JP3428092B2 - Thermoplastic elastomer composition - Google Patents

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 is widely known, but in addition to that, 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. The present invention provides a polypropylene-based resin (1), A
An olefin-based thermoplastic elastomer resin composition comprising a kryl rubber (2) and an ethylene / α-olefin copolymer elastomer (3), wherein (3) ethylene / α-
The α-olefin of the olefin copolymer elastomer (3) has a carbon number of 4 or more, and the α-olefin content is 30 mol% or more, which is a thermoplastic elastomer resin composition. 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. In particular, in the present invention, as the polypropylene resin (1), a polypropylene homopolymer part or a low ethylene content ethylene-propylene random copolymer part 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.

It is desired that the polypropylene resin (1) is blended in an amount of 3 parts by weight or more and 50 parts by weight or less, and further 5 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the acrylic rubber (2) described later. 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.

Thermoplastic elastomer resin composition of the present invention
When heat resistance, oil resistance, ozone resistance, etc. are required, acrylic rubber is preferably used.

When an acrylic rubber is used, it is preferable to use one having a non-conjugated diene component as a copolymerization component as a cross-linking point, and a rubber having no such cross-linking point is cross-linked by a peroxide or the like. Thus, ethylene / α-, which is a component of the elastomer composition of the present invention,
The olefin copolymer elastomer (3) may also be crosslinked. Further, here, as the non-conjugated diene component, 1,4-pentadiene, 1,4-hexadiene,
Dicyclopentadiene, methylene norbornene, ethylidene norbornene and the like can be mentioned.

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

Such an ethylene / α-olefin copolymer elastomer (3) is an acrylic rubber (2) 10.
It is desired to blend 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 or less with respect to 0 parts by weight. 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 the polypropylene resin, crosslinkable uncrosslinked Akurirugo
Beam, can be prepared by carrying out the crosslinking of the uncrosslinked acrylic rubber ethylene / alpha-olefin copolymer elastomer and a crosslinking agent for promoting crosslinking uncrosslinked acrylic rubber is heated and melted mixed while. As for the devices used at this time, those normally used can be used,
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, 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 uncrosslinked acrylic rubber . It is more preferable to add 3 parts by weight or more and 50 parts by weight or less, 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 may be an uncrosslinked acrylic resin.
Is appropriately selected depending on the arm, for example, paraffinic process oils, naphthenic oils, aromatic process oils,
Any oil such as ester plasticizer and ether plasticizer may be used, and two or more kinds of these oils may be used at the same time. Particularly when acrylic rubber (2) is used, it is preferable to use a blend of polyester oil and paraffinic process oil, and by using this, the moldability 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 acrylic rubber (2).
Particularly when acrylic rubber (2) is used, it is desirable to add a compatibilizing agent because it has poor compatibility with the polypropylene resin (1). As the compatibilizing agent, in particular (a) a carboxyl group or an acid anhydride group is added. 100 parts by weight of the modified polyolefin containing 0.01 to 15% 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 ( 0.1) of a) carboxyl group or acid anhydride group
The elastomer-modified polyolefin contained in an amount of up to 30 equivalents is preferably used because it is inexpensive, has a large effect of improving physical properties, and is easy to synthesize.

The elastomer composition of the present invention contains
Calcium carbonate, mica, talc, silica, barium sulfate, calcium sulfate, kaolin, clay, pyroferrite, bentonite, serisanite, if necessary.
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 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 in combination as the 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 300 ml of toluene and 200 ml of hexene-1 were added to a 2 liter autoclave, 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.

[0031]

Example 1 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 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 were thoroughly kneaded with a roll kneader to prepare 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 / α-olefin copolymer ERAS
Ethylene / hexene-1 obtained in Reference Example as a tomer
Copolymer (Hexene-1 content 34 mol%, Mw = 120
000, Mw / Mn = 2.1) 7.5 g, and internal volume 1
The mixture was put into a Brabender mixer of 00 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 the peroxide (C-1
3 (manufactured by Shin-Etsu Chemical Co., Ltd.) and 1.5 g of a vulcanization aid (Sumifine BM (manufactured by Sumitomo Chemical Co., Ltd.)) were sufficiently kneaded. The material thus obtained is again heated to a temperature of 18
Put into a Brabender mixer at 0 ° C and rotate at 140r
Peroxide crosslinking was carried out while melt-kneading at pm.
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 2 A target composition was obtained in the same manner as in Example 1 except that 10 g of polypropylene resin was used and 5 g of ethylene / hexene-1 copolymer was used.

Example 3 The same method as in Example 1 was used except that an ethylene / hexene-1 copolymer having a hexene-1 content of 52 mol%, Mw of 190000 and Mw / Mn of 2.0 was used. The desired composition was obtained.

[0035] EXAMPLE 4 Ethylene / 1-hexene content as hexene-1 copolymer 61 mol%, in Mw of 210000, Mw / Mn is the same method as in Example 1, except that used was a 2.1 The desired composition was obtained.

[0036]

[0037]

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

Comparative Example 2 A composition was prepared in the same manner as in Example 1 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]

1 is a diagram showing the measurement results of dynamic viscoelasticity of the elastomer composition of the present invention obtained in Example 1. FIG.

FIG. 2 is a diagram showing measurement results of dynamic viscoelasticity of a resin composition obtained in Comparative Example 2 . [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 (5)

(57) [Claims] 1. A polypropylene resin (1), acrylic resin
An ethylene / α-olefin copolymer elastomer (3), wherein the α-olefin of the ethylene / α-olefin copolymer elastomer (3) has 4 or more carbon atoms. A thermoplastic elastomer resin composition having an α-olefin content of 30 mol% or more. 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. An acrylic rubber having a non-conjugated diene as a crosslinking point.
It is a peroxide cross-linking type elastomer having components and cross-linking
The total amount of uncrosslinked acrylic rubber after 10% or less
Claims characterized by being a bridge-type thermoplastic elastomer
Item 3. The resin composition according to Item 1 or 2. 4. Polypropylene resin, uncrosslinked acrylic resin
And ethylene / α-olefin copolymer elastomers
The above uncrosslinked acrylic resin is mixed while heating and melting and mixing the crosslinking agent and the crosslinking agent.
The cross-linking of a rubber is performed as set forth in claim 1.
A method for producing a resin composition. 5. The resin composition according to claim 1, wherein
Elastomer modified polyolefin shown in A, Polyester
Oil and / or paraffinic process oil
A resin composition obtained by adding. A elastomer-modified polyolefin (a) has a carboxyl group or acid anhydride group of 0.01 to 15
100 parts by weight of modified polyolefin containing 100% by weight,
(B) an carboxyl group-containing 0.01 to 5% by weight
1-500 weight of acrylic ester copolymer elastomer
Part and (c) metal salt to (a) carboxyl group or acid
Elastomer containing 0.1 to 30 equivalents of anhydride group
Modified polyolefin.