polyurethane, vinyl chloride, and phenolic resins, paper, and metals. Examples include honeycomb cores. Further, as the core material, an aluminum honeycomb having minute pores is suitable in consideration of heat insulation, sound insulation, and fire resistance, but the core material is not necessarily limited to this.

Further, as the stone material for the surface, natural stone is desirable from the viewpoint of aesthetics and other aspects, and the thickness thereof is preferably about 3 to 15 mm from the viewpoint of strength and weight.

In the present invention, the core material and the stone are bonded together with a phenolic adhesive layer, but the phenolic adhesive layer is compatible with the following materials: (1) phenolic resin and the phenolic resin; A phenolic adhesive containing a thermoplastic resin as an essential component, and/or
(2) It is formed using a phenolic resin prepreg obtained by impregnating organic fibers such as glass fibers, carbon fibers, and aramid fibers with phenolic resin.

First, phenol adhesives can be in either liquid or film form, but from the viewpoint of the amount of volatile content, uniform application of the adhesive, and handling, it is preferable to use film form. is simpler and more effective.

There are two possible methods for processing this phenolic adhesive into a film. First, a resin composition containing a base phenolic resin, a thermoplastic resin, and other additives is prepared,
There is a method of applying this resin composition on paper or the like whose surface has been subjected to a release process using silicone, etc., and then removing the solvent to obtain a film.Also, there is a method of obtaining a film by heating and dissolving a thermoplastic resin in a base phenolic resin. This method involves adding additives, removing volatile components from the phenol resin until it reaches a viscosity that is easy to use at room temperature, and then coating the resin thinly on release paper while heating it to an appropriate temperature to obtain a film. Comparing both these methods,
The former method has a high thermoplastic resin content and is suitable for making a high viscosity resin into a film, and can be manufactured with relatively simple equipment, whereas the latter method requires complicated equipment and is expensive. Although it has the disadvantage that the range of resin viscosity that can be used is narrow, it is possible to precisely control the thickness and weight. Both of these methods can be used depending on the quality, required characteristics, and resin composition of the target film adhesive.

The phenolic resin used for these adhesive layers is
Generally known novolak type phenolic resins and resol type phenolic resins can be used, but liquid resol type phenolic resins are preferred due to ease of prepreg or film processing, ease of handling prepregs or films, etc. used.

The thermoplastic resin added to the phenolic resin must be compatible with the base phenolic resin, but it can be added by hot melting or by dissolving it in a solvent and then adding it. . Particularly suitable thermoplastic resins are alcohol-soluble copolymerized nylon, polyvinyl formal,
Polyvinyl acetal, etc. These thermoplastic resins not only have excellent compatibility with phenolic resins, but also have a certain degree of strength and flexibility, especially when the resin composition is stretched into a thin film, making them extremely easy to use. It will be a good film. In addition, since the thermoplastic resin itself is very tough, it has a large toughness improvement effect, and at the same time it controls the flow of the phenolic resin, resulting in a good fillet, especially when used as a film adhesive for honeycomb sandwich panels. can be formed, making it possible to obtain adhesive strength comparable to that of epoxy resin.

The amount of these thermoplastic resins used is 0 parts by weight of the resin composition. If the amount is less than this, problems will arise in improving toughness, flow control properties, and film processability, and if it is more than this, there will be problems in deterioration of flame retardancy.

Next, as for the phenolic resin prepreg, a preferable example is a glass/phenol prepreg in which a glass cloth is impregnated with a resol type phenolic resin. If even more strength is required, aramid fibers, carbon fibers, etc., which are even stronger than glass fibers, can be used.
Cost increases are inevitable. Typical resin content is 30
It is about 45% by weight.

Two methods can be considered for prepreg processing to produce this phenolic resin prepreg. First, a matrix resin composition containing a base phenolic resin, a thermoplastic resin, and other additives is prepared, and after impregnating reinforcing fibers with this matrix resin composition, the solvent is removed to obtain a prepreg. be. Another method is to prepare a matrix resin composition by heating and dissolving a thermoplastic resin in a base phenolic resin, adding additives, and removing volatile components from the phenolic resin until it reaches a viscosity that is easy to use at room temperature. Next, this matrix resin composition is heated to an appropriate temperature and coated thinly on a release paper to create a resin film.Then, reinforcing fibers are sandwiched between the resin films, and heated and pressed with hot rolls to form reinforcing fibers. This is a method of obtaining prepreg by impregnating the material with resin.

Comparing these two methods, the former has a high thermoplastic resin content and is suitable for making high viscosity resin into prepreg, and can be manufactured with relatively simple equipment, while the latter method However, the disadvantages are that the equipment is complicated and expensive, and the usable resin viscosity range is narrow.
Precise control of thickness and weight is possible. Both of these methods determine the quality of the desired prepreg adhesive, the required characteristics,
It is best to use different types depending on the resin composition. In general, the former method is often used in the case of cross prepregs that use woven fabrics of reinforcing fibers.

Regarding the resin composition for producing the phenolic adhesive and phenolic resin prepreg used in the present invention, epoxy resin is used to improve the compatibility of thermoplastic resin, prepreg processability, film processability, cured product toughness, etc. It is also a preferred embodiment to add and modify. The epoxy resin added for this purpose can be used in various ways depending on the effect of addition, but basically any epoxy resin can be used. - For example, Epicote 828.1
Liquid or solid bisphenol A type epoxy resins such as 001.1007 (manufactured by Yuka Shell Epoxy Company), phenol novolac type epoxy resins such as DEN431 (manufactured by Dow Chemical Japan Company), and ECN12
Talesol novolac type epoxy resins such as 73 (manufactured by Nippon Ciba Geigy ■), bisphenol F type epoxy resins such as Evicron 830 (manufactured by Dainippon Ink Industries ■), ELM-434, ELM-120 (Sumitomo Chemical In addition to glycidylamine type epoxy resins such as (manufactured by Kogyo Corporation), epoxy resins such as brominated epoxy resins, glycidyl ester type epoxy resins, and alicyclic epoxy resins can be mentioned.

Flame retardant materials, fillers,
Various additives such as dyes, curing accelerators, and reaction retarders can also be added.

When forming a phenolic adhesive layer between the core material and the stone, it is possible to use either the above-mentioned phenolic adhesive or phenolic resin prepreg, or both can be used together, depending on the application etc. It is a matter of choice.

In addition, in order to manufacture a sandwich panel in which a core material and stone are bonded together using the phenolic adhesive layer, the phenol adhesive and/or phenolic resin prepreg is interposed between the core material and the stone during molding. It is extremely easy to manufacture sandwich panels by performing heat and pressure molding using a press molding machine, autoclave, etc.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on Examples and Comparative Examples.

Example 1 (1) Production of film adhesive A resol-type phenolic resin using cresol (Nibryophen J326 manufactured by Dainippon Ink Chemical Industries, Ltd., solid content concentration: 61.2 WtX, 25°C viscosity: 113 cp)
s, 150°C gelation time: 2 minutes, solvent used: 30 parts by weight of methanol), copolymerized nylon (manufactured by Toshi ■ Co., Ltd.:
CM-6000) 70 parts by weight, 10 parts by weight of epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd.: Ebiko) 1001), and 10 parts by weight of antimony dioxide as a flame retardant, in a mixed solvent of ethanol:methylene chloride = 100:5. The resin solution was added, stirred until uniform, and further stirred at room temperature for 30 minutes, then the resin solution was thinly coated on release paper using a knife coater.

Thereafter, the solution was allowed to stand at room temperature for 4 hours to evaporate the solvent. As a result, a flexible and strong film adhesive having a thickness of 35/IJW1 and a basis weight of 40 g/rrr was obtained.

(2) Glass cloth prepreg (manufactured by Nippon Steel Chemical CM: L-525) made by impregnating phenol resin with molded glass cloth for the sandwich panel (Manufactured by Clark Schubel Co., Ltd., 7781 type, 8-ply satin weave, weight 304 g/rrr;) , resin content 36wtX) 2
The ply and one ply of the film adhesive created in (1) above are superimposed, and then the adhesive layer is placed on both sides of the aluminum honeycomb core (manufactured by Showa Aircraft Company: A L 3/8-5052-001) on the honeycomb side. A natural marble board with a thickness of 5 mm was pasted on the outside so that the thickness was 13 cm.
A composite stone panel was formed by heating and pressing at 3 kg/cnf for 60 minutes at 5°C.

When the resulting panel was exposed to flame to evaluate its combustion characteristics, the adhesive layer on the back was black and carbonized, but little smoke was emitted.

Comparative Example 1 Instead of the film adhesive mainly composed of phenolic resin and thermoplastic resin used in Example 1, an epoxy resin film adhesive (manufactured by American Cyanamid Co., Ltd.: FM-12) was used.
A composite stone panel was molded in exactly the same manner as in Example 1, except that 3-2, basis weight: 150 g/po) was used.

When this panel was also exposed to flame in the same manner as in Example 1 in order to evaluate its combustion characteristics, a large amount of smoke was generated from the adhesive layer.

〔Effect of the invention〕

The composite stone panel of the present invention is lightweight and highly rigid, and has greatly improved ease of manufacturing.Furthermore, it has the flame retardant properties of phenolic resin, so it cannot be used with other resins. Compared to panels, it generates significantly less heat and smoke in the event of a fire, making it highly safe. Therefore, the composite stone panel of the present invention is useful as an exterior material or interior material for buildings, or as an interior panel for internal structures of buildings, furniture, and transportation equipment such as ships, vehicles, and aircraft,
It is particularly useful for aircraft interior materials, vehicle interior panels, and building interior wall materials that require properties such as flame retardancy, light weight, and high strength.

Claims (2)

[Claims] (1) It is a composite stone panel formed by pasting thin stones on both sides or one side of a core material such as a fiber-reinforced plastic board, lightweight foam sheet, or honeycomb core, and the core material and the stones are bonded using phenolic adhesive. A composite stone panel characterized by being joined in layers. (2) The composite stone panel according to claim 1, wherein the phenolic adhesive layer comprises a phenolic adhesive containing as essential components a phenolic resin and a thermoplastic resin that is compatible with the phenolic resin.