JPH045016A - Lightweight plate-shaped molded product - Google Patents

Abstract

PURPOSE:To manufacture a light-weight plate-shaped molded product by disposing a substratum with a mounting structure in a manner of exposing the mounting structure section of a plate- shaped core material formed with a foamed material, disposing the plate-shaped core material in a mold, feeding reaction liquid containing a norbornane monomer and a metathesis catalyst and bulk polymerizing therein. CONSTITUTION:A light-weight plate-shaped molded product comprises a substratum with a mounting structure with its mounting structure section disposed on a plate-shaped core material formed with a foamed body, the plate-shaped core material disposed in a mold in a manner of forming a space between the plate-shaped core material and the mold inner face by means of the substratum, and an outer peripheral layer composed of a norbornane polymer is formed by feeding reaction liquid containing a norbornane monomer and a metathesis catalyst in the mold and bulk polymerizing therein. For instance, in the case of disposing a core material 1 in a space encircled with upper and lower molds 5 and 6, a substratum 2 is buried in the core material 1 from the side section end in a manner of exposing said end. A space corresponding to the thickness of the exposed section is formed in the lower mold 6 and the core material is set with a constant space from the mold inner face. Reaction raw liquid containing the norbornane monomer is injected into the space and bulk polymerized to form an outerperipheral layer 4.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a lightweight plate-shaped molded article, and more specifically, a plate-shaped core material formed of a foam and an outer periphery of a bulk polymer of norbornene monomer. The present invention relates to a lightweight plate-shaped molded product having layers and a structure for attaching the molded product to other members.

[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, and then a thermosetting resin is applied and cured. 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 of heating and curing to obtain a composite molded product (
(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 there are no reinforcing fibers, the resin strength of the outer layer is weak (
Become. Therefore, in order to provide sufficient strength with resin alone, it is necessary to use an expensive material such as epoxy resin.

Further, when a fiber reinforcing material is used, it is difficult to fill the reaction liquid, and moreover, the reinforcing material is exposed on the surface of the molded product, making it difficult to obtain a composite molded product with good surface smoothness.

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 a lightweight, heat-resistant, and strong plate-shaped molded product can be created by using foam as the core material and resin imitation as the outer layer, it can be used as partition boards, display boards, table boards, etc. However, with conventional methods, it is difficult to produce a plate-like composite molded product with a good appearance and excellent smoothness.

[Problems to be Solved by the Invention] By the way, when a norbornene monomer such as dicyclopentadiene is bulk polymerized 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, with this method, it is necessary to provide a certain gap between the core material and the inner surface of the mold, and to inject the reaction liquid into that gap, but there is a problem in that the appropriate methods for creating the gap are limited. be.

For example, a method can be considered in which a support is installed at a desired location on the core material and a gap is created between the core material and the inner surface of the mold using the support, but the adhesion between the support and the norbornene polymer layer is insufficient. In many cases, the ends of the support are exposed on the surface of the molded product, which impairs its appearance. In particular, when using a large plate-shaped core material, a large number of supports are required, and this problem becomes serious.

On the other hand, when using a plate-shaped composite molded product as a partition plate, display board, etc., it is necessary to install mounting parts to attach these to other parts, but such mounting parts cannot be attached to the molded product. The work to install it is complicated.

Therefore, as a result of extensive research, the present inventors installed a support provided with an attachment structure on a plate-shaped core material formed of foam so that the attachment structure was exposed, and the support A plate-shaped core material is installed in the mold so that a gap is created between the core material and the inner surface of the mold, and a norbornene monomer and a metasense catalyst are placed in the gap between the core material and the inner surface of the mold. By supplying a reaction solution containing and performing bulk polymerization, it is possible to suitably form an outer peripheral layer made of a norbornene-based polymer, and to obtain a lightweight plate-like molded product in which a member having a mounting structure is integrally molded. I discovered that.

The present invention has been completed based on these findings.

[Means for Solving the Problems] Thus, according to the present invention, at least one support body provided with an attachment structure is arranged on a plate-shaped core material formed of a foam so that the attachment structure portion is exposed. The plate-shaped core material is placed in the mold so that a gap is created between the plate-shaped core material and the inner surface of the mold due to the support, and the reaction solution containing the norbornene monomer and metasense catalyst is poured into the mold. Provided is a lightweight plate-shaped molded article characterized in that it is made of a norbornene-based polymer, which is supplied into the interior of the vessel and polymerized in bulk to form an outer peripheral layer made of a norbornene-based polymer.

The present invention will be explained in detail below.

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

If a plate-shaped foam having a skin layer (dense layer) and a foaming ratio of about 5 to 15 times is used as this foam, there will be no voids or unevenness, and there will be no waving phenomenon. This is preferred because a plate-shaped molded product with excellent properties and smoothness 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.

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.

The shape of the foam is smaller than the shape of the plate-shaped molded product by the thickness of the resin forming the outer peripheral layer (plate-shaped foam).

(Lightweight plate-shaped molded product) The lightweight plate-shaped molded product in the present invention is a rectangular, circular, or other flat plate-shaped molded product.

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

Such lightweight plate-shaped molded products can be used, for example, as partition plates, display plates, table plates, and the like. In this case, since it has an attachment structure, it can be easily attached to other members using it.

(Installation of core material in mold) In the present invention, a plate-shaped core material made of foam is installed in a mold, and 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 a means of creating a gap between the plate-shaped core material and the inner surface of the mold,
In the present invention, the plate-shaped core material is provided with a support provided with a mounting structure, and the plate-shaped core material is placed in the mold so that a gap is created between the plate-shaped core material and the inner surface of the mold. Installed inside.

A specific example of this method will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing one embodiment in which a lightweight plate-shaped molded product is molded by disposing a core material in a mold. FIG. 2 is a plan view of the obtained lightweight plate-shaped molded product.

When the core material 1 is disposed in a space surrounded by the upper and lower molds 5 and 6, the support body 2 is embedded in the core material 1 from the side end surface, and is disposed so that the end portion thereof is exposed.

At least one end of the support body 2 is provided with a mounting structure 3 such as a hole for a bolt.

On the other hand, a cavity corresponding to the size and thickness of the exposed part of the support is formed in the lower mold 6, and the part protruding from the core of the support is placed in the cavity, and the upper and lower molds are By sandwiching the core material with the inner surface of the mold, it is possible to install the core material with a certain gap between the inner surface of the mold and the inner surface of the mold.

In this way, the reaction stock solution containing the norbornene monomer is injected into the gap provided in the mold (the injection port is not shown).
Bulk polymerization is performed to form the outer peripheral layer 4 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. If the core material moves during molding, the thickness of the outer peripheral layer will become uneven, and in severe cases, it may be exposed to the surface.

Such a support is made of a high-strength material that does not deform during molding, such as metal such as aluminum, thermosetting resin such as norbornene polymer, polyester resin, or epoxy resin; wood, etc.

Although the shape of the support can be modified as appropriate, a plate-like support is usually suitably used. Further, at least one end of the special holiday is provided with a mounting structure for the molded product. Examples of the mounting structure include bolts, screw holes, grooves, etc., and a desired structure can be selected depending on the application of the molded product.

The support, for example, as shown in FIGS. 1 and 2,
It can be disposed by penetrating the plate-shaped core material. in this case,
The support also functions as a reinforcing plate.

In addition, there are methods such as placing the supports crosswise from both end faces of the core material, inserting each support from both end faces (without penetrating them), and embedding the supports only from one end face. be. The number of supports used is at least one.

The support has a mounting structure for the molded product (finished product) formed at one end thereof, and if unnecessary, the other end may be buried inside or cut after molding.

Another example of a support provided with a mounting structure is shown in a sectional view in FIG. A reinforcing plate (for example, an aluminum plate) 8 is provided with one or more supports 9 (only one is shown in the drawing) having a female thread type attachment structure 10 at the pointed end, and is made of foam. The tip of the support 9 is fitted into the cavity 7 provided in the lower mold 6 and fixed. Then, a reaction stock solution containing a norbornene monomer is injected into the gap between the core material 1 and the inner surface of the upper and lower molds 5.6 (the injection port is not shown), and bulk polymerization is performed to form an outer peripheral layer made of norbornene polymer. form 4. The thus obtained plate-shaped molded product can be used as a table by attaching, for example, legs having a male screw structure to the tip using the female screw structure provided at the tip of the structure 9. be able to. In addition, in order to arrange such a reinforcing plate and a support body in the plate-shaped core material 1, for example, when carrying out foam molding in a mold, a reinforcing plate with a support body is installed in advance in a mold, A suitable method is to inject a foaming stock solution into the foam and perform foam molding.

(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 monomer.

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 Monocyclics such as cyclododecene, dimethyltetracyclododecene, ethylidenetetracyclododecene, phenyltetracyclododecene, bicyclics such as tricyclopentadiene, heptacyclics such as tetracyclopentadiene, etc. is exemplified. These monomers may be used in combination of one or more types.

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

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 norbornene monomers mentioned above, may be used in combination without impairing the purpose of the present invention. can.

(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 monomers (for example, JP-A-58-127728,
No. 58-129013, No. 59-51911, No. 6
No. 0-79035, No. 60-186511, No. 61-
No. 126115, 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 601 to 50 mmol, preferably 0.1 to 10 mmol. The activator (cocatalyst) is generally used in an amount of 0.1 to 200 (mole ratio), preferably 2 to 10 (mole ratio), based on the catalyst component.

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 metasense catalyst is added to one part, and the activator is added to the other part, to prepare two types of stable reaction solutions. . These two types of reaction solutions are mixed and then poured into a mold of a predetermined shape, where ring-opening polymerization is carried out in bulk.

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, a container containing one reaction stock becomes a source for 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, 0.1 to 10 kg/crtr
, preferably 5 kg/crr? It is within the range of

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

Note that, 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-genterpolymer (EPDM), ethylene-vinyl acetate copolymer (EVA), and these There are hydrides, etc.

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] The present invention will be described in more detail with reference to Examples below. Note that parts in the examples are based on weight unless otherwise specified.

[Example 1] A foaming stock solution for polyurethane foam (manufactured by Mudenka 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 12 g/crtr and had a skin layer on the surface.

On both sides of the plate-shaped foam, a support of 100 mm
Two aluminum plates measuring 250 mm x 3 mm each with holes (10 mm in diameter) for bolts were buried at one end in the long direction, and the ends with the holes (
100mm x 100mm) was made to protrude.

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

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 (A? night).

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 (solution B).

Both reaction solutions (mixing ratio of solution A/solution 1/1) were quickly injected into the mold at approximately normal pressure using a gear pump 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. The support was integrated with the molded body and did not come off even when pulled strongly.

Since it has an attachment structure, it can be easily attached to other members.

[Effects of the Invention] Thus, according to the present invention, light and strong (, surface smoothness,
A lightweight plate-shaped molded product with good flatness can be provided. Furthermore, according to the present invention, by using a member having an attachment structure as a support, a plate-shaped composite molded product in which the attachment structure member is integrally molded can be quickly molded by a simple method.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing one embodiment of manufacturing the lightweight plate-shaped molded product of the present invention in a mold. FIG. 2 is a plan view of the obtained lightweight plate-shaped molded product. FIG. 3 is a schematic cross-sectional view showing another embodiment of manufacturing the lightweight plate-shaped molded product of the present invention in a mold. 1. Plate foam (core material), 2. Support, 3. Mounting structure (holes for bolts), 4. Outer peripheral layer, 5. Upper mold, 6. Lower mold, 7. Hollow space provided in the lower mold. 8: Reinforcement plate, 9, Support body, 10, Mounting structure (female thread type). Figure 1 Figure 2 Figure 1

Claims (1)

[Claims] (1) At least one support body provided with a mounting structure is arranged on a plate-shaped core material formed of foam so that the mounting structure part is exposed, and the support body connects the plate-shaped core material and the mold. A plate-shaped core material is placed in a mold so that a gap is created between it and the inner surface, and a reaction solution containing a norbornene monomer and a metasense catalyst is supplied into the mold and polymerized in bulk, resulting in a material made of norbornene polymer. A lightweight plate-shaped molded product characterized by forming an outer peripheral layer.