JP2009221339A - Method for producing cyclic olefinic resin pellet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing cyclic olefinic resin pellets for reducing cutting powder generated in pelletizing and preventing occurrence of cracking of a pellet when pelletizing a cyclic olefinic resin having a high glass transition point. <P>SOLUTION: The method for producing cyclic olefinic resin pellets comprises a discharge process for melting and kneading the cyclic olefinic resin to discharge a rod-shaped material, a cooling process for cooling the discharged rod-shaped material, and a cutting process for cutting the cooled rod-shaped material into pellets. In polymerization and/or the melting and kneading process, 5 pts.mass or more of polyethylene is added to 100 pts.mass of the cyclic olefinic resin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a cyclic olefin resin pellet in which polyethylene is added during the production process of the cyclic olefin resin pellet.

  Thermoplastic resins are used for various applications because of their excellent characteristics, and resins that satisfy the required performance required in each field are selected and used properly.

  On the other hand, the form of the raw material for forming is provided as a pellet shape. As the manufacturing method of the processing pellets, it is melt kneaded with an extruder or the like, extruded as a rod-shaped molten resin from the die at the tip of the extruder, quickly cooled in a water tank or the like, and then about 2 to 4 mm in length by a pelletizer. Are cut into cylindrical pellets. In this cutting process, fine cutting powder is generated in addition to pellets having a desired shape. The cutting powder is deposited and mixed in the roll cutter portion of the pelletizer, the pellet conveying line after the pelletizer, and the packing bag.

  Due to the mixing of cutting powder in the pellet production line, much time and labor are required for maintenance such as cleaning of the roll cutter unit, the conveying line, and the air filter for removing cutting powder and replacement of parts. In addition, the cutting powder mixed in the pellet may be unstable in the extrusion amount in the extrusion molding process, or may be unstable in the injection molding process. In addition, pellets with a large amount of powder have a risk of dust explosion during transportation, and when the melted and kneaded thermoplastic resin rods are cooled and then pelletized using a pelletizer, etc., the generated cutting powder Reduction is desired.

As a technique for reducing cutting powder generated at the time of pelletization, a technique in which polycaprolactone is blended with a thermoplastic resin and melt kneaded is disclosed (Patent Document 1).
JP 2006-21467 A

  By the way, among the thermoplastic resins, the cyclic olefin resin is particularly high in transparency, low birefringence, high heat distortion temperature, light weight, dimensional stability, low water absorption, hydrolysis resistance, chemical resistance, low dielectric constant. It is a resin having many characteristics such as low dielectric loss and no inclusion of environmental load substances, and is used in various fields where these characteristics are required. Among the cyclic olefin-based resins, there are resins having a high glass transition point and extremely excellent heat resistance. Although this is a very excellent material, a cyclic olefin-based resin having a high glass transition point is liable to generate cutting powder when pelletized, and as a result, pellets are also likely to crack. For this reason, there is a need for cutting powder reduction technology that can be applied even when pelletizing a cyclic olefin resin having a high glass transition point.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to reduce the generation of cutting powder and to generate cracks in pellets even when pelletizing a cyclic olefin resin having a high glass transition point. It is providing the manufacturing method of the cyclic olefin resin pellet which suppresses.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, a cyclic olefin system having a discharge step of melting and kneading the cyclic olefin-based resin and discharging it into a rod shape, a cooling step of cooling the discharged rod-shaped material, and a cutting step of cutting the cooled rod-shaped material into a pellet Cyclic olefin type in which polyethylene is added in an amount of 5 parts by mass or more with respect to 100 parts by mass of cyclic olefin type resin during polymerization of cyclic olefin type resin and / or melt kneading of cyclic olefin type resin in the process of manufacturing resin pellets. The present inventors have found that the above problems can be solved by a method for producing resin pellets, and have completed the present invention. More specifically, the present invention provides the following.

  (1) A cyclic olefin having a discharge step of melting and kneading a cyclic olefin-based resin and discharging it into a rod shape, a cooling step of cooling the discharged rod-like material, and a cutting step of cutting the cooled rod-like material into a pellet. A method for producing a resin-based resin pellet, wherein 5 parts by mass or more of polyethylene is added to 100 parts by mass of the cyclic olefin-based resin during polymerization of the cyclic olefin-based resin and / or during the melt-kneading. Manufacturing method.

  (2) The manufacturing method of the cyclic olefin resin pellet as described in (1) whose glass transition point of the said cyclic olefin resin is 150 degreeC or more.

  (3) The manufacturing method of the cyclic olefin-type resin pellet as described in (1) or (2) whose said cooling process is a process of cooling the said rod-shaped object by water cooling.

  (4) The method for producing a cyclic olefin-based resin pellet according to (1) or (2), wherein the cooling step is a step of cooling the rod-like material by air cooling.

  (5) The total amount of the cutting powder having a particle diameter of less than 800 μm remaining in the production line of the cyclic olefin resin pellets and the cutting powder having a particle diameter of less than 800 μm included in the cyclic olefin resin pellets is the cyclic olefin resin. The manufacturing method of the cyclic olefin resin pellet in any one of (1) to (4) which is 10 mass parts or less with respect to 100 mass parts of total amounts of a resin pellet and cutting powder.

  (6) A resin pellet package in which the amount of cutting powder having a particle size of less than 800 μm is less than 5% by mass.

  (7) A resin pellet package obtained by the method for producing a cyclic olefin-based resin pellet according to any one of (1) to (5), wherein the mixing amount of the cutting powder having a particle size of less than 800 μm is 5% by mass. The resin pellet package which is less than.

  According to the present invention, in the production of cyclic olefin resin pellets, 5 parts by mass or more of polyethylene is added to 100 parts by mass of cyclic olefin resin during polymerization of cyclic olefin resin or melt kneading of cyclic olefin resin. Therefore, when pelletizing a cyclic olefin resin having a high glass transition point, the production of high-quality cyclic olefin resin pellets can be reduced by reducing the generation of cutting powder and suppressing cracking of the pellets. Can do. By reducing the generation of cutting powder, the amount of cutting powder mixed into the production line is reduced, and the labor and time required for maintenance of the production line can be reduced.

  In addition, by using resin pellets to which cutting powder is attached as a raw material, there is a possibility that the extrusion amount becomes unstable in the extrusion molding process, or the measurement becomes unstable in the injection molding process.

  In particular, when used as a material with cutting powder having a particle size of less than 800 μm adhered to the pellet, this cutting powder is often mixed into the molded product, which greatly affects the performance and quality of the injection molded product. The cyclic olefin-based resin pellet produced by the production method of the present invention greatly reduces the amount of cutting powder generated, and therefore hardly affects the quality and performance of a molded product such as an injection molded product.

  In order to improve the working environment, the pelletizing temperature is preferably low. According to the production method of the present invention, even if the pelletizing temperature is lowered, the generation of a large amount of cutting powder is suppressed, and in particular, a cyclic olefin resin having a high glass transition point and a low viscosity cyclic olefin resin are molded. Also usable resin pellets can be produced.

  Even in the case of a cyclic olefin resin pellet having a low glass transition point, cracking is likely to occur in the pellet when the molecular weight is low, but according to the method for producing a cyclic olefin resin pellet of the present invention, this crack is Can be suppressed.

  Hereinafter, an embodiment of the present invention will be described in detail. However, the present invention is not limited to the following embodiment, and may be implemented with appropriate modifications within the scope of the object of the present invention. it can.

  The present invention is a method for producing a cyclic olefin-based resin pellet and is characterized by the timing of addition of the cyclic olefin-based resin, polyethylene, and polyethylene used as raw materials. Hereinafter, the present invention will be described in the order of raw materials and manufacturing methods.

<Cyclic olefin resin>
Hereinafter, the cyclic olefin resin used in the present invention will be described. The cyclic olefin resin used in the present invention contains a cyclic olefin component as a copolymerization component, and is not particularly limited as long as it is a polyolefin resin containing a cyclic olefin component in the main chain. For example,
(A1) Cyclic olefin addition polymer or hydrogenated product thereof,
(A2) an addition copolymer of a cyclic olefin and an α-olefin or a hydrogenated product thereof,
(A3) A ring-opening (co) polymer of a cyclic olefin or a hydrogenated product thereof.

In addition, as the (A) cyclic olefin resin containing the cyclic olefin component used in the present invention as a copolymerization component,
(A4) A resin obtained by grafting and / or copolymerizing an unsaturated compound having a polar group to the resins (a1) to (a3).

  Examples of the polar group include a carboxyl group, an acid anhydride group, an epoxy group, an amide group, an ester group, and a hydroxyl group. Examples of the unsaturated compound having a polar group include (meth) acrylic acid and maleic acid. Acid, maleic anhydride, itaconic anhydride, glycidyl (meth) acrylate, alkyl (meth) acrylate (carbon number 1-10) ester, maleic acid alkyl (carbon number 1-10) ester, (meth) acrylamide, (meta ) 2-hydroxyethyl acrylate.

  In the present invention, the cyclic olefin-based resins (a1) to (a4) containing the cyclic olefin component as a copolymerization component may be used alone or in combination of two or more. In the present invention, (a2) an addition copolymer of cyclic olefin and α-olefin or a hydrogenated product thereof can be preferably used.

  Moreover, as the cyclic olefin-based resin containing the cyclic olefin component used in the present invention as a copolymerization component, a commercially available resin can be used. Examples of commercially available cyclic olefin-based resins include TOPAS (registered trademark) (Topas Advanced Polymers), Apel (registered trademark) (manufactured by Mitsui Chemicals), Zeonex (registered trademark) (manufactured by Nippon Zeon), Examples include ZEONOR (registered trademark) (manufactured by ZEON Corporation), ARTON (registered trademark) (manufactured by JSR Corporation), and the like.

（式中、
Ｒ^１〜Ｒ^１２は、それぞれ同一でも異なっていてもよく、水素原子、ハロゲン原子、及び、炭化水素基からなる群より選ばれるものであり、
Ｒ^９とＲ^１０、Ｒ^１１とＲ^１２は、一体化して２価の炭化水素基を形成してもよく、
Ｒ^９又はＲ^１０と、Ｒ^１１又はＲ^１２とは、互いに環を形成していてもよい。
また、ｎは、０又は正の整数を示し、
ｎが２以上の場合には、Ｒ^５〜Ｒ^８は、それぞれの繰り返し単位の中で、それぞれ同一でも異なっていてもよい。） The addition copolymer of (a2) cyclic olefin and α-olefin preferably used in the composition of the present invention is not particularly limited. Particularly preferred examples include a copolymer containing [1] an α-olefin component having 2 to 20 carbon atoms and [2] a cyclic olefin component represented by the following general formula (I).

(Where
R ^{1 to} R ¹² may be the same or different from each other, and are selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group,
R ⁹ and R ¹⁰ , R ¹¹ and R ¹² may be integrated to form a divalent hydrocarbon group,
R ⁹ or R ¹⁰ and R ¹¹ or R ¹² may form a ring with each other.
N represents 0 or a positive integer;
When n is 2 or more, R ^{5 to} R ⁸ may be the same or different in each repeating unit. )

[[1] α-olefin component having 2 to 20 carbon atoms]
The C2-C20 alpha-olefin used as the copolymerization component of the addition polymer of the cyclic olefin component preferably used for this invention and other copolymerization components, such as ethylene, is not specifically limited. For example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-octene, Examples include decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicocene. These α-olefin components may be used alone or in combination of two or more. Of these, ethylene is most preferably used alone.

[[2] Cyclic olefin component represented by formula (I)]
In the addition polymer of the cyclic olefin component preferably used in the present invention and another copolymer component such as ethylene, the cyclic olefin component represented by the general formula (I) serving as the copolymer component will be described.

R ^{1 to} R ¹² in the general formula (I) may be the same or different and are selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group.

Specific examples of R ^{1 to} R ⁸ include, for example, a hydrogen atom; a halogen atom such as fluorine, chlorine and bromine; a lower alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group. May be different from each other, may be partially different, or all may be the same.

Specific examples of R ^{9 to} R ¹² include, for example, hydrogen atom; halogen atom such as fluorine, chlorine, bromine; methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, hexyl group, stearyl. Alkyl group such as cyclohexyl group; cycloalkyl group such as cyclohexyl group; substituted or unsubstituted aromatic hydrocarbon group such as phenyl group, tolyl group, ethylphenyl group, isopropylphenyl group, naphthyl group, anthryl group; benzyl group, phenethyl And an aralkyl group in which an aryl group is substituted with an alkyl group, and the like. These may be different from each other, may be partially different, or all may be the same.

Specific examples of the case where R ⁹ and R ¹⁰ or R ¹¹ and R ¹² are integrated to form a divalent hydrocarbon group include, for example, alkylidene groups such as an ethylidene group, a propylidene group, and an isopropylidene group. Can be mentioned.

When R ⁹ or R ¹⁰ and R ¹¹ or R ¹² form a ring with each other, the formed ring may be monocyclic or polycyclic, or may be a polycyclic ring having a bridge. , A ring having a double bond, or a ring composed of a combination of these rings. Moreover, these rings may have a substituent such as a methyl group.

  Specific examples of the cyclic olefin component represented by the general formula (I) include bicyclo [2.2.1] hept-2-ene (common name: norbornene), 5-methyl-bicyclo [2.2.1] hepta. 2-ene, 5,5-dimethyl-bicyclo [2.2.1] hept-2-ene, 5-ethyl-bicyclo [2.2.1] hept-2-ene, 5-butyl-bicyclo [2 2.1] hept-2-ene, 5-ethylidene-bicyclo [2.2.1] hept-2-ene, 5-hexyl-bicyclo [2.2.1] hept-2-ene, 5-octyl -Bicyclo [2.2.1] hept-2-ene, 5-octadecyl-bicyclo [2.2.1] hept-2-ene, 5-methylidene-bicyclo [2.2.1] hept-2-ene 5-vinyl-bicyclo [2.2.1] hept-2-ene, - propenyl - bicyclo [2.2.1] of the two rings, such as hept-2-ene cyclic olefin;

Tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene), tricyclo [4.3.0.1 ^2,5 ] dec-3-ene; tricyclo [ 4.4.0.1 ^2,5 ] undeca-3,7-diene or tricyclo [4.4.0.1 ^2,5 ] undeca-3,8-diene or a partial hydrogenated product thereof (or cyclopentadiene) Tricyclo [4.4.0.1 ^2,5 ] undec-3-ene; 5-cyclopentyl-bicyclo [2.2.1] hept-2-ene, 5-cyclohexyl-bicyclo [2.2.1] hept-2-ene, 5-cyclohexenylbicyclo [2.2.1] hept-2-ene, 5-phenyl-bicyclo [2.2.1] hept-2-ene A cyclic olefin of a ring;

Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene (also simply referred to as tetracyclododecene), 8-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-ethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-methylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-vinyltetracyclo [4,4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-propenyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] tetracyclic olefins such as dodec-3-ene;

8-cyclopentyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-cyclohexyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-cyclohexenyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-phenyl-cyclopentyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene; tetracyclo [7.4.1 ^3,6 . 0 ^1,9 . 0 ^2,7 ] tetradeca-4,9,11,13-tetraene (also referred to as 1,4-methano-1,4,4a, 9a-tetrahydrofluorene), tetracyclo [8.4.1 ^4,7 . 0 ^1,10 . 0 ^3,8 ] pentadeca-5,10,12,14-tetraene (also referred to as 1,4-methano-1,4,4a, 5,10,10a-hexahydroanthracene); pentacyclo [6.6.1. 1 ^3,6 . 0 ^2,7 . 0 ^9,14 ] -4-hexadecene, pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13] -4-pentadecene, pentacyclo [7.4.0.0 ^2,7. 1 ^3,6 . 1 ^10,13] -4-pentadecene; heptacyclo [8.7.0.1 ^2,9. 1 ^4,7 . 1 ^{11, 17} . 0 ^3,8 . 0 ^12,16 ] -5-eicosene, heptacyclo [8.7.0.1 ^2,9 . 0 ^3,8 . 1 ^4,7 . 0 ^12,17 . 1 ^13,16 ] ^-14-eicocene ; a polycyclic cyclic olefin such as a tetramer of cyclopentadiene.

  These cyclic olefin components may be used singly or in combination of two or more. Among these, it is preferable to use bicyclo [2.2.1] hept-2-ene (common name: norbornene) alone.

[Other copolymer components]
The (a2) addition copolymer of cyclic olefin and α-olefin, which is particularly preferably used in the composition of the present invention, comprises the above [1] α-olefin component having 2 to 20 carbon atoms and [2] general formula (I In addition to the cyclic olefin component represented by (), other copolymerizable unsaturated monomer components may be contained as necessary within the range not impairing the object of the present invention.

  The unsaturated monomer that may be optionally copolymerized is not particularly limited, and examples thereof include hydrocarbon monomers containing two or more carbon-carbon double bonds in one molecule. Can be mentioned. Specific examples of hydrocarbon monomers containing two or more carbon-carbon double bonds in one molecule include 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 4 A chain non-conjugated diene such as methyl-1,5-hexadiene, 5-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene; cyclohexadiene, di Cyclopentadiene, methyltetrahydroindene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl- 2-norbornene, 4,9,5,8-dimethano-3a, 4,4a, 5,8,8a, 9,9a-octahydro-1H-benzoy Cyclic non-conjugated dienes such as Den; 2,3-isopropylidene-5-norbornene; 2-ethylidene-3-isopropylidene-5-norbornene; may be mentioned 2-propenyl-2,2-norbornadiene and the like. Among these, 1,4-hexadiene, 1,6-octadiene, and cyclic non-conjugated dienes, especially dicyclopentadiene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 5-methylene-2 -Norbornene, 1,4-hexadiene, 1,6-octadiene are preferred.

  In particular, when pelletizing a cyclic olefin resin having a high glass transition point, generation of cutting powder is promoted and cracking of the pellet becomes remarkable. However, generation of cutting powder and cracking of pellets can be suppressed by adding polyethylene described later during polymerization of the cyclic olefin resin or during melt kneading of the cyclic olefin resin as in the production method of the present invention. The increase in cutting powder and pellet cracking during pelletization becomes remarkable, and the glass transition point of the cyclic olefin-based resin in which the production method of the present invention is more effective is 150 ° C. or higher, and more effective is 170 ° C. or higher. is there.

  As the cyclic olefin component in the cyclic olefin-based resin increases, the flexibility of the pellet decreases, and the pellet becomes easily broken. Therefore, the content of the cyclic olefin component in the cyclic olefin resin in which the crack of the pellet becomes remarkable and the production method of the present invention becomes more effective is 70 mass% of the cyclic olefin component in the cyclic olefin resin. % Or more, and in a more effective case, the cyclic olefin component is 75 mass% to 85 mass%. According to the method for producing a cyclic olefin resin pellet of the present invention, a pellet with few cracks can be easily produced without reducing the cyclic olefin component in the cyclic olefin resin.

  In addition, this invention is a manufacturing method of a cyclic olefin resin pellet, and contains the cyclic olefin component more than a fixed level. The cyclic olefin resin in the present invention refers to a resin containing 50% by mass or more of a cyclic olefin component in the cyclic olefin resin.

<Polyethylene>
The polyethylene that can be used in the present invention is a polymer having a structure in which ethylene is polymerized, and examples thereof include high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. Among these, low density polyethylene and linear low density polyethylene are preferable.

  High-density polyethylene is preferable because crystallinity is increased and mechanical strength is increased, and when added to a cyclic olefin resin, cracking of the pellet can be suppressed from the viewpoint of improving mechanical strength.

  Since low-density polyethylene and linear low-density polyethylene have flexibility, flexibility can be imparted to the cyclic olefin-based resin pellets. When the flexibility of the cyclic olefin-based resin pellet is increased and flexibility is provided, it is preferable because it leads to suppression of cracking when pelletized.

  Polyethylene is added in an amount of 5 parts by mass or more based on 100 parts by mass of the cyclic olefin resin. If it is 5 mass parts or more, the quantity of the cutting powder which generate | occur | produces when pelletizing can reduce, and generation | occurrence | production of the crack of a pellet can be suppressed. Moreover, it is preferable that the addition amount of polyethylene is 30 mass parts or less with respect to 100 mass parts of cyclic olefin resin. If it is 30 mass parts or less, it can prevent that the glass transition point of the cyclic olefin resin pellet obtained falls too much, and can prevent the fall of the physical property of the pellet obtained. More preferably, they are 5 mass parts-15 mass parts. In order to sufficiently obtain the effect of the cyclic olefin resin having a high glass transition point and high heat resistance, it is preferable that the polyethylene content is small. However, within the above range, the heat resistance is maintained and the processing is easy. It can be compatible.

  However, even if the addition amount of polyethylene is 30 parts by mass or more with respect to 100 parts by mass of the cyclic olefin resin, the amount of cutting powder generated when pelletizing is reduced, and cracking of the pellets is suppressed. Can do. Therefore, depending on the application, a high glass transition point and high transparency are not required, so even when producing such a cyclic olefin resin pellet, the pellet is produced by the method for producing a cyclic olefin resin pellet of the present invention. Can improve productivity.

  High-density polyethylene, low-density polyethylene, and linear low-density polyethylene that can be used in the production method of the present invention have a melt flow rate (MFR) defined by JIS K6922-1 of 0.1 g / 10 min to 10 g / 10 min. It is preferably 0.4 g / 10 min to 5 g / 10 min. More preferably, it is 0.4 g / 10min-2g / 10min. If it is lower than 0.1 g / 10 min, flexibility can be obtained, but fluidity may deteriorate and good moldability may not be obtained. If it exceeds 10 g / 10 min, the moldability is good. However, flexibility may not be obtained.

  Other thermoplastic resins, various compounding agents, and the like can be added to the cyclic olefin-based resin of the present invention as necessary within a range not losing the effects of the present invention. Examples of other resins include other polyolefin resins, polystyrene resins, and fluororesins. These other resins may be used alone or in combination of two or more. In addition, as compounding agents, stabilizers (antioxidants or antioxidants, UV absorbers, heat stabilizers, etc.), antistatic agents, flame retardants, flame retardant aids, colorants (dyes, pigments, etc.), lubrication Examples include agents, plasticizers, lubricants, mold release agents, crystal nucleating agents, anti-dripping agents, and crosslinking agents.

  The cyclic olefin resin pellets of the present invention can be applied to films, injection-molded products, fibers, sheets, pipes, foams, profile extrusions, and other materials processed with pellets. In particular, it can be preferably applied to materials that require heat resistance.

<Method for producing cyclic olefin-based resin pellet>
A polymerization process for polymerizing the cyclic olefin resin, a discharge process for melting and kneading the polymerized cyclic olefin resin and discharging it in a rod shape, a cooling process for cooling the discharged rod material, and cutting the cooled rod material into a pellet Cutting step. Hereinafter, the manufacturing method of the cyclic olefin-type resin pellet of this invention is demonstrated in order of a polymerization process, a discharge process, a cooling process, and a cutting process.

[Polymerization process]
The polymerization step is a step of polymerizing a cyclic olefin-based resin, and [1] a method and a method for polymerizing an α-olefin component having 2 to 20 carbon atoms and a cyclic olefin component represented by the general formula (I). The method for hydrogenating the obtained polymer is not particularly limited. Polymerization can be performed according to a conventionally known method. Random copolymerization or block copolymerization may be used, but random copolymerization is preferred.

  The polymerization catalyst used is not particularly limited, and can be obtained by a known method using a conventionally known catalyst such as a Ziegler-Natta, metathesis, or metallocene catalyst. The cyclic olefin and α-olefin addition copolymer or hydrogenated product thereof preferably used in the present invention is preferably produced using a metallocene catalyst.

  Examples of the metathesis catalyst include molybdenum or tungsten-based metathesis catalysts (for example, described in JP-A Nos. 58-127728 and 58-129003) as a catalyst for ring-opening polymerization of cycloolefin. In addition, the polymer obtained by the metathesis catalyst uses an inorganic carrier-supported transition metal catalyst or the like, and 90% or more of the main chain double bond and 98% or more of the carbon-carbon double bond in the side chain aromatic ring are hydrogenated. It is preferable to add.

  As the polymerization form, any of solution polymerization, bulk polymerization and slurry polymerization can be adopted, and any of continuous polymerization and batch polymerization can be carried out. Examples of the polymerization catalyst used in the copolymerization include aliphatic hydrocarbons such as hexane, heptane, octane and kerosene; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and decahydronaphthalene; aromatics such as benzene, toluene and xylene. A group hydrocarbon etc. can be illustrated. These solvents can be used alone or in combination of two or more.

  In the present invention, by adding polyethylene during the polymerization of the cyclic olefin-based resin, the amount of cutting powder generated when pelletizing the cyclic olefin-based resin is reduced, and the generation of cracks in the pellet can be suppressed. By adding polyethylene, the flexibility of the cyclic olefin resin is improved, so that the effect of the present invention can be obtained.

  In particular, when pellets are used as raw materials for injection molded products or the like with cutting powder having a particle size of less than 800 μm attached, the shear force generated between the screw and the cutting powder having a particle size of less than 800 μm is small, so the particle size in the molding machine Cutting powder of less than 800 μm is not melted, and this cutting powder is mixed into the molded product, greatly affecting the performance and quality of the injection molded product. In the present invention, since the cutting powder generated at the time of pelletization can be reduced, the generation of the cutting powder having the above particle diameter can be further reduced as compared with the conventional one. As a result, a high-quality cyclic olefin resin pellet for obtaining a high-quality molded product can be produced.

  The generation of such cutting powder is particularly remarkable in cyclic olefin resins having a high glass transition point. According to the production method of the present invention, even if it is a resin pellet of a cyclic olefin resin having a high glass transition point, generation of cutting powder having the above particle size can be significantly suppressed as compared with the conventional production method. it can. As a method for adding polyethylene at the time of polymerization, for example, it is also possible to add it to a polymerization solution composed of the above solvent, disperse and dissolve it, and add it to the cyclic olefin resin.

  Further, immediately after the preparation of the polymer, the solvent is removed by high temperature and reduced pressure, and when the polymer is in a molten state, polyethylene is added to the polymer, and then the polymer is extruded into a strand shape, which is cut to produce pellets.

[Discharge process]
In the discharging step, the cyclic olefin-based resin obtained in the polymerization step is melt-kneaded and discharged into a rod shape. The method of melt-kneading and discharging in a rod shape is not particularly limited. For example, a cyclic olefin resin can be kneaded in a kneading extruder, and a rod-shaped cyclic olefin resin can be discharged from an opening of the apparatus. Examples of the opening from which the rod-shaped cyclic olefin-based resin is discharged include a small hole of a die attached to an extrusion kneader. The shape of the opening is not particularly limited, and examples thereof include a circle, an ellipse, and a square. These shapes determine the cross-sectional shape of the rod-shaped pellet. From the viewpoint of reducing the amount of cutting powder generated during pelletization and suppressing the occurrence of pellet cracking, the cross section of the pellet is preferably circular and has a diameter of 1 mm to 3 mm.

  The rod-shaped object includes a string shape and a strand shape. From the viewpoint of reducing the amount of cutting powder generated when pelletizing and suppressing the occurrence of pellet cracking, a rod-like material having a length of about 3 mm to 8 mm is preferable.

  In the present invention, by adding polyethylene during melt kneading of the cyclic olefin resin, the amount of cutting powder generated when pelletizing the cyclic olefin resin can be reduced, and the occurrence of cracking of the pellet can be suppressed. This is because flexibility can be imparted to the cyclic olefin resin in the same manner as when polyethylene is added during the polymerization.

[Cooling process]
The cooling step is a step of cooling the rod-shaped cyclic olefin-based resin, and the cooling method is not particularly limited. For example, a water cooling method for cooling with cooling water or the like and an air cooling method for cooling using cooling air can be used.

  In the present invention, the water cooling method is applicable to a method such as a strand bath method in which a molten strand is cooled by being attached to a water tank having a length of about 0.3 m to about 10 m. Among these, the length of the strand bath is 1 m or more. preferable. If it is a water cooling system, since the generation | occurrence | production of powder | flour can be further reduced by making the temperature of a water bath into 40 degreeC or more, it is preferable. This is because, when the strands described later are cut at a low temperature, the strands are fragile, so that cutting powder is easily generated during the cutting. If the temperature of the water bath is raised, the length of the bath required for solidification becomes longer, making industrial implementation difficult, so the temperature of the water bath in the present invention is not particularly limited, and the production of resin pellets is facilitated It can be changed as appropriate.

  However, if the water temperature is too high, it may be preferable that the temperature of the water bath is low due to the problem that it is difficult to cut and the temperature control is difficult to maintain at an appropriate temperature, and that the working environment is improved as described later. In particular, according to the production method of the present invention, even when the temperature of the water bath is lowered and the pelletizing temperature is lowered, the generation of cutting powder can be greatly reduced as compared with the conventional case. Therefore, according to the production method of the present invention, by setting the temperature of the water bath to a low temperature, temperature control is facilitated, and a certain high quality pellet can be easily obtained. In addition, the work environment is greatly improved. In order to obtain such an effect, it is preferable to set the temperature of the cooling water to 80 ° C. or less and the cooling time to 20 seconds or less. By cooling under the above cooling conditions, high quality resin pellets can be stably obtained. In addition, the working environment is improved. The “cooling time” refers to the time from when discharged from the die and introduced into the cooling water until cutting.

  In the present invention, the air cooling method is applicable to a method of cooling the strands on an inclined metal groove or a metal belt conveyor. However, in the method for producing the cyclic olefin resin pellets of the present invention, water cooling is preferred.

[Cutting process]
A cutting process means cut | disconnecting the said rod-shaped thing cooled and pelletizing. A cutting method is not particularly limited, and a conventionally known method can be used. A conventionally known method is, for example, a pelletizing method.

  In the present invention, the length of the cut pellet is preferably about 3 mm to 8 mm from the viewpoint of reducing the amount of cutting powder generated when pelletizing and suppressing the occurrence of cracking of the pellet.

  The total amount of the cutting powder having a particle diameter of less than 800 μm remaining in the production line of the cyclic olefin resin pellets and the cutting powder having a particle diameter of less than 800 μm of the cyclic olefin resin pellets obtained by the above production method is a cyclic olefin. It is preferable that it is 10 mass parts or less with respect to 100 mass parts of total amounts of a system resin pellet and the whole cutting powder. In particular, if the cutting powder having a particle size of less than 800 μm remains attached to the pellet, the above-described problem occurs.

  In addition, if cutting powder is mixed into the production line, it is not preferable because much labor and time are required for maintenance regardless of the particle size of the cutting powder.

<Resin pellet package>
The pellet package manufactured by the manufacturing method of the present invention is particularly preferable as a material for a molded product or the like because the amount of mixed cutting powder having a particle size of less than 800 μm is small compared to the conventional one. Specifically, the cutting powder having a particle size of 800 μm or less is less than 5% by mass in the pellet package. Compared with a pellet package obtained by a conventional manufacturing method, the amount of cutting powder having a particle size of 800 μm or less is reduced. More preferably, it is less than 3 mass%.

  As described above, the total amount of the cutting powder having a particle size of less than 800 μm remaining in the production line for the cyclic olefin resin pellets and the cutting powder having a particle size of less than 800 μm possessed by the cyclic olefin resin pellets obtained by the production method. However, if it is 10 parts by mass or less with respect to 100 parts by mass of the total amount of the cyclic olefin-based resin pellets and the entire cutting powder, the mixing amount of the cutting powder having a particle size of 800 μm in the pellet package is easily 5% by mass. Can be less than. This is because the cutting powder is usually easily removed from the pellet by cooling water or the like, and most of it remains in the production line.

  The resin pellet package of the present invention refers to one in which resin pellets are weighed, for example, by 15 to 25 kg and filled into a container. The container is not particularly limited, and examples thereof include a plastic container, a plastic bag, a paper bag, a can, a cardboard container, and a flexible container.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<Manufacture of cyclic olefin resin pellets>
[Discharge process]
In the composition shown in Table 1, the cyclic olefin resin and the polyethylene resin were melt-extruded in a 30 mmφ twin screw extruder set at a cylinder temperature of 280 ° C., an extrusion rate of 12 kg / hr (using a quantitative feeder), and a screw rotation speed of 150 rpm, A strand was obtained.

[Cooling process]
The extruded strand was immersed in 65 ° C. cooling water in a water bath for about 5 seconds.

[Cutting process]
The cooled strand-like extrudate was cut into a length of about 5 mm using a pelletizer and then dried at 105 ° C. for 3 hours to collect resin pellets of the present invention and comparative examples. Note that most of the pellets and cutting powder from the pelletizer were collected in a package. In addition, all of the cutting powder and pellets attached to the pelletizer or scattered around the pellets were collected, and both the amount of cutting powder and pellets in the package and the amount of cutting powder and pellets that did not enter the package were evaluated. Table 1 Table 4 summarizes the total amount of cutting powder and the amount of cutting powder in the package. The specific evaluation was performed by weighing the amount of cutting powder having a particle diameter of less than 800 μm that was passed through a 20-mesh sieve with 2 kg of the resin pellet package of the above Examples and Comparative Examples.

<Evaluation>
The pelletized pellet shape was observed and evaluated by the five-point method as follows. The determination results are shown in Table 1.
When the evaluation is 1, many pellets are crushed and it is determined that they cannot be used for molding.
When the evaluation is 2, it is an intermediate state between the evaluations 1 and 3, and it is determined that it cannot be used for molding.
When the evaluation is 3, there are many pellets that retain their shape, but it is determined that they can be used for molding.
When the evaluation is 4, it is an intermediate state between the evaluations 3 and 5, and is determined to be usable for molding.
When the evaluation is 5, the pellets are not crushed and the pellet shape is maintained.

環状オレフィン系樹脂：メタロセン系触媒（イソプロピリデン（シクロペンタジエニル）（インデニル）ジルコニウムクロリド）を用いて得られたエチレン・ノルボルネンランダム共重合体（ノルボルネン単位含量：８５質量％、ＭＦＲ：１５ｇ／分、Ｔｇ：１９３℃）
ポリエチレン：直鎖状低密度ポリエチレンExceed 1018CA、ExonMobil社製

Cyclic olefin resin: ethylene / norbornene random copolymer (norbornene unit content: 85% by mass, MFR: 15 g / min) obtained using a metallocene catalyst (isopropylidene (cyclopentadienyl) (indenyl) zirconium chloride) , Tg: 193 ° C)
Polyethylene: Linear low density polyethylene Exceed 1018CA, manufactured by ExonMobil

  As can be seen from Table 1, when producing pellets of cyclic olefin resin having a high glass transition point, the pellets are molded without breaking despite the fact that the strands are cut at a low temperature in order to increase work safety. It was confirmed that it can be used. Moreover, since the generation amount of cutting powder having a particle size of less than 800 μm is small, it was confirmed that high-quality cyclic olefin resin pellets can be produced.

  The amount of cutting powder in the packaging bodies of the examples was less than 5% by mass, and it was confirmed that the amount of cutting powder decreased as the polyethylene content increased. On the other hand, in Comparative Examples 2 and 3, it was confirmed that the amount of the cutting powder having a particle size of less than 800 μm was less than 5% by mass, both of which were higher than those of the Examples. Further, in the comparative example, the amount of cutting powder remaining on the production line is larger than that in the example. Therefore, it was confirmed that the blending of 5 parts by mass or more of polyethylene with 100 parts by mass of the cyclic olefin-based resin can reduce a great amount of time and labor for maintenance.

Claims (6)

Cyclic olefin resin pellets having a discharge step of melting and kneading the cyclic olefin resin and discharging it into a rod shape, a cooling step of cooling the discharged rod material, and a cutting step of cutting the cooled rod material into a pellet A manufacturing method of
The manufacturing method of the cyclic olefin resin pellet which adds 5 mass parts or more with respect to 100 mass parts of said cyclic olefin resin at the time of the polymerization of the said cyclic olefin resin and / or the said melt-kneading.   The method for producing a cyclic olefin resin pellet according to claim 1, wherein the cyclic olefin resin has a glass transition point of 150 ° C or higher.   The method for producing a cyclic olefin-based resin pellet according to claim 1 or 2, wherein the cooling step is a step of cooling the rod-like material by water cooling.   The method for producing a cyclic olefin-based resin pellet according to claim 1 or 2, wherein the cooling step is a step of cooling the rod-like material by air cooling.   The total amount of cutting powder having a particle size of less than 800 μm remaining in the production line for the cyclic olefin resin pellets and cutting powder having a particle size of less than 800 μm included in the cyclic olefin resin pellets is the cyclic olefin resin pellets. It is 10 mass parts or less with respect to 100 mass parts of total amounts with cutting powder, The manufacturing method of the cyclic olefin resin pellet in any one of Claim 1 to 4.   A resin pellet package in which the amount of cutting powder having a particle size of less than 800 μm is less than 5 mass%.