JPH05239192A - Thick molded product - Google Patents

Abstract

PURPOSE:To obtain a lightweight and inexpensive thick molded product good in heat resistance, mechanical strength, resistance to water absorption and dimensional stability and free from holes by a reactive injection molding method using a norbornene based monomer. CONSTITUTION:The objective thick molded product substantially free from holes consists of a polycylic norbornene based polymer obtained by subjecting a tri or more polycyclic norbornene based monomer to bulk polymerization in a frame mold in the presence of a metathesis catalyst system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thick-walled molded product made of a polycyclic norbornene-based polymer, and more specifically, it has substantially no pores inside, has good heat resistance and mechanical strength, and is lightweight. The invention relates to a thick-walled molded article having low water absorption.

[0002]

2. Description of the Related Art Conventional engineering plastics are excellent in heat resistance and mechanical strength, but it is difficult to make thick molded products and large molded products by injection molding.
Molds are also expensive.

Recently, reaction injection molding using a polycyclic norbornene-based monomer represented by dicyclopentadiene (R
IM) is being developed. This RIM
According to the method, since a low-viscosity liquid material is used, a relatively inexpensive mold can be used, and a molded product excellent in heat resistance, mechanical strength, water absorption resistance, etc. can be obtained. it can. However, most of the conventional molded products by the RIM method have a thin thickness of 10 mm or less, and thick molded products have not been manufactured. Further, for example, even if an attempt is made to manufacture a thick molded product that can be used in a field requiring a high degree of mechanical strength, such as a forged product or a cast product, by the RIM method using a norbornene-based monomer. However, there is a defect that voids or voids having a size of 1 mm or more, sometimes 5 mm, which are so-called cavities, are likely to be formed inside the molded product, and a thick molded product without voids cannot be obtained.

[0004]

The object of the present invention is to obtain heat resistance by the RIM method using a norbornene-based monomer,
An object of the present invention is to provide a thick-walled molded product having good mechanical strength, water absorption resistance, and dimensional stability, being lightweight, inexpensive, and having no pores.

The inventors of the present invention have conducted extensive studies in order to overcome the above-mentioned problems of the prior art. As a result, in the bulk polymerization of polycyclic norbornene-based monomers by the RIM method, the maximum curing exothermic temperature is controlled to 160 ° C. or lower. Alternatively, in the step of cooling from the maximum curing exothermic temperature of the reaction product to at least the glass transition temperature of the reaction product, by controlling the temperature difference inside the reaction product within 80 ° C., even a thick molded product can be empty. It has been found that a thick-walled molded product having substantially no pores and excellent physical properties can be obtained.

The present invention has been completed based on these findings. In the present invention, the thick-walled molded product is a molded product having a portion having a thickness of at least 20 mm or more, and means a thick-walled molded product other than the material for cutting.

[0007]

Thus, according to the present invention, a substantial amount of a polycyclic norbornene-based polymer is obtained by bulk-polymerizing a tricyclic or higher norbornene-based monomer in a mold in the presence of a metathesis catalyst system. A wall-thick molded product having no holes is provided.

The present invention will be described in detail below. (Norbornene-based Monomer) In the present invention, the monomer used as a raw material for the thick molded article is a polycyclic norbornene-based monomer having a tricyclic or higher ring. When the polymer has three or more rings, a polymer having a high heat distortion temperature can be obtained and the heat resistance level required as a thick molded product can be satisfied.

Further, in the present invention, the norbornene-based polymer to be produced is preferably thermosetting type, and for that purpose, at least 10% by weight, preferably 30% by weight or more of the total monomer is used. It

Examples of the norbornene-based monomer having three or more rings are tricycles such as dicyclopentadiene and dihydrodicyclopentadiene, tetracycles such as tetracyclododecene, and pentacycles such as tricyclopentadiene. Heptacycles such as tetracyclopentadiene, their alkyl substitutions (eg, methyl, ethyl, propyl, butyl substitutions, etc.), alkylidene substitutions (eg, ethylidene substitutions), aryl substitutions (eg, phenyl, (Such as a tolyl-substituted product), and the like.

On the other hand, the crosslinkable monomer is a polycyclic norbornene-based monomer having two or more reactive double bonds,
Specific examples thereof include dicyclopentadiene, tricyclopentadiene, tetracyclopentadiene and the like. The crosslinkable monomer may be the same as the norbornene-based monomer. These norbornene-based monomers can be used alone or in combination of two or more.

The norbornene-based monomer having three or more rings is
It can also be obtained by heat-treating dicyclopentadiene. The conditions for the heat treatment include a method of heating the dicyclopentadiene at a temperature of 120 to 250 ° C. for 0.5 to 20 hours in an inert gas atmosphere. By this heat treatment, a monomer mixture containing pentacyclopentadecadiene and unreacted dicyclopentadiene is obtained.

It should be noted that 2-norbornene, 5-methyl-2-norbornene and 5-ethylidene-which can be subjected to ring-opening polymerization with at least one norbornene-based monomer having three or more rings.
A bicyclic norbornene-based monomer such as 2-norbornene or 5-phenyl-2-norbornene, or a monocyclic cycloolefin such as cyclobutene, cyclopentene, cyclopentadiene, cyclooctene, or cyclododecene is within a range not impairing the object of the present invention. Can be used together.

(Metathesis Catalyst System) The catalyst used in the present invention is a metathesis catalyst system comprising a metathesis catalyst and an activator (cocatalyst), and is a metathesis catalyst system known as a catalyst for bulk polymerization of norbornene-based monomers. Either may be used (for example, JP-A-58-127728 and JP-A-5-127728).
8-129013, 59-51911, 60-
79035, 60-186511, 61-12
No. 6115), and there is no particular limitation.

As the metathesis catalyst, tungsten,
Examples thereof include halides such as molybdenum and tantalum, oxyhalides, oxides, organic ammonium salts, and the like. Suitable examples are tungsten hexachloride, tungsten oxytetrachloride, tungsten oxide, tridodecyl ammonium tungstate, and methyl trichloride. Tungsten compounds such as capryl ammonium tungstate, tri (tridecyl) ammonium tungstate, trioctyl ammonium tungstate: molybdenum pentachloride, molybdenum oxytrichloride, tridodecyl ammonium molybdate, methyl tricapryl ammonium molybdate, tri (tridecyl) ammonium Molybdenum compounds such as molybdate and trioctyl ammonium molybdate: tantalum compounds such as tantalum pentachloride .

Among them, it is preferable to use a metathesis catalyst soluble in the norbornene-based monomer used in the reaction, and from the viewpoint, an organic ammonium salt is preferred. When the metathesis catalyst is a halide, the metathesis catalyst can be solubilized in the monomer by previously treating it with an alcohol compound or a phenol compound. If necessary, a Lewis base such as benzonitrile or tetrahydrofuran, or a chelating agent such as acetylacetone or alkyl acetoacetate can be used in combination, whereby premature polymerization can be prevented.

Examples of the activator include alkylaluminum halides, alkoxyalkylaluminum halides, aryloxyalkylaluminum halides and organic tin compounds. Suitable examples are ethylaluminum dichloride, diethylaluminum monochloride and ethylaluminum sesqui. Chloride, diethyl aluminum iodide, ethyl aluminum diiodide, propyl aluminum dichloride, propyl aluminum diiodide, isobutyl aluminum dichloride, ethyl aluminum dibromide, methyl aluminum sesquichloride, methyl aluminum sesquibromide, tetrabutyl tin, alkyl aluminum halides and alcohols Preliminary reaction products with.

Among these activators, alkoxyalkylaluminum halides and aryloxyalkylaluminum halides have an appropriate pot life at room temperature even when the metathesis catalyst component is mixed, and are therefore advantageous in operation (for example, JP Sho 59-51911).
In the case of alkylaluminum halide, there is a problem that polymerization starts immediately when the metathesis catalyst is mixed, but in that case, the activator and ethers, esters,
The initiation of polymerization can be delayed by using a regulator such as ketones, nitriles, alcohols (for example, JP-A Nos. 58-129013 and 61-12).
0814).

If these regulators are not used, it is necessary to give consideration to the equipment and operation so that even those having a short pot life can be used. However, in the case of a catalyst system having a short pot life, it is difficult to efficiently remove the heat of reaction because the reaction proceeds rapidly, so the pot life at 25 ° C. is 5 minutes or more, preferably 10 minutes or more, and more preferably It is better to use the one for 30 minutes or more.

In addition to the metathesis catalyst and the activator, halogenated hydrocarbons such as chloroform, carbon tetrachloride, hexachlorocyclopentadiene and the like may be used in combination (for example, JP-A-60-79035). further,
Halides such as tin tetrachloride, silicon tetrachloride, magnesium chloride and germanium chloride may be used in combination.

The metathesis catalyst is usually used in an amount of about 0.01 to 50 mmol, preferably 0.1 to 10 mmol, relative to 1 mol of the norbornene-based monomer. The activator is generally used in the range of 0.1 to 200 (molar ratio), preferably 2 to 10 (molar ratio) with respect to the catalyst component.

Both the metathesis catalyst and the activator are preferably dissolved in the monomer before use, but may be suspended or dissolved in a small amount of solvent as long as the properties of the product are not substantially impaired. Good.

(Manufacturing Method of Thick Molded Product) In the present invention, a norbornene-based monomer is used as a mold (mold) having a predetermined shape.
A thick molded product is produced by a polymerization method in which the compound is introduced into the mold and bulk polymerization is carried out in a mold in the presence of a metathesis catalyst system.
It suffices if it is substantially bulk polymerization, and a small amount of an inert solvent may be present.

In a preferred method for producing a thick-walled molded product, the norbornene-based monomer is divided into two liquids and placed in another container, a metathesis catalyst is added to one and an activator is added to the other, and two stable reactions are carried out. Prepare the solution. The two types of reaction solutions are mixed and then poured into a mold having a predetermined shape, where ring-opening polymerization is performed in a bulk form to obtain a thick molded product.

The form of injection is not particularly limited, but when the pot life at room temperature is relatively long, after the mixing of the two reaction solutions in the mixer is completed, 1
The injection or injection may be performed once or several times, or more times as necessary (for example, Japanese Patent Laid-Open Publication No. Sho 5).
9-51911). Alternatively, the mixture can be fed continuously into the mold. This system has the advantage that the device can be made smaller than the collision mixing system and can be operated at low pressure. The injection pressure is not particularly limited, but usually 10 kg / cm ² or less is sufficient, and it is preferably carried out under normal pressure.

The present invention is not limited to the mode in which two kinds of reaction liquids are used. As can be easily understood by those skilled in the art, various modifications are possible, for example, by putting the reaction solution and the additive in the third container and using it as the third reaction solution or stream.

The polymerization time may be appropriately selected in relation to the exothermic temperature, but if the polymerization time is too short, it becomes difficult to control the maximum curing exothermic temperature. The components used in the polymerization reaction are stored under an atmosphere of an inert gas such as nitrogen gas,
And it is preferable to operate. The molding form may or may not be sealed with an inert gas.

In the present invention, unlike the injection molding of a thermoplastic resin, the RIM method of injecting a reaction stock solution having a low viscosity and reacting and curing in a mold is adopted, so that the mold (mold) is used. Is not necessarily an expensive mold for ordinary thermoplastics. For molding thick molded products, metal molds such as steel, aluminum,
An epoxy resin, an unsaturated polyester resin, a resin type such as polyfluoroethylene, or a wooden type is used.

Since the bulk polymerization reaction of the norbornene-based monomer by the RIM method usually proceeds within a relatively short time in the mold kept at a high temperature, when molding a large-sized thick molded product, the mold is removed from the mold. Due to the rapid heating of the reaction solution, the reaction solution becomes too hot and volatilization of monomer decomposition products (cyclopentadiene) and unreacted products occurs, or the cooling process after the reaction is rapid. An extreme temperature difference occurs between the mold part and the mold wall surface contact part, and a large difference in the degree of shrinkage occurs, so that cavities (fine voids or voids) are likely to be formed inside the molded product.

The first method for producing a wall-thick molded article having substantially no pores according to the present invention is to remove reaction heat from the mold positively and control the reaction rate to maximize the curing of the reaction product. There is a method of controlling the temperature at 160 ° C or lower, preferably 150 ° C or lower.

The second method is a step of removing the reaction heat from the mold when the maximum curing exothermic temperature of the reaction product cannot be controlled within 160 ° C. In the process of cooling to
There is a method of controlling the temperature difference inside the reaction product within 80 ° C, preferably within 70 ° C, more preferably within 50 ° C.

Methods for controlling the maximum curing exothermic temperature of the reaction product There are various methods for removing the reaction heat from the mold, but it is convenient to cool the outside of the mold by air cooling or water cooling. As the water-cooled solvent, water, various refrigerants, antifreeze liquid or the like can be used. In order to improve the cooling efficiency, the structure of the formwork was devised and folds were attached to the outside,
A cooling water passage may be provided. Further, the mold may be formed of a material having a high thermal conductivity such as aluminum or copper. As an air cooling method, a method of sending air by a fan is simple.
As a water cooling method, there is also a method of simply attaching a mold to a water tank.

The mold temperature is selected so that the maximum curing exothermic temperature of the reactants is below 160 ° C. That temperature is
The temperature is usually 60 ° C. or lower, preferably 50 ° C. or lower, though it depends on the reaction conditions such as the size of the mold, the cooling method, and the pot life of the reaction stock solution. In any case, it is preferable to perform a test in advance according to the shape of the mold to be used and to determine the suitable cooling conditions.

Method of controlling the temperature difference inside the reactants The reaction stock solution injected into the mold starts the reaction due to its own chemical reactivity. Usually, the reaction starts from the center of the reaction solution. Although it is possible to heat the mold from the outside to start the reaction, cavities are easily formed inside the molded product. The thicker the molded product, the more difficult it becomes to control the maximum curing exothermic temperature, and the more likely it is that voids will form.

After pouring the reaction stock solution into the mold, the reaction starts, but the reaction product reaches the maximum curing exothermic temperature, and is taken out while cooling after the reaction is completed. The maximum curing exothermic temperature varies depending on the composition of the reaction stock solution, but is usually 20
0-230 ° C, and in some cases 235 ° C or higher.

When the reaction product is cooled from the maximum curing exothermic temperature to the glass transition temperature, it is important to control the temperature difference within the reaction product within 80 ° C, preferably within 70 ° C, more preferably within 50 ° C. is there. Since the temperature difference inside the reaction product is usually the maximum between the central part of the thick part and the part in contact with the mold, while controlling this temperature difference within 80 ° C, the entire reaction product is made uniform. Cool down.

The method of cooling while controlling the temperature difference is not particularly limited, but specific examples thereof include, for example, steam and an electric heater on the outside of the mold at the same time when the reactant reaches the maximum curing exothermic temperature. In this case, a method of heating and gradually cooling while maintaining a temperature difference within a predetermined range can be mentioned. It is important for the heating temperature to select a temperature difference as large as possible under the above conditions from the viewpoint of increasing the cooling rate and increasing the productivity.

As the temperature of the reaction product is lowered by cooling, the temperature of the mold is also lowered, and when the temperature of the reaction product is cooled below the glass transition temperature, even if the reaction product is rapidly cooled, cavities are formed. Does not affect.

As a cooling method, when steam is used as the heating means, the pressure is lowered or water is introduced, and when an electric heater is used, the current is lowered. can do. Although it is possible to provide a cooling device for each form, it is also possible to aggregate several forms and provide a common cooling facility.

In order to control the above temperature difference, it is preferable to introduce a temperature sensor into the reaction product to control the temperature of the mold. However, once the composition and pot life of the reaction stock solution have been determined, the reaction temperature and cooling rate can be changed with time in almost the same pattern, so it is necessary to conduct a test in advance and determine a suitable cooling rate. However, it is not always necessary to introduce temperature sensors into the individual molds.

(Optional components) By mixing various additives such as a filler, a pigment, a colorant, an antioxidant, an elastomer, a dicyclopentadiene type thermopolymer resin, a flame retardant and a sliding member, the meat of the present invention can be blended. The properties of thick molded products can be modified.

Particularly, when an antioxidant is blended in the reaction product, the ignition point of the norbornene-based polymer (molded product) becomes 1
The temperature can be set to 20 ° C. or higher, and heat discoloration and deformation can be prevented.

The antioxidant which can be used in the present invention includes:
There are various types of antioxidants for plastics and rubber such as phenol, phosphorus and amine. These antioxidants are
They may be used alone or in combination. The blending ratio is within a range such that the ignition point of the norbornene-based polymer is 120 ° C. or higher, preferably 130 ° C. or higher,
Normally, 0.5 wt% or more based on the norbornene-based polymer,
It is preferably 1 to 3% by weight. If the mixing ratio of the antioxidant is extremely low, the ignition point of the molded product cannot be increased. There is no particular upper limit of the blending ratio, but if the amount of the antioxidant is too large, it is uneconomical and may hinder the polymerization, which is not preferable. In particular, amine-based antioxidants
It has been found that the use of 2% by weight or more inhibits the polymerization reaction, so that it is preferably used in the range of 0.5 to 2% by weight.

Examples of phenolic antioxidants are 4,4'-dioxydiphenyl, hydroquinone monobenzyl ether, 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butylphenol,
2,6-di-amylhydroquinone, 2,6-di-t-butyl-p-cresol, 4-hydroxymethyl-2,6
-Di-t-butylphenol, 4,4'-methylene-bis- (6-t-butyl-o-cresol), butylated hydroxyanisole, phenol condensate, butyleneated phenol, dialkylphenol sulfide, high molecular weight Examples include hydric phenol and bisphenol.

Examples of phosphorus-based antioxidants include aryl or alkylaryl phosphites such as tri (phenyl) phosphite and tri (nonylphenyl) phosphite.

Examples of amine antioxidants include phenyl-α-naphthylamine, 4,4'-dioctyldiphenylamine, N, N'-di-β-naphthyl-p-phenylenediamine, N, N'-diphenyl-amine. p-phenylenediamine, N-phenyl-N'-cyclohexyl-
p-phenylenediamine, N, N'-di-o-tolyl-
Examples thereof include ethylenediamine and alkylated diphenylamine.

As these antioxidants, various commercially available products other than those mentioned above can be used. The antioxidant may be copolymerizable with a monomer, and specific examples thereof include norbornenylphenol-based antioxidants such as 5- (3,5-di-t-butyl-4-hydroxybenzyl) -2-norbornene. Examples thereof include compounds (JP-A-57-83522).

Examples of the filler include inorganic fillers such as glass, carbon black, talc, calcium carbonate and mica. As the elastomer, natural rubber, polybutadiene, polyisoprene, styrene-butadiene copolymer (SBR), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), ethylene- Propylene-
Examples include diene terpolymer (EPDM), ethylene vinyl acetate copolymer (EVA) and their hydrides. The additive is usually used by mixing it with one or both of the reaction solutions in advance.

(Thick Molded Product) By the above-described manufacturing method, a high quality thick molded product having substantially no pores can be efficiently obtained. In the present invention, the holes are identifiable when the cut surface is visually observed, and have a diameter of about 0.1 mm or more. Such holes have 0.5 to 1
It can also be found by sending 0 MHz of ultrasonic waves to the molded product and detecting the disturbance of the reflected wave. Further, “having substantially no pores” means that when a molded product is cut at 100 mm intervals, there are no pores in any cross section.

The thick molded product of the present invention can be formed into various shapes such as a round bar, a square bar, a tubular shape, a sheet shape and the like, and can also be a three-dimensional shape having a predetermined shape. ..

The thick molded article of the present invention has a thickness (or diameter)
Has a portion of at least 20 mm or more, preferably 50 mm or more, and its shape can be selected according to the purpose of use. Taking the size of a round bar as an example,
It is possible to manufacture a product having a diameter of about 300 mm, and even a product having a diameter of more than 300 mm, and a product having a weight of 20 kg or more can be easily obtained.

The thick molded article of the present invention has a glass transition temperature of 80 ° C. or higher, preferably 100, from the viewpoint of heat distortion resistance.
It is desirable that the temperature is not lower than 0 ° C, particularly preferably not lower than 130 ° C. Further, from the viewpoint of physical properties and odor prevention, the thick-walled molded product of the present invention has a heating loss by a thermobalance method (heating under a nitrogen atmosphere at a heating rate of 20 ° C./min and measuring the weight loss at 400 ° C.). It is desirable to be 5% by weight or less, and more preferably 3% by weight or less. The heating loss represents the total of unreacted monomers and decomposed products of the polymer. The smaller this value is, the more sufficient the reaction is, the better the physical properties of the molded article and the less the monomer odor.

When 0.5% by weight or more, preferably 1 to 3% by weight of an antioxidant is added, the ignition point measured by a high pressure differential thermal analysis method (using a high pressure differential thermal balance as a device, under high pressure oxygen, a sample Is 10 mg that has been freeze-pulverized and passed through a 100-mesh wire net, and the point at which the differential heat curve shows a sharp rise is defined as the ignition point.)
Preferably, it can be set to 130 ° C. or higher.

The thick molded article of the present invention has low water absorption,
As a result, the dimensional stability is good, and since it has a low specific gravity, it is lightweight. The thick molded product of the present invention can be used in a wide range of applications as various molded products such as a casing part of a plastic pump, a pump motor base, a thick box, a large-diameter thick pipe, and a tank.

[0055]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Parts and% are based on weight unless otherwise specified.

[Example 1] 2% of phenolic antioxidant (trade name Irganox 259, manufactured by Ciba Geigy)
The contained dicyclopentadiene (DCP) was placed in two containers, one containing DCA with diethylaluminum chloride (DEAC) at a concentration of 33 mmol, n-propanol at a concentration of 42.9 mmol, and silicon tetrachloride at a concentration of 20 mmol. Was added. On the other hand, tri (tridecyl) ammonium molybdate was added to DCP at a concentration of 4 mmol.

Both reaction solutions kept at 25 ° C. were mixed at a ratio of 1: 1 using a gear pump and a power mixer (pot life was about 10 minutes at 25 ° C.), and the shapes shown in Table 1 were obtained. Under the heat removal conditions of the mold shown in Table 1, it was injected into the steel mold having an open upper part at almost normal pressure from the upper part of the mold. These series of operations were performed under a nitrogen atmosphere. The round rod-shaped thick molded product thus obtained was cut at intervals of 100 mm in the height direction, and its cross section was visually observed. The results are shown in Table 1.

The glass transition temperature (Tg) of each molded product
Is 145 to 150 ° C, and the heating weight loss by the thermobalance method is 2 to
It was within the range of 3%, and it was found that the reaction proceeded sufficiently in all the molded articles. Furthermore, oxygen pressure 10kg / cm
As a result of measuring the ignition point by differential thermal analysis under high pressure of ² ,
All the molded products showed a value exceeding 120 ° C.

[0059]

[Table 1] * 1: Observe the cut surface at intervals of 100 mm for holes of 0.1 mm or more. If there are no holes at all, ○, 1 hole
The case of ~ 9 is indicated by Δ, and the case of 10 or more is indicated by x.

As is clear from Table 1, in the present invention examples (Experiment Nos. 1 to 3) in which bulk polymerization was performed while controlling the maximum curing exothermic temperature of the reaction product to 160 ° C. or less, voids were formed in the cut surface of the molded product. In contrast, in the case of Comparative Examples (Experiment Nos. 4 to 6) in which the maximum curing exothermic temperature is high and exceeds 160 ° C. and the cooling rate of the reactants is not controlled, a large number of holes are formed. I understand. Conventionally, in the RIM method using a norbornene-based monomer, the reaction stock solution is injected after heating the mold, but in the case of such a method for a thick molded product, the cooling rate is If the temperature is not controlled, a satisfactory molded product cannot be obtained (Experiment No. 6).

[Example 2] The amount of n-propanol added was examined in order to examine the presence or absence of pores in relation to the pot life of the reaction stock solution and the size (diameter) of the round bar-shaped thick molded product. Example 1 except that the concentration is 49.3 mmol.
Round bar-like thick molded products of various diameters were obtained in exactly the same manner as.
The pot life of the reaction stock solution was 1 hour or more at 25 ° C. The shape of the mold and the heat removal conditions of the mold were as shown in Table 2. In addition, the glass transition temperature (T
g) is 145 to 150 ° C, and the weight loss on heating by the thermobalance method is 2
.About.3%, the ignition point by differential thermal analysis was 120.degree.

[0062]

[Table 2] * 1: By the same evaluation method as in Table 1.

From the results shown in Table 2, it is understood that when the pot life is extended, the heat generation start time is extended and the productivity is slightly deteriorated, but a molded product having a larger diameter can be obtained without forming voids.

Example 3 DCP containing 2% of a phenolic antioxidant (Irganox 259, trade name, manufactured by Ciba-Geigy) was placed in two containers, one of which was DC.
DEAC was added to P such that the concentration of DEAC was 33 mmol, the concentration of n-propanol was 42.9 mmol, and the concentration of silicon tetrachloride was 20 mmol. On the other hand, tri (tridecyl) ammonium molybdate was added to DCP at a concentration of 4 mmol.

Both reaction solutions kept at 25 ° C. were mixed at a ratio of 1: 1 using a gear pump and a power mixer (pot life was about 10 minutes at 25 ° C.), and the shapes shown in Table 3 were obtained. It was poured into a steel mold having the same. The formwork is
It has a jacket on the outside to allow steam or cooling water to flow.

The mold was kept at room temperature during the injection of the reaction stock solution, and after the maximum curing exothermic temperature was reached, the reaction product was cooled under the heat removal conditions of the mold shown in Table 3. These series of operations were performed under a nitrogen atmosphere. The round rod-shaped thick molded product thus obtained was cut at intervals of 100 mm in the height direction, and its cross section was visually observed. The results are shown in Table 3.

The glass transition temperature (Tg) of each molded product
Is 145 to 150 ° C, and the weight loss on heating by the thermobalance method is 2 to 3
%, And it was found that the reaction proceeded sufficiently for all molded products. Furthermore, oxygen pressure 10kg / cm
As a result of measuring the ignition point by differential thermal analysis under high pressure of ² ,
All the molded products showed a value exceeding 120 ° C.

As is clear from Table 3, in the present invention, which is a bulk polymer obtained by cooling while controlling the temperature difference between the center of the reaction product and the temperature of the mold to 80 ° C. or less, the molded product No holes are observed on the cut surface, whereas a large number of holes are generated in the case of the comparative example obtained by quenching after the temperature difference exceeds 80 ° C.

[0069]

[Table 3] * 1: The temperature difference between the center of the reaction liquid (the portion showing the maximum exothermic temperature) and the mold, and the time until the mold is cooled to the glass transition temperature while maintaining the temperature difference. * 2: By the same evaluation method as in Table 1.

Example 4 As a norbornene-based monomer, instead of DCP, 55% of DCP and 45% of cyclopentadiene trimer (a mixture of about 80% of asymmetric trimer and about 20% of symmetrical trimer) were used. A round bar-shaped thick molded product was obtained in the same manner as in Example 3 except that the monomer mixture was used. In addition, the shape of the steel mold has an inner diameter of 100 mm,
It has a height of 800 mm and is equipped with a jacket for flowing steam and cooling water. The round bar-shaped molded product thus obtained was cut at intervals of 100 mm in the height direction, and its cross section was visually observed. The results are shown in Table 4.

The glass transition temperature (Tg) of each molded product
Is 175 to 180 ° C, and the weight loss on heating by the thermobalance method is 2 to 3
%, And it was found that the reaction proceeded sufficiently for all molded products. Furthermore, oxygen pressure 10kg / cm
As a result of measuring the ignition point by differential thermal analysis under high pressure of ² ,
All the molded products showed a value exceeding 120 ° C.

As is clear from Table 4, in the present invention, which is a bulk polymer obtained by cooling while controlling the temperature difference between the center of the reaction product and the temperature of the mold to 80 ° C. or less, the molded product It can be seen that no holes are found on the cut surface, whereas a large number of holes are formed in the case of the comparative example obtained by rapid cooling with a temperature difference exceeding 80 ° C.

[0073]

[Table 4] * 1: The temperature difference between the center of the reaction liquid (the portion showing the maximum exothermic temperature) and the mold, and the time until the mold is cooled to the glass transition temperature while maintaining the temperature difference. * 2: By the same evaluation method as in Table 1.

Example 5 As the norbornene-based monomer, 55% of DCP and 45% of cyclopentadiene trimer (a mixture of about 80% of asymmetric trimer and about 20% of symmetric trimer) were used instead of DCP. Both reaction solutions were prepared in the same manner as in Example 1 except that the monomer mixture was used.

Both reaction solutions kept at 25 ° C. were mixed at a ratio of 1: 1 using a gear pump and a power mixer, and 75 ×
Poured into a steel mold with an internal space of 600 x 600 mm. This steel mold was equipped with a water cooling jacket, and the reaction was performed while maintaining the mold temperature at 40 ° C. by water cooling. The heat generation start time was 200 ° C, and the maximum curing heat generation temperature was 142 ° C. The thick plate thus obtained was cut at intervals of 100 mm and the cross section was visually observed, and no holes were found.

[0076]

According to the present invention, by the RIM method using a polycyclic norbornene-based monomer, it is possible to provide a thick molded product having no pores, small water absorption, light weight and excellent physical properties. it can. Further, according to the present invention, since the RIM method is used, it is economically excellent in that a large-sized thick molded product can be manufactured with an inexpensive mold.

Claims (2)

[Claims] 1. A wall-thin molded product having substantially no pores, which comprises a polycyclic norbornene-based polymer obtained by bulk-polymerizing a norbornene-based monomer having three or more rings in a mold in the presence of a metathesis catalyst system. 2. The thick molded product has a portion having a thickness of at least 20 mm or more, and when cut at intervals of 100 mm, pores having a diameter of 0.1 mm or more are formed in every cross section. The thick-walled molded article according to claim 1, which is substantially absent.