JP3511809B2 - Method for producing norbornene resin molded article - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a norbornene-based resin molded product, and more particularly to a method for producing a norbornene-based resin molded product without causing internal strain or cracking on the surface. And a method for producing a norbornene-based resin molded product having good form stability. [0002] A method of obtaining a molded product by reaction injection molding (RIM) of a norbornene-based monomer such as dicyclopentadiene or methyltetracyclododecene, that is, by ring-opening bulk polymerization in a mold. Is well known. When performing polymerization in a mold by RIM, if the polymerization proceeds to some extent, the polymerization rate is extremely reduced, or it takes a very long time to complete the polymerization. In such a case, if the molded article is taken out before the curing by polymerization is completely completed, stress is generated inside the molded article, which may cause distortion or cracks on the surface. In order to avoid such inconveniences, there is known a method in which after the reaction has progressed to a certain extent, the entire mold is heated and sufficiently cured, and then a molded product is removed from the mold. However, in this method, the production efficiency is reduced because the mold is used for a long time in one molding cycle. [0003] When the mold is cured to a certain extent in the mold and then cooled to such a degree that the mold can be removed from the mold, a molded article having a portion having a different thickness or an insert having good heat conductivity such as metal is included. In a molded product, a temperature difference is generated depending on the part of the molded product, and the degree of cooling shrinkage is different, and also in a molded product including an insert having a smaller linear expansion coefficient than a resin such as a metal, the temperature difference is reduced. Even without this, the degree of shrinkage is different, so stress occurs inside the molded product, causing distortion,
The surface may crack. [0004] The object of the present invention is to provide an RI
An object of the present invention is to provide a method for producing a norbornene-based resin molded product by using M, which can produce a molded product having good form stability and appearance without lowering production efficiency while avoiding generation of distortion and cracks. According to the present invention, in a method for producing a norbornene-based resin molded article by bulk-polymerizing a norbornene-based monomer in a mold, the polymerization is substantially completed. The molded product removed from the mold is immediately heated to a temperature of 80-2.
A method for producing a norbornene-based resin molded article, characterized in that the method is held at 00 ° C. for 1 hour or more and then gradually cooled at a rate of 5 to 30 ° C./hour. DETAILED DESCRIPTION OF THE INVENTION In the production method of the present invention, bulk polymerization of a norbornene-based monomer in a mold can be carried out by a conventional method. The norbornene-based monomer used in the present invention is not particularly limited as long as it has a norbornene ring, but since a molded article having excellent heat resistance is obtained, a tricyclic or higher polycyclic norbornene-based monomer is obtained. It is preferable to use As the norbornene-based monomer, for example,
Bicyclics such as norbornene and norbornadiene; tricyclics such as dicyclopentadiene and dihydrodicyclopentadiene; tetracyclics such as tetracyclododecene; pentacyclics such as cyclopentadiene trimer; Ring; alkyl such as methyl, ethyl, propyl, butyl, alkenyl such as vinyl;
Substituents such as alkylidene such as ethylidene, aryl such as phenyl, tolyl, and naphthyl; further having a group containing an element other than carbon and hydrogen such as an ester group, an ether group, a cyano group, and a halogen atom, a so-called polar group Substitutes and the like. These monomers are used alone or in combination of two or more. Tricyclic, tetracyclic, and pentacyclic monomers are preferred from the viewpoint of easy availability, excellent reactivity, and excellent heat resistance of the obtained resin molded product. The norbornene-based resin molded product is preferably of a thermosetting type. For this purpose, at least 10% by weight, preferably at least 30% by weight of a monomer to be used is used in combination with a crosslinkable monomer. Is desirable. The crosslinkable monomer is a polycyclic norbornene monomer having two or more reactive double bonds, and specific examples thereof include dicyclopentadiene,
Cyclopentadiene trimer, tetracyclopentadiene and the like can be mentioned. In addition, a monocyclic cycloolefin such as cyclobutene, cyclopentene, cyclopentadiene, cyclooctene and cyclododecene, which can be ring-opened copolymerized with a norbornene-based monomer, may be used as the comonomer within a range not to impair the object of the present invention. (Metathesis Catalyst) In the method for producing a norbornene-based resin molded article of the present invention, the catalyst used for polymerizing the norbornene-based monomer is a metathesis catalyst. The metathesis catalyst is not particularly limited as long as it allows ring-opening polymerization of the norbornene-based monomer by bulk polymerization, and may be a known one. Examples thereof include halides such as tungsten, molybdenum, and tantalum, oxyhalides, oxides, and organic ammonium salts. The amount of the metathesis catalyst to be used is usually 0.01 mmol or more, preferably 0.1 mmol or more, and 50 mmol or less, preferably 20 mmol, per 1 mol of the monomers used in the entire polymerization reaction solution. It is as follows. If the amount of the metathesis catalyst used is too small, the polymerization activity is too low and the reaction takes a long time, resulting in poor production efficiency. Conversely, if the amount used is too large, the reaction is too vigorous and the reaction is not sufficiently filled in the mold. , And the catalyst is likely to precipitate, making it difficult to store homogeneously. The metathesis catalyst is usually used by dissolving it in a monomer.However, as long as the properties of the bulk polymerized resin molded article are not substantially impaired, the suspension is dissolved and dissolved in a small amount of a solvent. By mixing with the monomer, precipitation may be suppressed, or solubility may be enhanced. (Activator and activity regulator) In the production of a norbornene-based resin molded product, bulk polymerization is usually carried out using an activator, also called a metathesis cocatalyst, together with a metathesis catalyst. The activator is not particularly limited as long as it can activate a metathesis catalyst capable of ring-opening polymerization of a norbornene monomer by bulk polymerization, and may be a known one. For example,
Examples thereof include alkyl aluminum, alkyl aluminum halide, alkoxyalkyl aluminum halide, aryloxyalkyl aluminum halide, and organotin compounds. These activators may be used alone or in combination of two or more. The amount of the activator used is not particularly limited.
Usually, 0.1 mol or more, preferably 1 mol or more, and 1 mol per 1 mol of the metathesis catalyst used in the whole reaction solution.
It is at most 00 mol, preferably at most 10 mol. However,
If the activator is not used, or if the amount used is too small, the polymerization activity is too low and the reaction takes a long time, resulting in poor production efficiency. Conversely, if the amount is too large, the reaction of the polymerization reaction solution starts up quickly, and the object of the present invention may not be achieved in some cases. The activator is usually used by dissolving it in a monomer,
After suspending or dissolving in a small amount of a solvent, as long as the properties of the molded article by the bulk polymerization are not essentially impaired,
By mixing with a monomer, precipitation may be difficult, or solubility may be increased before use. In the present invention, generally, an activity regulator is used in combination with the above-mentioned active agent. The use of an activity regulator can change the reaction rate, the time from the mixing of the reaction solution to the start of the reaction, the reaction activity, and the like. As the activity regulator, a compound having an action of reducing the metathesis catalyst is used, and as the activity regulator, alcohols, haloalcohols, esters, ethers and the like are exemplified. Specific examples of alcohols include n-propanol, n-butanol, n-hexanol, 2-butanol, isobutyl alcohol, isopropyl alcohol, t-butyl alcohol, and the like. Specific examples of halo alcohols include 1, 3-Dichloro-2-propanol, 2-chloroethanol, 1-chlorobutanol and the like can be mentioned. The amount of the activity modifier varies depending on the compound used and is not uniform. For example, in the case of alcohols and haloalcohols, the molar ratio of the activity modifier / activator is 1.0 or more, preferably 1.1. that's all,
And it is 1.5 or less, preferably 1.4 or less. If the amount of the activity modifier is too small, the reaction is too fast. Conversely, if the amount is too large, the reaction is too slow even when heated, resulting in poor molding efficiency. (Optional components) If desired, antioxidants, fillers, pigments, coloring agents, foaming agents, sliding agents, flame retardants,
Various additives, such as combustibles, inorganic halides, elastomers, dicyclopentadiene-based thermopolymerized resins and their hydrogenated products, can be blended into the molding stock solution to improve the properties of the resulting RIM products. be able to. As the antioxidant, various antioxidants for plastics and rubbers such as phenolic, phosphorous, and amine are used. As the filler, inorganic fillers such as glass, carbon black, talc, calcium carbonate, and mica are used. Agent is used. Particularly, in order to obtain a molded article having high mechanical strength, a fiber reinforcing material can be filled in a mold in advance, and then a polymerization reaction solution can be poured into the mold and cured. As the fiber reinforcement, those having good mechanical strength and heat resistance are used. Specific examples thereof include inorganic fibers such as glass fiber, carbon fiber, silicon carbide fiber, steel fiber and amorphous metal fiber, and aramid fiber. And organic fibers such as ultrahigh molecular weight polyethylene.
The fibers may be either long fibers or short fibers, but long fibers are more preferable. The form of the fiber is not particularly limited.
Any of woven fabric, knitted fabric, continuous strand mat, filament winding and the like may be used. However, a continuous glass strand mat is most preferable because the polymerization reaction liquid easily permeates and has high strength. The filling amount of the fiber reinforcing material is usually 20% by weight, preferably 25% by weight or more, more preferably 30% by weight or more, and 50% by weight or less, preferably 45% by weight or less, more preferably 40% by weight of the resin weight. % Or less. If the filling amount is small, the ratio of the mechanical strength is small. If the filling amount is too large, uneven filling may occur without uniform filling or polymerization inhibition may occur. Further, an elastomer may be added to the reaction solution for the purpose of adjusting the viscosity of the reaction solution. Examples of the elastomer used include natural rubber, polybutadiene, polyisoprene, styrene-butadiene copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene copolymer, and ethylene-propylene-diene copolymer. Diene elastomers, ethylene-vinyl acetate copolymers, and hydrides thereof. By adding these elastomers to the reaction stock solution, the impact resistance of the resulting molded article is improved. The amount of the elastomer added is such that the viscosity of the reaction stock solution is 5 cp.
s or more, preferably 50 cps or more, and 1000 cp
s or less, preferably 500 cps or less. These additives may be mixed in advance with one or both of the reaction stock solutions, or may be placed in a cavity of a mold. (Polymerization reaction solution) As a reaction stock solution used in the production of norbornene-based resin molded products, a norbornene-based monomer, a metathesis catalyst, an activator, an activity regulator and optional components are prepared by dividing into two or more solutions. Is used. These reaction stock solutions do not undergo bulk polymerization with only one solution, but when all the solutions are mixed, each component has a predetermined ratio,
The norbornene-based monomer undergoes bulk polymerization. For example, a reaction stock solution comprising a norbornene-based monomer, a metathesis catalyst and an optional component and a reaction stock solution comprising a norbornene-based monomer, an activator, an activity regulator and an optional component do not polymerize as they are. If the total amount of each component contained in the two liquids is the amount of each component used in the present invention, these two liquids are the reaction stock solutions used in the present invention, respectively, and when both are mixed, bulk polymerization is started. For the sake of good workability, bulk polymerization is usually carried out using two reaction stock solutions, but three or more reaction stock solutions may be used. In order to allow other components to sufficiently diffuse into the norbornene-based monomer after mixing of the reaction stock solution, usually, any reaction stock solution contains a norbornene-based monomer. It is preferable that the reaction solution is dissolved or dispersed in the monomer, but a reaction stock solution containing no norbornene-based monomer may be used.
In addition, when the three components of the norbornene-based monomer, the metathesis catalyst, and the activator are contained in one reaction solution, the bulk polymerization starts, so that the metathesis catalyst and the activator are not usually contained in one reaction solution. . The reaction stock solution is usually preferably prepared, stored, and transferred under an atmosphere of an inert gas such as nitrogen gas for the purpose of preventing deactivation of the metathesis catalyst and the like. (Bulk Polymerization) In the production of a norbornene-based resin molded product, a polymerization reaction liquid mixed with a reaction stock solution is cured. Generally, if necessary, a mold is filled with a fiber reinforcing material in advance, and then two or more reaction stock solutions are instantaneously mixed using a mixing head or the like, and immediately, the mixed polymerization reaction solution is immediately mixed. Is injected into a mold, heated to initiate bulk polymerization, and cured. The mold used here is not limited to a metal mold, and may be a glass mold, a wooden mold, or a resin mold. In addition,
In the bulk polymerization step, in order to avoid a problem such as deactivation of the catalyst, it is preferable to make the inside of the mold an inert atmosphere by purging an inert gas such as a nitrogen gas. In the present invention, after pouring the reaction solution into the mold, the bulk polymerization is started without heating or by heating. When using a bulk polymerization reaction solution in which the reaction rises slowly, it is preferable to heat the mold. If the heating temperature is too low, it takes a long time to cure. On the other hand, if the heating temperature is too high, not only energy loss is large, but also reaction may run away and carbonization may occur. Generally, the heating temperature is 5
0-100 degreeC is preferable and 70-90 degreeC is especially preferable. In the present invention, when the polymerization is substantially completed, the molded article is taken out of the mold and immediately held for a predetermined time in a heated atmosphere. “Substantially complete polymerization” means that the polymerization and curing have progressed to such an extent that no deformation occurs when the molded product taken out of the mold is immediately placed in a high-temperature atmosphere according to the method of the present invention. Point to. The molded product removed from the mold is immediately
It is kept in an atmosphere heated to 200 ° C., preferably 100 to 160 ° C. for 1 hour or more, preferably 1.5 to 3 hours. If the temperature and / or time is insufficient, stress is generated inside the molded product, which may cause distortion or cracks on the surface. If the temperature is too high, internal stress is also generated, which may cause distortion or cracks, and heat consumption is large, which is not economically advantageous. It is not advantageous that the time is too long. The above-mentioned high-temperature holding may be carried out in the atmosphere or in an inert gas atmosphere, but it is easier to carry out in the atmosphere. After the above high temperature holding, the molded product is 5 to 30
C./hour, preferably at a rate of 10 to 20.degree. C./hour. Usually, the slow cooling is performed until the temperature of the molded article reaches 35 ° C. to room temperature. The generation of internal stress is completely prevented by the slow cooling, and a molded product without any distortion can be obtained. Cooling rate is 30
When the temperature exceeds ℃ / hour, internal stress is easily generated, and when the cooling rate is too low, the standing time is too long, which is not industrially advantageous. EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Parts and percentages are by weight unless otherwise specified. Reference Example 1 Ten glass mats (M9600, manufactured by Asahi Fiberglass Co., Ltd.) cut into 500 mm × 500 mm were set in the cavity of a 500 mm × 500 mm × 50 mm plate-forming mold, and 480 mm × 480mm × 3
A 0 mm aluminum insert was placed, and 10 glass mats were further set. On the other hand, 3% of vinyl norbornene is added to a norbornene-based monomer composed of 90% of dicyclopentadiene (DCP) and 10% of a cyclopentadiene trimer (asymmetric trimer), and divided into two containers. On the other hand, diethyl aluminum chloride (DEAC) was added so as to have a 40 molar concentration and 1,3-dichloro-2-propanol (dCPrOH) 48 mmol concentration (Solution A). On the other hand, tri (tridecyl) ammonium molybdate was added to the monomer at a concentration of 10 mmol (Solution B). The same volume of Solution A and Solution B are mixed and injected into the gap between the mold and the insert by a reaction injection molding machine, and after the reaction liquid is completely filled, hot water is supplied to a temperature control pipe penetrating into the mold. Thus, the temperature of the mold was raised to about 80 ° C., and curing was performed for about 5 minutes. Thereafter, when the molded article was taken out of the mold and left to stand, the reaction was not sufficiently completed, and the surface of the molded article was in a soft rubber state. Example 1 Immediately after the molded article was taken out of the mold, the molded article was immediately stored in an oven set at 150 ° C. in advance. Then, after a lapse of 2 hours, molding was performed in the same manner as in Reference Example except that the temperature in the oven was lowered at a rate of 10 ° C./hour, and when the temperature reached about 30 ° C., the molded product was taken out of the oven.
The reaction of the obtained molded product was sufficiently advanced, and the rubber-like portion as seen in the reference example was not generated. Next, the surface residual stress of the molded product was measured as follows. That is, a strain gauge (KFG-3-120-C1-23L5M manufactured by Kyowa Electric Industry Co., Ltd.)
3R) is attached to the stress measurement site (4 locations on each side) of the molded product, the surroundings are cut out, and Dada Rose (UCA manufactured by Kyowa Dengyo)
M-70A), read the strain value, and read the elastic modulus (40
0 kgf / mm ² ) to calculate the surface residual stress.
The surface residual stress had a small value of max 1 kgf / mm ² . Comparative Example 1 Immediately after the molded article was taken out of the mold, the molded article was immediately stored in an oven set at 150 ° C. in advance. Then, after 2 hours, quenched outside the oven, and over 3 hours
It was cooled to about 0 ° C. When the residual stress of the molded product was measured, it was a large value of max 4.1 kgf / mm ² . The norbornene resin molded article obtained by the method of the present invention has no internal stress, no distortion,
Also, there is no crack on the surface, and good morphological stability is maintained. (Preferred Embodiment) In the method for producing a norbornene-based resin molded article of the present invention, ie, a method for producing a norbornene-based resin molded article by bulk-polymerizing a norbornene-based monomer in a mold, substantially Polymerization is complete,
Preferred practice of a method for producing a norbornene-based resin molded article, wherein the molded article taken out of the mold is immediately held at a temperature of 80 to 200 ° C. for 1 hour or more, and then gradually cooled at a rate of 5 to 30 ° C./hour. The modes are summarized as follows. (1) The molded product taken out of the mold has a temperature of 1
Heat to 00-160 ° C. (2) The molded product taken out from the mold is kept in a heated atmosphere for 1.5 to 3 hours. (3) After holding at a high temperature, the molded article is gradually cooled at a rate of 10 to 20 ° C / hour. (4) The norbornene-based monomer forms two reactive double bonds.
The polycyclic norbornene-based monomer having at least one polycyclic norbornene-based monomer or a monomer mixture containing the polycyclic norbornene-based monomer at 10% by weight or more, more preferably 30% by weight or more.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-292124 (JP, A) JP-A-7-132563 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 61/00-61/12

Claims (1)

(57) [Claim 1] In a method for producing a norbornene-based resin molded product by bulk-polymerizing a norbornene-based monomer in a mold, polymerization is substantially completed, and A method for producing a norbornene-based resin molded product, wherein the molded product taken out is immediately held at a temperature of 80 to 200 ° C. for 1 hour or more, and then gradually cooled at a rate of 5 to 30 ° C./hour.