JPH045015A - Composite molded product - Google Patents

Abstract

PURPOSE:To manufacture a large plate-shaped composite molded product, light, strong and of good smoothness and flatness by providing a core material composed of a plate-shaped foamed body of low expansion ratio having a skin layer on its surface, feeding reaction liquid containing a norbornane monomer and a metathesis catalyst into a mold and bulk polymerizing. CONSTITUTION:A composite molded product is composed of a core material of plate-shaped foamed body of low expansion ratio set in a mold, reaction liquid containing a norbornane monomer and a metathesis catalyst is fed and bulk polymerized in the mold and an outer peripheral layer composed of a norbornane polymer. For instance, in the case of disposing a core material 1 in a space encircled with upper and lower molds 4 and 5, a supporting metal 2 is buried in the core material 1 from the side, and a space 6 corresponding to the thickness of the supporting metal is formed in the lower mold 5. The site of the metal coming out of the core material is clamped by the upper and lower molds, and the core material 1 is disposed in the mold leaving a constant space from the inner face of the mold. Raw liquid containing the norbornane monomer is injected into the space and bulk polymerized therein to form an outer peripheral layer 3 composed of the norbornane polymer.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a composite molded article, and more specifically, the present invention relates to a composite molded article, and more specifically, the present invention relates to a composite molded article, in which a plate-shaped foam having a skin layer and a low expansion ratio is used as a core material, and a block polymer of norbornene monomer is used as a core material. The present invention relates to a large plate-shaped composite molded product that has a combined outer peripheral layer, has a good appearance, and has excellent adhesion between the core material and the outer peripheral layer.

[Conventional technology] Unsaturated polyester, epoxy resin, phenolic resin,
Composite molded products with an outer layer of polyurethane resin and a foam core are lightweight and are commercially available as leisure items such as windsurfing and surfboards, boats and canoe paddles, and large pallets.

These composite molded products are made using the so-called hand lay-up method, in which reinforcing fibers such as glass fibers are placed around the foam, a thermosetting resin is applied on top of the reinforcing fibers, and then hardened. However, productivity is poor (and unsuitable for mass production) because it is mainly manual work.

Another method is to wrap the core foam with a woven fabric made of reinforcing fibers such as glass, carbon, or aramid, set it in a mold, and then inject liquid thermosetting resin into the mold. There is a method to obtain a composite molded product by heating and curing (
(Japanese Unexamined Patent Publication No. 63-162207). With this method, it is difficult to wrap the reinforcing fibers around the core material to a uniform thickness, and when handling the glass fibers, broken pieces of the fibers can pierce the body, such as the hands and face, making it extremely difficult to work in. Undesirable. Furthermore, when a foam partially wrapped with reinforcing fibers is set in a mold and thermosetting resin is injected,
In areas where reinforcing fibers are not present, the resin strength of the outer peripheral layer is weakened. Therefore, in order to provide sufficient strength with resin alone, it is necessary to use an expensive material such as epoxy resin.

For this reason, it is desired to inexpensively produce a strong molded product using an industrially simple molding method in a composite molded product using a foam as a core material.

Furthermore, if it is possible to create a large plate-shaped molded product that is lightweight, has excellent heat resistance and strength, and uses a foam as the core material and a resin layer as the outer layer, Although it can be used for applications such as partition plates and display boards, it is extremely difficult to obtain products with a good appearance and excellent flatness and smoothness using conventional methods.

[Problem to be Solved by the Invention 1] By the way, when a norbornene monomer such as dicyclopentadiene is subjected to bulk polymerization in a mold in the presence of a metasense catalyst, a molded article that is rigid and has high impact strength can be obtained. Reaction liquids containing norbornene monomers are generally low-viscosity liquids, so they can be injected into molds and molded with relatively low pressure, making it easy to mold even large molded products. Can be molded.

Therefore, the present inventors attempted to manufacture a composite molded product with a foam as a core material using a norbornene monomer, and found that since the molding pressure was low, there was no destruction or deformation of the cells in the foam. It has been found that this method has many advantages, including the ability to use low-strength and inexpensive molds, and the ability to obtain composite molded products with sufficient strength without using reinforcing fibers.

However, when a large plate-like composite molded product was created using this method, it was found that the following problems occurred.

The foam that serves as the core material is usually a pre-formed foam that is sliced or cut into a predetermined shape. When attempting to manufacture a shaped composite molded product, voids and unevenness occur on the surface of the molded product, making it impossible to obtain a molded product with a good appearance.

In addition, when a plate-shaped foam with a large expansion ratio is used as a core material, the adhesion state at the interface between the core material and the outer layer becomes poor.
The central part of the plate-shaped composite molded product is dented, making it impossible to obtain a large-sized plate-shaped composite molded product with good flatness.

Therefore, an object of the present invention is to produce a large plate-like composite molded product using a norbornene monomer and a foam core material, which is lightweight, strong, and has good surface smoothness and flatness, by a relatively simple molding method. Our goal is to provide the following.

As a result of intensive research, the present inventors used a plate-shaped foam having a skin layer and a low expansion ratio as the foam serving as the core material, and installed this in a mold to form the core material. By supplying a reaction solution containing a norbornene-based monomer and a metasense-based catalyst to the gap provided between the mold and the inner surface of the mold, and performing bulk polymerization, an outer peripheral layer made of norbornene-based polymer can be suitably formed. It has been discovered that a large plate-like composite molded article with excellent flatness and smoothness can be obtained.

The present invention has been completed based on these findings.

[Means to solve the problem]

Thus, according to the present invention, a core material made of a plate-shaped foam with a low expansion ratio and having a skin layer on the surface is installed in a mold,
A large plate-shaped composite molded article is provided, characterized in that a reaction solution containing a norbornene monomer and a metasense catalyst is supplied into a mold and polymerized in bulk to form an outer peripheral layer made of a norbornene polymer. .

The present invention will be explained in detail below.

(Core material made of foam) The composite molded article of the present invention uses a polymer foam as a core material. This results in a molded product that is lightweight and strong even though it is large.

Furthermore, by using a plate-shaped foam with a skin layer (dense layer) and a low expansion ratio as this foam, there will be no voids or unevenness, and it will have flatness and smoothness without waving. Excellent large plate-shaped molded products can be obtained.

The polymeric foam may be any material as long as it retains its original shape during molding, and specific examples include foams of polyurethane, polyethylene, polypropylene, polystyrene, polyvinyl chloride, and the like. Among these, thermosetting foams such as polyurethane and crosslinked polyethylene are preferred. If a thermoplastic foam is used, it may melt during molding of a composite molded product and cause undulations on the surface of the molded product, so care must be taken to control the molding temperature.

A plate-shaped foam having a skin layer can be obtained in a predetermined shape by molding a polymer foam in a mold. For example, in the case of polyurethane foam, a reaction injection molding (RIM) method in which a reaction stock solution containing a blowing agent is injected into a closed mold and foam molded is used to suitably produce a foam having a skin layer on the surface. Obtainable.

If a plate-shaped core material is used by slicing or cutting a pre-formed foam, voids or unevenness may occur on the surface of the molded product, resulting in large plate-shaped composite molding with excellent smoothness and flatness. unable to obtain goods. Similarly, foam molding into a plate shape by extrusion molding or casting and without a skin layer is also inappropriate. However, the side portions (side end surfaces) of the plate-shaped foam in the thickness direction may be cut.

The foam serving as the core material needs to have a low expansion ratio. Specifically, the foaming ratio is about 5 to about 15 times. When the expansion ratio greatly exceeds 15 times, for example, about 20 times, the surface of the molded product becomes wavy, making it impossible to obtain a large plate-like composite molded product with good flatness. Moreover, peeling occurs at the interface between the core material and the outer peripheral layer, impairing the reinforcing effect of the core material.

The shape of the foam is smaller than the shape of a large plate-shaped composite molded product by the thickness of the resin that forms the outer layer (plate-shaped foam)
shall be.

(Large plate-shaped composite molded product) The large-sized plate-shaped composite molded product in the present invention is a rectangular, circular, or other flat plate-shaped molded product.

For example, if it is rectangular, it is 500 mm long.
Width 500mm or more, and if circular, diameter 50mm
Refers to objects with a diameter of 0 mm or more.

The thickness is usually about 10 mm to several tens of mm.

Further, the thickness of the outer peripheral layer made of norbornene-based polymer is about 2 to 10 mm.

Such a large plate-like composite molded product can be used, for example, as a partition plate, a display plate, etc.

(Installation of core material in mold) In the present invention, a plate-shaped foam serving as a core material is installed in a mold, and a norbornene-based A reaction solution containing a monomer and a metasense catalyst is supplied and subjected to bulk polymerization to form an outer peripheral layer made of a norbornene polymer.

As means for providing a gap between the core material and the inner surface of the mold, there are various methods as follows, for example.

(1) There is a method of providing a support made of an olefin polymer such as polystyrene, polyethylene, polypropylene, or EPDM or a hydrocarbon elastomer at a desired location of the core material. The support prevents the core material from floating due to the reaction stock solution in the mold, provides a gap between the core material and the inner surface of the mold, and forms a uniform resin layer as an outer peripheral layer. Furthermore, by selecting a specific material for the support, the adhesion between the support and the norbornene polymer can be strengthened.

The support body can take various shapes such as a cylindrical shape, a flat plate shape, a conical shape, and a truncated conical shape.

To provide a support to a core made of foam, the support may be glued to the surface of the core, a part of the support may be inserted into the core and fixed, or it may be wrapped in a rubber band. There are appropriate methods.

Alternatively, when molding a core material made of a foam in a foaming mold, a support can be placed in the foaming mold at this stage to obtain a foam molded product with a support.

(2) There is a method of embedding supporting metal fittings in the core material.

This method will be explained with reference to the drawings. 1st
The figure is a schematic cross-sectional view when a composite molded product is molded by disposing a core material in a mold. FIG. 2 is a plan view of the obtained composite molded product.

When the core material 1 is placed in the space surrounded by the upper and lower molds 4.5, the support fittings 2 are embedded in the core material 1 from the side, and on the other hand,
A gap 6 corresponding to the thickness of the support metal fitting is formed in the lower mold 5, and the core material 1 is inserted into the mold by sandwiching the part of the support metal fitting that protrudes from the core material between the upper and lower molds. It can be placed with a certain gap between it and the inner surface. The support fittings 2 may be provided at multiple locations.

(The reaction stock solution containing the norbornene monomer is then injected into the void provided in the mold. The injection port is not shown.)
Bulk polymerization is performed to form the outer peripheral layer 3 made of norbornene-based polymer.

In the case of large composite molded products, it is especially important to secure the core material properly within the mold. The core material moves during molding (
As a result, the thickness of the outer peripheral layer becomes uneven, and in severe cases, it may be exposed on the surface.

The support fitting may be removed or cut after molding, or may be used as an accessory part of the molded product.

(Norbornene-based monomer) The norbornene-based monomer used in the present invention may be one having a norbornene ring, but when trying to obtain a composite molded product with a high heat distortion temperature, it is necessary to It is preferable to use a norbornene monomer.

Further, in the present invention, it is preferable that the norbornene polymer to be produced be a thermosetting type, and for that purpose, it is preferable to use a crosslinkable polymer.

Examples of norbornene monomers include 2-norbornene, 5-methyl-2-norbornene, 5-ethyl-
2-norbornene, 5-butyl-2-norbornene, 5
-hexyl-2-norbornene, 5-ethylidene-2-
Bicyclics such as norbornene, 5-vinyl-2-norbornene, 5-phenylnorbornene, bicyclics such as dicyclopentadiene and dihydrodicyclopentadiene, tetracyclododecene, methyltetracyclododecene, ethyltetra Tetracyclics such as cyclododecene, dimethyltetracyclododecene, ethylidenetetracyclododecene, phenyltetracyclododecene, bicyclics such as tricyclopentadiene, heptacyclics such as tetracyclopentadiene, etc. is exemplified. One or more of these may be used in combination.

Among these, bicyclics and bicyclics are preferred from the viewpoint of ease of availability, reactivity, heat resistance, etc.

On the other hand, the crosslinking monomer is a polycyclic norbornene monomer having two or more reactive double bonds, and specific examples thereof include dicyclopencdiene, tricyclopentadiene, and tetracyclopentadiene. Therefore, when the norbornene monomer and the crosslinking monomer are the same, there is no need to use any other crosslinking monomer.

These norbornene monomers may be used alone or in combination of two or more.

In addition, monocyclic cycloolefins such as cyclobutene, cyclopentene, cyclopencdiene, cyclooctene, and cyclododecene, which can undergo ring-opening polymerization together with one or more of the above norbornene monomers, may be used in combination without impairing the purpose of the present invention. I can do it.

(Metasense Catalyst) The catalyst used in the present invention may be any metasense catalyst system known as a catalyst for ring-opening polymerization of norbornene-based monomers (for example, JP-A-58-127728, JP-A-58-129013, JP-A-Sho 58-129013; No. 59-51911, No. 60
-79035, 60-186511, 61-1
No. 26115, etc.), there are no particular restrictions.

Specific examples of metasense catalysts include halides, oxyhalides, oxides, and organic ammonium salts of tungsten, molybdenum, and tantalum, and specific examples of activators (cocatalysts) include alkyl aluminum halides. , alkoxyalkylaluminum halides, aryloxyalkylaluminum halides, organotin compounds, and the like.

In the case of alkylaluminum halides, there is a problem that polymerization starts immediately when a solution containing a catalyst is mixed, so in that case, the activator and ethers, esters, etc.
The initiation of polymerization can be delayed by using regulators such as ketones, nitriles, and alcohols (
For example, JP-A-58-129013, JP-A-61-1
20814). When using a filler such as glass fiber, it is advantageous to use a filler with a long pot life in order to uniformly impregnate the filler. , especially preferably 10 minutes or more.

In addition to catalysts and activators, halogenated hydrocarbons such as chloroform, carbon tetrachloride, and hexachlorocyclopentadiene (e.g., JP-A-60-79035), silicon tetrachloride, germanium tetrachloride, lead tetrachloride, etc. A metal halide may be used in combination.

The metasense catalyst is typically used at a concentration of about 0 per mole of monomer.
．． It is used in a range of 0.01 to 50 mmol, preferably 0.1 to 10 mmol. The activator (cocatalyst) is usually used in a proportion of 0. It is used in a range of 1 to 200 (molar ratio), preferably 2 to 10 (molar ratio).

Both the metasense catalyst and the activator are preferably used after being dissolved in a monomer, but they may also be used after being suspended or dissolved in a small amount of a solvent as long as the properties of the product are not essentially impaired.

(Bulk Polymerization) In the present invention, a core material made of a plate-shaped foam with a low expansion ratio and a skin layer on the surface is placed in a mold, and a norbornene monomer is ring-opening polymerized in bulk using a metasense catalyst. used. Substantially bulk polymerization is sufficient, and a small amount of inert solvent may be present.

In a preferred method for producing bulk polymers, the norbornene-based monomer is divided into two parts, placed in separate containers, and the mecthesis catalyst is added to one part, and the activator is added to the other part, to prepare two types of stable reaction solutions. . This one type of reaction solution is mixed and then poured into a mold of a predetermined shape, where ring-opening polymerization is carried out in bulk form.

The mold is not particularly limited, but is preferably made of metal such as aluminum or a low melting point alloy.

In the present invention, an impingement mixer conventionally known as a RIM molding device can be used to mix the two reaction stock solutions. In this case, the vessels containing the two reaction stock solutions become sources of separate streams. The two streams are instantaneously mixed in the mixing head of the RIM machine and then injected into the mold, where they are immediately bulk polymerized to obtain a molded article.

In addition to impingement mixers, low pressure injection machines such as dynamic mixers and static mixers can also be used. In cases where the pot life at room temperature is as long as 1 hour, the two reaction solutions may be injected or poured several times into a preheated mold after the two reaction solutions have been mixed in a mixer, e.g. , Japanese Unexamined Patent Publication No. 59-51911, US Pat. No. 4,426,502), or continuous injection may be performed.

This method has the advantage that it can be made more compact than an impingement mixer, and can be operated at low pressure. By slowing down the speed, it becomes possible to uniformly impregnate the reaction stock solution into the system.

Furthermore, the present invention is not limited to the method of using two types of reaction stock solutions. As can be easily understood by those skilled in the art,
For example, various modifications are possible, such as placing monomers and desired additives in a third container and using it as a third stream.

The mold temperature is usually 10 to 150°C, more preferably 3
The temperature is 0 to 100°C.

The pressure within the mold is within a range that does not deform the core foam. Specifically, it is within the range of 0.1 to 10 kg/cri, preferably up to 5 kg/cri.

The polymerization time may be selected as appropriate, but is usually shorter than about 20 minutes, preferably within 5 minutes, but may be longer.

Although the reaction stock solution is usually stored and operated under an atmosphere of an inert gas such as nitrogen gas, the mold does not necessarily need to be sealed with an inert gas.

(Optional ingredients) Antioxidants, fillers, reinforcing materials, pigments, colorants, foaming agents,
By blending various additives such as flame retardants, sliding agents, elastomers, and hydrogenated dicyclopentadiene thermopolymer resins, the properties of the resulting polymer can be modified.

As antioxidants, there are various types of antioxidants for plastics and rubber, such as phenol-based, phosphorus-based, and amine-based antioxidants.

Fillers include inorganic fillers such as milled glass, long glass fibers, glass mats, carbon black, talc, calcium carbonate, and mica.

Reinforcing fibers can also be used in conjunction with the present invention for the purpose of further increasing the strength of the outer peripheral layer.

Elastomers include natural rubber, polybutadiene, polyisoprene, styrene-butadiene copolymer (SBR
), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), ethylene-propylene-genta polymer (EPDM), ethylene-vinyl acetate copolymer (EVA), and These include hydrides.

The additives are mixed in advance with one or both of the reaction solutions, or placed in the mold cavity. Furthermore, it is also possible to increase the strength of the resin by wrapping reinforcing fibers around the foam as long as it does not impede the object of the present invention.

〔Example〕

EXAMPLES The present invention will be explained in more detail by giving Examples and Comparative Examples below. Note that parts in Examples and Comparative Examples are based on weight unless otherwise specified.

[Example 1] A foaming stock solution for polyurethane foam (manufactured by Asahi Denka Co., Ltd., Azocafoam Mix; a liquid mixture of polyol, isocyanate, and foaming material) was poured into a foaming mold (made of aluminum) having a space of 545 mm x 545 mm x 30 mm. A polyurethane plate-shaped foam was obtained in about 15 minutes.

The obtained plate-shaped foam has an expansion ratio of about 10 times and a density of 0.
．． It was 12g/cr11' and had a skin layer on the surface.

A support metal fitting of 100 mm x 100 mm was placed on the plate-shaped foam.
Aluminum plates with a size of 250 mm x 250 mm were buried from both sides, and their ends (100 mm x 100 mm) were allowed to protrude.

The plate-shaped foam with support fittings was placed in a mold having a space of 550 mm x 550 mm x 40 mm. In addition, a gap corresponding to the protruding size and thickness of the support metal fittings is provided in advance at both ends of the lower mold, so that when the upper and lower molds are closed, there is a gap between the plate-shaped foam and the inner surface of the mold. This is done so that there is a gap between the two.

The mold was heated to 60°C and stood vertically. An injection port for the reaction solution was provided below the mold.

Styrene-isoprene-styrene block copolymer (SIS) (
6.5 parts of FinTac 3421 (trade name, manufactured by Nippon Zeon Co., Ltd.) were added and mixed. This solution was placed in two containers, one containing diethylaluminum chloride (DE) for DCP.
AC) was added at a concentration of 41 mmol, n-propyl alcohol at a concentration of 41 mmol, and silicon tetrachloride at a concentration of 21 mmol (solution A).

On the other hand, tri(tridecyl)ammonium molybdate was added to DCP at a concentration of 10 mmol, and a phenolic antioxidant (Ethanoxfu 02, manufactured by Ethyl Corporation) was added per 100 parts of DCP.
4 parts were added (overnight).

Both reaction solutions (mixing ratio of Al solution/B solution 1/1) were quickly injected into the mold at approximately normal pressure using a gas bomb and a power mixer.

After injection, a polymerization reaction is performed for about 3 minutes, and the foam is used as a core material.
A large plate-shaped composite molded product was obtained with a DCP resin as the outer peripheral layer.

The obtained composite molded product had good smoothness without the occurrence of voids or irregularities, and had excellent flatness without waving.

[Comparative Example 1] Large-sized plate-shaped composite molding was carried out in the same manner as in Example 1, except that a plate-shaped foam made of Polyurekun with an expansion ratio of about 20 times and a density of 0.06 g/c was used as the core material. I got the item.

The obtained composite molded product has undulations in the center,
It had poor flatness. Further, when this was cut and examined, it was found that the interface between the outer peripheral layer and the core material had peeled off.

[Comparative Example 2] A large plate-shaped composite molded product was produced in the same manner as in Example 1, except that the polyurethane foam was cut into a plate-shaped foam without a skin layer, and this was used as the core material. .

The surface of the obtained composite molded product had many irregularities, had poor smoothness, and had no commercial value.

[Effects of the Invention] Thus, according to the present invention, light and strong (, surface smoothness,
A large plate-like composite molded product with good flatness can be provided. Further, according to the present invention, a large plate-shaped composite molded product can be quickly molded using a simple method.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of manufacturing the composite molded article of the present invention in a mold. FIG. 2 is a plan view of the composite molded product immediately after molding. 1: Plate-shaped foam (core material), 2. Supporting metal fittings, 3: Outer peripheral layer, 4. Upper mold, 5. Lower molding, 6. Gap into which the end of the supporting metal fitting provided in the lower mold is received. Figure 1

Claims (1)

[Claims] (1) A core material made of a plate-shaped foam with a low expansion ratio and a skin layer on the surface is placed in a mold, and a reaction liquid containing a norbornene monomer and a metasense catalyst is supplied into the mold to carry out bulk polymerization. A large plate-like composite molded product characterized by forming an outer peripheral layer made of a norbornene-based polymer.