JPH02113932A - Sandwich structure and production thereof - Google Patents

Abstract

PURPOSE:To obtain a sandwich structure excellent in the interlaminar adhesive strength between a surface material and a core material by using a foamed body having paper on the surface thereof as a core material. CONSTITUTION:Paper is provided between a core material composed of a foamed body and a surface material. The paper to be used is formed by dispersing extracted plant fibers in water and entangling the same thinly and flatly through the medium of water and, as a kind, newspaper, printing/writing/ drawing paper, packing paper, tissue paper, household tissue paper, various papers or the like are designated. The molding of urethane foam is generally called mold form molding and, as the material quality of a mold at this time, wood, resin, aluminum, iron, nickel, plating iron or the like are designated. Any foamed body may be used and, pref., urethane foam is used.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sandwich structure with excellent interlaminar M strength consisting of a foam having paper and a fiber-reinforced thermosetting resin composition, and a method for producing the same. It is something.

(Prior art) The sandwich structure is light and has high rigidity;
Due to its excellent sound insulation properties, it is widely used in ships, tanks, and general industrial materials. This sandwich structure is composed of a surface material and a core material, and F'RP, Kinko Hakkuma, etc. are used as the surface material. For such sandwich structures, for example those used in ships and tanks, FRP is often used as the surface material, and glass foam is often used as the core material. As the plastic foam at this time, thermosetting resin foam and thermoplastic resin foam are used,
Thermosetting resin foams include urethane foams, phenol resin foams, area resin foams, epoxy resin foams, etc., but hard urethane resin foams are often used for thermosetting.

Examples of the thermoplastic resin foam include polystyrene resin foam, polyethylene resin foam, polypropylene resin foam, polyvinyl chloride resin foam, polyacrylate resin foam, and polystyrene-polyethylene copolymer resin foam. Thermoplastic fallen fat foam is used. Methods for producing foam can be broadly divided into slab foaming and injection foaming. When produced by slab foaming and used as a core material for a subsequent foam all-sandwich structure, it is necessary to slice and cut into a predetermined shape, resulting in poor productivity. Foams made by injection foaming do not require slicing, force, or tinging because they are foamed in the mold. However, in some cases, the surface of the mold for a molded product is coated with an external mold release agent diluted with a heronized solvent, industrial gasoline, etc. with all components such as aliphatic hydrocarbons, anionic surfactants, and ester waxes. The surface of the urethane foam molded product is injected with raw materials such as urethane foam for foam molding.

A skin is formed and the above mold release agent remains. For that reason,
When a fiber-reinforced thermosetting resin composition is directly formed on this surface as a surface material, there is a problem that peeling occurs easily.

As a method to improve such defects, the obtained urethane 7
A method has been proposed to remove the mold release agent remaining on the surface of the molded product by heating the surface of the molded product i5Q to 901 or treating it with a heated solvent such as methylene chloride or trichloroethane. .

However, in this case, it has a negative effect on the foam molded product, requires a device for recovering the TFC solvent, increases equipment costs, is unfavorable from the sanitary aspect of the working environment, and requires removal of the epidermis. I can't do anything.

In addition, as a method for removing the skin, a method has been implemented in which the narrow side of the urethane foam molded product is roughened using sandpaper, sandblasting, or the like. However, especially in the case of injection foam molded products having a high degree of W, the surface skin layer portion is very hard, so that the sanding operation, which is usually carried out manually, is labor intensive and takes a long time, making it inefficient. Although it is conceivable to carry out this operation mechanically, it is practically impossible if the shape of the foam molded product becomes complicated, and there are disadvantages in that it requires a large number of steps.

(Means for Solving the Problems) In order to solve these drawbacks, the present inventors have conducted research and found that by having paper on the surface and using a secondary foam as the core material, the surface material and the core Santoi discovered that it was possible to obtain a structure with excellent interlayer adhesion strength to materials, and was unable to complete the invention.

That is, in the present invention, when a foam is injected into a mold and foamed, and a foam is manufactured, paper is placed in the mold, and the foam with paper on the surface of the foam is produced by &! A process of forming the foam as a core material and a surface material of a fiber-reinforced thermosetting resin - (
B) One or more steps - (AJ, - (BJ) comprising a foam and a fiber-reinforced thermosetting resin composition,
The present invention provides a method for manufacturing a sandwich structure having excellent interlayer adhesion strength, and a sandwich structure having a foam as a core material and paper between the surface material and the core material.

(W-made) The paper used in the present invention is produced by extracting plant fibers, dispersing them in water, and then flattening them through the medium of water. Examples include newspaper roll paper, stamp paper, drawing paper, wrapping paper, thin paper, household thin paper, miscellaneous paper, etc., but preferably kraft paper is used as newspaper roll paper and wrapping paper. Further, raw materials include conifers, hardwoods, mixtures of softwoods and hardwoods, straw, etc., but are not particularly limited in the present invention.

Further, as pulping methods, there are a sulfite pulping method and a kraft pulping method, which are chemical pulping methods, and a mechanical pulping method and a semi-chemical pulping method. There are no particular restrictions on tL.

The thickness of the paper is preferably 40μ to 180μ, and the porosity is preferably 26 to 73%. The paper can be used on only one side and does not need to cover the entire surface of the foam.
Preferably, it is acceptable as long as it covers at least 50% of all six sides.

The method of molding the urethane foam in the present invention is generally called seven-piece molding, and the materials used for the mold include wood, resin, aluminum, iron, nickel, and plated iron. , F'i is not particularly limited in the present invention.

The core material of the present invention may be any foam material, but urethane foam is preferred, and known materials are used. A hard 7 ohm is particularly suitable. Such foam raw materials include, for example, polyols, polyinsyanates), water or volatile solvents, emulsifiers, and, if necessary, catalysts, crosslinking agents, foam regulators, stabilizers, and the like. In particular, as the main component polyol,
Polyether polyols, polyester polyols and mixtures thereof are preferred, although other polyhydroxy compounds are, of course, convenient. Examples of the polyinsyanate include 2.4-tolylene diisocyanate and 2.4-tolylene diisocyanate.
Examples thereof include 6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), and MDI.

The fiber-reinforced thermosetting resin composition used in the present invention includes reinforcing fibers such as glass fibers, carbon fibers, synthetic fibers, and metal fibers, and thermosetting resins such as unsaturated polyester resins, vinyl ester resins, and epoxy resins. In particular, those made of glass fiber and unsaturated polyester resin are preferred. Such molding materials may be mixed with 9 reinforcing fibers and a thermosetting resin on the spot, or may be made into SMC' (sheet molding cone or land) or BMC (bulk molding material).
The reinforcing fibers and thermosetting resin may be mixed in advance, such as in Konnomo Tsundo.

In addition, the thermosetting resin contains fillers, low shrinkage agents, pigments,
τ may be adjusted depending on the amount of molding agent, curing agent and other additives.

The sandwich structure of the present invention is a general FRP IX
j.

Forming methods such as the hand-laying method, the spray-up method, the reiso injection method, the machined mold die method, and the compression method of SMC and BMC are discussed, but the present invention is not particularly limited thereto.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 4 Various papers were placed in the upper and lower molds of a 300x300x30 aluminum a urethane foam mold, and the following raw materials for urethane foam were injected and foamed.

[Raw material composition]

Hl prox 0D-X-1048 (Dainichi Fu Ink Chemical Company H) 100 copies // 5P-1225 (1)
164 parts water
0.48 parts [Foaming conditions] Mold temperature 35-40℃ Raw material temperature 20℃ Mold clamping pressure 31- Injection time 7 seconds Demolding time 15 minutes The basic physical properties of foam are foam density o, 12, pressure m yield point Strength 4.0ψ- (23℃, parallel to the foaming direction)
Met. This foam molded product was made from an unsaturated polyester resin (Polylite FH-123: Dainippon Ink Chemical Co., Ltd.
) 100 cities, 55 envy Methyl Ethyl Ketone Nose Oxide (MEKPO) 1.2 copies, 450
9/m2, Tsubuto Strand Mat (manufactured by Nittobo Co., Ltd. 9
The top and bottom surfaces of each of the three sheets were laminated using a handley rug so that the total glass coverage was 30% by weight.

A test piece was cut out from the molded product and tested according to ASTM-C-299.
Tensile peeling: ip test was conducted based on 61-61. The results are shown in Table-1.

Comparative Example-1 The same mold as in Example-1 was coated with a mold release agent Rim-7 (Chemtrend M, WAX series), and the same raw material for urethane foam as in Example-1 was injected and foamed.

All tensile peel tests were conducted in the same manner as in Example-1. The results are shown in Table-1.

7,・' Examples 5 to 8 Similar to Example 1, 30 pieces of paper were arranged on the top and bottom surfaces.
A urethane foam of 0x300x30- is made, and this foam is placed in a compression molding mold.

Two pieces of continuous mat (Asahi Fiber Co., Ltd.) impregnated with the same unsaturated polyester compound as in Example 1 (Asahi Fiber Co., Ltd.) were placed on the bottom and side walls, and the pressure was 20 mm. 62, temperature 80℃
, compression molding was carried out in 10 minutes. The resin compound used at this time was 100 parts of Polylite PM-141 (unsaturated polyester resin: Dainippon Ink Chemical Co., Ltd. DJ), 50 parts of calcium carbonate, 55% M, 1.0 part of EKPO, and 0.6 parts of cobalt with 6% Kaften. I used one consisting of parts. Hereinafter, a tensile peel test was conducted in the same manner as in Example-1. The results are shown in Table-2.

Comparative Example-2 A urethane foam prepared in the same manner as in Comparative Example-1 was placed in a compression molding mold in the same manner as in Example-1 to obtain a molded product. Hereinafter, a tensile peel test was conducted in the same manner as in Example-1. The results are shown in Cloth-2.

As is clear from the examples, the structure of the present invention can prevent interlayer liquid by providing paper between the surface material and the foam. It had excellent strength.

representative person

Claims (4)

[Claims] (1) A sandwich structure characterized by using a foam as a core material and having paper between the surface material and the core material. (2) The sandwich structure according to claim 1, wherein the foam is urethane foam. (3) The sandwich structure according to claim 1, wherein the surface material is a fiber-reinforced thermosetting resin composition. (4) Step (A) of injecting and foaming a foam into a mold to produce a foam, placing paper in the mold and manufacturing a foam with paper on the surface of the foam. Step (B) of forming a fiber-reinforced thermosetting resin composition as a core material and as a surface material. A method for manufacturing a sandwich structure comprising the above steps (A) and (B).