JPH07126452A - Thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic elastomer composition having excellent balance of tensile strength and characteristics of compression set resistance. CONSTITUTION:This thermoplastic elastomer composition comprises a polypropylene-based resin (1), a cross-linked rubber (2) and an ethylene/alpha-olefin copolymer elastomer (3), is obtained by mixing 100 pts.wt. of the component (2) with 3-50 pts.wt. of the component (1) and 3-50 pts.wt. of the component (3). The alpha-olefin of the component (3) is a >=4C alpha-olefin and the content of the alpha-olefin is >=30mol%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermoplastic elastomer resin composition having excellent compression set resistance.

[0002]

2. Description of the Related Art Conventionally, as a thermoplastic polyolefin-based elastomer, one mainly composed of polypropylene and ethylene-propylene-based rubber has been widely known. In addition, a mixture of acrylonitrile-butadiene rubber as a cross-linked rubber component, There was a mixture of butyl rubber and a mixture of natural rubber. However, none of these materials are satisfactory in terms of compression set resistance and tensile rupture strength, and the current situation is that substitution in the field of crosslinked rubber has not progressed.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermoplastic elastomer resin composition having excellent compression set resistance and tensile rupture strength.

[0004]

The present inventors have completed the present invention as a result of intensive studies in view of the above-mentioned present situation. That is, the present invention is an olefin thermoplastic elastomer resin composition comprising a polypropylene resin (1), a crosslinked rubber (2) and an ethylene / α-olefin copolymer elastomer (3), wherein (3) ethylene / α The α-olefin of the olefin copolymer elastomer (3) has 4 or more carbon atoms and has an α-olefin content of 3
It is a thermoplastic elastomer resin composition characterized by being 0 mol% or more. The details of the present invention will be described below.

Examples of the polypropylene resin (1) used in the present invention include polypropylene homopolymers, propylene / ethylene block copolymers and propylene / ethylene random copolymers. Of these, the ethylene content of the ethylene-containing copolymer is not particularly limited, and the polypropylene resin may be used alone or in combination of two or more. Particularly, in the present invention, as the polypropylene resin (1), a homopolymerized portion of polypropylene or a low ethylene-propylene random copolymerized portion having an ethylene content of 10% by weight or less and a high ethylene-content ethylene-propylene having an ethylene content of 20 to 95% by weight. Random copolymerization part, high ethylene content ethylene-propylene random copolymerization part is 2
The use of the resin of 0 to 70% by weight is preferable because the obtained elastomer composition has excellent rubber properties.

The polypropylene resin (1) is used in an amount of 3 parts by weight or more and 5 parts by weight based on 100 parts by weight of a crosslinked rubber (2) described later.
It is desired to add 0 parts by weight or less, and further 5 parts by weight or more and 30 parts by weight or less. If the amount is less than 3 parts by weight, the molding processability of the resulting elastomer composition may be significantly reduced, while if it exceeds 50 parts by weight, the surface hardness of the elastomer composition is remarkably increased and rubber-like properties are exhibited. There is a risk of damage.

Crosslinked rubber used in the present invention (2)
Examples of the acrylic rubber, acrylonitrile-butadiene rubber, ethylene-propylene rubber, butyl rubber, natural rubber, urethane rubber, chlorosulfonated polyethylene, chloroprene rubber, styrene-butadiene rubber, butadiene rubber, isoprene rubber, etc. Or two or more types are used together. Among them, ethylene-propylene rubber is preferably used when importance is attached to cost performance and heat resistance, and acrylic rubber is preferably used when heat resistance, oil resistance, ozone resistance and the like are required.

When any rubber is used, it is preferable to use a rubber having a non-conjugated diene component as a crosslinking component as a crosslinking point, and a rubber having no such crosslinking point is crosslinked by a peroxide or the like. When it is tried to squeeze ethylene / α, which is a component of the elastomer composition of the present invention,
-The olefin copolymer elastomer (3) may also be crosslinked. Examples of the non-conjugated diene component include 1,4-pentadiene, 1,4-hexadiene, dicyclopentadiene, methylene norbornene and ethylidene norbornene.

Further, when acrylic rubber is used as the crosslinked rubber (2), it is a peroxide crosslinked elastomer having a non-conjugated diene component as a crosslinking point, and the amount of uncrosslinked acrylic rubber after crosslinking is 10% or less. By using the completely cross-linking type elastomer, the acrylic rubber is sufficiently cross-linked and the physical properties of the resulting elastomer composition are improved.

In the present invention, the ethylene / α-olefin copolymer elastomer (3) is used, and the α-olefin contained in this is one having 4 or more carbon atoms,
For example, 1-butene, 1-pentene, 1-hexene, 4-
Methyl-1-pentene, 1-heptene, 1-octene,
1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicodecene and the like. One or more of these are used. Among them, 1-butene, 1-hexene,
1-octene and the like are preferably used. The α-olefin content of the ethylene / α-olefin copolymer elastomer (3) used in the present invention is 30 mol%.
It is essential that the content be at least the above, and the α-olefin content is 3
When it is less than 0 mol%, the compatibility between the ethylene / α-olefin copolymer elastomer (3) and the polypropylene resin (1) becomes poor, and the resulting elastomer composition has remarkably poor mechanical properties.

Further, the molecular weight of the ethylene / α-olefin copolymer elastomer (3) used in the present invention is not particularly limited, but the number average molecular weight measured by gel permeation chromatography (GPC) is 5,000 to 1,000 in terms of polyethylene
It is preferably 50,000, more preferably 1
It is 50,000 to 600,000. If the number average molecular weight is less than 5,000, the effect of modifying the properties of the resulting elastomer composition is small, and the problem of surface stickiness may occur, while the number average molecular weight of 1,000,
If it exceeds 000, the fluidity of the obtained elastomer composition may be lowered, and molding process may become difficult.

The method for producing the above-mentioned ethylene / α-olefin copolymer elastomer (3) is not particularly limited, and it may be produced by using various catalysts such as titanium catalyst, vanadium catalyst or metallocene catalyst. You can

The ethylene / α-olefin copolymer elastomer (3) is used in an amount of 3 parts by weight or more and 50 parts by weight or less, more preferably 5 parts by weight or more and 30 parts by weight, based on 100 parts by weight of the crosslinked rubber (2). It is desirable that the amount is less than or equal to parts. If the content is less than 3 parts by weight, the elastomeric properties of the obtained elastomer composition may be insufficient, and if it exceeds 50 parts by weight, the surface of the obtained elastomer composition may become sticky.

In the elastomer composition of the present invention, the ethylene / α-olefin copolymer elastomer (3) used together with the polypropylene resin (1) form a matrix of the composition, and as a result, there has been a problem with compression resistance. It is considered to play a major role in improving permanent set, permanent elongation and flexibility. Further, in the stress-strain curve in the tensile test, while the conventional olefin-based thermoplastic elastomer showed a large stress in a relatively small strain region,
The elastomer composition of the present invention does not exhibit a very large stress value and exhibits more crosslinked rubber-like properties. The components of the matrix will be described in detail below.

The polypropylene resin (1) and the ethylene / α-olefin copolymer elastomer (3) in which the α-olefin has 4 or more carbon atoms and the α-olefin content is 30 mol% or more are obtained because of excellent compatibility. The physical properties of the resulting elastomer composition are improved. However, if the compatibility of the two is impaired, the physical properties will deteriorate. As an index of compatibility, for example, mechanical relaxation represented by dynamic viscoelasticity measurement,
Furthermore, dielectric relaxation, magnetic relaxation, etc. can be mentioned, and it is also possible to measure the orientation of molecular chains that have been mechanically vibrated by using an optical system.

Next, in order to evaluate this state from the temperature dispersion in the tensile mode of dynamic viscoelasticity, it was obtained by blending a polypropylene resin and an ethylene / α-olefin copolymer elastomer in a weight ratio of 50:50. The measurement results of the dynamic viscoelasticity of the composition are shown in FIGS. 1 and 2. In Figure 1, polypropylene-based resin and α-olefin are hexene-
1 is the measurement result of the elastomer composition of the present invention containing an ethylene / α-olefin copolymer elastomer having a content of 34 mol% and the composition is attributable to the glass transition temperature of the polypropylene resin alone. tan
The maximum value of tan δ exists on the lower temperature side than the temperature showing the maximum value of δ, and its peak is a single peak, and the size of the peak is 0.2 or more, and the compatibility is very excellent. I understand. It can be seen that since the maximum value of tan δ exists on the low temperature side, the cold resistance is superior to the polypropylene resin alone. On the other hand, FIG. 2 shows the measurement results of a composition containing an ethylene / α-olefin copolymer elastomer in which the α-olefin is hexene-1 and the content thereof is 27 mol%. The tan δ of the poor polymer blend shows a maximum according to each glass transition temperature, so that it does not form a single peak but two or more peaks, and accordingly the maximum value of the peaks becomes relatively small. It can be seen that the value becomes smaller than 0.2.

The above-mentioned elastomer composition of the present invention is obtained by heating and melting and mixing a polypropylene resin, a crosslinkable uncrosslinked rubber, an ethylene / α-olefin copolymer elastomer, and a crosslinking agent for promoting crosslinking in the uncrosslinked rubber. However, it can be produced by crosslinking the uncrosslinked rubber. As the apparatus and the like used at this time, those usually used can be used, and for example, a kneader, roll, Banbury mixer, extruder or the like can be used.
Further, the cross-linking agent used at this time is also not particularly limited and can be arbitrarily selected according to the type of rubber used, and a cross-linking auxiliary agent, a retarder, an accelerator and the like may be used in combination as necessary. You can also In this production method, it is necessary to crosslink the rubber component during melting of the polypropylene resin, and the composition obtained by crosslinking when the polypropylene resin is not melted is not only inferior in physical properties. Molding is also very difficult.

In the production of the above-mentioned elastomer composition of the present invention, the oil is used in an amount of 3 parts by weight or more and 120 parts by weight or less, preferably 3 parts by weight or more and 100 parts by weight or less, based on 100 parts by weight of the uncrosslinked rubber. Preferably 3 parts by weight or more 5
Addition of 0 parts by weight or less is preferable because the elastomer composition of the present invention has further excellent moldability. If the amount of oil added exceeds 120 parts by weight, bleeding may occur. Further, the oil used is not particularly limited and is appropriately selected depending on the uncrosslinked rubber. For example, any oil such as paraffin type process oil, naphthene type oil, aroma type process oil, ester type plasticizer and ether type plasticizer can be selected. These oils may be used, or two or more of these oils may be used at the same time.
Particularly when acrylic rubber is used as the crosslinked rubber (2), it is preferable to use a blend of polyester oil and paraffinic process oil, and by using this, the molding processability of the elastomer composition obtained is significantly improved.

Further, a compatibilizer may be added to the elastomer composition of the present invention for the purpose of improving the interfacial adhesion between the polypropylene resin (1) and the crosslinked rubber (2). In particular, when acrylic rubber is used as the crosslinked rubber (2), it is desirable to add a compatibilizing agent because it has poor compatibility with the polypropylene resin (1), and particularly as the compatibilizing agent (a) a carboxyl group or an acid. Anhydrous group 0.01 to 15
100 parts by weight of modified polyolefin containing 100% by weight,
(B) 1 to 500 parts by weight of an acrylic acid ester copolymer elastomer containing 0.01 to 5% by weight of a carboxyl group and (c) a metal salt of 0.1 to 0.1 of the carboxyl group or acid anhydride group of (a). The elastomer-modified polyolefin containing 30 equivalents is preferably used because it is inexpensive, has a great effect of improving physical properties, and is easy to synthesize.

The elastomer composition of the present invention contains
If necessary, calcium carbonate, mica, talc, silica, barium sulfate, calcium sulfate, kaolin, clay, pyroferrite, bentonite, serisanite,
Zeolite, nepheline sinite, attapulgite,
Wollastonite, ferrite, calcium silicate, magnesium carbonate, dolomite, antimony trioxide, zinc oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite, gypsum, glass beads, glass powder, glass balloons, quartz, Inorganic fillers such as quartz glass and organic and inorganic pigments can also be blended. Also,
Release agents, slip agents, lubricants, heat resistance stabilizers, weather resistance stabilizers, foaming agents, rust inhibitors, ion trap agents, crystal nucleating agents, clarifying agents, flame retardants, flame retardant auxiliaries, etc. You may add. Further, the elastomer composition of the present invention can be blended with another resin, and in this case, a compatibilizing agent for the elastomer composition of the present invention and another resin can be used as a third component.

As described above, the obtained elastomer composition of the present invention is blended with a reinforcing filler, an inorganic filler and the like, and various molded articles, films, sheets, etc. are obtained by injection molding, extrusion molding, inflation molding and calender molding. It can be molded into a tube or the like.

[0022]

The present invention will be described below with reference to examples.
These are exemplary and not limiting. Various measurements in the examples were carried out by the following methods.

(Measurement of Hexene-1 Content of Ethylene / Hexene-1 Copolymer Elastomer) It was calculated by measuring ¹³ C-NMR spectrum (JNM GX400 manufactured by JEOL Ltd.) in o-dichlorobenzene as a solvent at 100 MHz.

(Measurement of molecular weight and molecular weight distribution) o-
Gel permeation chromatography (manufactured by Millipore Corporation) at 140 ° C. using dichlorobenzene.
It was calculated in terms of polyethylene by using 150C type GPC).

(Measurement of Dynamic Viscoelasticity) Viscoelasticity measuring apparatus which is a measuring apparatus based on the non-resonance type forced vibration method: DVE-V4
(Manufactured by Rheology), the measurement frequency was 10 Hz, the measurement mode was pulled, and the temperature dependence of the dynamic viscoelasticity was measured at a temperature rising rate of 5 ° C./min. The applied strain is 0.
It was performed in the linear region of 1% or less. Then, in this measurement, the loss tangent (tan δ) and the storage elastic modulus (E ′) were measured.

(Tensile test) Using a test piece having a thickness of 1 mm, a No. 2 type test piece at a speed of 200 mm / min according to JIS K71
It measured according to 13.

(Measurement of compression set) According to JISK6301, the compression set after 70 ° C. and 22 hours was measured.

Reference Example Synthesis of Ethylene / Hexene-1 Copolymer Elastomer To a 2 liter autoclave, 300 ml of toluene and 200 ml of hexene-1 were added, and ethylene was added at 4 kg / cm.
Introduced to be ² . Next, 10 ml of toluene, 5 mmol of methylaluminoxane, and 5 μmol of diphenylmethane (cyclopentadienyl-1-fluorenyl) zirconium dichloride synthesized by a known method were added to another reaction vessel, and the mixed solution was stirred for 20 minutes. , And introduced into an autoclave to start polymerization. In this polymerization, the ethylene pressure was kept at 4 kg / cm ² and the temperature was 40 ° C.
For 30 minutes.

After completion of the polymerization, the obtained polymer was washed with a large amount of ethanol and dried under reduced pressure at 60 ° C. for 12 hours. As a result, 144 g of an ethylene / hexene-1 copolymer elastomer having a hexene-1 content of 34 mol% was obtained. The weight average molecular weight Mw of this elastomer was 120,000, and the molecular weight distribution Mw / Mn was 2.1.

Further, by changing the charged amount of hexene-1, the temperature and the like and carrying out the same operation as above, hexene-
Ethylene / hexene-1 having a content of 27 to 61 mol%
A copolymer elastomer was obtained.

Example 1 Low ethylene content ethylene with an ethylene content of 3.1% by weight
Polypropylene block copolymer having 50% propylene random copolymerization part and 50% high ethylene content ethylene-propylene random copolymerization part having ethylene content of 79% by weight (MFR 7.2 g / 10 min, 230 ° C., 2.16).
(kg load) 20 parts by weight and ethylene / α-olefin copolymer ethylene obtained in the reference example as an elastomer /
Hexene-1 copolymer (hexene-1 content 34 mol%,
20 parts by weight of Mw = 120,000, Mw / Mn = 2.1), and ethylene-propylene-ethylidene norbornene random copolymer rubber (manufactured by Nippon Synthetic Rubber Co., Ltd., EP57P, Mooney viscosity) as an uncrosslinked rubber that can be further crosslinked. ML _{1 + 4} : 88) 60 parts by weight, 0.5 parts by weight of dicumyl peroxide as a cross-linking agent and 5 paraffinic mineral oils.
Part by weight is mixed with a Henschel mixer, 150-160
The mixture was put into a pressure kneader preheated to ℃ and kneaded for 5 minutes, and then the temperature was further raised to 185 to 195 ℃ and the kneading was continued for 10 minutes. At this time, two kinds of heat stabilizers (Irganox 1010 and Irgafos 168 (manufactured by Ciba-Geigy)) were added at 2000 ppm, and calcium stearate was added at 5000 ppm as a lubricant. The composition thus produced was cut into fine pieces and then molded using a press molding machine to obtain the desired composition.

Example 2 Acrylate ester copolymer rubber (Nissin acrylic rubber) containing a non-conjugated diene as a copolymerization component as a crosslinkable rubber
100 parts by weight of RV-2540 (manufactured by Nissin Chemical Industry Co., Ltd.), 60 parts by weight of HAF carbon, polyester-based plasticizer (Adeka Sizer PN-170 (manufactured by Asahi Denka Co., Ltd., molecular weight: about 1100) ) 10 parts by weight, paraffinic process oil (Diana Process Oil PW-90
(Idemitsu Kosan Co., Ltd.) 10 parts by weight, antioxidant (NAUGARD 445 (manufactured by Uniroyal Chemical Co.)) 2 parts by weight, and 1 part by weight of stearic acid are thoroughly kneaded in a roll kneader to form an acrylic rubber compound. Got Next, 85 g of acrylic rubber compound and polypropylene resin (Tosoh Polypro J5100A (Tosoh Corp.))
7.5 g of ethylene / hexene-1 used in Example 1
7.5 g of copolymer (hexene-1 content 34 mol%)
Was charged into a Brabender mixer having an internal volume of 100 cc and a temperature of 180 ° C., and kneaded at a rotation speed of 140 rpm for 5 minutes. Next, this was taken out, and 1.5 g of peroxide (C-13 (manufactured by Shin-Etsu Chemical Co., Ltd.)
Vulcanization aid (Sumifine BM (Sumitomo Chemical Co., Ltd.))
Kneaded well with 0.75 g. The material thus obtained was again charged into a Brabender mixer having a temperature of 180 ° C.,
Peroxide crosslinking was performed while melt-kneading at a rotation speed of 140 rpm. After 5 minutes, the product was taken out of the mixer and again formed into a sheet by a roll forming machine, followed by press forming to obtain a desired composition. Moreover, the result of having measured the dynamic viscoelasticity of the obtained composition is shown in FIG.

Example 3 A target composition was obtained in the same manner as in Example 2 except that 10 g of polypropylene resin was used and 5 g of ethylene / hexene-1 copolymer was used.

Example 4 The same procedure as in Example 2 was repeated except that an ethylene / hexene-1 copolymer having a hexene-1 content of 52 mol%, Mw of 190,000 and Mw / Mn of 2.0 was used. The desired composition was obtained.

Example 5 The same procedure as in Example 2 was repeated except that an ethylene / hexene-1 copolymer having a hexene-1 content of 61 mol%, Mw of 210,000 and Mw / Mn of 2.1 was used. The desired composition was obtained.

Comparative Example 1 A composition was obtained in the same manner as in Example 1 except that 40 parts by weight of polypropylene resin was used and the ethylene / hexene-1 copolymer was not used.

Comparative Example 2 A composition was obtained in the same manner as in Comparative Example 1 except that polypropylene homopolymer (MFR: 6 g / 10 minutes, 230 ° C., 2.16 kg load) was used as the polypropylene resin.

Comparative Example 3 A composition was obtained in the same manner as in Example 2 except that the amount of polypropylene resin was 15 g and the ethylene / hexene-1 copolymer was not used.

Comparative Example 4 A composition was prepared in the same manner as in Example 2 except that an ethylene / hexene-1 copolymer having a hexene-1 content of 27 mol%, Mw of 160,000 and Mw / Mn of 1.9 was used. I got a thing. Moreover, the result of having measured the dynamic viscoelasticity of the obtained composition is shown in FIG.

Table 1 shows the results of measuring the tensile strength and compression set of the composition obtained by the above method.

[0041]

[Table 1]

[0042]

As described above, the elastomer resin composition of the present invention is a material having a good balance between tensile strength and compression set resistance.

[Brief description of drawings]

FIG. 1 is a view showing a measurement result of dynamic viscoelasticity of an elastomer composition of the present invention obtained in Example 2.

FIG. 2 is a diagram showing measurement results of dynamic viscoelasticity of a resin composition obtained in Comparative Example 4.

Claims (7)

[Claims] 1. An olefin thermoplastic elastomer comprising a polypropylene resin (1), a crosslinked rubber (2) and an ethylene / α-olefin copolymer elastomer (3), which is an ethylene / α-olefin copolymer elastomer. (3) The α-olefin has a carbon number of 4 or more and the α-olefin content of 30 mol% or more, a thermoplastic elastomer resin composition. 2. A polypropylene resin (1) comprising a homopolymerized portion of polypropylene or a low ethylene content ethylene-propylene random copolymerization portion having an ethylene content of 10% by weight or less and a high ethylene content ethylene content of ethylene content of 20 to 95% by weight. A propylene random copolymerization part, wherein the proportion of the high ethylene content ethylene-propylene random copolymerization part is 20 to 70% by weight.
The resin composition according to. 3. The resin composition according to claim 1 or 2, wherein the crosslinked rubber (2) is an ethylene-propylene rubber. 4. The resin composition according to claim 1, wherein the crosslinked rubber (2) is an acrylic acid ester copolymer elastomer. 5. A completely crosslinked type thermoplastic elastomer in which the acrylic acid ester copolymer elastomer is a peroxide crosslinked type elastomer having a non-conjugated diene component as a crosslinking point, and the amount of uncrosslinked acrylic rubber after crosslinking is 10% or less. It is a plastic elastomer, The resin composition of Claim 4 characterized by the above-mentioned. 6. The non-crosslinked rubber is cross-linked while the polypropylene resin, the non-cross-linked rubber, the ethylene / α-olefin copolymer elastomer and the cross-linking agent are heated and melt-mixed with each other. A method for producing the resin composition described. 7. A resin composition obtained by adding the elastomer-modified polyolefin, polyester-based oil and paraffin-based process oil shown in A below to the resin composition according to claim 4 or 5. A elastomer-modified polyolefin (a) 0.01 to 15 carboxyl group or acid anhydride group
100 parts by weight of modified polyolefin containing 100% by weight,
(B) 1 to 500 parts by weight of an acrylic acid ester copolymer elastomer containing 0.01 to 5% by weight of a carboxyl group and (c) a metal salt of 0.1 to 0.1 of the carboxyl group or acid anhydride group of (a). An elastomer-modified polyolefin containing 30 equivalents.