JPH06145500A - Urethane-based thermoplastic elastomer alloy - Google Patents

Abstract

PURPOSE:To provide a urethane-based thermoplastic elastomer alloy exhibiting little or small lowering of the thermal deformation resistance and abrasion resistance of a urethane-based elastomer used as a main component of the alloy and capable of easily giving a molded article having low hardness. CONSTITUTION:The objective urethane-based thermoplastic elastomer alloy is produced by compounding (A) a urethane-based thermoplastic elastomer containing a polymer chain consisting of a diisocyanate and a short-chain glycol as a hard phase and a polymer chain consisting of a diisocyanate and a long- chain glycol as a soft phase with (B) a subsidiary component consisting of an ethylene-alpha-olefin copolymer rubber (EPR) having polar groups introduced into a part or total of the copolymer rubber at an A/B ratio of 97/3 to 30/70, preferably 95/5 to 40/60. A general-purpose EPR having a viscosity of >=20 ML1+4 (100 deg.C) may be used as the component B in the case of partially or totally substituting with EPR having introduced polar groups, however, an EPR having a viscosity of 40 ML1+4 (100 deg.C) is used in the case of using EPR as the exclusive component.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a urethane-based TPE alloy. Especially, heat resistance and light weight are required,
Further, the invention is suitable for automobile interior parts and the like which are often contacted with hands and the like and are required to have soft feeling and abrasion resistance.
Here, examples of the automobile interior parts include a ring portion / pad portion of a steering wheel (hereinafter abbreviated as “wheel”), an arm / headrest, a shift lever knob, and the like.

A list of polymer abbreviations and meanings of the terms, which have not been described in the present specification, is given below.

(1) Polymer abbreviation TPE: thermoplastic elastomer EPR: ethylene-α-olefin copolymer rubber E
Includes both PM and EPR.

EPM: ethylene-α-olefin binary copolymer rubber EPDM: ethylene-α-olefin-non-conjugated diene terpolymer rubber TPU: urethane type thermoplastic TPE PP: crystalline PP (2) term alloy Main component: It does not mean the largest component quantitatively, but the component that contributes to the basic physical properties of the alloy. For alloy subcomponents.

ML ₄ ... Abbreviation of "ML _{1 + 4} (100 ° C)", which is a unit of Mooney viscosity when preheating for 1 minute, rotor operating time for 4 minutes, and test temperature at 100 ° C with an L type rotor.

[0006]

2. Description of the Related Art Urethane-based TPE has a wear resistance of TPE.
Since it is the best in the medium and has excellent strength and load bearing capacity, it is attracting attention as a coating material for the ring portion of the above wheels.

However, the urethane-based TPE has a relatively large specific gravity (1.1 to 1.25), does not meet the demand for wheel weight reduction, and has a high material unit price.

Therefore, it is conceivable to use a polymer alloy obtained by mixing urethane TPE with olefin TPE (0.88) having a small specific gravity.

[0009]

However, as a result of examinations and examinations conducted by the present inventors, the mixing of olefinic TPE results in a large decrease in the physical properties of the material, and in particular, a significant decrease in heat distortion resistance and wear resistance. It turned out that it was difficult to obtain a low hardness.

In view of the above, the present invention has a urethane-based TPE, which is mainly composed of an alloy, with little or little reduction in the heat deformation resistance and abrasion resistance originally possessed, and a urethane product which is low in hardness is easy to obtain. It is intended to provide a system TPE alloy.

[0011]

Means for Solving the Problems The inventors of the present invention have made intensive efforts to solve the above problems, and as a result, have come up with a urethane-based TPE alloy having the following structure.

The invention according to claim 1 is a urethane-based TP
A urethane-based TPE alloy containing E as an alloy main component, which contains EPR as an alloy subcomponent, and a part or all of the EPR is a polar group-introduced EPR.

The invention according to claim 3 is a urethane-based TP
A urethane-based TPE alloy containing E as a main component is characterized by containing EPR as an alloy subcomponent and having a viscosity of 40 ML ₄ or more.

[0014]

[Detailed description of means]

(1) The urethane-based TPE (TPU) means that the polymer chain composed of diisocyanate and short chain glycol serves as a hard phase and the polymer chain composed of diisocyanate and long chain polyol serves as a soft phase. Further, any of caprolactone-based, adipate-based, polycarbonate-based, and polyether-based, which are classified according to the long-chain polyol, can be used. Of these, caprolactone-based and adipate-based are preferable because they have high mechanical strength and have a good balance between heat aging resistance and cold resistance.

Specifically, "Pandex T-5070.T-
5965D "(Dainippon Ink Co., Ltd.)," Elastolan E-5
74FNAT "(manufactured by Nippon Elastollan Co., Ltd.), etc. can be used.

(2) The above EPR includes ethylene-α-olefin binary copolymer (E) which is an amorphous random high polymer.
PM) and ethylene-α-olefin-non-conjugated diene terpolymer (EPDM).

Here, the α-olefin has 3 to 12 carbon atoms, for example, propylene, 1-butene, 4
-Methyl-1-pentene, 1-hexene and the like can be used, and usually propylene or propylene and other α-
Used in combination with olefin. As the non-conjugated diene, ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene, methylene norbornene and the like can be used, and ethylidene norbornene is preferable.

When the polar group-introduced EPR is partially or wholly replaced, the viscosity of the above EPR can be generally 20 ML ₄ or more.
In case of PR, it is 40 ML ₄ or more.

It is also possible to replace a part of the EPR with a crystalline olefin resin (PP, PE, etc.) or an olefinic TPE, styrene TP, etc. within a range not impairing the object of the present invention.

(3) EPR with modified polar group (modified EPR)
Means that it has a polar group such as a carboxyl group, an acid anhydride group, a hydroxyl group, chlorine, an amino group or an epoxy group in the main chain or side chain. For the introduction method, for example, in the case of a carboxyl group, an unsaturated carboxylic acid is graft-copolymerized with the EPR, or an unsaturated carboxylic acid is simultaneously copolymerized with the EPR during polymerization.

Here, examples of the unsaturated carboxylic acid include maleic acid, acrylic acid, methacrylic acid and the like and their derivatives.

The rate of introduction of unsaturated carboxylic acid is usually 0.
5 to 5 wt%. If the introduction rate is too low, the effect of compounding (prevention of deterioration of wear resistance and heat deformability) is difficult to be obtained, and if the introduction rate is too high, a problem occurs in blendability.

The substitution ratio of the EPR having the polar group introduced therein to the EPR is such that the R value defined by the following formula is usually
It is set to 0.01 to 1.0, preferably 0.05 to 0.5. If the R value is less than 0.01, it is difficult to achieve the compounding effect, and conversely, if the R value exceeds 1.0, TP
Gelation occurs during the kneading process with U, making molding difficult, and causing problems such as deterioration of surface appearance and increase of surface hardness.

R (wt%) = r · x / 100 where r: polar group introduction ratio of polar group-introduced EPR (wt%), x: substitution ratio of polar group-introduced EPR to EPR (wt%) When the introduction rate of the introduced EPR is low, if the R value is within the above range, the EPR is not used and the polar group introduced E is used.
You may replace by PR entirely.

(4) Further, in order to improve wear resistance and heat distortion resistance, it is desirable that the EPR has a substantially partially crosslinked structure. As the method, there is a method of adding a crosslinking agent such as organic peroxide and sulfur (when EPDM is used), or a method of introducing a metal ion to obtain an ionomer.

As the organic peroxide, those used in EPR can be used, and 1,3-bis- (t-butylperoxy-isopropyl) -benzene, 2,5-dimethyl-
2,5-di (t-butylperoxy) hexane, 2,5
-Dimethyl-2,5-di (t-butylperoxy) hexyne-3,1,1-bis- (t-butylperoxy)-
3,3,5-Trimethylcyclohexane, dicumyl peroxide and the like can be preferably used.

The ionomer is prepared by blending a metal that ionically bonds with the polar group of the polar group-introduced EPR. For example, when the polar group is a carboxylic acid,
In the form of carboxylic acid salt of magnesium, sodium, zinc, Fe, barium, calcium, silver, etc., it is compounded in the carboxylic acid-introduced EPR. It is also possible to mix them at the same time during the kneading process with the urethane-based TPE.

(5) In the above urethane-based TPE alloy, the proportion of urethane-based TPE (TPU) as a main component and EPR (including a polar group-introduced EPR) as a subcomponent is required for each component type and molded product. Depending on the physical properties, TPU / EPR = 97 / 3-30 / 70,
It is preferably 95/5 to 40/60. If the EPR is excessive, problems with respect to wear resistance and heat distortion resistance tend to occur, and if it is too small, the effect of the present invention becomes difficult to be obtained.

The urethane-based TPE alloy having the above structure is usually dry-blended, then melt-kneaded by a twin-screw extruder or the like, pelletized by a pelletizer, and injection-molded.
Used as a molding material for extrusion molding. In the dry blending step, a colorant (pigment / dye), an antioxidant (ultraviolet absorber, etc.), a filler, a release agent, a softening agent, a plasticizer, etc. can be appropriately mixed.

[0030]

The urethane-based TPE alloy of the present invention is a urethane-based TPE alloy containing urethane-based TPE as a main component, and is an EPR as an alloy sub-component.
Characterized in that part or all of the EPR is a polar group-introduced EPR, or EPR is contained as an alloy subcomponent, and the viscosity of the EPR is 40 ML ₄ or more. As a result, the following actions and effects are exhibited.

As shown in Examples described later, it is easy to obtain a molded product having a urethane-based TPE, which is the main component of the alloy, with little or little reduction in the heat deformation resistance and abrasion resistance originally possessed and having a low hardness.

Incidentally, Japanese Patent Application Laid-Open No. 2-120358 discloses "a thermoplastic polyurethane resin composition comprising (A) a thermoplastic polyurethane resin and (B) a modified polyolefin resin". However, the main use of the composition is planned to be an elastic film which is a material such as a paper diaper whose flexibility is required to be removed.
We are not planning interior parts for automobiles that require low hardness, heat distortion resistance and wear resistance (especially wear resistance).

The polyolefin resin in the above publication is essentially a crystalline olefin polymer, which is different from the EPR which is an amorphous random high polymer in the present invention. Therefore, the above publication does not disclose or suggest the present invention.

That is, the present inventors have completed the present invention by challenging the common sense of those skilled in the art that, when EPR is blended with TPU, the hardness is lowered and the abrasion resistance is greatly lowered. is there.

[0035]

[Test Examples] Examples, reference examples, and comparative examples conducted to confirm the effects of the present invention will be described.

A. The characteristics of the raw materials used are shown below.

(1) Urethane type TPE TPU-A (hexamethylene diisocyanate type polyester type) JISA hardness: 87, specific gravity: 1.16, Vicat softening point: 82 ° C., elongation at break: 700%, strength at break: 36 MP
a TPU-A (hexamethylene diisocyanate polyester type) JISA hardness: 79, specific gravity: 1.11, Vicat softening point: 65 ° C, elongation at break: 700%, strength at break: 28MP
a (2) EPR EPM-A ("EP02P" manufactured by Japan Synthetic Rubber Co., Ltd.) Viscosity: 24 ML ₄ , C3 content: 26 wt% EPM-B ("EP07P" manufactured by Japan Synthetic Rubber Co., Ltd.) Viscosity: 70 ML ₄ , C3 content: 27 wt % EPDM-A ("EP57P" manufactured by Japan Synthetic Rubber Co., Ltd.) Viscosity: 88 ML ₄ , C3 content: 28 wt%, iodine value: 1
5.0 (3) Polar group-introduced EPR (modified EPR) Modified EPM-A ("T7711SP" manufactured by Nippon Synthetic Rubber Co., Ltd.) Viscosity: 24 ML ₄ , maleic anhydride addition amount: 0.8 wt% Modified EPM-B ("T7761P""Nippon Synthetic Rubber Co., Ltd.) Viscosity: 88 ML ₄ , maleic anhydride addition amount: 0.8 wt% (4) Crosslinking agent Organic peroxide: 1,3-bis- (t-butylperoxy-isopropyl) -benzene 30 wt% inclusions (5) Others Crystalline PP (“Hypol J640”, an ethylene propylene copolymer manufactured by Mitsui Petrochemical Co., Ltd.) MFR: 10 g / 10 min, specific gravity: 0.91 Softening agent ... paraffinic softening agent (“ Cole process P-400 "made by Fuji Kosan Co., Ltd.) Specific gravity: 0.89, pour point: 15 ° C, aniline point: 112
C. B. Preparation of test pieces (1) The raw materials of the formulations shown in Tables 1 and 2 (Examples) and 3 (Reference Examples and Comparative Examples) were dry blended with a Henschel mixer, and then melt-kneaded with a twin-screw extruder (cylinder temperature). : 20
Then, the mixture was pelletized to obtain a material for injection molding. The compounding unit in the table is vol%.

(2) Each molding material was injection molded (cylinder temperature: 200 ° C.) using an injection molding machine (inline screw type, mold clamping force: 80 ton), and a test piece (1
0 cm □ × 3 mmt) was prepared.

C. Test Method The following items were tested for each test piece.

(1) Hardness: Measured according to JIS K-7331.

(2) Specific gravity: Measured according to JIS K-7331.

(3) Vicat softening temperature ... JIS K-72
Measured according to 06.

Conditions: load 1 kgf, temperature rising rate 50 ° C./h (4) Abrasion amount: Measured according to JIS K-7311.

Conditions: Using Taber wear wheel H-22, the amount of wear was measured after 500 revolutions under a load of 1 kgf. E. Test results and evaluation Tables 1 and 2 showing the test results show the following.

It can be seen that each example is superior in heat distortion resistance and abrasion resistance when the hardness is similar to each comparative property.

For example, in Example 3 in which the modified (polar group-introduced) EPM was used as a part of the EPM in the formulation of Comparative Example 1, and in the formulation of Comparative Example 2, the low-viscosity EPM was changed to the high-viscosity EP
In Example 4 in which M is substituted, the hardness and the heat distortion resistance are almost the same, but the wear resistance is remarkably excellent.

In addition, in the formulations of Example 9, Examples 11 and 13, which are of the crosslinked type, have slightly increased hardness, but improved wear resistance.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

Claims (5)

[Claims] 1. A urethane-based TPE alloy containing a urethane-based thermoplastic elastomer (hereinafter "urethane-based TPE") as a main component, wherein an ethylene-α-olefin copolymer rubber (hereinafter "EPR") is used as an alloy subcomponent. The urethane-based TPE alloy is characterized in that part or all of the EPR is a polar group-introduced EPR. 2. The urethane-based TPE alloy according to claim 1, wherein the EPR has a viscosity of 40 ML _{1 + 4} (100 ° C.) or more. 3. The urethane-based TPE alloy according to claim 1, which is substantially partially crosslinked. 4. A urethane TPE alloy containing urethane TPE as an alloy main component, wherein EPR is contained as an alloy subcomponent, and the viscosity of the EPR is 40 ML _{1 + 4} (100 ° C.) or more. Urethane TPE alloy. 5. The urethane-based TPE alloy according to claim 4, wherein the urethane-based TPE alloy is substantially partially crosslinked.