JPH01190420A - Reaction injection molding - Google Patents

Abstract

PURPOSE:To prevent the fault in surface and material properties and the occurrence of underfill caused by air bubbles, by preparing an air vent having a specified interstice in obtaining a curable polymer from metathesis polymerizable monomer under the presence of metathesis polymerizing catalyst by means of reaction injection molding. CONSTITUTION:Metathesis polymerizable monomer is poured into a molding template having an air vent with an interstice of 0.02-0.15mm, or having an air vent where air is trapped in case that no interstice exists, and the molding is performed. Considering the processing precision of the interstice, it is preferable to insert a tapered pin into a tapered hole. As an practical example of metathesis polymerizable monomer, dicyclopentadiene, tricyclopentadiene or others may be used, and as a catalyst content of metathesis polymerizing catalyst, salts such as halide of metal as tungsten, rhenium, etc. are used. In such a way, the air in recessed portions such as boss and rib of the molding template is perfectly removed so that the fault such as underfill does not occur and the productivity is excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to an improved method for obtaining polymerizable molded articles using a metasense polymerizable monomer by reaction injection molding in the presence of a metathesis polymerization catalyst system.

More specifically, when a molded article is obtained by reaction injection molding of a metasense polymerizable monomer in the presence of a metathesis polymerization catalyst system, the ffi of 0.02 or more is 0.15. By pouring the metathesis-polymerizable 7-mer into a mold that has the following slits and forming it in a place where air would be trapped if there were no slits, the air that was present in the mold can be The present invention relates to an improved method for obtaining a cured polymer molded product having excellent appearance and strength and having no defects by preventing it from being taken into the molded product and remaining as bubbles.

b. Prior Art It is known that cyclic olefins can be given ring-opened polymers by metathesis polymerization catalysts. Therefore, a method has been proposed in which a liquid metathesis-polymerizable cyclic olefin such as dicyclopentadiene (DCP) is polymerized and molded in a mold in one step using a metathesis polymerization catalyst system to obtain a polymerized product. Ta. That is, by utilizing the fact that the metathesis polymerization catalyst system consists of two components, a main catalyst component such as tungsten chloride, and an activator component such as an alkyl aluminum, two types of liquids consisting of each of the two components and a sulfuric acid were used. A method of obtaining a cured molded product by reaction injection molding by collisional mixing was proposed, for example, in JP-A-58-1
(See Publication No. 29013).

According to this method, large-sized molded products with good performance can be obtained using inexpensive low-pressure molds, so it can be said to be a very attractive method from an industrial perspective.However, when applied to actual molding, several improvements are required. It has become clear that there are some points.

One of them is that if there is a concave structure such as a boss or a tab on the top surface of the mold, the air existing in this part cannot escape when the metathesis monomer is poured into the mold and becomes trapped in the molded product, forming air bubbles. It will be left behind, or it will be left behind.
Defects such as insufficient filling due to insufficient filling may occur. This can lead to fatal problems such as the surface of the molded product caving in, making it impossible to obtain a flat surface and impairing its aesthetic appearance, deteriorating the physical properties of the air bubbles, or not being able to function as a boss or lip due to lack of thickness. It turns out that it can happen. In order to solve this problem, the concave structure can be improved by changing the shape of the concave structure, such as by making the slope of the concave structure part such as a boss or pipe gentler, or by adding a sub-channel.
However, this method not only limits the shape of the concave structure, but also makes it extremely difficult to completely replace the monomer and air depending on the shape and position. It can be difficult. Another method is to make a hole in the upper part of a concave structure such as a boss or a valve to let air escape, but with this method, the monomer flows into the hole and clogs the hole immediately, or the hole is clogged with monomer outside the hole. Problems such as water blowing out may occur, making it impossible to continue production.

Solving this problem and significantly improving the productivity of molded products,
The present invention was arrived at as a result of intensive research into a method for obtaining molded products with outstanding commercial value that are free from defects in surface and physical properties due to air bubbles and lack of thickness.

Structure of the C0 Invention That is, the present invention involves pouring a metathesis, cis polymerizable monomer into a mold in the presence of a metathesis polymerization catalyst system, and obtaining a cured polymer molded product by reaction injection molding.
Reaction injection characterized in that the metasense polymerizable monomer is poured into a molding mold provided with an air vent having a slit of 0.1 m or more and 0.15 jIl or less in a place where air would be trapped if the slit was not present. It is a molding method.

According to the present invention, it is possible to produce molded products with good productivity without defects in surface properties and physical properties due to air bubbles, and without missing parts.

The present inventor believes that if the air present in the mold when the metasense polymerizable monomer is poured into a mold having a concave structure such as a boss spear on the upper surface of the mold can be easily released to the outside of the mold, the present invention can be achieved. Thinking that the purpose could be achieved, we considered the thickness of the air vent slit and set it to 0.02 am or more, 0.151
It was discovered that by setting a slit of M1 or less, the monomer would not enter the slit and clog it, or flow out, and only air could escape, leading to the present invention. did.

FIG. 2 shows an example of a structure in which a gap is provided on the upper surface of a mold in the present invention. Considering machining accuracy, it is better to bury a tapered bottle in a tapered hole.

As shown in Figure 3, one side of the bottle should be covered with a surface of 0.02 m or more.
．． It is best to use a sand vapor tool or the like to scrape the gap so that it is less than the ``law'' gap.

Any surface material for the mold or mold can be used as long as it is used for RIM molding.

Generally made of steel, copper with nickel or chrome plated surface, aluminum (cut or cast), and kirksite.

Examples include nickel shell molds (electroforming or CVD), metal molds such as tin, and epoxy resin molds.

In one mold, there is no problem even if the capacity side and core side are made of different materials.

The mold temperature is generally raised to allow the curing reaction to occur smoothly. In the case of curing using a metathesis polymerization catalyst system in the present invention, the temperature of the mold is generally 50°C.
The temperature range between 0°C and 0°C is often used.

Specific examples of the metasense polymerizable monomer used in the reaction injection molding method of the present invention include dicyclopentadiene, tricyclopentadiene, cyclopentadiene-medylcyclopentadiene cyta prisoner, 5-ethylidenenorbornene, norbornene, norbornadiene, 5-Schiff0hexenylnorbornene, 1,4,5.8-dimethano-1,
4,4a,5,6,7,8,8a-octahydronaphthalene, 1,4-methano-1,4°4a,5,6,7,8
．． 8a-octahydronaphthalene, 6-ethylidene-
1.4,5.8-dimethano-1,4,4a,5,7゜8
．． 8a-heptahydro-naphthalene, 1,4,5.8-
Dimethano-1,4,4a, 5,8.8a-hexahydronaphthalene, ethylenebis(5-norbornene), etc. can be mentioned. In particular, dicyclopentadiene or a mixture containing 50 mol% or more of dicyclopentadiene is preferably used.

Further, if necessary, a metasense polymerizable monomer having a polar group containing a different element such as oxygen or nitrogen can be used for copolymerization. Such a copolymerizable monomer also preferably has a norbornene structural unit, and the polar group is an ester group.

Ether groups, cyano groups, N-Ef-substituted imide groups, halogens, and the like are preferred. Specific examples of such copolymerizable monomers include 5-methoxycarbonylnorbornene, 5-(2-
ethylhexyloxy)carbonyl-5-methylnorbornene, 5-phenyloxymethylnorbornene, 5-cyanonorbornene, 6-diatu 1.4,5.8-dimethano-1,4,4a, 5,6,7°8. Examples include 8a-octahydronaphthalene, N-butyl±Dick acid imide, and 5-dioxylnorbornene.

As mentioned above, the metasense polymerizable monomer is required to contain as little impurities as possible that would inactivate the metathesis polymerization catalyst system.

In the reaction injection molding method of the present invention, as described above, a seven-mer solution (solution A) containing a catalyst component of a metathesis polymerization catalyst system is used.
and a monomer solution (solution B) containing the active ingredient.
A method is used in which two solutions are mixed and then press-fitted into a mold.

Catalyst components in the metathesis polymerization catalyst system for such molding include tungsten and rhenium.

Salts such as metal halides such as tantalum and molybdenum are used, and tungsten compounds are particularly preferred.

As such a tungsten compound, tungsten halide, tungsten oxyhalide, etc. are preferable, and more specifically, tungsten hexachloride, tungsten oxychloride, etc. are preferable. Furthermore, organic ammonium tungstate and the like can also be used.

Such tungsten compounds are known to immediately start cationic polymerization when added directly to monomers, which is not preferred. Such tungsten compounds can therefore be used in inert solvents such as benzene, toluene.

It is preferable to use it by first suspending it in chlorobenzene or the like and solubilizing it by adding a raw alcoholic compound and/or a phenolic compound.

Further, in order to prevent undesirable polymerization as described above, it is preferable to add about 1 to 5 moles of a Lewis base or a chelating agent per mole of the tungsten compound. Such additives include acetylacetone and acetoacetic acid alkyl esters.

Examples include tetrahydrofuran and benzonitrile. When using a polar monomer, as mentioned above, it is Lewis J3! In some cases, the compound may have the effect without adding any of the above-mentioned compounds.

Thus, the 7mer solution (solution A) containing the catalyst component is
It has sufficient stability for practical use.

On the other hand, the activator component in the metathesis polymerization catalyst system is preferably an organometallic compound mainly consisting of alkylated products of metals from Groups 1 to 2 of the periodic table, particularly tetraalkyltin, alkylaluminum compounds, and alkylaluminum halide compounds. Specific examples include diethylaluminum chloride, ethylaluminum dichloride, trioctylaluminum, dioctylaluminum iodide, and tetrabutyltin. The other solution (corresponding to solution B) is formed by dissolving these organometallic compounds as activator components in a 7-mer solution.

In the present invention, a crosslinked polymer molded article can basically be obtained by mixing the solution A and solution B, but if the above composition remains unchanged, the polymerization reaction will start very quickly, so the molding Hardening may occur before it has sufficiently flowed into the casting mold, which is often a problem, and as mentioned above, it is preferable to use an activity regulator for this purpose.

As such regulators, Lewis bases are generally used, among which ethers, esters, nitriles, etc. are used. Specific examples include ethyl benzoate, butyl ether, diglyme, etc. Such modifiers are generally added to the solution of the activator component of the organo-gold compound. When a monomer having a Lewis space group is used as described above, it can also serve as a regulator.

When using a metathesis polymerization catalyst system, for example, when a tungsten compound is used as a catalyst component, the ratio of the tungsten compound to the raw material monomer is about 1 on a molar basis.
000:1 to 15000:1, preferably 2000:1
In addition, when an alkyl aluminum is used as the activator component, the ratio of the aluminum compound to 1ffi of the above raw material is approximately 100:1 to 1 on a molar basis.
About 2000:1, preferably about 200:1 to about 500:1 is used.

Furthermore, as described above, the masking agent and regulating agent can be appropriately adjusted and used depending on the period of use of the catalyst system through experiments.

The crosslinked polymer molded product obtained by the reaction injection molding method according to the present invention may further contain various additives in order to improve or maintain its properties in practical use. Such additives include fillers, pigments, antioxidants, light stabilizers, flame retardants.

Examples include polymer modifiers. Such additives cannot be added after the crosslinked polymer of the present invention has been molded, so if they are added, they must be added to the above-mentioned raw material solution in advance.

The easiest method is to use the solution A and solution B.
One method is to add it to either or both of the above in advance; however, in this case, it is necessary to add it to either or both of the liquids in advance, but in this case, it does not react with the highly reactive catalyst component or activator component in the liquid to a practical extent, and It must not inhibit polymerization. If the reaction cannot be avoided, but polymerization is not substantially inhibited even if the reaction coexists, the third liquid can be prepared by mixing with the monomer and mixed and used immediately before assembly. In addition, in the case of solid fillers, if the two components are mixed and the shape is such that the voids can be sufficiently filled immediately before starting the polymerization reaction or during polymerization, the filler may be filled into the mold. It is also possible to leave it as is.

Reinforcements or fillers as additives are effective in improving the flexural modulus. Glass I
I1. Examples include mica, carbon black, and wollastonite. Those surface-treated with a so-called silane coupler can also be suitably used.

Further, it is preferable that an antioxidant is added to the crosslinked polymer molded product obtained by the reaction injection molding method of the present invention, and therefore, a phenol-based or amine-based antioxidant may be added to the solution in advance. is desirable. Specific examples of these antioxidants include 2,6-di[-butyl-P-
Cresol, N.

Examples include N'-diphenyl-P-phenylenediamine, tetrakis[methylene(3,5-di-t-butyl-4-hydroxycinnamate)]methane, and the like.

In addition, other polymers, especially in the form of monomer solutions, can be added to the small polymer molded product obtained by the reaction injection molding method according to the present invention. As such polymer additives, the addition of elastomers is effective in increasing the impact resistance of molded products and adjusting the viscosity of the solution. Elastomers used for this purpose include styrene-butadiene-
A wide variety of elastomers can be mentioned, including styrene triblock rubber, styrene-isoprene-styrene triblock rubber, polybutadiene, polyisoprene, butyl rubber, ethylene propylene-diene terpolymer, and nitrile rubber.

In the reaction injection molding method of the present invention, once a polymerization reaction is started in the mold, the temperature of the monomer rapidly rises due to the reaction heat, and the polymerization reaction is completed in a short time.

In addition, when the molded product undergoes metathesis polymerization, double bonds remain, resulting in an oxidized layer on the surface.
Adhesion to commonly used paints such as epoxy and polyurethane is good.

d0 Effects of the Invention According to the present invention, the air existing in the concave structure such as the boss spear of the mold is completely exhausted and does not become trapped in the molded product and remain as air bubbles.

Further, filling of the seven fillers is carried out sufficiently over the details of the recessed portions, and defects such as underfilling do not occur.

Furthermore, troubles such as monomer flowing into the slits and causing the slits to become clogged immediately, or hemotsmer blowing out of the slits, do not occur. As described above, according to the present invention, it is possible to produce molded products with high productivity without defects in surface properties and physical properties due to air bubbles, and without missing parts.

The metathesis polymer molded products obtained by the reaction injection molding method of the present invention are of high quality, free from defects in surface properties and physical properties due to air bubbles, and lack of thickness. Various luck wins including
It can be used for a wide range of purposes, mainly for large molded items such as parts for vessels.

e. Examples The present invention will be explained in detail with reference to Examples below. Note that the examples are for illustrative purposes only, and are not intended to be limiting.

Examples 1-4. Comparative Examples 1 to 2 [Catalyst component solution made by M] 20 parts by weight of tungsten hexachloride was added to 70 parts by volume of dry toluene under a nitrogen stream, and then a solution consisting of 2 parts by weight of nonylphenol and 16 parts by volume of toluene was added. A 0.5M tungsten-containing catalyst solution was prepared as II, and this solution was purged with nitrogen gas overnight to remove hydrogen chloride gas produced by the reaction between tungsten hexachloride and nonylphenol, and the solution was made into a polymerization catalyst solution. did.

A tungsten-containing ffi 0.001M solution A was prepared by mixing 500 volume ω parts of purified dicyclopentadiene with 1 volume part of acetylacetone in 10 volumes of the catalyst solution for unification.

[Active component solution made by WA] Trioctylaluminium and dioctylaluminum iodide were used in a molar ratio of 85:15 and mixed with purified dicyclopentadiene to give 0.003% aluminum.
A solution B of M was prepared.

Using these solutions A and B, molded products were obtained using a reaction injection molding machine manufactured by Niigata Tekkosho Co., Ltd. and the mold shown in FIG.

The mold shown in Figure 1 has a length of 50α x width so, -, Ix thickness of 5.
It has a cavity of m and is made of steel. FIG. 1 shows a top view and a vertical sectional view taken along lines X-X' and Y-Y'. B is the vent, C is the gate and runner.

D indicates a runner. A space (E) for a boss with a diameter of 30 mm and a height of 5 α is made in the center (A) of the core side mold (upper mold) of the molding mold, and a space (E) with a diameter of 1 mm in the upper part is made as shown in Fig. 2.
m x height 5 ctpr tapered hole for air vent (F
), so that a replaceable tapered bottle (G) can be installed in it with a nut (1''), and as shown in Figure 3, one side of G is polished with a sandpaper to remove the gap between G and F (
H) was adjusted.

While replacing G with a predetermined gap, molding was performed and the infiltration of the solution into the boss space was observed.

The mold temperatures on the cavity side and core side were set to 90℃ and 60℃, respectively, and after injecting the solution into the mold, 1
．． After holding for 5 minutes, the mold was removed.

The heights of the bosses of the first and second shot moldings are shown in the table.

In the case of Comparative Example 1, where the gap is 0.201Il1m, the boss space is sufficiently filled with solution in the first shot, but at this time, the solution penetrates into the gap and is partially filled, resulting in the second shot. It became difficult to fill the solution.

When no gap was provided as in Comparative Example 2, the boss space could not be filled with the solution from the first shot.

table

[Brief explanation of the drawing]

FIG. 1 shows the molds used in Examples and Comparative Examples. FIGS. 2 and 3 are detailed views of the air venting gap. Patent applicant Teijin Ltd. 1°)

Claims (7)

[Claims] (1) When a metathesis polymerizable monomer is poured into a mold in the presence of a metathesis polymerization catalyst system and a cured polymer molded article is obtained by reaction injection molding, the thickness of 0.02 mm or more and 0.1
A reaction injection molding method characterized in that a metathesis-polymerizable monomer is poured into a molding mold provided with an air vent having a slit of 5 mm or less in a place where air would be trapped if the slit was not present. (2) Reaction injection molding (RIM) of the surface material of the mold
2. The molding method according to claim 1, wherein a material that is used for commercial purposes is used. (3) The mold is made of steel, copper with a nickel or chrome plating surface, aluminum (cutting or casting), kirksite, nickel shell (electroforming or CVD), tin metal injection mold; The molding method according to claim 1, wherein the mold is at least one mold selected from the group consisting of epoxy resin molds. (4) The metathesis polymerizable monomer is dicyclopentadiene, tricyclopentadiene, cyclopentadiene-
Methylcyclopentadiene codimer, 5-ethylidenenorbornene, norbornene, norbornadiene, 5-cyclohexenylnorbornene, 1,4,5,8-dimethano-1,4,4a,5,6,7,8,8a-octa Hydronaphthalene, 1,4-methano-1,4,4a,5,6
, 7,8,8a-octahydronaphthalene, 6-ethylidene-1,4,5,8-dimethano-1,4,4a,5,
7,8,8a-heptahydro-naphthalene, 1,4,5
, 8-dimethano-1,4,4a,5,8,8a-hexahydronaphthalene, ethylenebis(5-norbornene)
The reaction injection molding method according to claim 1, comprising at least one metathesis polymerizable monomer selected from the group consisting of: (5) The molding method according to claim 1, wherein the catalyst component in the metathesis polymerization catalyst system comprises at least one metal halide selected from the group consisting of tungsten, rhenium, tantalum, and molybdenum. (6) The molding method according to claim 1, wherein the catalyst component in the metathesis polymerization catalyst system comprises at least one catalyst selected from the group consisting of tungsten hexachloride and tungsten oxychloride. (7) The molding method according to claim 1, wherein the activator component in the metathesis polymerization catalyst system comprises at least one type of activator selected from the group consisting of tetraalkyltin, alkylaluminum compounds, and alkylaluminum halide compounds.