JP2006256099A - Method for producing thermoplastic elastomer composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a thermoplastic elastomer composition which is a method for melting/kneading a rubber component and a resin component by using a twin-screw extruder and in which the rubber component is supplied to the twin-screw extruder by a metering pump, and the accuracy of the quantitative supply of the rubber component and the resin component is excellent. <P>SOLUTION: In the method for producing the thermoplastic elastomer composition, the rubber component and the resin component are melted/kneaded by using the twin-screw extruder. The rubber component is supplied to the extruder by the metering pump, and each of the amounts of the rubber component and the resin component to be supplied to the extruder is controlled independently. In the method for producing the thermoplastic elastomer composition, the rubber component and the resin component are melted/kneaded by using the twin-screw extruder. The rubber component is supplied to the extruder by the metering pump, and the amounts of the rubber component and the resin component to be supplied to the extruder are controlled proportionally. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a thermoplastic elastomer composition. More specifically, the present invention relates to a method of melt kneading a rubber component and a resin component using a twin screw extruder, and supplying the rubber component to the twin screw extruder with a metering pump. The present invention relates to a method for producing a thermoplastic elastomer composition having excellent supply quantitative accuracy.

  Thermoplastic elastomer compositions do not require a vulcanization process and can be processed on ordinary thermoplastic resin molding machines, and are used in a wide range of fields such as automobile parts, home appliance parts, and miscellaneous goods. Is being used. Among thermoplastic elastomers, olefinic thermoplastic elastomer compositions are widely used as environmentally friendly materials that are lightweight and recyclable and do not contain chlorine.

  As a method for producing a thermoplastic elastomer composition, for example, in the case of an olefin-based thermoplastic elastomer composition, a massive olefin copolymer rubber and an olefin polymer resin are kneaded by a closed kneader exemplified by a Banbury mixer. The method of doing is known. A method using a closed kneader such as a Banbury mixer is excellent in the quantitativeness of raw materials, but has a problem that it is not efficient because it is a batch type and is low in productivity.

  As a method of continuously supplying a lump of rubber to a twin screw extruder, a vulcanizable rubber composition in which a bale rubber cut into a strip shape is plasticized with a short screw extruder and supplied to the twin screw extruder via a gear pump. A manufacturing method is shown in Patent Document 1.

Further, Patent Document 2 discloses a method for continuously producing a thermoplastic elastomer composition comprising a rubber component and a resin component using a rubber supply device comprising a screw extruder and a gear pump. In addition, this document features a control method including the following first to fifth steps.
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 5 for calculating: Step for 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.

  Generally, it has a residence time of several tens of seconds to several minutes from when the raw rubber component or resin component is supplied to the twin-screw extruder until it is melt-kneaded in the extruder and reaches the exit of the extruder. Therefore, in the supply amount control method disclosed in Patent Document 2, the thermoplastic elastomer composition at the time when the rubber component in the first step and the resin component in the second step are supplied, and the raw material supplied in the third step is at the outlet of the extruder. There is a time difference due to the residence time between the time points at which the materials are weighed. Therefore, the step of calculating the supply amount of the rubber component based on the resin component and the amount of the thermoplastic elastomer composition in the fourth step, and the supply of the bulk rubber component in the first step based on the calculated supply amount of the fifth step There is a problem that it is difficult to accurately perform the process of controlling the amount without considering the influence of the residence time.

  In addition, the method of Patent Document 2 has a problem that, in terms of equipment, an apparatus for quantifying the thermoplastic elastomer composition at the exit of the extruder in the third step is essential, and equipment costs increase.

JP-T-2004-534679 JP 2004-299379 A

  In such a situation, the problem to be solved by the present invention is a method of melt kneading a rubber component and a resin component using a twin screw extruder, and supplying the rubber component to the twin screw extruder using a metering pump. The object of the present invention is to provide a method for producing a thermoplastic elastomer composition having excellent supply and quantitative accuracy of a rubber component and a resin component.

  That is, one of the present inventions is a method for producing a thermoplastic elastomer composition in which a rubber component and a resin component are melt-kneaded using a twin screw extruder, and the rubber component is converted into a twin screw extruder by a metering pump. The present invention relates to a method for producing a thermoplastic elastomer composition in which a rubber component and a resin component are independently supplied to a twin-screw extruder.

  Another invention of the present invention is a method for producing a thermoplastic elastomer composition in which a rubber component and a resin component are melt kneaded using a twin screw extruder, and the rubber component is converted into a twin screw extruder by a metering pump. The present invention relates to a method for producing a thermoplastic elastomer composition that supplies and controls proportionally the supply amounts of a rubber component and a resin component to a twin screw extruder.

  According to the present invention, the rubber component and the resin component are melt-kneaded using a twin screw extruder, and the rubber component and the resin component are supplied to the twin screw extruder by a metering pump. A method for producing an excellent thermoplastic elastomer composition can be provided.

  The twin-screw extruder that can be used in the present invention has two screw rotation directions in the same direction, different directions, or those in which the two screws are completely or partially engaged, etc. Among them, an arbitrary one is mentioned, and among them, those in which the screw rotation direction is the same direction and the two screws are completely or partially engaged are preferable. The ratio (L / D) of the length (L) to the screw diameter (D) of the screw of the twin screw extruder used in the present invention is usually 25 to 70, preferably 30 to 65, more preferably 35 to 60.

  Examples of the metering pump that supplies the rubber component that can be used in the present invention include a positive displacement pump having a piston, a blade pump (vane pump), a gear pump, and the like. Among these, a gear pump is particularly preferable. Further, a screw extruder can be combined with the upstream side of the metering pump to be used as a rubber supply device. In particular, a rubber supply device in which a screw extruder and a gear pump are combined is preferable. By installing a screw extruder on the upstream side of the metering pump, the rotation speed of the screw extruder is adjusted according to the pressure on the supply side of the gear pump, and the pressure of the rubber sent from the screw extruder to the gear pump is easily and constant. It can be controlled and the supply stability of rubber is increased. 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.

  The metering pump for supplying the rubber component is connected to the barrel of the twin-screw extruder via a pipe. Normally, the metering pump for supplying the rubber component is connected to the uppermost barrel of the twin screw extruder, but depending on the required characteristics of the thermoplastic elastomer composition to be manufactured, the twin screw extrusion is connected via a pipe. The barrel position of the machine may be changed.

  In order to produce a thermoplastic elastomer composition having a predetermined composition, the supply amount of the rubber component to the twin-screw extruder is ± 3%, preferably ± 2%, more preferably ± 1.5% with respect to the set value. It is desirable that the control be performed within the range.

  Examples of the apparatus for supplying the resin component to the twin screw extruder that can be used in the present invention include feeders such as a capacity-type or weight-type, screw-conveying feeder, belt-conveying feeder, Among them, a weight type feeder is preferable, and a weight type feeder whose supply amount can be controlled with an accuracy within ± 1% of the set value is more preferable.

  The device that supplies the resin component to the twin screw extruder is connected to the upper part of the barrel of the twin screw extruder via a pipe, or connected to the side feeder connected to the barrel of the twin screw extruder via a pipe. To do. The barrel position of the twin screw extruder to which the apparatus for supplying the resin component is connected can be arbitrarily selected according to the characteristics of the thermoplastic elastomer composition to be produced, and if necessary, a plurality of two or more locations. From the barrel, the resin component or the rubber component that can be supplied by the apparatus can also be supplied in two or more places.

  The method of independently controlling the supply amount of the rubber component and the resin component to the twin screw extruder used in the present invention is a set discharge amount (A) of the thermoplastic elastomer composition produced by the twin screw extruder, And the set supply rate (a) of the rubber component and the set supply rate (b) of the resin component obtained from the blended composition (B) of the thermoplastic elastomer composition to be produced, the supply rate of each component is maintained independently. It is a method to control.

For example,
(A) Setting discharge amount of thermoplastic elastomer composition produced by a twin screw extruder: 500 (Kg / hr)
(B) Composition of thermoplastic elastomer composition: rubber component / resin component = 80/20 (wt%)
When,
The rubber component is controlled at a set supply rate (a) of 400 (kg / hr), and the resin component is set at a set supply rate (b) of 100 (kg / hr) so that each supply rate is maintained independently. is there.

  In this control method, even when the measured supply rate of the rubber component is 420 (kg / hr), the resin supply rate is controlled to be 100 (kg / hr).

  The method of proportionally controlling the supply amounts of the rubber component and the resin component to the twin-screw extruder used in the present invention is the set discharge amount (A) of the thermoplastic elastomer composition produced by the twin-screw extruder, and the production. The rubber component obtained from (A) and (B) by controlling the rubber supply rate so as to maintain the set supply rate (a) of the rubber component, which is obtained from the blended composition (B) of the thermoplastic elastomer composition The method of controlling the resin supply rate (b) so that the actual ratio of rubber component / resin component calculated by calculating from the measured supply rate of the rubber component and the actual supply rate of the resin component matches the set ratio of the resin component It is.

For example,
(A) Setting discharge amount of thermoplastic elastomer composition produced by a twin screw extruder: 500 (Kg / hr)
(B) Composition of thermoplastic elastomer composition: rubber component / resin component = 80/20 (wt%)
When,
When the supply rate of the rubber component is controlled so that the set supply rate (a) of 400 (kg / hr) of the rubber component is maintained, and the measured supply rate of the rubber component is 400 (kg / hr) In this method, the resin supply rate is controlled to 100 (kg / hr) (b) so as to meet the set ratio of rubber component / resin component = 80/20 = 4.

  In this control method, if the measured supply rate of the rubber component is 420 (kg / hr), the resin supply rate is set so as to meet the set ratio of rubber component / resin component = 80/20 = 4. It is controlled to be 105 (kg / hr) (b).

  In the present invention, the lump rubber component refers to a rubber lump having various shapes such as a spherical shape, a cylindrical shape as well as a rectangular parallelepiped shape, a flake shape, a crumb shape, a lint shape, and an internal gap. The shape is not limited as long as it can be identified as a lump. 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 rubber component used in the method for producing the thermoplastic elastomer composition of the present invention is not particularly limited, but olefin copolymer rubber, particularly ethylene-α-olefin copolymer rubber is preferred. The olefin copolymer rubber is a copolymer containing at least one olefin and is in a rubbery state at room temperature. The ethylene-α-olefin copolymer rubber is a copolymer containing at least ethylene and one or more α-olefins, and is in a rubbery state at room temperature. Examples of the ethylene-α-olefin copolymer rubber include ethylene-α-olefin copolymer rubber, ethylene-α-olefin-nonconjugated diene copolymer rubber, and ethylene-α-olefin copolymer rubber. It may be a mixture of polymer rubber and ethylene-α-olefin-nonconjugated diene copolymer rubber. In addition, oil-extended ethylene-α-olefin copolymer rubber may be used as the rubber component.

  The α-olefin in the ethylene-α-olefin copolymer is an olefin having 3 or more carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1- Examples include octene and 1-decene. Among them, 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-nonconjugated 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. Non-conjugated dienes include 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, and 7-methyl-1,6-octadiene. Chain non-conjugated dienes such as: cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, Cyclic non-conjugated dienes such as 6-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-deca Triene are mentioned as Lien, 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 (ML _{1 + 4} 100 ° C.) at 100 ° C. of 30 to 350, more preferably 40 to 200. 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 propylene homopolymer and / or 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 production of a crosslinked olefinic thermoplastic elastomer composition, 35 to 90/65 to 10, preferably 60 to 90/40 to 10, are used, and in the case of production of an uncrosslinked olefinic thermoplastic elastomer composition. Is 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 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 thermoplastic elastomer composition, N, N'-m-phenylene bismaleimide, toluylene bismaleimide P-quinone dioxime, nitrobenzene, diphenyl are used as crosslinking aids during dynamic crosslinking with organic peroxides. Peroxide crosslinking aids such as guanidine 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 rubber pulverizer, rubber supply device, extruder, resin supply device, additive mixture supply device, and twin screw extruder used in the examples are as follows.
Rubber crusher: Made by Horai Rubber crusher Rubber supply device: Made by Nippon Steel Works Constructed by screw extruder and gear pump Resin feed equipment: Nippon Steel Works heavy weight feeder Additive supply equipment: Nippon Steel Works heavy weight feeder Biaxial Extruder: Nippon Steel Works TEX90
The rubber, thermoplastic resin, additive mixture, and crosslinking agent used in the examples are as follows.

Rubber-1: Veiled ethylene-propylene copolymer rubber (Mooney viscosity (ML _{1 + 4} 100 ° C.) 95: measured in accordance with ASTM D-927-57T, propylene content = 31 wt%)
Rubber-2: Bale-like 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.) 53: ASTM Measured according to D-927-57T).

Thermoplastic resin PP-1: Polypyropylene (manufactured by Sumitomo Chemical Co., Ltd .; trade name: Nobrene Z144A, MFR 20 g / 10 min: measured at a temperature of 230 ° C. and a load of 21.18 N according to JIS K6758).
PP-2: Polypyropylene (manufactured by Sumitomo Chemical Co., Ltd .; trade name: Nobren Y501N, MFR 13 g / 10 min: measured at a temperature of 230 ° C. and 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 Sumitizer BP101) = 0.9 / 0.25 A mixture consisting of.
Cross-linking agent: 2,5-dimethyl-2,5-di (t-butylperoxy) hexane diluted to 10% by weight with a mineral oil-based oil (manufactured by Idemitsu Kosan; trade name Iana Process Oil PW380).

Example 1
The rubber-1 was made into a band-like lump rubber by a rubber crusher, and the lump rubber was fed to a screw extruder of a rubber feeding device and continuously fed from a barrel position at the uppermost stream of a twin screw extruder through a gear pump. The rubber pressure at the gear pump inlet was detected by a pressure sensor, and control was performed to keep the rubber pressure constant and constant at a constant rubber supply speed by changing the screw speed of the screw extruder of the rubber supply device according to the value.
From a barrel in the middle of the twin screw extruder, PP-1 was added as a resin component using a weight feeder in which the quantitativeness of the supply rate was confirmed in advance.
The feed rates of the rubber component and the resin component were independently controlled so as to be the set feed rates.
In a stable state where the instantaneous fluctuation of the supply rate of PP-1 is within ± 1% of the set value, the thermoplastic elastomer composition melted and kneaded and extruded at the exit of the twin screw extruder is collected for 1 minute. The measurement was performed several times, and the actually measured discharge amount of the thermoplastic elastomer composition was determined. The PP-1 supply amount was subtracted from the measured discharge amount to determine the measured supply rate of the rubber component.
The measured supply speed of the measured rubber component was within a range of ± 3% relative to the set value under any of the three different discharge amount conditions.
The results are shown in Table 1.

Example 2
The same procedure as in Example 1 was performed except that the thermoplastic elastomer composition-2 using rubber-2 and PP-2 was used.
The results are shown in Table 2.

Example 3
It was carried out in the same manner as in Example 1 except that the blending was a thermoplastic elastomer composition-3, and the proportional control was performed so that the supply rate of the rubber component and the ratio of the rubber component / resin component matched the set values. .
The accuracy of the rubber supply amount calculated from the amount of raw material used was within ± 3% of the set value.
The results are shown in Table 3.

Example 4
In the same manner as in Example 1, rubber-2 was continuously supplied from the rubber supply device from the uppermost barrel of the twin screw extruder, and PP was used as a resin component from the middle barrel of the twin screw extruder using a weight feeder. -2 was added. The feed rates of the rubber component and the resin component were independently controlled so as to be the set feed rates.
Further, the additive mixture was continuously fed from the weight feeder of the additive feeder to the twin screw extruder from the same barrel as PP-2. From the barrel downstream from the position where PP-2 and the additive mixture are added, the crosslinking agent is continuously supplied to the twin-screw extruder by the plunger pump of the crosslinking agent supply apparatus to perform dynamic crosslinking, and crosslinked thermoplastic. An elastomer composition was obtained.
The accuracy of the rubber supply amount calculated from the amount of raw material used was within ± 3% of the set value.
The results are shown in Table 4.

Claims (4)

A method for producing a thermoplastic elastomer composition in which a rubber component and a resin component are melt kneaded using a twin screw extruder, wherein the rubber component is supplied to the twin screw extruder by a metering pump, and the rubber component and the resin component are A method for producing a thermoplastic elastomer composition, wherein the amount supplied to a screw extruder is independently controlled. A method for producing a thermoplastic elastomer composition in which a rubber component and a resin component are melt kneaded using a twin screw extruder, wherein the rubber component is supplied to the twin screw extruder by a metering pump, and the rubber component and the resin component are A method for producing a thermoplastic elastomer composition, wherein the amount supplied to a screw extruder is proportionally controlled. The production method according to claim 1 or 2, wherein the supply amount of the rubber component to the twin screw extruder is controlled within a range of ± 3% relative to the set value. The heat according to any one of claims 1 to 3, wherein the rubber component is an olefin copolymer rubber composed of a block-like ethylene-α-olefin copolymer rubber or an ethylene-α-olefin-nonconjugated diene copolymer rubber. A method for producing a plastic elastomer composition.