JP2985622B2 - Thermoplastic elastomer composition for calender molding - Google Patents

Abstract

PURPOSE:To provide a composition remarkably reduced in bleeding, excelling in mechanical properties, appearance, etc., and suited for calendering. CONSTITUTION:This composition is prepared by mixing 100 pts.wt. partially croosslinked composition prepared by dynamically heat-treating a mixture comprising 40-95wt.% oil-extended olefin copolymer rubber containing 20-150 pts.wt. mineral oil softener per 100 pts.wt. olefin copolymer rubber having a Mooney viscosity (ML1+4, 100 deg.C) of 120-350 and 5-60wt.% propylene polymer resin in the presence of an organic peroxide with 5-100 pts.wt. ethylene polymer resin and 0.03-2 pts.wt. higher fatty acid amide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermoplastic elastomer composition. More specifically, the present invention relates to an olefin-based thermoplastic elastomer composition for calender molding which has excellent mechanical properties, has little bleeding, and has good appearance, and which can substitute for vulcanized rubber.

[0002]

2. Description of the Related Art Thermoplastic elastomers (hereinafter referred to as "TP")
E ". ) Does not require a vulcanization step and can be processed with a normal thermoplastic resin molding machine. Applications have been developed in a wide range of fields, including automobile parts, home electric parts, and miscellaneous goods. I have. Among them, the olefin-based TPE composition is known from JP-A-48-26838 and the like. However, this composition is inferior to vulcanized rubber in terms of flexibility, tensile strength at break, elongation at break, compression set and the like, and thus has limited applications.
In order to improve these performances, the addition of a mineral oil-based softening agent or a peroxide non-crosslinked hydrocarbon-based rubber-like substance imparts flexibility, and the use of a crosslinking aid increases the degree of crosslinking and improves compression set. Various attempts have been made. (For example, JP-B-56-15740).

However, in these compositions, even if the degree of cross-linking is increased to improve the compression set, the flexibility is reduced, the breaking strength and elongation at break in a tensile test are reduced, or the composition is softened to the surface. It is difficult to obtain an olefin-based TPE composition having an excellent balance of physical properties due to bleeding of the agent.

[0004]

The problem to be solved by the present invention under the present circumstances is that olefin-based TPEs, especially olefin-based TPEs having a low hardness (90 or less in Shore A hardness).
In PE, less bleed, good appearance, flexibility,
It is an object of the present invention to provide an olefin-based TPE composition which can be substituted for a vulcanized rubber in terms of mechanical properties (particularly, tensile strength at break, elongation at break, compression set) and has good calenderability.

[0005]

The present inventors have conducted intensive studies to overcome the above-mentioned drawbacks of the conventional method, and as a result, an oil-extended olefin copolymer containing a specific mineral oil-based softener in advance. The present inventors have found that a composition obtained by partially cross-linking this mixture using a rubber and a propylene-based polymer resin has excellent flexibility and mechanical properties, and completed the present invention. That is, the present invention provides a 100 ° C. Mooney viscosity (ML _{1 + 4} 100
C) of 120 to 350 per 100 parts by weight of the olefin copolymer rubber.
Add a mineral oil-based softener to the solution and then remove the solvent.
Is, oil-extended olefinic copolymer rubber containing 20 to 150 parts by weight of the mineral oil softening agent (A) 40 to 95 wt%
And a propylene-based polymer resin (B) in an amount of 5 to 60% by weight in the presence of an organic peroxide. C) 5 to 100 parts by weight of a higher fatty acid amide (D) and 0.03 to 2 parts by weight of a thermoplastic elastomer composition for calender molding. Hereinafter, the present invention will be described in detail.

In the present invention, the olefin copolymer rubber used in the oil-extended olefin copolymer rubber (A) includes, for example, ethylene-propylene copolymer rubber, ethylene-propylene-nonconjugated diene copolymer rubber. It is an amorphous random elastic copolymer containing an olefin as a main component, such as a united rubber, an ethylene-butene-non-conjugated diene-based copolymer rubber, and a propylene-butadiene-based copolymer rubber. Among these, an ethylene-propylene-nonconjugated diene copolymer rubber is particularly preferred. Examples of the non-conjugated diene include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, and ethylidene norbornene, with ethylidene norbornene being particularly preferred.

As a more preferred specific example, the propylene content is 10 to 55% by weight, preferably 20 to 40% by weight.
Ethylene-propylene-ethylidene norbornene copolymer rubber (hereinafter referred to as "EPDM") having a non-conjugated diene content of 1 to 30% by weight, preferably 3 to 20% by weight, such as ethylidene norbornene. Part 1
00 ° C Mooney viscosity (ML _{1 + 4} 100 ° C) is 120 ~
350, preferably 140-300. If the propylene content is less than 10% by weight, flexibility is lost and 55
If it is more than 10% by weight, the mechanical properties tend to decrease. If the content of non-conjugated diene typified by ethylidene norbornene is less than 1%, mechanical properties tend to decrease, and if it exceeds 30% by weight, injection moldability tends to decrease. If the Mooney viscosity at 100 ° C. (ML _{1 + 4} 100 ° C.) is lower than 120, the mechanical properties are lost, and if it is higher than 350, the appearance of the molded article is impaired. However, when EPDM having a Mooney viscosity of 120 to 350 is used, the mechanical properties are large, the tensile strength at break and the elongation at break are dramatically improved, and the crosslinking efficiency is increased. This leads to improved distortion. EPDM manufactured by a known method can be used.

Next, the mineral oil-based softener used in the present invention is a high-boiling petroleum fraction blended for the purpose of improving molding processability and mechanical properties, and is a paraffinic, naphthenic or Although there are aromatic compounds and the like, paraffin compounds are preferably used. As the aromatic component increases, the pollution becomes stronger,
Limits the use of transparent or light-colored products,
Not preferred.

The oil-extended olefin-based copolymer rubber (A) is
Mineral oil-based per 100 parts by weight of olefin-based copolymer rubber
20 to 150 parts by weight of a softening agent, preferably 30 to 120 parts by weight
It contains parts by weight. If less than 20 parts by weight,
The fluidity of the refining TPE composition is reduced,
Dough molding processability is impaired. On the other hand, from 150 parts by weight
When it increases, the plasticity increases significantly and the processability deteriorates,
In addition, the performance of the product, such as physical properties, is reduced.
Absent. And the oil-extended olefin copolymer rubber (A)
100 ° C Mooney viscosity (ML _{1 + 4}100 ° C) is preferable
More preferably 30 to 100, more preferably 40 to 90.
If it is lower than 30, mechanical properties are lost, and if it is higher than 100,
Molding tends to be difficult.

EPDM having a Mooney viscosity of 120 to 350
When a large amount of a mineral oil-based softening agent is blended using olefin, an olefin-based TPE composition capable of simultaneously satisfying improvement of processability by securing flexibility and improvement of fluidity, and improvement of mechanical properties is obtained. I can do it. Generally, a mineral oil-based softener is used as a flowability improver in an olefin-based TPE composition.
When PDM is not used, regardless of the viscosity of EPDM, 40 parts by weight of mineral oil-based softener per 100 parts by weight of EPDM is used.
If it is added in an amount of not less than part by weight, bleeding of the softening agent occurs on the surface of the TPE composition, which is not preferable because contamination and adhesion of the product are observed. However, 100 ° C Mooney viscosity is 120-350
Using oil-extended EPDM in which 20 to 150 parts by weight of a mineral oil-based softening agent is previously blended per 100 parts by weight of EPDM,
There is no bleeding of the softener, no contamination or sticking of the product is observed, and a TPE composition having excellent physical properties such as breaking strength, breaking elongation and compression set can be obtained. Despite the large blending ratio of this mineral oil-based softener, no bleeding of the softener was observed because EPD having a high Mooney viscosity
It is considered that when M is used, the upper limit of the allowable oil extension amount of the mineral oil-based softening agent increases, and the softening agent suitably added in advance is uniformly dispersed in EPDM.

[0011] Olefin-based copolymer rubber such as EPDM
As the oil extension method, there is a solution containing an olefin-based copolymer rubber.
Add a certain amount of mineral oil softener to the liquid,
Desolvation method such as mustripping is used.
Can be Here, the solution containing the olefin copolymer rubber
As for the operation, it is more convenient to use the solution obtained by polymerization.
It is easy.

The propylene polymer resin (B) used in the present invention is preferably polypropylene or a copolymer resin of propylene and an α-olefin having 2 or more carbon atoms. Specific examples of the α-olefin having 2 or more carbon atoms include ethylene, 1-butene, 1-pentene, and 3-methyl-
1-butene, 1-hexene, 1-decene, 3-methyl-
There are 1-pentene, 4-methyl-1-pentene, 1-octene and the like. The melt flow rate of these polymer resins is
0.1 to 100 g / 10 min is preferred, and more preferably
It is in the range of 0.5 to 50 g / 10 minutes. If the melt flow rate is smaller than 0.1 g / 10 min or larger than 100 g / 10 min, problems arise in the formability. When the amount of the propylene-based polymer resin (B) in the olefin-based TPE composition of the present invention is less than 5% by weight, the fluidity is reduced, resulting in poor appearance of the molded article. Loses sex.

As the ethylene polymer resin (C) in the present invention, high-density polyethylene, low-density polyethylene, ethylene-α-olefin copolymer resin (ethylene having an ethylene unit of more than 85 mol% and carbon number of 3 to 10 And a monomer having a polar group such as vinyl acetate, acrylate and methacrylate and an olefin-based double bond with ethylene having more than 85 mol% of ethylene units. Preferred examples include polyethylene resins such as copolymers having a melt index (190 ° C.).
0.01 to 200 g / 10 min, especially 0.1 to 100
A g / 10 minute polyethylene resin is preferred. Such an ethylene polymer resin of the component (C) can be blended in a step of dynamically heat-treating and partially co-crosslinked with the oil-extended olefin copolymer rubber of the component (A). It is also possible to mix after obtaining the partially crosslinked composition.

In order to achieve the effect of compounding the component (C),
The content of the ethylene polymer resin (C) is 5 to 100 parts by weight, preferably 10 to 80 parts by weight, based on 100 parts by weight of the partially crosslinked composition. When the amount of the component (C) is less than 5 parts by weight, calender moldability is inferior. When the amount exceeds 100 parts by weight, heat resistance decreases.

In the present invention, the higher fatty acid amide (D)
Specific examples of lauric amide, valmitic acid amide, stearic acid amide, saturated fatty acid amide such as behenic acid amide, erucic acid amide, oleic acid amide,
Unsaturated fatty acid amides such as pyridine acid amide and elaidic acid amide, and bis fatty acid amides such as methylenebisstearic acid amide, methylenebisoleic acid amide, ethylenebisstearic acid amide and ethylenebisoleic acid amide are used. Particularly preferred higher fatty acid amides are compounds having a melting point of about 70 ° C to 110 ° C. The higher fatty acid amide (D) can be blended in a step of dynamically heat-treating, or can be blended after obtaining a partially crosslinked composition. The content of the higher fatty acid amide (D) depends on the partially crosslinked composition 100 according to the present invention.
It is 0.03 to 2 parts by weight, preferably 0.04 to 1 part by weight based on parts by weight. If the content is more than this, leaching of higher fatty acid amide to the surface and deterioration of physical properties when a thermoplastic elastomer composition is formed occur, which is not preferable.

As the organic peroxide for partially cross-linking a mixture comprising the oil-extended olefin-based copolymer rubber (A) and the propylene-based polymer resin (B), 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) hexyne-3, dicumyl peroxide and the like. Of these, odor and scorch are particularly favorable in terms of 2,5-dimethyl-.
2,5-di (t-butylperoxy) hexane is preferred.

The organic peroxide is added in an amount of 0.005 to 2.0 parts by weight, preferably 0.01 to 0.6 parts by weight, based on 100 parts by weight of the total of the oil-extended olefin copolymer rubber (A) and the propylene polymer resin (B). It can be selected in the range of parts by weight. 0.0
If the amount is less than 05 parts by weight, the effect of the crosslinking reaction is small, and if it exceeds 2.0 parts by weight, control of the reaction is difficult, and it is not economically advantageous.

In the preparation of the composition of the present invention, N, N'-m-
Multifunctionality such as phenylene bismaleimide, toluylene bismaleimide, p-quinone dioxime, nitrobenzene, diphenylguanidine, trimethylolpropane, divinylbenzene, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, allyl methacrylate Can be blended. By compounding such a compound, a uniform and mild crosslinking reaction occurs,
It is possible to improve the mechanical properties.

The amount of the crosslinking aid to be added is selected in the range of 0.01 to 4.0 parts by weight based on 100 parts by weight of the total of the oil-extended olefin-based copolymer rubber (A) and the propylene-based polymer resin (B). Can be done. Preferably it is 0.05 to 2.0 parts by weight.
If the amount is less than 0.01 part by weight, the effect is hardly exhibited, and if it exceeds 4 parts by weight, it is not economically advantageous.

A partially crosslinked composition is obtained by dynamically heat-treating a mixture comprising an oil-extended olefin-based copolymer rubber (A) and a propylene-based polymer resin (B) in the presence of an organic peroxide. The typical production method will be described below. An oil-extended olefin-based copolymer rubber (A), a propylene-based polymer resin (B), an organic peroxide, and, if necessary, a crosslinking aid are further mixed at a specific ratio and dynamically heat-treated. That is, they are melted and kneaded. As the mixing and kneading apparatus, a conventionally known non-open type Banbury mixer, twin screw extruder, or the like is used.
The kneading temperature may be 150 to 300 ° C. for about 1 to 30 minutes. In the production of this composition, auxiliary materials such as an inorganic filler, an antioxidant, a weathering agent, an antistatic agent, and a coloring agent can be blended as required.

More specifically, an oil-extended olefin-based copolymer rubber (A) and a propylene-based polymer resin (B), if necessary, a crosslinking aid, an ethylene-based polymer resin (C), and a higher fatty acid amide (D) And the above-mentioned auxiliary materials are blended at a predetermined ratio, and the mixture is mixed with a Banbury mixer of a non-opening type kneader.
After sufficiently kneading and homogenizing in a temperature range of 50 to 250 ° C., the obtained composition and the organic peroxide are sufficiently blended by an internal mixer such as a tumbler or a super mixer. Next, this blend is dynamically heat-treated at 200 to 300 ° C. using a twin-screw continuous extruder or the like capable of obtaining strong mixing strength, whereby a partially crosslinked composition can be obtained.

Examples of the auxiliary material include the following as specific examples of the antistatic agent. That is,
(A) cationic amines such as primary amine salts, tertiary amines, quaternary ammonium compounds, and pyridine derivatives;
(B) Sulfated oil, soap, sulfated ester oil, sulfated amide oil, sulfated salts of olefins, fatty alcohol sulfates, alkyl sulfates, fatty acid ethyl sulfonates, alkylnaphthalene sulfonates,
Alkylbenzene sulfonate, succinate sulfonate, anionic ones such as phosphate ester salts,
(C) Polyhydric alcohol partial fatty acid ester, fatty alcohol ethylene oxide adduct, fatty acid ethylene oxide adduct, fatty acid amino or fatty acid amide ethylene oxide adduct, alkylphenol ethylene oxide adduct, alkyl naphthol ethylene oxide Adducts, ethylene oxide adducts of partial fatty acid esters of polyhydric alcohols, nonionic ones such as polyethylene glycol, and (d) amphoteric ones such as carboxylic acid derivatives and imidazoline derivatives are generally usable. In particular, non-ionic compounds, particularly, polyoxyethylene alkylamines, polyoxyethylene alkylamides, fatty acid esters thereof, and fatty acid esters of glycerin are preferable.

As the above-mentioned antistatic agent, a single kind may be used, or a mixture of two or more kinds may be used. The compounding amount is preferably about 0.03 to 2 parts by weight, more preferably about 0.03 to 2 parts by weight, based on 100 parts by weight of the partially crosslinked composition according to the present invention.
0.04 to 1 part by weight. If the mixing ratio is more than this,
It is not preferable because it oozes out to the surface and decreases the physical properties of the thermoplastic elastomer composition. By the addition of the antistatic agent, a molded article having flexibility and without stickiness can be obtained. In addition, the adhesion of dust and the like due to the absence of stickiness and the bleeding of the softener is reduced, and at the same time, the chargeability, which is the original function of the antistatic agent, is reduced, and the adhesion of dust due to charging is also reduced.

The above-mentioned auxiliary materials can be compounded at the stage of producing the thermoplastic elastomer composition according to the present invention, which will be described later, or at the time of molding or use of a product after molding.

The thermoplastic elastomer composition according to the present invention may contain an inorganic filler such as calcium carbonate, calcium silicate, clay, kaolin, talc, silica, diatomaceous earth, mica as long as the fluidity and rubber properties are not impaired. powder,
Asbestos, alumina, barium sulfate, aluminum sulfate, calcium sulfate, basic magnesium carbonate, molybdenum disulfide, graphite, glass fiber, glass sphere, shirasu balloon, carbon fiber, etc. or coloring agents, such as carbon black, titanium oxide, zinc oxide, Bengal, ultramarine, navy blue, azo pigments, nitroso pigments, lake pigments, phthalocyanine pigments and the like can be blended. In the present invention, known heat-resistant stabilizers such as phenol-based, sulfite-based, phenylalkane-based, phosphite-based or amine-based stabilizers, anti-aging agents, weather-resistant stabilizers, antistatic agents, lubricants such as metal soaps and waxes. And the like can be blended to the extent that they are used in olefin-based plastics or olefin-based copolymer rubbers. Furthermore, the heat according to the invention
The plastic elastomer composition does not impair the purpose of the present invention
Within the range, a polymer such as polyisobutylene is appropriately added.
It may be blended.

In the present invention, after obtaining the partially crosslinked composition, a preferred method of uniformly blending (C) the ethylene polymer resin or (D) the higher fatty acid amide is as follows. Once a pellet of ethylene polymer resin and a higher fatty acid amide are blended in a V-type blender,
After mixing with a tumbler blender, ribbon blender, Hensiel mixer, or the like, a method of kneading with an extruder, a mixing roll, a kneader, a Banbury mixer, or the like can be given. A weathering agent, an antioxidant, a coloring agent and the like may be blended at any stage of the above process.

The thermoplastic elastomer composition according to the present invention has excellent calendering processability when molded by a calendering apparatus used for ordinary thermoplastics.

The thermoplastic elastomer composition according to the present invention is excellent in rubber properties such as heat resistance, weather resistance, tensile properties, flexibility and rebound resilience, since the component (A) is partially crosslinked. In addition, since the fluidity is good, the sheet can be processed at high speed by calendering, and a product having a good appearance can be obtained.

The applications of the calender-formed sheet obtained from the thermoplastic elastomer composition according to the present invention include automobile parts such as body panels, side shields and interior parts skins, footwear such as shoe soles and sandals, swimming pools and swimming fins. And other products such as leisure goods, gaskets, waterproof cloths, belts and the like.

[0030]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In addition, the test methods used for the calendering sheet forming process and the physical property measurement in these Examples and Comparative Examples are as follows. (1) Mooney viscosity (ML _{1 + 4} 100 ° C): ASTM
D-927-57T. Equation 1 for EPDM
Was calculated.

[0031]

Log (ML ₁ / ML ₂ ) = 0.0066 (△ PHR) ML ₁ : Mooney viscosity of EPDM ML ₂ : Mooney viscosity of oil-extended EPDM ΔPHR: Oil extension amount per 100 parts by weight of EPDM

(2) Calender molding workability: Judgment was made on the molded sheet skin. The judgment rank is as follows. ：: Excellent △: Good ×: Poor

(3) Oil bleeding property: The calendered sheet was left in an oven at 70 ° C. for 1 hour, and the oil bleeding on the surface of the molded article was visually observed. The judgment rank is as follows. ：: No bleed at all. Δ: Slight bleed. X: There is bleed.

Example 1 In a 5% by weight hexane solution of EPDM (ML _{1 + 4 at} 100 ° C. = 143, propylene content = 30% by weight, iodine value = 10), a mineral oil softener (100% by weight of EPDM) (Idemitsu Kosan Co., Ltd.) , Diana Process Oil PW-380), and 77 parts by weight of oil-extended EPDM (ML _{1 + 4} 100 ° C. = 78) desolvated by steam stripping, 77 parts by weight of Vistanex MML-100 (polyisobutylene, Esso). 8 parts by weight, manufactured by Kagaku Co., Ltd., polypropylene (MF
R = 12g / 10min, Sumitomo Noblen FL8013) 1
5 parts by weight, erucamide 0.5 part by weight, and Sumilizer BM (N, N'-m-phenylenebismaleimide,
0.3 parts by weight with a Banbury mixer 17
After kneading at 0 to 200 ° C for 7 minutes, a pelletized master batch was prepared using an extruder. Then, 0.1 part by weight of 2,5-dimethyl-
2,5-di (t-butylperoxy) hexane (hereinafter, referred to as
It is referred to as "organic peroxide". ) Was uniformly blended for 10 minutes using a Henschel mixer. Using a twin-screw kneading extruder capable of obtaining a strong kneading force, the blend was subjected to 22 kneading.
A dynamic heat treatment was performed at 0 ° C. ± 10 ° C. for 70 seconds to obtain a partially crosslinked composition. Low-density polyethylene (Sumikacene G801) was added to 4 parts by weight of the obtained partially crosslinked composition.
0 parts by weight were blended, and molding, physical property evaluation and the like were performed. The evaluation results are shown in Table 1.

Comparative Example 1 When a master batch was produced in Example 1,
77 parts by weight of PDM were added to JSR EP-24 (ML _{1 + 4} 10
0 ° C. = 70, propylene content = 44% by weight, iodine value =
Example 12 was carried out in the same manner as in Example 1, except that 55 parts by weight of EPDM, manufactured by Nippon Synthetic Rubber Co., Ltd.) and 22 parts by weight of a mineral oil-based softener PW-380 were used. Table 1 shows the evaluation results.

[0036]

[Table 1]

[0037]

As described above, according to the present invention, it is possible to provide a thermoplastic elastomer composition for calender molding which has very little oil bleed and excellent mechanical properties and appearance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI (C08L 23/26 57:02 23:04) (56) References JP-A-54-16554 (JP, A) JP-A-57 -209941 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 23/00-23/36 C08K 5/00-5/59 B29C 55/18

Claims (6)

(57) [Claims] 1. A 100 ° C. Mooney viscosity (ML _{1 + 4} 100
C) of 120 to 350 per 100 parts by weight of the olefin copolymer rubber.
Add a mineral oil-based softener to the solution and then remove the solvent.
Is, oil-extended olefinic copolymer rubber containing 20 to 150 parts by weight of the mineral oil softening agent (A) 40 to 95 wt%
And a propylene-based polymer resin (B) in an amount of 5 to 60% by weight in the presence of an organic peroxide. C) A thermoplastic elastomer composition for calender molding, comprising 5 to 100 parts by weight and 0.03 to 2 parts by weight of a higher fatty acid amide (D). 2. An olefin copolymer rubber comprising ethylene-
The composition according to claim 1, which is a propylene-nonconjugated diene copolymer rubber. 3. An ethylene-propylene-ethylidene norbornene copolymer rubber having a propylene content of 10 to 55% by weight and an ethylidene norbornene content of 1 to 30% by weight. Item 3. The composition according to Item 2. 4. An oil-extended olefin-based copolymer rubber (A)
00 ° C Mooney viscosity (ML _{1 + 4} 100 ° C) is 30 ~
The composition of claim 1 wherein the composition is 100. 5. The composition according to claim 1, wherein the propylene polymer resin (B) is a polypropylene or a propylene-α-olefin copolymer resin. 6. The composition according to claim 1, wherein the mineral oil softener is a paraffin softener.