JPS5855906B2 - Manufacturing method of sandwich structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a sandwich structure, which is characterized by integrally molding a laminate made of a sheet-like preform, a foam, and a crosslinkable covering material under heat and compression.

Conventional methods for manufacturing sandwich structures used for cushioning materials such as chairs, instrument panels of automobiles, etc. require a large number of molding steps because one layer is formed in one step, resulting in problems in terms of productivity.

For example, to manufacture an automobile instrument panel, urethane foam is glued onto a die-cast aluminum plate.
Furthermore, a laser coating liquid is applied to the surface of this urethane foam and heated to give it a laser finish, which requires at least a three-step lamination process.

In addition, in the manufacturing method of other sandwich structures such as floorboards, a PVC board or an ABS board is placed on the lower mold, a leather sheet is attached to the inner surface of the upper mold, and then the mold is placed between the closed upper and lower molds. A polyurethane solution is injected into the mold cavity and foamed to obtain a laminate.

However, all of these methods require many molding steps and are unsuitable for producing laminated molded products having complex shapes such as unevenness.

The present invention has been made in view of the above problem, and its object is to produce a sheet-like material in which a thermosetting resin is impregnated into a fiber fabric base material such as an inorganic or organic fiber non-woven fabric or a woven fabric base material. A foam is placed and laminated on a preformed material (prepreg), and a crosslinkable coating material is applied or laminated on the surface of the foam to form a laminate, and this laminate is compressed under heat and pressure. However, since it is integrally molded, each layer can be bonded and molded in a single compression molding process without the need for preforming or adhesives, reducing costs by shortening the process and reducing the weight of laminates such as instrument panels. An object of the present invention is to provide a method for manufacturing a sandwich structure.

Another object of the present invention is to provide a method for manufacturing a sandwich structure that can also manufacture cushioning laminates of complex shapes such as chairs and sofas.

The present invention will be explained in detail below.

First, the sheet-like preformed material (prepreg) is made by mixing a thermosetting resin liquid containing a catalyst with inorganic fibers (glass fiber, asbestos fiber, etc.) or organic fibers (thermoplastic polyester fiber, etc.). It is impregnated into a nonwoven fabric or woven fabric base material, and can be easily cut when used, and can be molded into any shape simply by placing it in a mold and heating and pressurizing it.

Further, this prepreg is generally non-adhesive and portable, and if necessary, a curing agent, filler, mold release agent, pigment, thickener, and anti-shrinkage agent may be appropriately added thereto.

Examples of the liquid thermosetting resin include unsaturated polyester resins, epoxy resins, allyl resins, phenol resins, other thermosetting acrylic resins, and silicone resins.

This unsaturated polyester resin contains unsaturated polybasic acids such as maleic anhydride, fumaric acid, and itaconic acid (and if necessary, saturated polybasic acids such as phthalic acid), ethylene glycol,
70 to 80 parts by weight of an unsaturated polyester obtained by condensation reaction with a polyhydric alcohol such as propylene glycol, and 70 parts by weight of a vinyl monomer such as styrene or methyl methacrylate.
~20 parts by weight is used.

Further, as the phenol resin, a condensate of phenol and formaldehyde is used.

The above catalysts include hensoil peroxide, t-butyl perbenzoate, dicumyl peroxide, di-t-butyl peroxide, 2.
There are organic peroxides with low volatility such as 5-dimethyl-2゜5-di(t-7tilperoxy)hexyne-3.

Further, as a catalyst for epoxy resin, there is 2-ethyl-4methylimidazole.

Further, the following may be added to the sheet prepreg as necessary.

Hardener: Dicyandiamide (for epoxy resin) Filler: Talc, calcium carbonate, silica, diatomaceous earth,
Mica, asbestos powder, aluminum hydroxide Mold release agent: Zinc stearate, stearic acid, aluminum stearate Pigment: Titanium oxide, carbon black, red iron oxide, cadmium yellow Thickener: MgOCaOMg(OH)2Ca(OH
)2 - Anti-shrinkage agent: Particles of polyacrylic acid, polyethylene, styrene-maleic acid copolymer, etc.

Next, the foams to be laminated on the sheet prepreg include open-cell foams such as soft urethane foam, foam rubber, silicone foam, and vinyl chloride foam;
Alternatively, any closed cell type such as phenol resin foam or polyethylene foam can be used.

Soft urethane foam is produced by reacting polyisocyanate with an activator mixture containing polyester or polyether, water or polyol to generate carbon dioxide gas or chlorofluorocarbon gas, using a one-shot method or a prepolymer (two-pronged) method, for example, to form a reaction mixture. A foamed product is used.

Similarly, in this reaction, a crosslinking agent such as N-diethylaminoethanol acylate and a blowing agent such as trichloromonofluoromethane may be added as necessary.

The polyisocyanates used in the above reaction include toluene diisocyanate, 331-bitrylene=4.4'-
Diisocyanate, diphenylmethane diisocyanate, etc. are used.

In addition, as polyesters, condensates of adipic acid and diethylene glycol, condensates of dimer acid and diethylene glycol or trimethylolpropane, adipic acid,
A condensate of a mixture of phthalic anhydride and dimer acid and a mixture of glycerin and ethylene glycol is used.

Further, as the polyether, polyoxypropylene glycol, polyoxybutylene glycol, polyoxypropylene, polyoxyethylene glycol, etc. are used.

Similarly, sulfonated castor oil, ammonium oleate, and paraffin oil are used as bubble size regulators.

Furthermore, the foam rubber is, for example, a rubber to which a vulcanizing agent, a vulcanization accelerator, a softening agent, a filler (such as talc), and a foaming agent are added, and which is heated, vulcanized, and foamed. The foam is, for example, made by absorbing carbon dioxide gas into vinyl chloride plastisol and causing it to foam.

The closed cell type phenolic resin foam is, for example, -
A composition in which a blowing agent and a curing agent are blended with a novolak-type phenolic prepolymer using an acidic catalyst is heated.
It is manufactured by expanding it (see Japanese Patent Publication No. 38-1738).

Furthermore, polyethylene foam is obtained by physically foaming low-density polyethylene or ethylene-vinyl acetate copolymer, for example.

These foams can be classified into those having flexible, semi-hardened, and rigid properties, and are used depending on the intended use of the final product of the sandwich structure.

For example, when the main purpose is cushioning properties, flexible polyurethane foam and rubber foam are preferred.

In addition, from the viewpoint of materials, foams can be divided into thermoplastic materials and thermosetting materials, but in terms of heat resistance during molding by heat compression, thermosetting materials such as polyurethane foam, phenolic resin foam, and silicone foam are preferred. Preferably a sexual one.

Similarly, polyurethane can be produced into three types of foams: open-cell flexible foam, semi-rigid foam, and closed-cell rigid foam, depending on the molding material and method.

Next, as the crosslinkable coating material to be applied or placed and laminated on the surface of the foam as described above, a surface skin layer forming material conventionally used for forming leather or synthetic leather can be used.

Bend down below.

(1) 10 to 50 parts by weight of a rubber substance such as polybutadiene, styrene-butadiene copolymer, etc., and 50 to 50 parts by weight of a vinyl monomer such as styrene, methyl methacrylate, vinyl chloride, etc.
A paste prepared by dissolving 90 parts by weight and blending a catalyst such as benzoyl peroxide or t-butyl perbenzoate.

(2) A paste containing 100 parts by weight of a vinyl chloride resin, 10 to 40 parts by weight of a non-reactive plasticizer, 10 to 50 parts by weight of a reactive plasticizer, and a catalyst (non-reactive plasticizers include, for example, dioctyl phthalate, There is butyl benzyl phthanate.

In addition, examples of the reactive plasticizer include trimethylolpropane trimethacrylate, diallyl phthalate, ethylene glycol dimethacrylate, low molecular weight alkyd,
There are low molecular weight epoxy resins.

Examples of catalysts include benzoyl peroxide and lauroyl peroxide.

) (3) Crosslinkable vinyl acetate latex (4) Urethane coating agent (5) Woven fabric, nonwoven fabric, p paper impregnated with the paste of (1), (2), (3) or (4) above (6 ) An unvulcanized rubber prepared by blending 3 to 5 parts by weight of a vulcanizing agent with ioo parts by weight of a rubber substance and forming it into a sheet shape using a roll.

(7) Add 1 vulcanizing agent to liquid rubber, which is butadiene or styrene-butadiene polymer with a molecular weight of 1000 to 10000.
-io compound with a large amount of weight.

The manufacturing process of the sandwich structure of the present invention using a sheet-like prepreg such as a diagonal, a foam, and a crosslinkable covering material will be explained.

First, as shown in FIG. 1, the covering material 2 is laminated on the surface of a foam 10 having a wall thickness of 5 to 100 mm to a thickness of 0.1 to 3 In7rL.

Next, this foam 1 has a wall thickness of 1 or more, preferably 2 to 5
Place and laminate it on my friend's prepreg 3 (lamination process).

Similarly, if it is necessary to form a beautiful skin layer on the surface of the final product, a desired woven fabric impregnated with a surface skin layer paste is laminated on the foam 1.

Such a laminate 4 is loaded into a hot press mold 5 consisting of an upper mold 5a and a lower mold 5b configured to match the shape of the final product, and heated at a heating temperature of 90 to 200°C, preferably 1
Heat compression molding is performed at 10-170°C and a pressure of 20-150/9/cm2 to form the desired shape of the sandwich structure product (compression step).

During this hot compression molding, the covering material 2 penetrates into the foam 1 and is physically or cross-linked, and is also bonded to the foam 1 and the prepreg 3, and the fabric base material of the prepreg 3 is compressed into a predetermined shape. It will be formed into a rigid plate.

FIG. 2 shows another embodiment of the present invention, in which a skin layer crosslinking paste 21 is coated on the surface of a pulverized foam product 1 by a dipping method and then laminated on the prepreg 3.

Next, a laminate 41 is constructed by laminating fabric materials 2'' impregnated in advance with a substance of the same quality as the paste 2' or with another crosslinkable paste that is compatible with the paste 2'.

If this laminate 4' is subjected to heat compression molding in the same manner as shown in FIG. 1, bonding will be achieved with the paste 2' penetrating between the foam bodies, making it possible to form a stronger laminate.

Next, the content of the present invention will be explained more specifically using Examples.

Example 1 A butadiene-styrene paste with the following composition was made into a wall with a thickness of 1 a.
A polyurethane foam coated with a wall thickness of 50 m is placed on the surface of a sheet molding compound (SMC, wall thickness: 2 mm) having the following composition to form a laminate, and this laminate is placed on the surface of a sheet molding compound (SMC, wall thickness: 2 mm), with the SMC on the bottom side. The sandwich structure was then placed on a lower mold to obtain a sandwich structure by heating and compression molding the lower mold and an upper mold having a pattern on the inner surface at a temperature of 150°C and a pressure of 32 ky/cm2 for 10 minutes. .

When this molded article was subjected to a peel test, it tore at the polyurethane foam part.

(Components of butadiene-styrene paste) (1) Polybutadiene rubber 15 parts ffi (2)
Styrene monomer s5 parts by weight (3)
1 part by weight of t-butyl perbenzoate (curing agent) (4) 2 parts by weight of carbon black (pigment) (components of SMC) (1) Mannic acid anhydride 2 moles isophthalic acid 1 mole and 17 parts by weight of propylene glycol
70 polystyrene solution of 3 mol condensate (unsaturated polyester) (2) 10 parts by weight of 40 polystyrene solution of filler polystyrene for low shrinkage (3) Filler calcium carbonate 42 parts by weight glass fiber
30 parts by weight (4) Curing agent t-butyl perbenzony) 0.27 parts by weight (5)
Thickener Mg0 0.03 parts by weight (6)
Mold release agent zinc stearate 0.7 parts by weight Example ■ Epoxy resin (made by Shell Chemical, trade name "Ebico") 100
A resin composition containing 100 parts of 1" epoxy equivalent (450-500), 7 parts by weight of dicyandiamide as a curing agent, and 0.5 parts by weight of 2-ethyl-4-methylimidazole as a catalyst was dissolved in methyl ethyl ketone to obtain a solid content of 40 parts by weight. A glass cloth was impregnated with this resin solution and dried for 5 minutes to obtain a prepung with a wall thickness of 3IILm.

A urethane paste having the following components was applied to the surface of a urethane foam having a thickness of 50rIL7IL so that the wall thickness was 1rItm, and this was laminated on the prep V-g to form a laminate, which was used in the above example (2). The material was then heated and compression molded in a compression mold at a temperature of iso° C. and a pressure of 30 kg/cIn2 for 50 minutes.

The resulting product tore at the V tongue foam portion during the peel test.

(Ingredients of urethane paste) (1) Tesmodur AP Stable 34.5 parts by weight (manufactured by Bayer AG, trade name) (2) Tesmofene 800 14.2 parts by weight (manufactured by Bayer AG, trade name) (3) Methyl glycol Acetate 17.1 parts by weight (
4) Ethylene acetate) 17.1 parts by weight (
5) Toluene 17.1 parts by weight Example 2 A sandwich structure was molded in the same manner as in Example 2, except that the following butadiene paste was used instead of the butylene-styrene paste.

This molded article was torn from the urethane foam portion during the peel test.

(Components of butadiene paste) (1) Liquid rubbers Liquid polybutadiene rubber 91.75 parts by weight (ARC
POLY Bd R45 (manufactured by Company O) (2) Curing agent toluene diisocyanate 6.2 parts by weight Dibutyltin diurarate 0.05 parts by weight (3) Pigment carbon black 2 parts by weight Examples
(2) A sandwich structure was molded in the same manner as in Example (2) except that the following vinyl chloride paste was used instead of the butylene-styrene paste.

This molded article was torn from the urethane foam portion during the peel test.

(Components of vinyl chloride paste) (1) Polyvinyl chloride (average polymerization cold 1300) 10
0 parts by weight (2) Dioctylphthanate 30 parts by weight (3) ) Liftirol propane triacrylate-13
0 parts by weight (4) Benzoyl peroxide 0.3 parts by weight (0) Basic zinc 5 parts by weight (6
) Azodicarbonamide 1 part by weight (7)
Carbon black 1 part by weight Example (2) A sandwich structure was obtained in the same manner as in Example (2) except that rubber foam was used instead of urethane foam.

This molded article was torn from the rubber foam portion during the peel test.

Example ■ A mixture consisting of 90 parts by weight of low-density polyethylene and 10 parts by weight of ethylene-vinyl acetate copolymer was melt-kneaded in an extruder, and in the middle of the extruder, dichlorofluoroethane was mixed as a foaming agent to perform extrusion foaming. Let the density be 2 o g/l
A foam was obtained.

A sandwich structure was obtained in the same manner as in Example I except that this foam was used.

During the peel test, this molded article was torn from the foam section.

Examples ■ Crosslinkable coating material composition (1) Natural rubber 100 parts by weight (2) Zinc white 5 parts by weight (
3) Stearic acid 2 parts by weight (4
) Sulfur 3 parts by weight (5) Accelerator 1.5 parts by weight (6) Azocarbonamide (foaming agent) 5 parts by weight (7) Oleic oil 10 parts by weight (8) Paraffin oil 1 part by weight (9) Calcium carbonate 100 parts by weight The above composition was kneaded and made into a sheet with a thickness of 1 rnm using a calender, and a laminated rubber foam with a wall thickness of 30 rnrIL was placed on the SMC used in Example 1. With the compression mold used in 7.%l1135°G, pressure 30kg/
cm2 for 30 minutes and compressed to obtain a sandwich structure.

This molded article was torn from the rubber foam part during the peel test.

Example ■ Waste urethane foam with a diameter of 1 rnm to 3I/1rI
After crushing L into lumps, immersing this crushed product in the butadiene paste used in Example ①, stacking it on the SMC used in Example I to a thickness of about 30 mm, and adding the same components as this paste. A laminate was constructed by coating a nonwoven fabric impregnated with the paste of
A sandwich structure was obtained by heat compression molding for 10 minutes at a pressure of .

This molded article was torn from the urethane foam portion during the peel test.

As described in detail above, according to the present invention, a three-layered sandwich structure can be formed into a bottom shape in a single heat compression process, so productivity can be improved by improving work efficiency and reducing costs.

Furthermore, since the bottom shape is formed at the same time as the bonding of the three layers, it is possible to form a sandwich structure having any uneven shape.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the present invention, and FIG. 2 is an explanatory diagram of another embodiment of the sandwich structure according to the present invention. 1... Foam, 1'... Crushed product of foam, 2... Crosslinkable coating, 2/... Crosslinkable paste, 2・・・・・・Fabric material, 3・・・・・・
Prepreg, 4.4'... Laminate, 5...
···Mold.

Claims (1)

[Claims] 1. A foam is placed and laminated on a sheet-like preformed material in which a fiber cloth base material is impregnated with a thermosetting resin, and a crosslinkable coating material is further applied or laminated on the surface of the foam, and the lamination is performed. A method for manufacturing a sandwich structure, characterized by integrally molding an object while heating and compressing it under pressure.