JPH05426A - Manufacture of molded object - Google Patents

Abstract

PURPOSE:To deform a molded object and to make its mold release easy in the manufacture of a deep molded object by the reaction molding method in which the reaction liquid containing norbornane monomer and metathesis catalyst is used. CONSTITUTION:The reaction liquid containing norbornane monomer and metathesis catalyst is poured in the cavity of a mold and is block-polymerized, and a deep molded object is produced. In said producing method, in the state where the molded object is stuck to the core mold provided with an air ejector, the mold is opened and then mold release is advieved by injecting gas from the air ejector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a deep molded article by reaction molding using a norbornene-based monomer.

[0002]

2. Description of the Related Art In recent years, a reaction molding method (RIM, LIM, LIM, LIM, LIM, LIM, LIM Technology development is underway for RTM). The norbornene-based polymer molded product obtained by this method is excellent in heat resistance, dimensional stability, water absorption resistance, and the like, and is characterized by being lightweight.

In reaction molding using a norbornene-based monomer, generally, a reaction liquid (A liquid) containing a monomer and a metathesis catalyst, and a reaction liquid (B liquid containing a monomer and an activator).
Liquid) is mixed in a mixing part such as a mixing head, and then the mixed liquid is injected into a mold and reacted. These operations are usually performed in an inert gas atmosphere.

By the way, in the reaction molding method using a norbornene-based monomer, when the mold is opened and the molded product is taken out and the molded product is left adhered to the core mold, shrinkage due to cooling of the polymer (molded product) occurs. For this reason, it becomes difficult to remove the mold, so that a method of leaving the mold in the cavity mold is generally adopted. However, deep-formed parts (for example,
In the case of a molded product having a depth of 50 cm or more and a diameter of 50 cm or more), it is difficult to uniformly remove the mold if left in the cavity mold, and if the mold is forcibly removed, the molded product will be deformed and a satisfactory product will be obtained. I won't. Even if an air ejector is installed in the cavity type and you try to demold with compressed air,
Due to the shrinkage of the molded product, a gap is created between the cavity mold and the molded product, and air is released, which does not function effectively.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to deform a molded product when producing a molded product having a deep depth by a reaction molding method using a reaction liquid containing a norbornene-based monomer and a metathesis catalyst system. It is an object of the present invention to provide a method for producing a molded product that is easy to remove from the mold.

As a result of intensive studies to overcome the problems of the prior art, the inventors of the present invention injected a reaction liquid containing a norbornene-based monomer and a metathesis catalyst system into the cavity of a mold to carry out bulk polymerization. When manufacturing a deep-molded product, provide an air ejector on the core mold, open the mold with the molded product attached to the core mold, and then eject gas from the air ejector to release the mold. Due to
The present invention has been completed based on the finding that the molded product can be easily demolded without being deformed.

[0007]

Thus, according to the present invention, a reaction liquid containing a norbornene-based monomer and a metathesis catalyst system is injected into a cavity of a mold having a core mold and a cavity mold, and bulk polymerization is performed to deepen the mixture. In a method for producing a deep molded product, the mold is opened in a state where the molded product is attached to a core mold equipped with an air ejector, and then a gas is ejected from the air ejector to release the mold. A method for manufacturing a molded article is provided.

The present invention will be described in detail below. (Reaction Liquid) In the present invention, a reaction liquid containing a norbornene-based monomer and a metathesis catalyst system is used.

Norbornene-based Monomer The norbornene-based monomer used in the present invention may be any one having a norbornene ring, but when a polycyclic norbornene-based monomer having a tricyclic or higher ring is used, a polymer having a high heat distortion temperature can be obtained. can get. Further, in order to make the resulting ring-opening polymer a thermosetting type, at least 10% by weight, preferably 30% by weight or more of the total monomers may be used as the crosslinkable monomer.

Specific examples of the norbornene-based monomer include bicyclic compounds such as norbornene and norbornadiene, tricyclic compounds such as dicyclopentadiene and dihydrodicyclopentadiene, tetracyclic compounds such as tetracyclododecene, tricyclopentadiene and the like. Pentacycles, heptacycles such as tetracyclopentadiene, and their alkyl-substituted products (for example, methyl,
Ethyl, propyl, butyl substitution, etc.), alkenyl substitution (eg, vinyl substitution), alkylidene substitution (eg, ethylidene substitution, etc.), aryl substitution (eg, phenyl, tolyl, naphthyl substitution, etc.),
Examples thereof include substituents having a polar group such as an ester group, an ether group, a cyano group, and a halogen atom. These monomers may be used alone or in combination. Among them, tricyclic or pentacyclic compounds are favored from the viewpoint of availability, reactivity, heat resistance and the like.

The crosslinkable monomer has two reactive double bonds.
It is a polycyclic norbornene-based monomer having two or more thereof, and specific examples thereof include dicyclopentadiene, tricyclopentadiene, tetracyclopentadiene and the like.
When the norbornene-based monomer and the crosslinkable monomer are the same, it is not necessary to use any other crosslinkable monomer.

It should be noted that monocyclic cycloolefins such as cyclobutene, cyclopentene, cyclopentadiene, cyclooctene, and cyclododecene, which are capable of ring-opening polymerization with one or more of the above norbornene-based monomers, are used together within the range not impairing the object of the present invention. be able to.

Metathesis Catalyst System In the present invention, a metathesis catalyst system comprising a known metathesis catalyst and an activator can be used as a catalyst for ring-opening polymerization of norbornene-based monomers. Specific examples of the metathesis catalyst include halides such as tungsten, molybdenum and tantalum, oxyhalides, oxides and organic ammonium salts. Specific examples of the activator (cocatalyst) include alkylaluminum halides, alkoxyalkylaluminum halides, aryloxyalkylaluminum halides, and organic tin compounds.

The metathesis catalyst is usually used in an amount of about 0.01 to 50 mmol, based on 1 mol of the norbornene-based monomer.
It is preferably used in the range of 0.1 to 20 mmol.
The activator is preferably 1 relative to the metathesis catalyst component.
It is used in the range of 10 to 10 (molar ratio). Both the metathesis catalyst and the activator are preferably used by dissolving them in the monomer, but they may be used by suspending or dissolving them in a small amount of solvent as long as the properties of the product are not substantially impaired.

The norbornene-based polymer may be blended with additives such as an antioxidant, a filler, a reinforcing material, a pigment, a coloring agent and an elastomer. These additives are
It is dissolved or dispersed in the reaction solution and blended, but it may be disposed in a mold in some cases.

As the elastomer to be added to the reaction solution,
For example, natural rubber, polybutadiene, polyisoprene,
Styrene-butadiene copolymer (SBR), styrene-
Butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), ethylene-propylene-diene terpolymer (EPD)
M), ethylene-vinyl acetate copolymer (EVA), and hydrides thereof. When these elastomers are added to the reaction liquid, not only impact resistance is given to the obtained polymer, but also the viscosity of the reaction liquid can be adjusted.

(Bulk Polymerization) In a preferable method for producing a norbornene-based polymer, generally, a norbornene-based monomer is divided into two liquids and placed in another container, a metathesis catalyst is added to one of the two liquids, and an activator is added to the other. Prepare a stable reaction of the type. The two kinds of reaction liquids are mixed and then poured into a mold having a predetermined shape, where ring-opening polymerization is performed in a bulk form.

In the present invention, reaction injection (RI
M) A collision mixing device known as a molding device can be used for mixing two types of reaction stock solutions. In this case, the containers containing the two types of reaction stock solutions serve as separate flow sources. The two streams are mixed instantaneously with the mixing head of a RIM machine and then injected into a mold where they are immediately bulk polymerized to give a molding.

In addition to the impingement mixer, a low pressure injector such as a dynamic mixer or a static mixer can be used. When the pot life at room temperature is as long as 1 hour, it may be injected or injected into the preheated mold several times after the mixing of the two reaction solutions in the mixer is completed. , May be continuously injected. In the case of this method, the device can be downsized as compared with the impingement mixing device, and in addition to having the advantage that it can be operated at low pressure, when the filling amount of the filler such as glass fiber is large, By slowing down the speed, it becomes possible to uniformly impregnate the reaction solution into the system.

Further, the present invention is not limited to the method using two kinds of reaction stock solutions. As will be readily appreciated by those skilled in the art, various modifications are possible, such as, for example, putting the monomer and the desired additive in the third container and using it as the third stream. The reaction liquid is usually stored and operated under an atmosphere of an inert gas such as nitrogen gas.

The mold temperature is usually room temperature or higher, preferably 40 to 200 ° C, particularly preferably 50 to 130 ° C. The components used in the polymerization reaction are preferably stored and manipulated under an atmosphere of an inert gas such as nitrogen gas.
The polymerization time is usually shorter than 20 minutes, preferably within 5 minutes.

(Reaction Molding Mold) In the present invention, a mold having a core mold and a cavity mold is used, and the reaction solution is injected into the cavity (cavity) to perform bulk polymerization.

The molded article targeted by the present invention is a deep molded article having a depth of 50 cm or more as shown in FIG. 1, and the core mold and the cavity mold are such molded articles. It is created so as to form a void that matches the shape. FIG. 2 is a partial cross-sectional view of a reaction molding die used in the present invention.

The mold used in the present invention has a split mold structure and is composed of a core mold 1 and a cavity mold 2. When the mold is completely tightened, a void 3 is formed to form a molded product. . The core mold and the cavity mold are sealed by the sealing material inserted in the seal groove 4.

The core type is provided with an air ejector. The air ejector is configured to inject gas from a gas source 5 such as compressed air, through a valve, and through an air line 6 in the core mold from an opening portion at a predetermined position on the surface of the core mold. The position and number of openings for gas injection can be appropriately determined according to the structure of the mold, the size of the molded product, etc., but as shown in FIG. In general, it is desirable to arrange at about 2 to 6 places so that the injection pressure is evenly applied.

When the molded product has no bottom, it is effective to provide a pressure holding member 9 at the bottom of the molded product so as not to release gas pressure, as shown in FIG.
This portion is a portion to be removed after molding, and it is desirable to make it as thin as possible within the range where the gas pressure can be maintained.

In order to prevent clogging due to invasion of the reaction liquid, the opening of the core type gas jet is sealed by a seal member 7 as shown in FIG. 3, for example. As the seal member, an aluminum tape or the like that can be easily peeled off by injection of gas at the time of demolding is used. The opening is not limited to the shape of sealing with a sealing member,
A check valve may be used, a filter having a pore size such that the reaction solution does not enter, or a capillary tube may be used.

The size of the diameter of the air line is not particularly limited, but should be such that the pressure necessary for releasing the molded product can be secured. However, if the diameter is too large, the reaction liquid may intrude into the air line due to the pressure at the time of injection of the reaction liquid.
It is set to 0 mm, preferably about 2 to 5 mm.

The gas pressure is set to a pressure at which the molded product can be released from the mold, but it may be appropriately set according to the shape, size, etc. of the molded product.

The shape, material and size of the mold are not particularly limited. Since a low-viscosity reaction liquid is used, not only a metal-made reaction liquid but also a synthetic liquid made of various materials such as various synthetic resins and low-melting point alloys can be used.

(Manufacturing Method of Molded Article) In the present invention,
The reaction liquid containing the norbornene-based monomer and the metathesis catalyst system is injected into the cavity of the mold, and the molded product obtained by bulk polymerization is attached to a core mold equipped with an air ejector to open the mold.

The adhesion of the molded product to the core mold is usually carried out by controlling the molding conditions. In reaction molding using a norbornene-based monomer, the higher the mold temperature or the longer the curing time, the higher the possibility that a deep-molded product adheres to the core mold.

A reaction liquid containing a norbornene-based monomer and a metathesis catalyst system immediately starts a bulk polymerization reaction when injected into a mold and is cured. The polymerization reaction is exothermic,
The temperature of the molded product in the mold gradually decreases as the curing time (curing time) increases.

When the curing time is short, when the mold is opened, the molded product remains attached to the cavity mold. As the curing time increases, the molded product cools and shrinks, so that it adheres to the core mold. However, even if it adheres to the core mold, if the curing time is too long, the shrinkage of the molded product due to cooling has progressed to a considerable extent, so the adhesion force to the core mold becomes too strong, and the gas from the air ejector is removed. It is extremely difficult or impossible to remove the mold even if it is jetted. On the other hand, even if the molded product is adhered to the core mold, if the molded product is soft in a high temperature state, the molded product may be deformed by the injection pressure of gas from the air ejector.

In order to attach the molded product to the core mold and to remove the molded product without causing deformation, the mold is molded when the temperature of the molded product in the mold falls near the heat distortion temperature (HDT) of the polymer. It is preferable to open the mold and inject gas from the air ejector to remove the mold. The temperature near the heat distortion temperature is usually when the temperature of the molded product in the mold is in the range of HDT ± 15 ° C., preferably HDT ± 10 ° C.

The temperature of the molded product in the mold can be estimated by the cure time by previously examining the relationship between the cure time and the temperature of the molded product. If the cure time is sufficient to adhere the molded product to the core mold, open the mold and allow the molded product to adhere to the core mold to cool to near the heat distortion temperature, then A mold may be released by injecting gas from the air ejector.

By the way, if the molded product is released from the mold near the heat distortion temperature of the polymer, it may shrink due to subsequent cooling, and the dimension of the molded product may not be stable. To solve this problem, it is effective to use a dimension holding jig having a shape that fits into the opening of the molded product.

For example, in the case of a molded product as shown in FIG. 1 (inner diameter of opening is 600 mm), dimensional accuracy of the upper circular opening is required. Therefore, the circular jig shown in FIG. 5 is molded. Dimensional stability is improved by cooling with the product fitted in the opening. There is no particular limitation on the material of such a dimension holding jig, and the dimension can be appropriately determined. However, since some shrinkage often occurs even after removing the dimension jig, the opening of the molded product It is preferable to make the size slightly larger than the size. The cooling time of the molded product after demolding requires a time for the internal temperature of the molded product to drop sufficiently, and varies depending on the thickness of the molded product.

[0039]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below. In the following examples, parts and% are based on weight unless otherwise specified.

[Example 1] (Preparation of reaction solution) Dicyclopentadiene (DCP) and asymmetric tricyclopentadiene (TCP) containing 2% of a phenolic antioxidant (manufactured by Ciba-Geigy, trade name Irganox 259). Monomer mixture with (DCP /
TCP = 85/15) was put in two containers, and for one of the monomers, diethyl aluminum chloride (DE) was added.
AC) at 33 mM and n-propanol at 34.
6 millimolar concentration and silicon tetrachloride were added so as to have a 20 millimolar concentration. On the other hand, tri (tridecyl) ammonium molybdate was added to the monomer so as to have a concentration of 4 mmol. The pot life of the reaction solution was 1 minute at 25 ° C.

(Manufacture of Molded Product) A molded product having a deep shape as shown in FIG. 1 (upper opening inner diameter 600 mmφ, height 70)
0mm, bottom inner diameter 500mmφ, wall thickness 6mm, weight about 1
0 kg) was manufactured using a mold having a core mold equipped with the air ejector shown in FIG. 2 at four places.

Both the cavity mold and the core mold are made of aluminum, and the shape of the cavity is the same as the shape of the molded product. The reaction solution was mixed with a gear pump and a power mixer at a ratio of 1: 1 to form a cavity mold 70.
The core was injected into the mold heated to 50 ° C. from the injection port. The bulk polymerization time was about 20 seconds.

As shown in Table 1, the curing time (the time from the injection of the reaction solution into the mold to the opening of the mold) was variously changed to change the molding product into a cavity mold or a core mold. The state of adhesion and the temperature of the molded product at that time were examined. As is clear from Table 1, when the curing time is short, the molded product adheres to the cavity mold, but as the curing time becomes longer and the temperature of the molded product decreases, the core mold starts from a certain point. To adhere to.

When the demolding time (the time from the opening of the mold to the removal of the molded product from the mold) was examined, it took about 20 to 40 minutes when it was attached to the cavity mold, and the molding was performed. The product was deformed by the demolding operation.

When the temperature of the molded product was lowered to 105 to 130 ° C., it adhered to the core mold and could be easily demolded by the injection of compressed air (pressure 5 kg / cm ² G). However, when the temperature of the molded product decreased to 100 ° C., the molded product contracted due to cooling and the adhesion to the core mold became too high, so that the mold could not be released. Heat distortion temperature of this polymer (JIS K7207-
1983), since the temperature of the molded product is lowered to around 120 ° C., the mold is opened, gas is ejected from the air ejector to release from the core mold, the molded product is not deformed, Can be easily demolded.

[0046]

[Table 1]

Example 2 In Example 1, the curing time was set to 180 seconds (molding product temperature 120 ° C.), the molded product was released from the core mold, and then the dimension holding jig (cooling jig) shown in FIG. 5 was used. ) Was cooled while it was fitted in the opening of the molded product with the opening facing down. For reference, the molded article was similarly cooled without using the dimension holding jig. Table 2 shows the number of each data, the average value of the diameter of the molded product, and σ _n-1 (standard deviation).

[0048]

[Table 2] (* 1) However, none is shorter than the standard (598 to 602 mm).

As is clear from Table 2, when the molded product is removed from the core mold and then the dimension holding jig is fitted and cooled,
It can be seen that the dimensional accuracy of the molded product increases.

[0050]

According to the present invention, when a deep molded article is manufactured by a reaction molding method using a reaction liquid containing a norbornene-based monomer and a metathesis catalyst system, the molded article does not deform, and Provided is a method for manufacturing a molded product that can be easily demolded.

[Brief description of drawings]

FIG. 1 is a schematic view showing the shape of one embodiment of a deep-formed product.

FIG. 2 is a partial cross-sectional view of a mold having a core mold provided with an air ejector.

FIG. 3 is a partially enlarged sectional view of a core type.

FIG. 4 is a schematic view showing a pressure holding member at the bottom of a molded product.

FIG. 5 is an external view showing one embodiment of a dimension holding jig.

[Explanation of sign]

1 core type 2 cavity type 3 void 4 seal groove 5 Compressed gas source 6 Air ejector line 7 Seal member 8 Liquid reservoir 9 Pressure holding member

Claims (2)

[Claims] 1. A method for producing a deep-molded article by injecting a reaction solution containing a norbornene-based monomer and a metathesis catalyst system into a cavity of a mold having a core mold and a cavity mold to perform bulk polymerization, A method for producing a molded product, comprising: opening a mold in a state where the molded product is attached to a core mold equipped with an air ejector, and then ejecting a gas from the air ejector to release the molded product. 2. The method according to claim 1, wherein after the molded product is released from the core mold, cooling is performed with a dimension holding jig having a shape fitting into the opening of the molded product fitted in the opening of the molded product. Molded article manufacturing method.