JP2008031445A - Thermoplastic elastomer composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an olefin thermoplastic elastomer composition which, through dynamic crosslinking of an olefin resin and an ethylene-α-olefin copolymer rubber as polymer components, has excellent appearance of the extrusion molded product thereof while also having excellent physical properties such as compression set and tensile strength. <P>SOLUTION: The method for producing the thermoplastic elastomer composition comprises the steps of dynamically heat treating the following components(A) to (D), adding a component(E) to the resulting composition, and kneading the resulting mixture. (A): 40-95 pts.wt. of an ethylene-α-olefin copolymer rubber; (B): 5-60 pts.wt. of a polyolefin resin; (C): 0.1-20 pts.wt. of a halogenated alkylphenolic resin-based crosslinking agent; (D): 0.001-0.7 pt.wt. of an iron oxide; and (E): 0.1-20 pts.wt. of a halogen capturing agent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an olefinic thermoplastic elastomer composition and a method for producing the same. Specifically, the appearance skin of the extruded product of the composition obtained by dynamic heat treatment containing an olefin resin and ethylene-α-olefin copolymer rubber as a polymer component is excellent, and tensile strength, compression set, etc. The present invention relates to an olefinic thermoplastic elastomer composition having excellent physical properties and a method for producing the same.

  In the case of obtaining a thermoplastic elastomer by dynamically heat-treating an olefin resin and rubber, it is already known to use an alkylphenol resin as a crosslinking agent and tin chloride as an activator. Such thermoplastic elastomers do not require a vulcanization process, have the same molding processability as thermoplastic resins, and are attracting attention from the viewpoint of process rationalization and recyclability, and are used for automobile parts, home appliance parts, medical equipment parts, Widely used in fields such as electric wires.

  However, thermoplastic elastomers obtained by a conventionally known technique are satisfactory in terms of physical properties such as tensile strength and compression set, but have a problem that the appearance, skin, etc. of the extruded product are inferior (patent document) 1 and Patent Document 2). The cause of this problem is that when a resin crosslinking agent and an activator are added together and dynamic crosslinking is carried out, the crosslinking reaction becomes remarkably fast, so that the morphology of the olefin resin and rubber becomes inappropriate.

JP-A-4-63851 Japanese Patent No. 3303005

  The problems to be solved by the present invention include an olefin resin and an ethylene-α-olefin copolymer rubber as polymer components, and by dynamic crosslinking, the appearance and skin of the extruded product are excellent, and further, compression permanent The object is to provide a method for producing an olefinic thermoplastic elastomer composition having physical properties such as strain, oil resistance, and tensile strength.

The first invention of the present invention is a method for producing a thermoplastic elastomer composition in which a component (E) is added and kneaded to a composition obtained by dynamic heat treatment of the following components (A) to (D). It is concerned.
(A): Ethylene-α-olefin copolymer rubber 40-95 parts by weight (B): Polyolefin resin 5-60 parts by weight (C): Halogenated alkylphenol resin-based crosslinking agent 0.1-20 parts by weight (D): 0.001 to 0.7 parts by weight of iron oxide (E): 0.1 to 20 parts by weight of halogen component scavenger The second invention of the present invention is the heat obtained by the above production method. The present invention relates to a plastic elastomer composition.

  According to the present invention, an olefin resin and an ethylene-α-olefin copolymer rubber are included as polymer components and dynamically cross-linked, so that the appearance and skin of the extruded product are excellent, and further physical properties such as compression set and tensile strength. Thus, it is possible to provide an olefinic thermoplastic elastomer composition having both of the above.

  The component (A) of the present invention is an ethylene-α-olefin copolymer rubber, specifically, an ethylene-α-olefin copolymer rubber and an ethylene-α-olefin-nonconjugated diene copolymer rubber. I can give you.

  Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene, and propylene is particularly preferable. Examples of the non-conjugated diene include 1,4-hexadiene, dicyclopentadiene, vinyl norbornene, and 5-ethylidene-2-norbornene.

  The ratio (weight ratio) of ethylene / α-olefin in (A) is preferably 90/10 to 30/70. An ethylene-α-olefin copolymer rubber and an ethylene-α-olefin-nonconjugated diene copolymer rubber may be mixed and used. Either oil-extended rubber or non-oil-extended rubber may be used. The content of the extending oil in the oil-extended rubber is preferably 20 to 200 parts by weight per 100 parts by weight of the copolymer rubber.

The extender oil has effects such as lowering the hardness of the thermoplastic elastomer composition and improving oil resistance.
When oil-extended rubber is used, the weight regarded as the copolymer rubber is applied to the extending oil.

  Preferable examples of the ethylene-α-olefin copolymer rubber include ethylene-propylene copolymer rubber having an ethylene / propylene weight ratio of 85/15 to 45/55.

The ethylene-α-olefin copolymer rubber preferably has a Mooney viscosity at 100 ° C. (ML _{1 + 4} 100 ° C.) of 10 to 350, more preferably 30 to 300. If the Mooney viscosity is too low, the mechanical strength may be inferior. On the other hand, if the Mooney viscosity is too high, the appearance of the molded product may be impaired.

  When the ethylene-α-olefin-nonconjugated diene copolymer rubber is used, the content of the nonconjugated diene is preferably 1 to 30% by weight, more preferably 3 to 20% by weight. When the ethylene content exceeds 90% by weight, the flexibility of the resulting composition is lost, and when it is less than 50% by weight, the mechanical strength tends to decrease. Further, when the non-conjugated diene content is less than 1% by weight, the degree of cross-linking of the resulting composition does not increase, so that the mechanical strength decreases. When it exceeds 30% by weight, the injection moldability tends to be inferior. This is also disadvantageous in terms of cost.

  The component (B) of the present invention is a polyolefin resin. Examples of polyolefin resins include homopolymers or copolymers such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, Of these, polypropylene is preferable.

  Polypropylene is a known polymer and is polymerized by a known polymerization method. When propylene is polymerized, an α-olefin such as ethylene, butene-1, pentene-1, 4-methylpentene-1 may be copolymerized. As the three-dimensional structure, an isotactic structure is preferable, but a syndiotactic structure, a mixture of these structures, or a structure partially including an atactic structure can also be used. Polypropylene is a polymer mainly composed of propylene, such as a propylene homopolymer, a random copolymer or block copolymer of propylene-α-olefin. The melt flow rate of polypropylene (measured according to JIS K6758 at a temperature of 230 ° C. and a load of 21.18 N) is preferably 0.05 to 100 g / 10 minutes, more preferably 0.1 to 50 g / 10 minutes. is there.

  The component (C) of the present invention is a halogenated alkylphenol resin crosslinking agent system.

式中、ｎは０〜１０の整数；Ｒは炭素数１〜１５の飽和炭化水素基である。 The heat-crosslinkable phenol resin is produced by a known reaction method. An alkylphenol resin having a methylol group, a brominated alkylphenol resin having a terminal hydroxyl group brominated, and the like are provided as a crosslinking agent for the component (C). . Among these, the alkylphenol resin having a methylol group is preferably a brominated alkylphenol resin because it requires a chlorinated activator, and therefore has a significant corrosiveness in production facilities.
Examples of the brominated alkylphenol crosslinking agent include compounds represented by the following formula.

In the formula, n is an integer of 0 to 10; R is a saturated hydrocarbon group having 1 to 15 carbon atoms.

  The component (D) of the present invention is iron oxide.

The component (E) of the present invention acts as a halogen component scavenger, preferably a substance having a bromine scavenging action, and more preferably from zinc oxide, magnesium oxide, hydrotalcite, calcium oxide and calcium carbonate. At least one selected. Of these, zinc oxide and magnesium oxide are particularly preferable. Zinc oxide can be used in a wide range of types such as rubber, paint, and printing regardless of the particle size, such as 1 type, 2 types, and activated zincation.
Magnesium oxide can be used for rubber, resin, food additives, etc. regardless of particle size.

  The amount of each component used in the production method of the present invention is as follows. The addition amount of (A) is 40 to 95 parts by weight, the addition amount of (B) is 5 to 60 parts by weight (provided that the total of (A) and (B) is 100 parts by weight), and The addition amount of (C) per 100 parts by weight of the total amount of (A) and (B) is 0.1 to 20 parts by weight, and the addition amount of (D) is 0.001 to 0.7 parts by weight. , (E) is added in an amount of 0.1 to 20 parts by weight. The amount of (A) when oil-extended rubber is used is based on the amount including extended oil. The amount of each component is based on the total amount when two or more types are used in combination.

  One of the greatest features of the present invention is that the addition amount of iron oxide (crosslinking activator) as component (D) is preferably a trace amount. When the component (D) is in a very small amount, the crosslinking speed becomes slow and the dynamic crosslinking proceeds well, so the morphology of the olefin resin and rubber becomes preferable, and the appearance and skin of the extruded product tend to be improved. is there. Since the addition amount of the component (D) is very small, the effect of the component (D) as an activator is lost when the halogen component scavenger (E) and the component (D) are added simultaneously and subjected to dynamic heat treatment. Therefore, the degree of cross-linking is lowered, and physical properties such as compression set and tensile strength are inferior. As a measure to solve such problems, it was discovered that the components (A) to (D) were added and subjected to dynamic heat treatment, and then the component (E) was added to the resulting composition and kneaded. However, the present invention has been achieved.

  In the present invention, other components can be used according to various purposes within a range not impairing the effect. Examples of such components include fillers, antioxidants, heat stabilizers, light stabilizers, UV absorbers, mold release agents, tackifiers, colorants, neutralizers, lubricants, dispersants, flame retardants. , Antistatic agents, conductivity imparting agents, antibacterial agents, bactericides, carbon black, talc, clay, silica and other inorganic fillers, glass fibers, carbon fibers, process oils, softeners, and the like.

  The production method of the present invention will be described. In the production method of the present invention, the components (A) to (D) are subjected to dynamic heat treatment, and then the component (E) is added to the resulting composition and kneaded. According to the present invention, the extrusion processability is excellent. A thermoplastic elastomer can be obtained.

  The weight ratio ((A) / (B)) of the component (A) to the component (B) is 40/60 to 95/5. If the amount of the component (A) is too small, the resulting composition tends to be less elastic, while if the amount of the component (A) is excessive, the fluidity is lowered, resulting in poor appearance such as extrudates and injection molded products. Tend to be. When the component (B) is too small, the fluidity is lowered and the appearance of the extrudate tends to be poor. On the other hand, when the component (B) is excessive, the resulting composition has a high hardness and tends to lose its flexibility.

  Component (C) is a halogenated alkylphenol resin-based crosslinking agent. Component (C) is added in an amount of 0.1 to 20 parts by weight per 100 parts by weight in total of (A) and (B). If the component (C) is too small, a sufficient degree of cross-linking of the olefin copolymer rubber cannot be obtained, and the physical properties such as tensile strength and compression set of the resulting composition tend to be inferior. On the other hand, if the amount of component (C) is excessive, the resulting composition tends to have problems such as a decrease in fluidity, an increase in odor, and a disadvantage in terms of cost.

  Component (D) acts as a crosslinking activator. Component (D) is added in an amount of 0.001 to 0.7 parts by weight, preferably 0.001 to 0.5 parts by weight, more preferably 0, per 100 parts by weight in total of (A) and (B). 0.001 to 0.3 parts by weight, more preferably 0.001 to 0.1 parts by weight. When the component (D) is too small, the degree of crosslinking of the olefin copolymer rubber becomes low, and the resulting composition tends to be inferior in physical properties such as heat resistance, tensile strength and compression set. On the other hand, if the component (D) is excessive, the cross-linking speed of the olefin copolymer rubber is increased, so that the extruded skin of the obtained composition tends to deteriorate.

  The component (E) is a halogen component scavenger. (E) The addition amount of a component is 0.1-20 weight part per 100 weight part in total of (A) and (B). When the component (E) is too small, it is insufficient to supplement the halogen gas generated by the crosslinking reaction by dynamic heat treatment, and there is a tendency that problems such as corrosion of the production apparatus and environmental pollution occur. On the other hand, when the component (E) is excessive, the above-mentioned problems are solved, but physical properties such as tensile strength and compression set of the obtained composition tend to be inferior.

  (E) The timing which adds a component is after adding (A)-(D) component and performing dynamic heat processing. When (A) to (E) are simultaneously added and subjected to dynamic heat treatment, the degree of crosslinking decreases, and the resulting composition has poor physical properties such as tensile strength and compression set. Alternatively, when zinc oxide is used as the component (E) and the components (A) to (E) are added at the same time, the crosslinking rate increases, so that the resulting composition has good physical properties such as tensile strength and compression set, The appearance and skin of the extruded product will be deteriorated.

  This invention is a manufacturing method of the thermoplastic elastomer composition which adds and knead | mixes the (E) component to the composition obtained by carrying out the dynamic heat processing of the said (A)-(D) component. As the dynamic heat treatment apparatus, a known apparatus such as an open type mixing roll, a non-open type Banbury mixer, a kneader, an extruder, or a twin screw extruder can be used. Alternatively, it is possible to combine two or more types of apparatuses, but a twin screw extruder is preferably used particularly in terms of productivity. The conditions (temperature, time) of the dynamic heat treatment are usually 150 to 300 ° C., preferably 170 to 280 ° C., and the time is 0.5 to 30 minutes, preferably 1 to 20 minutes. The kneading after adding the component (E) can be carried out by the same apparatus and method as the dynamic heat treatment.

  The thermoplastic elastomer composition obtained by the present invention is molded by a commonly used molding method such as an injection molding method, an extrusion molding method, a hollow molding method, a compression molding method, or the like. Applications include automotive parts (weather strips, ceiling materials, interior seats, bumper moldings, side moldings, air spoilers, air duct hoses, cup holders, side brake grips, shift knob covers, seat adjustment knobs, flapper door seals, wire harness grommets, rack and racks. Pinion boot, suspension cover boot, glass guide, inner belt line seal, roof guide, trunk lid seal, molded quarter window gasket, corner molding, glass encapsulation, hood seal, glass run channel, secondary seal, various packing, etc. ), Civil engineering / building material parts (water-stopping materials, joint materials, window frames for construction, etc.), sports equipment (golf clubs, tennis rackets) S etc.), industrial parts (hoses tubes, gaskets, etc.), household electric appliance parts (hoses, packings, etc.), medical equipment parts, electric wires, are used as materials in extensive fields such as miscellaneous goods.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded.

The raw materials and evaluation methods used in the following examples are as follows.
[Raw materials used]
EPDM (component A): ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber (Esprene 670F manufactured by Sumitomo Chemical Co., Ltd.) 100 parts paraffinic oil exhibition PP-1 (component B): polypropylene (Sumitomo Chemical Co., Ltd.) Company nobren HR100)
Antioxidant: Irganox 1010 (Ciba Specialty Chemicals)
Phenol resin (component C): Brominated alkylphenol resin (Takiroll 250-I manufactured by Taoka Chemical Co., Ltd.)
Iron oxide (component D): iron (III) oxide and iron (IV) oxide (both grades made by Kanto Chemical)
Zinc oxide (component E): 2 types of zinc oxide (manufactured by Shodo Chemical)
Magnesium oxide (component E): Kyowa Mag 150 (manufactured by Kyowa Chemical)

[Evaluation methods]
The thermoplastic elastomer composition obtained by the present invention was compression molded at 200 ° C. to prepare a test piece having a thickness of 2 mm, and the physical properties were measured by the following methods.
Hardness: JIS K6253 compliant (Shore-A instantaneous value)
Breaking strength: Conforms to JIS K6251 (JIS No. 3 dumbbell, tensile speed 200 mm / min)
Elongation at break: Same as above Compression set: Compliant with JIS K6262 (70 ° C., 22 hours, 25% compression)
Extruded skin surface roughness (Rz) and extruded skin practicality determination: 25 mmφ single screw extruder (Union Plastics Co., Ltd.) L / D = 20, full flight screw, width 100 mm × thickness 1 mm flat plate die) Then, molding was performed under the conditions of a molding temperature hopper 150 ° C., a cylinder 220 ° C., a die 220 ° C., and a screw rotation speed 40 rpm. The 10-point average roughness Rz of the surface of the obtained extruded product was measured with a surface roughness meter Surfcom manufactured by Tokyo Seimitsu Co., Ltd. (Conforms to JIS B0601) Further, the superiority or inferiority of the practicality was evaluated by visual observation with ○ × (with practicality = ◯, without practicality = ×).
Corrosion judgment of extruder: After applying dynamic heat treatment with a twin screw extruder under the following conditions, the extracted screw is 450 ° C. × 1 hour in a cleaning furnace (full clean IFB type manufactured by Toray Engineering Co., Ltd.) After the heat treatment, the corrosion state of the screw was determined (no corrosion = ◯, slight corrosion was observed = ×).

Examples 1-5 and Comparative Examples 1-5
Examples are shown below, but the amount of materials added is based on the total weight of component (A) and component (B) being 100 parts by weight. (See Table 1)
In twin screw extruder TEX44HCT (manufactured by Nippon Steel Works, L / D = 42), rotation speed = 280 rpm, cylinder temperature = C1-C2: 30 ° C., C3-C4: 150 ° C., C5-C11: 185 ° C. C12: Under the basic conditions of 200 ° C., head temperature = 200 ° C., extrusion speed = 50 kg / hr, the addition location of components (A) to (D) is added from the position of cylinder 2 and (E component) is added from the position of cylinder 9 did.

  Example 1: 0.01 parts by weight of iron oxide (III) (component D) was added from the position of the cylinder 2, and 0.3 parts by weight of zinc oxide (component E) was added from the position of the cylinder 9. Example 2: According to Example 1, the amount of iron (III) oxide (component D) added to the cylinder 2 was 0.03 part by weight. Example 3 According to Example 2, but 0.3 parts by weight of magnesium oxide (E component) was added from the cylinder 9 position. Example 4: According to Example 1, the amount of phenol resin (component C) added was 3.6 parts by weight. Example 5: Iron oxide (IV) (component D) was added from cylinder 2 and 0.8 part by weight of zinc oxide (component E) was added from cylinder 9. All of these have excellent extruding skin, excellent compression set, and no corrosiveness of the extruder screw.

In Comparative Example 1, since the component (E) is not added, there is corrosion of the extruder screw. In Comparative Example 2, although 1 part by weight of zinc oxide is added as the component (E) from the cylinder position 9, the extruded skin is inferior because the iron oxide (D component) from the cylinder 2 position is not added. In Comparative Example 3, since the iron oxide (III) (component D) is added in a large amount of 0.8 part by weight from the position of the cylinder 2, the extruded skin is inferior. In Comparative Example 4, since the iron oxide (IV) (component D) was added in a large amount of 1.5 parts by weight, the extruded skin was inferior. In Comparative Example 5, since the component (D) from the cylinder 2 position and the component (E) from the cylinder 9 position are not added, extrusion processing cannot be performed, and the extruder screw is corrosive.

It is a figure which shows the cylinder position of a twin-screw extruder.

Claims (6)

The manufacturing method of the thermoplastic elastomer composition which adds and knead | mixes a component (E) to the composition obtained by dynamic-heat-processing the following component (A)-(D).
(A): Ethylene-α-olefin copolymer rubber 40-95 parts by weight (B): Polyolefin resin 5-60 parts by weight (C): Halogenated alkylphenol resin-based crosslinking agent 0.1-20 parts by weight (D): Iron oxide 0.001-0.7 part by weight (E): Halogen component scavenger 0.1-20 part by weight The production method according to claim 2, wherein (C) is a brominated alkylphenol resin-based crosslinking agent. The production method according to claim 2, wherein (E) is at least one selected from zinc oxide, magnesium oxide, hydrotalcite, calcium oxide, and calcium carbonate. The thermoplastic elastomer composition obtained by the manufacturing method of the thermoplastic elastomer composition which adds and knead | mixes a component (E) to the composition obtained by dynamic-heat-processing the following component (A)-(D).
(A): Ethylene-α-olefin copolymer rubber 40-95 parts by weight (B): Polyolefin resin 5-60 parts by weight (C): Halogenated alkylphenol resin-based crosslinking agent 0.1-20 parts by weight (D): Iron oxide 0.001-0.7 part by weight (E): Halogen component scavenger 0.1-20 part by weight The thermoplastic elastomer composition according to claim 4, wherein (C) is a brominated alkylphenol resin-based crosslinking agent. The thermoplastic elastomer composition according to claim 4, wherein (E) is at least one selected from zinc oxide, magnesium oxide, hydrotalcite, calcium oxide, and calcium carbonate.

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