JP4155146B2 - Method for producing thermoplastic elastomer composition - Google Patents

Description

  The present invention relates to a method for producing a thermoplastic elastomer composition by melt-kneading a massive rubber component (hereinafter also referred to as massive rubber) and a resin component.

  Thermoplastic elastomers do not require a vulcanization process and can be processed with ordinary thermoplastic resin molding machines, and their applications have been developed in a wide range of fields including automobile parts, home appliance parts, and miscellaneous goods. ing. Among these, the olefinic thermoplastic elastomer composition includes a non-crosslinking type composition obtained by melt-kneading an olefinic copolymer rubber and an olefinic polymer resin, and in the presence of a crosslinking agent such as an organic peroxide. In addition, there is known a crosslinked type composition obtained by melt-kneading an olefin copolymer rubber and an olefin polymer resin and dynamically crosslinking them.

  As a method for producing a non-crosslinked type olefinic thermoplastic elastomer composition, a method is known in which an olefinic copolymer rubber and an olefinic polymer resin are kneaded by a closed kneader exemplified by a Banbury or a kneader. . However, this method has a problem that it is not an efficient method because it uses a batch-type kneader with low productivity exemplified by Banbury and kneader.

  As a method for producing a crosslinked type olefin-based thermoplastic elastomer composition, an olefin copolymer rubber and an olefin polymer resin are previously kneaded by a closed kneader exemplified by Banbury or kneader, and then the kneaded product is There is a method in which, after granulation and pelletization, the pellet and a crosslinking agent are melt-kneaded with an extruder to perform dynamic crosslinking. However, this method requires (1) a step of kneading rubber and resin prior to dynamic crosslinking, and (2) batch-type kneading with low productivity exemplified by Banbury and kneader. Since the machine is used, there is a problem that it is a complicated and inefficient method.

  In order to solve such a problem, at least one of the three sides of the substantially rectangular parallelepiped rubber has a length of at least one side shorter than the distance between the two screw shafts of the rubber feeder, and is bitten into a screw rotating in a different direction. Therefore, a method for producing a thermoplastic elastomer composition for supplying a block rubber to an extruder is shown (see Patent Document 1 and Patent Document 2). However, in this method, there is a restriction on the size of the substantially rectangular solid rubber and the size of the screw of the rubber feeder. For this reason, it is necessary to process the block rubber into the above-mentioned specific size, and it is also necessary to use a rubber feeder having the above-mentioned specific structure. And when an irregular-shaped lump rubber was used, there also existed a problem that the precision of the rubber supply amount to an extruder deteriorated.

  In addition, as a similar case, a method for producing a vulcanizable rubber composition in which the amount of sheet-like rubber supplied to a extruder is controlled by a screw feeder and a gear pump is described (see Patent Document 2).

JP 2000-309637 A (2nd to 7th pages) JP 2000-43032 A (pages 2 to 5)

  Under such circumstances, the present invention provides a method for producing a thermoplastic elastomer composition capable of stably supplying raw materials with little variation in the amount of rubber supplied to the melt-kneading extruder regardless of the shape and size of the bulk rubber. For the purpose.

That is, the present invention relates to a method for producing a thermoplastic elastomer composition including the following first to fifth steps in the production process of a thermoplastic elastomer composition by melt kneading of a rubber component and a resin component.
1st process: The process which supplies a block-like rubber component to a melt-kneading extruder 2nd process: The process which supplies a resin component and an additive to a melt-kneading extruder 3rd process: The melt-kneaded thermoplastic elastomer composition Step of measuring at the outlet of the melt-kneading extruder Fourth step: Based on the amount of the resin component, additive and thermoplastic elastomer composition measured in the second step and the third step, the supply amount of the bulk rubber component is Step of calculating Fifth step: A step of controlling the supply amount of the massive rubber component in the first step based on the supply amount of the massive rubber component calculated in the fourth step.

  The step of supplying the lump rubber component to the melt-kneading extruder in the first step is a method of supplying a lump rubber component by a rubber supply device comprising a screw extruder and a gear pump, so that the rubber supply pressure to the gear pump is constant. A method of controlling the rubber supply device is a preferred form of the invention. Further, the present invention is suitably applied when the bulk rubber component is an olefin copolymer rubber made of ethylene-α-olefin copolymer rubber or ethylene-α-olefin-nonconjugated diene copolymer rubber. .

According to the present invention, it is possible to provide a method for producing a thermoplastic elastomer composition capable of stably supplying raw materials with little variation in the amount of rubber supplied to the melt-kneading extruder regardless of the shape and size of the bulk rubber.

  The first step of the present invention is a step of supplying a block rubber to a melt-kneading extruder. As the rubber supply device in the first step, feeders such as a screw conveyance type feeder and a belt conveyance type feeder, extruders such as a single screw extruder and a biaxial extruder, and a gear pump can be used. Moreover, although these apparatuses can be used in combination, a rubber supply apparatus in which a screw extruder and a gear pump are combined is particularly preferable. The screw extruder easily adjusts the screw rotation according to the pressure on the supply side of the gear pump. By this combination, the rubber supply stability is controlled by controlling the pressure of the rubber sent from the screw extruder to the gear pump. Becomes higher. Examples of such screw extruders include a single screw extruder, a twin screw extruder, and a twin screw single screw extruder. A twin-screw single-screw extruder is an extruder in which the upstream side of the extruder has two axes rotating in different directions and the downstream side has one axis.

  Regarding the arrangement of the two screws of the twin-screw single-screw extruder, the screws may be arranged in parallel, or the two screws may be arranged in two as in the case of a skew type twin-screw extruder. You may arrange | position the screw diagonally.

  If the supply amount of bulk rubber fluctuates due to the influence of the non-uniform shape, it is actually performed in the fourth and fifth steps based on the supply amount of the bulk rubber obtained in the third step to the kneading extruder. The amount of the rubber component contained in the rubber is calculated and fed back to the first step to adjust and control the speed of the screw or the like of the rubber supply device so as to obtain a predetermined bulk rubber supply amount. As the melt-kneading extruder, a single-screw extruder, a twin-screw extruder or a multi-screw extruder having three or more axes equipped with a screw or rotor having a kneading function can be used.

  In the present invention, the lump rubber means a rubber lump having various shapes such as a sphere, a cylinder, a rectangular parallelepiped, a flake, a crumb, a lint, and a gap inside, Any shape can be used as long as it can be discriminated. As a method for obtaining such a lump rubber, for example, a method of pulverizing a bale-like rubber with a pulverizer, a method of cutting a bale-like rubber with a rubber cutting machine, depolymerization after rubber polymerization, drying and lump-like Examples thereof include a method for obtaining rubber (crumb), and any method may be used.

  The second step is a step of supplying the resin component and the additive to the melt-kneading extruder. The resin components and additives to be used are charged into a kneading extruder by a quantitative feeder and melt kneaded to produce a thermoplastic elastomer. The resin components and additives are pellets, granules, powders, etc., and the product shape is stable. By using a quantitative feeder, fluctuations in the amount charged into the kneading extruder are small. Preferably, if a mass control type feeder is used as the quantitative feeder, the input amount becomes more stable. In the present invention, additives refer to antioxidants, weathering agents, antistatic agents, lubricants, crosslinking agents, crosslinking aids, color pigments, inorganic fillers, mineral oil-based softeners and the like.

  The third step is a step of measuring the production amount of the melt-kneaded thermoplastic elastomer composition (hereinafter also referred to as a product) at the outlet of the melt-kneader. The production volume is measured with a measuring instrument. An example of a measuring instrument is one that receives a product in a container for a certain period of time and measures a production amount from a change in the mass of the container.

  The fourth step is a step of calculating the supply amount of the bulk rubber based on the resin component, the amount of the additive, and the production amount of the product measured in the second step and the third step. The amount of the resin and additive added to the kneading extruder is stable because the product shape is stable and the fluctuation is slight. Accordingly, the mass obtained by subtracting the input amount of the resin and the additive from the production amount of the product can be set as the supply amount to the kneading extruder for the bulk rubber.

  In the fifth step, based on the mass rubber supply amount calculated in the fourth step, the mass rubber supply amount is controlled by adjusting the number of rotations of a screw, a gear, etc., which are conveying means of the rubber supply device in the first step. It is a process.

  The control of the lump rubber supply amount in the first step by the third step to the fifth step is, for example, in FIG. 1 (schematic configuration diagram showing one example of the melt kneading extruder and the control method of the lump rubber supply amount in the present invention). As shown, prescriptions of various grades are stored in the distributed control system (DCS) 11, and information on the resin supply device 6, additive supply device 7, cross-linking agent supply device 8, and weighing machine 10 is transmitted to the distributed control system. Then, the operation is performed to control the supply amount of the gear pump 5.

  In the method for producing the thermoplastic elastomer composition of the present invention, the rubber component to be used is not particularly limited, but ethylene-α-olefin copolymer rubber is suitable. Examples of the ethylene-α-olefin copolymer rubber include ethylene-α-olefin copolymer rubber and ethylene-α-olefin-conjugated diene copolymer rubber. A mixture of ethylene-α-olefin copolymer rubber and ethylene-α-olefin-conjugated diene copolymer rubber may be used. As the rubber component, oil-extended ethylene-α-olefin copolymer rubber may be used.

  Examples of the α-olefin in the ethylene-α-olefin copolymer include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, and the like. Of these, propylene, 1-butene, 1-hexene and 1-octene are preferable. The α-olefin content is 10 to 55% by weight, preferably 20 to 40% by weight.

  Examples of the α-olefin in the ethylene-α-olefin-conjugated diene copolymer rubber include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene. Among them, propylene, 1-butene, 1-hexene and 1-octene are preferable. Conjugated dienes such as 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene Chain non-conjugated dienes; cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6 Cyclic unconjugated dienes such as chloromethyl-5-isopropenyl-2-norbornene; 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2 , 2-norbornadiene, 1,3,7-octatriene, 1,4,9-decato Triene are mentioned such as ene, among them 5-ethylidene 2-norbornene or dicyclopentadiene. The α-olefin content is 10 to 55% by weight, preferably 20 to 40% by weight.

  The ethylene-α-olefin copolymer rubber preferably has a Mooney viscosity (ML1 + 4100 ° C.) at 100 ° C. of 30 to 350, more preferably 120 to 350. If the Mooney viscosity is excessively low, the mechanical strength may be remarkably reduced. On the other hand, if the Mooney viscosity is excessively large, the appearance of the molded product may be impaired. The Mooney viscosity of the ethylene-α-olefin copolymer rubber when the oil-extended rubber is used as the ethylene-α-olefin copolymer rubber is based on the value including the extended oil.

  The resin component used in the present invention is a thermoplastic resin that can be made into a thermoplastic elastomer composition by melt-kneading with rubber, and among them, an olefin polymer resin is preferable. The olefin polymer resin is a resin obtained by polymerizing an olefin, for example, ethylene homopolymer; α-olefin homopolymer such as propylene homopolymer; ethylene-α such as ethylene-1-butene copolymer. -Olefin copolymer; Propylene-α-olefin copolymer such as propylene- (ethylene and / or 1-butene) copolymer; Ethylene such as ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer Examples thereof include system copolymers.

  Among these olefin polymer resins, propylene-based resins having isotactic crystallinity such as a propylene homopolymer and / or a propylene-α-olefin copolymer are preferable. Examples of the α-olefin herein include ethylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 1-decene, 3-methyl-1-pentene, and 4-methyl-1. -Pentene, 1-octene, etc. are mentioned. In the case of a propylene-α-olefin copolymer, a random copolymer or a block copolymer is generally known, but any of them can be used. The melt flow rate (230 ° C., 21.18 N) of the propylene-based resin is preferably in the range of 0.1 to 100 g / 10 minutes.

The manufacturing method in particular of the said olefin polymer resin is not restrict | limited, A well-known manufacturing method may be sufficient. The catalyst used for the production is not particularly limited, and examples of the catalyst include a multisite catalyst such as a conventional solid catalyst, and a single site catalyst exemplified by a catalyst obtained using a metallocene complex. A commercially available resin may be used as the olefin polymer resin.
Moreover, in this invention, 1 type, or 2 or more types of thermoplastic resins can be used as needed.

The blending weight ratio (A) / (B) of the olefin copolymer rubber (A) and the thermoplastic resin (B) is preferably 15 to 95/85 to 5. In the case of producing a crosslinked type thermoplastic elastomer composition, 35 to 90/65 to 10, preferably 60 to 90/40 to 10 are used, and in the case of producing a non-crosslinked type thermoplastic elastomer composition, 15 to 15 80 / 85-20, preferably 15-50 / 85-50. When using an oil-extended olefin copolymer rubber, the above-mentioned use ratio of the rubber means a use ratio of the oil-extended olefin copolymer rubber.
When producing a crosslinked type thermoplastic elastomer composition, an organic peroxide is used as a crosslinking agent. Examples of the organic peroxide include 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, 1 , 3-bis (t-butylperoxyisopropyl) benzene, 1,1-di (t-butylperoxy) 3,5,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (peroxybenzoyl) ) Hexin-3, dicumyl peroxide and the like. Among these, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane is particularly preferable in terms of odor and scorch. The amount of organic peroxide added is selected in the range of 0.005 to 2.0 parts by weight, preferably 0.01 to 0.6, based on 100 parts by weight of the total of the olefin copolymer rubber and the olefin polymer resin. I can do it. If it is less than 0.005 parts by weight, the effect of the crosslinking reaction is small, and if it exceeds 2.0 parts by weight, it is difficult to control the reaction and it is not economically advantageous. The organic peroxide can be diluted with a liquid or powdery substance. As the diluent, oil, organic solvent, inorganic filler (silica, talc, etc.) can be used.

  When producing a crosslinked type thermoplastic elastomer composition, N, N′-m-phenylene bismaleimide, toluylene bismaleimide P-quinone dioxime, nitrobenzene, as a crosslinking aid during dynamic crosslinking with an organic peroxide, Peroxide crosslinking aids such as diphenylguanidine and trimethylolpropane, or polyfunctional vinyl monomers such as divinylbenzene, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate can coexist. . By blending such a compound, it is possible to improve the mechanical properties by causing a uniform and mild crosslinking reaction and a reaction between the olefin copolymer rubber and the olefin polymer resin. The addition amount of the crosslinking aid can be selected in the range of 0.01 to 4.0 parts by weight with respect to 100 parts by weight in total of the olefin copolymer rubber and the olefin polymer resin. Preferably it is 0.05-2.0 weight part. If the amount is less than 0.01 parts by weight, the effect is hardly exhibited, and if it exceeds 4 parts by weight, it is not economically advantageous.

EXAMPLES Hereinafter, although the content of this invention is demonstrated concretely by an Example, this invention is not limited by these Examples.
The extruder, pulverizer, rubber, thermoplastic resin, additive mixture, and crosslinking agent used in the examples are as follows.

Rubber crusher: CONDUX rubber cutter Rubber feeder: Nippon Steel Works TEX44 and gear pump Melt-kneading extruder: Nippon Steel Works TEX44
Mass meter: K-tron Co., Ltd. Meter: Rubber oil-extended ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber (manufactured by Sumitomo Chemical Co., Ltd .; trade name: Esprene 670F, Mooney viscosity (ML) _{1 + 4} 100 ° C. 63: measured according to ASTM D-927-57T).
Thermoplastic resin: Polypyropyrene (manufactured by Sumitomo Chemical Co., Ltd .; trade name: Nobrene Y501N, MFR 13 g / 10 min: measured at 230 ° C. under a load of 21.18 N according to JIS K6758).
Additive mixture: cross-linking aid (manufactured by Sumitomo Chemical Co., Ltd .; trade name: Sumifen BM) / antioxidant (manufactured by Sumitomo Chemical Co., Ltd .; trade name: Sumilizer BP101) = 0.9 / 0.25 A mixture consisting of a weight ratio.
Cross-linking agent: 2,5-dimethyl-2,5-di (t-butylperoxy) hexane was diluted to 10% by weight with a mineral oil-based oil (manufactured by Idemitsu Kosan; trade name Diana Process Oil PW380).

Example 1
The rubber was made into an irregular bulk rubber having a size of 1 to 4 cm by the rubber crusher 1 shown in FIG. This massive rubber was continuously supplied to the melt-kneading extruder 12 via the gear pump 5 by the twin-screw extruder 2. A rubber supply pressure control device 4 detects the rubber pressure at the inlet of the gear pump 5 with the pressure sensor 3 and changes the screw speed of the twin-screw extruder 3 according to the detected value to keep the rubber pressure constant. To do. Polypropylene was added by the resin supply device 6 (quantitative feeder), and the additive mixture was continuously supplied to the melt-kneading extruder 12 by the additive supply device 7 (quantitative feeder) and melt-kneaded. Furthermore, a crosslinking agent is continuously supplied to the melt-kneading extruder 12 by a crosslinking agent supply device 8 (plunger pump), dynamic crosslinking is performed, and a crosslinked olefin-based thermoplastic elastomer which is a product from the product discharge port 9. A composition was obtained. The feed rates were 4 kg / hr for polypropylene, 0.35 kg / hr for the additive mixture, and 1 kg / hr for the cross-linking agent, respectively.
Based on the amount of product weighed by the weighing instrument 10 and the amount of resin components, additives, and cross-linking agent supplied by the distributed control system 11, the production amount 31.4 kg / hr, the mass rubber supply amount 26 kg / hr is calculated, the rotation speed of the gear of the gear pump 5 is adjusted, and the supply amount of the bulk rubber to the kneading extruder is supplied to the melt-kneading extruder at a stable supply amount regardless of the irregular bulk rubber. The production of the thermoplastic elastomer was carried out smoothly.

It is a schematic block diagram which shows an example of the control method of the melt-kneading extruder and block rubber supply amount in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rubber grinder, 2 ... Twin screw extruder, 3 ... Pressure sensor, 4 ... Rubber supply pressure control apparatus, 5 ... Gear pump, 6 ... Resin supply apparatus, 7 ... Additive supply apparatus, 8 ... Crosslinking agent supply apparatus, DESCRIPTION OF SYMBOLS 9 ... Product outlet, 10 ... Metering device, 11 ... Distributed control system, 12 ... Melt kneading extruder

Claims (3)

In a process for producing a thermoplastic elastomer composition by melt kneading of a rubber component and a resin component, a method for producing a thermoplastic elastomer composition including the following first to fifth steps: First step: melt kneading a massive rubber component Step for supplying to extruder Second step: Step for supplying resin component and additive to melt-kneading extruder Third step: Step for measuring melt-kneaded thermoplastic elastomer composition at outlet of melt-kneading extruder Fourth step: A step of calculating the supply amount of the bulk rubber component based on the amount of the resin component, additive and thermoplastic elastomer composition measured in the second step and the third step. Fifth step: Calculated in the fourth step. The step of controlling the supply amount of the lump-like rubber component in the first step based on the supply amount of the lump-like rubber component that has been made   The thermoplastic elastomer composition according to claim 1, wherein the step of supplying the lump rubber component in the first step according to claim 1 to the melt kneading extruder supplies the lump rubber component by a rubber supply device comprising a screw extruder and a gear pump. Manufacturing method. The heat according to any one of claims 1 to 2 , wherein the bulk rubber component is an olefin copolymer rubber comprising an ethylene-α-olefin copolymer rubber or an ethylene-α-olefin-nonconjugated diene copolymer rubber. A method for producing a plastic elastomer composition.

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