JPS63264313A - Reaction injection molding - Google Patents

Abstract

PURPOSE:To prevent sunken parts from developing on the surface of a cured molded product at the show-side surface by a method wherein a fluoroplastic film, which makes surface energy smaller, is formed on a core side surface in order to obtain a molded product. CONSTITUTION:The reaction injection molding concerned is to form a fluoroplastic film on the core side surface in a mold, when a cured polymer molded product is obtained by reaction injection molding by casting metathetically polymerizable monomer in a mold in the presence of metathetically polymerizing catalyst system. By employing the above-mentioned method, even when the difference is small between the temperature of the core side surface and that of a show side surface, almost no sunken part develops on the surface of the cured polymer molded product on its show side surface. Namely, under the notion that shrinkage may be possible to develop only on a surface side, if that side is made as non-tacky as possible, the fluoroplastic film is formed on the core side surface. Actually, the shrinkage occurs exclusively on the core side surface and a surface with no sunken part is easily obtained on the show side surface.

Description

Detailed Description of the Invention: a. Field of Industrial Application The present invention relates to an improved method for obtaining a polymerizable molded product by reaction injection molding a meta-cis polymerizable monomer in the presence of a metathesis polymerization catalyst hair. .

More specifically, when a meta-cis polymerizable monomer is used in the presence of a metathesis polymerization catalyst system to obtain a molded product by reaction injection molding, a thin film of fluororesin that reduces surface energy is formed on the core side surface of the mold. This invention relates to an improved method for preventing depressions from occurring on the surface of a cured molded product on the side surface side.

b. Prior Art It is known that cyclic olefins can be subjected to metathesis polymerization catalysts to give ring-opened polymers. Therefore, a method has been proposed in which a liquid metathesis-polymerizable cyclic A-refin, which can be obtained at low cost such as dicyc[1-pentadiene (DCP), is polymerized and molded in a mold in one step using a metathesis polymerization catalyst system to obtain a synthetic product. It was done. That is, by taking advantage of 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 monomer are used. 116 methods have been proposed for anti-gS injection molding by collisional mixing and curing molded products by the "! method" (for example, JP-A-58
(Refer to Publication No.-129013).

According to this method, a large molded product with good performance can be obtained using an inexpensive low-pressure mold, 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. I knew there were things I needed to do.

One of these problems is the occurrence of depressed areas called ridges or rakes on the surface of the molded product. It has been found that this impairs the aesthetic appearance of the surface of the molded product, which can be a fatal problem depending on the application. The reason why these depressed areas occur is that metathesis-polymerizable monomers always undergo polymerization shrinkage when a cured product is formed through a curing reaction mainly based on metathesis polymerization, so the monomers filled in the mold shrink and become depressed. This situation is inevitable in such polymerization types. In order to reduce the effect of this phenomenon, for example, in the case of polyurethane or unsaturated polyester, foaming or
A method of adding a solid filler such as milled glass has been adopted.

However, in the case of metathesis polymers using DCP or the like as a monomer, they are often used without foaming and with deep filling in order to take full advantage of their good mechanical properties. Therefore, in order to prevent such depressions from occurring on the surface of the mold that is in contact with the show side surface of the mold, which attracts people's attention and is required to be aesthetically pleasing, it is necessary to ensure that all the shrinkage occurs on the surface that originates from the core side surface on the opposite side. method is taken.

As such, a method for causing shrinkage to occur only on one side is to increase the temperature difference between the show side surface and the core side surface of the mold, that is, to make the show side surface high enough to cause solidification to start from that side. There is a way to do it. With this method, the previously hardened surface remains exactly as it is a replica of the mold, and all the shrinkage as a whole is radiated to the unhardened surface.

However, if the temperature difference is increased in this way, molding distortion will remain in the molded product, and when the molded product is exposed to high temperatures during baking surface painting or use, such distortion will be released and the molded product will deteriorate. In other words, from the standpoint of the thermal properties of the obtained molded product, it is desirable that the temperatures on both sides of the mold be as close as possible.

The present invention was achieved as a result of intensive research into a method that resolves this contradiction and prevents the occurrence of depressions on the surface of the cured molded product on the show side side even if the temperature difference between the core side surface and the show side surface is small.

Structure of the C0 Invention That is, the present invention involves pouring a metalthesis 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. This is a reaction injection molding method characterized by forming a thin resin film.

According to the present invention, even if the temperature difference between the core side surface and the show side surface is small, a depressed portion hardly occurs on the surface of the cured molded product on the show side surface side.

The present inventor believes that even if there is no difference in curing speed on both sides of the mold, if it is possible to create a large difference in the surface energy of the surface of the mold, that is, if one side is made as non-adhesive as possible, shrinkage will occur on that side. When we formed a thin fluororesin film on the core side surface, we found that even if we reduced the temperature difference between both sides, the shrinkage escaped to the core side surface. The inventors have discovered that a surface without depressions can be easily obtained, and have arrived at the present invention.
child .

The fluororesin used to form the thin film in the present invention generally has a surface energy of 20 dyn.
Those with a value of e/α or less are preferable (j4) Various types can be used in terms of structure.

An example of this is polytetrafluoroethylene (T).
FE), bozodetrafluoroethylene (FEP)-hexaterolopropylene copolymer.

Poly-tetrafluoroethylene-ethylene copolymer, polychlor!・Contains such as refluoroethylene, polychlorotrifluoroethylene-ethylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, m-(5-perfluoroisopropylphenylene)bis(perfluoroisopropylidene-glycyl ether type epoxy resin) λ9 fats such as fluoropolymers, modified products, blends, and oligomers are used.Furthermore, commercially available fluorinated mold release agents that have the ability to form a durable film can be used as the fluoropolymer in this defense. Wear.

As a method for forming 4 fats from such a fluororesin,
A suitable method can be selected depending on the mold material, mold surface material, properties, type of fluororesin, etc., including coating in the form of an emulsion, solution, etc., drying, high-temperature baking, or room-temperature curing. As for the coating method, in addition to the usual i♂ cloth method, aerosol spray, plasma spray, etc. can be used to uniformly form the A9 film even on curved surfaces.

It is also possible to form a multilayer film.

Furthermore, since fluororesins are generally soft, peeling may occur during repeated use, but in this case, thin films can be repeatedly formed. The thin film to be formed is preferably as thin as durability and processing conditions permit, but generally a thickness in the range of 10 to 0.1 μm is used. In some cases, it may be acceptable to exceed this range.

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

In general! $4 Iron, copper, iron with nickel or chrome plated surface, aluminum (cutting or casting), Kirksai +-'k.

Examples include nickel shell (electroforming or CUO), split metal molds made of tin, epoxy resin molds, etc. With one mold, the show side and core side U Y [
There is no problem even if they are different.

The temperature of the mold 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, JXi! Thirst is generally 50~
110°C, especially the range of 90°C ± 10°C is often used as showside. In order to obtain a molded product surface with no depressions on the show side surface using only a temperature difference on the mold surface, the temperature is generally at least 20°C or higher, preferably 25°C to 40°C, although this varies depending on the shape, size, thickness, etc. of the molded product. A temperature difference is necessary, and if there is such a humidity difference, a large amount of thermal distortion will remain, and if heated as described above, a large amount of thermal deformation will occur.

However, according to the present invention, even with a temperature difference of 20 DEG to 0 DEG C., a surface on the show side side in which almost no depressions such as rakes or dips are observed can be obtained, and the effect is extremely remarkable.

Specific examples of metathesis-polymerizable monomers used in the reaction injection molding method of the present invention include dicyclopentadiene, tricyclopentadiene, cyclopentadiene, methylcyclopentadiene codimer, 5-edylidene norbornene, and norbornene. , norbornadiene, 5-cyclohexenylnorbornene, 1,4,5.8-dimethano-1,
4, 4a, 5. '6,7,8,8゜8a-octahydronaphthalene, 1,4-methano-1゜4.4a, 5,6,
7,8,8.8a -Aphtahydronaphthalene, 6-nitylidene-1.4,5.8-dimethano-1,4,4a
.

5.7,8,8a-hebutahydro-naphthalene, 1,4
, 5.8-dimethano-1,4,4a, 5,8.8a-hexahydronaphthalene, edylenebis(5-norbornene), and the like. In particular, dicyclopentadiene or a mixture containing 50 mol% or more of dicyclopentadiene is preferably used.

Further, if necessary, a metathesis polymerizable monomer having a polar group containing a heterologous group 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 ester I, (.

Needel group, cyano 14. Preferred are N-substituted imide groups, H-IJ groups, and the like. Specific examples of such copolymerizable polymers include 5-methoxycarbonylnorbornene, 5-(2
-ethylhexyloxy)carbonylthylnorbornene,
5-cyanonorbornene, 6-diatu 1,,1,5
．． 8-dimethano-1.4.4a,5,6,7.

Examples include 8,8a-octahydronaphthalene, N-butylnadecimide, and 5-chloronorbornene.

Above) As you can see, the metathesis polymerizable monomer is meta,
Contains impurities that may inactivate the t7cis polymerization catalyst system
It is required that fl be as small as possible.

As mentioned above, the reaction molding method of the present invention uses a 7-mer solution containing the catalyst component of the Meklesis polymerization catalyst system: 41<7f
J solution A) and a monomer solution containing an active inhibitor component (solution B
) and press-fit them into a 1!12 mold for collisional mixing.

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

Salts such as metal halides such as tantalum 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, Kungsten thioxychloride, etc. are preferable. In addition, self-produced ammonium 1 cum tungstate or the like can be used. It is known that when such a tungsten compound is added directly to the upper layer, it immediately starts to form a cation.
Not good. Therefore, it is preferable to use such a tungsten compound by suspending it in advance in an inert solvent such as benzene, toluene, chloro-L1 benzene, etc., and solubilizing it by adding a small amount of an alcoholic compound and/or a phenolic compound.

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

Examples include te]-rahydrofuran, benzonitrile, and the like. When a polar monomer is used, it may itself be a Lewis base, as in (e) above, and may have this effect even without the addition of any of the above compounds.

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

On the other hand, the activation inhibitor component in the Metalipharolysis M catalyst system is an organometallic compound mainly containing alkylated products of metals from Groups 1 to Ⅰ of the periodic table, especially tetraalkyltin, alkylaluminum compounds, and alkylaluminum halide compounds. is preferable, and specific examples include diethylaluminum chloride, ethylaluminum dichloride, trioctylaluminum, dioctylaluminum iotide, and tetrabutyltin. The other solution (corresponding to solution B) is formed by dissolving these organometallic compounds as active inhibitor components in monomers.

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 as it is, 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 hexate benzoate, butyl ether, diglyme, etc. Such regulators are generally added to the solution of the organometallic compound activator component. When a monomer having a Lewis space group is used as described above, it can also serve as a regulator.

The amount of the metathesis polymerization catalyst system to be used is, for example, when a tungsten compound is used as a catalyst component, the ratio of the tungsten compound to the above-mentioned raw material is about 1 on a molar basis.
000:1 to 15000:1, preferably 2000:1
In addition, when argylaluminum is used as the deactivator component, the ratio of the aluminum compound to the raw material monomer is about 100:1 to about 2 on a molar basis.
000:1, preferably around 200:1 to about 500:1.

Further, as described above, the masking agent and the regulating agent can be appropriately adjusted and used depending on the amount of the catalyst system to be used through experiments.

In practical use, various additives can be added to the crosslinked polymer molded product obtained by the reaction injection molding method of the present invention in order to improve or maintain its properties. Such additives include fillers, pigments, antioxidants, light stabilizers, and H-burning agents.

Examples include polymer modifiers. It is impossible to add such additives after the frame [K(U) of the present invention is formed. - The easiest method is to add j3< to either or both of the solution and solution B in advance, but in that case - the highly reactive catalyst component in the liquid, It must not react with other active ingredients to a practical extent and must not inhibit polymerization.
If the reaction is unavoidable but the coexistence of -C does not substantially inhibit polymerization, it can be mixed with the monomer to prepare a third liquid and mixed and used immediately before polymerization. In addition, in the case of a solid filler, when both components are mixed, immediately before starting the polymerization reaction for 1 m, or during the polymerization,
For those with a shape that fully fills the void19,
It is also possible to fill the mold for molding.

Reinforcements or fillers as additives are effective in improving the flexural modulus. Examples of such materials include glass fiber, mica, carbon black, and Alastonite. These materials can also be suitably used after surface treatment with C using a so-called silane gobbler.

In addition, it is preferable to add an antioxidant to the crosslinked polymer molded product produced by the reaction injection molding method of the present invention. In addition, it is desirable that J3<.Specific examples of these antioxidants include 2.6-t-butyl-P-cresol, N.

Examples include N'-diphenyl-P-phenylenediamine, tetrakis[methylene(3,5-di[-butyl-4-hydroxycinname-1.)]methane, and the like.

In addition, other polymers can be added to the polymer-containing molded product produced by the reaction injection molding method according to the present invention when it is in a monomer solution state. 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 a wide range of elastomers, including styrene-butadiene-styrene triblock rubber, styrene-isobrene-styrene triblock rubber, polybutadiene, boron isobrene, butyl rubber, ethylene-butadiene-styrene terpolymer, and nitrile rubber. In the reaction injection molding method according to the present invention, once the polymerization reaction starts in the mold, the temperature of the monomer rapidly rises due to the reaction heat, and the polymerization reaction can be increased in a short time. Complete.

Unlike the case of polyurethane produced by reaction injection molding, shrinkage and depression are concentrated, and in the present invention, not only the core side to which the fluororesin thin film is applied, but also the core side, which is an exact replica of the mold surface, is produced. It is generally easy to remove l111 from the mold even from the surface, and a release agent is not particularly required in many cases.

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

The metathesis polymer molded product produced by the reaction injection molding method of the present invention has very few defects on one surface, is of high quality, has excellent cosmetic properties, has little thermal distortion, and is resistant to thermal deformation. It can be used for a wide range of purposes, including large molded items, such as parts for equipment, electrical and electronic equipment housings, etc.

The present invention will be described in detail below with reference to a practical example. Note that the examples are for illustrative purposes only and are not intended to be limiting.

Example 1 [Preparation of catalyst component solution] Dry 20 pieces of tungsten hexachloride and dry the damaged part with 70 volume M of toluene.
1 part 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 to prepare a solution containing 0.5M tungsten. A medium solution was prepared, and this solution was purged with nitrogen gas overnight to remove hydrogen chloride gas generated by the reaction between tungsten hexachloride and nonylphenol, thereby obtaining a polymerization catalyst solution.

50 parts of purified dicyclopentadiene to 10 parts of such polymerization catalyst solution, 1 part of acetylacetone, 1 part of n,
0 volume φ part 8 mixed with tungsden? r O,OOI
This was called solution A of M.

"Preparation of activator component solution" Trioctylaluminium and dioctylaluminum iodide were used in a molar ratio of 85:15 and mixed with purified dicyclopentadiene to prepare a solution of 0.003% aluminum.
A solution of M was prepared (Na J3, 416 above)
The parts correspond to 1d and 1s, 1M and I Kg).

Using such solutions A and B, a flat plate molding machine (reaction q manufactured by Niigata Tekko Co., Ltd.) (a flat plate molding machine in which the presence or absence of depressions on the surface can be clearly observed and a clear distinction between show side and core side) is applied to a molding machine manufactured by Niigata Tekko Co., Ltd. A mold was used.

The size of the flat plate is 50cm x 50cm, and the thickness is 8mm. Both the show side and the core side are made of steel.The show side of this mold was molded at 90℃ and the core side at 90℃, and the show side and core side were molded. Numerous cracks and rakes appeared on the sides.

Therefore, when a Polyte 1 to Lafluoroethylene (FEP) baking film was formed on the core side surface and molding was performed under the same conditions, the show side had a glossy surface with no whiskers or rake. The core side surface was obtained as a finely soppled surface, but no large sink marks occurred as a whole.

Example 2 Dicyclopentadiene 9 instead of dicyclopentadiene
A plate-like article was obtained using the same strip as in Example 1 except that 5 mol % and 5 mol % of 5-ethylidene norbornene were used.

When both were molded at 90°C, whiskers and rakes appeared on both sides, but in the JJJ case where the FEP coating was baked on the core side surface, a glossy surface with no depressions was obtained on the show side.

Example 3 A fluorine-based film-forming spray mold release agent MR-863 manufactured by Asahi Glass Co., Ltd. was sprayed only on the core side, and a glossy surface with no depressions was obtained on the show side.

Claims (1)

[Claims] A metathesis polymerizable monomer is poured into a mold in the presence of a metathesis polymerization catalyst system, and a cured polymer molded product is obtained by reaction injection molding, and a fluororesin thin film is formed on the core side surface of the mold. reaction injection molding method.