JP3529927B2 - Thermoplastic polyurethane composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic polyurethane composition comprising a thermoplastic polyurethane and a specific olefin copolymer. The thermoplastic polyurethane composition of the present invention has mechanical properties, abrasion resistance, hot water resistance,
Not only is it excellent in flexibility, but it is also lightweight and excellent in moldability, so it is useful as a material for extrusion molded products, injection molded products, and the like.

[0002]

2. Description of the Related Art Thermoplastic polyurethanes have mechanical properties,
It has excellent properties such as abrasion resistance, chemical resistance, oil resistance, and flexibility, and has attracted attention as a substitute material for rubber and plastics. In addition, conventional thermoplastic resin molding processing methods can be applied. Widely used in various fields. However, thermoplastic polyurethane has the drawbacks that it does not have sufficient heat resistance and molding processability, has high water absorption, and has poor hydrolysis resistance. For this reason, when molding the thermoplastic polyurethane, bubbles are generated in the molded product to cause a poor appearance, and the thermoplastic polyurethane reacts with water to deteriorate physical properties such as mechanical strength. On the other hand, polyolefin resins such as polyethylene and polypropylene are excellent in heat resistance, moldability, water resistance, solvent resistance, light weight, etc., but they are not sufficient in coatability, flexibility and low temperature characteristics. Therefore, in order to improve the respective drawbacks of the thermoplastic polyurethane and the polyolefin resin, it has been attempted to mix them. For example, attempts have been made to compound polyethylene resins or ethylene-propylene rubbers to improve the tackiness of thermoplastic polyurethanes.

[0003]

However, since the thermoplastic polyurethane has very poor compatibility with the polyethylene resin and the ethylene-propylene rubber, molded articles obtained from these resin compositions have poor flexibility. When the molded product is bent, surface peeling, delamination, or whitening occurs at the bent portion. Furthermore, only molded products having poor hot water resistance and mechanical strength can be obtained.

The object of the present invention is to obtain mechanical properties, wear resistance,
It is intended to provide a thermoplastic polyurethane composition having excellent hot water resistance, flexibility, moldability and the like. Furthermore, another object of the present invention is to provide a molded article made of the above-mentioned thermoplastic polyurethane composition.

[0005]

Means for Solving the Problems As a result of repeated studies by the present inventors in order to achieve the above object, ethylene unit and 1-
An olefin-based copolymer composed of an octene unit, in particular,
An olefin-based copolymer produced by using a single-site catalyst as a polymerization catalyst has very good compatibility with thermoplastic polyurethane, and gives a resin composition having excellent properties such as hot water resistance and flexibility. Based on these findings, the present invention has been completed.

That is, the present invention comprises a thermoplastic polyurethane (A) and an olefin copolymer (B),
And the weight ratio of component (A) / component (B) is 50/50 to 9
5/5 a is a thermoplastic polyurethane composition, prior to
The thermoplastic polyurethane (A) has a number average molecular weight of 500.
~ 8,000 polymeric diols, organic diisocyanates
And the JIS A hardness obtained by reacting a chain extender
55 to 98 thermoplastic polyurethane, the olefinic copolymer (B) is composed of ethylene units (I) and 1-octene units (II), and structural units (I)
/ The structural unit (II) has a molar ratio of 75/25 to 95/5, which is a thermoplastic polyurethane composition. The present invention is a molded article made of the thermoplastic polyurethane composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the polymer diol used for producing the thermoplastic polyurethane (A) include polyester diol, polyether diol, polycarbonate diol, polyester polycarbonate diol and polyester polyether diol. These can be used alone or in combination of two or more. Among these, polyester diol and polyether diol are preferably used.

The above polyester diol can be obtained, for example, by subjecting a dicarboxylic acid component or an ester-forming derivative such as an ester or anhydride thereof and a low molecular weight diol component to a direct esterification reaction or transesterification reaction according to a conventional method. .

Examples of the dicarboxylic acid component constituting the polyester diol include glutaric acid, adipic acid,
Pimelic acid, suberic acid, azelaic acid, sebacic acid,
Dodecanedicarboxylic acid, 2-methylsuccinic acid, 2-methyladipic acid, 3-methyladipic acid, 3-methylpentanedioic acid, 2-methyloctanedioic acid, 3,8-dimethyldecanedioic acid, 3,7-dimethyldecane Examples thereof include aliphatic dicarboxylic acids having 5 to 12 carbon atoms such as diacids; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and the like, and one or more of them can be used. . Among these, carbon number is 5
It is preferred to use aliphatic dicarboxylic acids of
More preferably, adipic acid, azelaic acid, sebacic acid are used.

The low molecular weight diol component constituting the polyester diol is, for example, ethylene glycol,
1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-
1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,8-
Octanediol, 1,9-nonanediol, 1,10
And aliphatic diols such as decanediol; alicyclic diols such as cyclohexanedimethanol and cyclohexanediol, and one or more of them can be used. Among these, it is preferable to use 3-methyl-1,5-pentanediol, and further 50% to the total low molecular weight diol component.
More preferably, 3-methyl-1,5-pentanediol is used in a proportion of at least mol%.

As the polyether diol, for example,
Polyethylene glycol, polypropylene glycol,
Examples thereof include polytetramethylene glycol, and these may be used alone or in combination of two or more.
Among these, it is preferable to use polytetramethylene glycol.

The polycarbonate diol can be obtained, for example, by reacting a low molecular weight diol with a carbonate compound such as dialkyl carbonate, alkylene carbonate or diaryl carbonate. As the low-molecular diol component constituting the polycarbonate diol, the low-molecular diol exemplified above as the constituent component of the polyester diol can be used. Examples of the dialkyl carbonate include dimethyl carbonate and diethyl carbonate, examples of the alkylene carbonate include ethylene carbonate, and examples of the diaryl carbonate include diphenyl carbonate.

The polyester polycarbonate diol can be obtained, for example, by simultaneously reacting a low molecular weight diol, a dicarboxylic acid and a carbonate compound. Alternatively, it can be obtained by previously synthesizing a polyester diol and a polycarbonate diol by the method described above and then reacting them with a carbonate compound or with a low molecular weight diol and a dicarboxylic acid.

The number average molecular weight of the polymeric diol is 500
~ 8,000 , 700 ~ 6,0
It is preferably 00. By using a polymer diol having a number average molecular weight within this range, a thermoplastic polyurethane composition having more excellent mechanical strength and moldability can be obtained. The number average molecular weight of the polymeric diols referred to in the present specification is the number average molecular weight calculated based on the hydroxyl value measured according to JIS K1577.

The type of organic diisocyanate used for producing the thermoplastic polyurethane (A) is not particularly limited,
Although any of the organic diisocyanates conventionally used for the production of ordinary thermoplastic polyurethanes can be used, one of aromatic diisocyanates having a molecular weight of 500 or less, alicyclic diisocyanates, and aliphatic diisocyanates can be used.
One or two or more species are preferably used. Examples of organic diisocyanates include 4,4′-diphenylmethane diisocyanate, p-phenylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, 1,5-naphthylene diisocyanate,
4,4'-dicyclohexylmethane diisocyanate and the like can be mentioned, and one or more of these can be used. Among these, 4,4'-
Preference is given to using diphenylmethane diisocyanate.

The type of chain extender used in the production of the thermoplastic polyurethane (A) is not particularly limited, and any of the chain extenders conventionally used in the production of ordinary thermoplastic polyurethane can be used. Molecular weight 3 having two or more active hydrogen atoms capable of reacting with an isocyanate group in the molecule
It is preferable to use a low molecular weight compound of 00 or less. For example, ethylene glycol, propylene glycol, 1,
4-butanediol, 1,6-hexanediol, 1,
4-bis (β-hydroxyethoxy) benzene, 1,4
Cyclohexanediol, bis- (β-hydroxyethyl) terephthalate, xylylene glycol and other diols; hydrazine, ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine,
Piperazine and its derivatives, phenylenediamine, tolylenediamine, adipic dihydrazide, diamines such as isophthalic acid dihydrazide; aminoethyl alcohol, and amino alcohols such as amino propyl alcohol and the like, one or two of these The above can be used. Among these, carbon number 2
It is preferred to use 10 aliphatic diols, 1,4
- it is more preferred to use butane diol.

The method for producing the thermoplastic polyurethane (A) is not particularly limited, and the above-mentioned polymer diol, organic diisocyanate and chain extender are used, and the known urethanization reaction technique is utilized to carry out the prepolymer method and the one-step method. It may be manufactured by any of the shot methods. Among them, it is preferable to carry out the melt polymerization substantially in the absence of a solvent, and the continuous melt polymerization method using a multi-screw extruder is particularly preferable.

JIS A for thermoplastic polyurethane (A)
Hardness must be 55-98 , 65-9
It is preferably 5. The thermoplastic polyurethane having JIS A hardness in this range is an olefin-based copolymer (B).
A thermoplastic polyurethane composition having excellent compatibility with and having excellent mechanical strength and low stickiness can be obtained by using such a thermoplastic polyurethane.

The olefin copolymer (B) is composed of ethylene units (I) and 1-octene units (II), and the molar ratio of structural unit (I) / structural unit (II) is 75/2.
It is 5 to 95/5. Structural unit (I) and structural unit (II)
By using those whose content ratio is within this range, a thermoplastic polyurethane composition having good compatibility and excellent mechanical properties, hot water resistance, abrasion resistance, flexibility and the like can be obtained. The molar ratio of structural unit (I) / structural unit (II) in the olefin-based copolymer (B) is 85/15 to 95 /
It is preferably 5.

The olefin copolymer (B) is, for example,
1-butene, 2-methyl-1-butene, 3-methyl-1
-Butene, 1-pentene, 4-methyl-1-pentene,
1-hexene down, 1 - decene, 1-octadecene one or two or more of units derived from such can including
It

The number average molecular weight (Mn) of the olefin copolymer (B) is preferably 10,000 to 180,000, and more preferably 20,000 to 150,000. Furthermore, the ratio M of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the olefin-based copolymer (B)
The w / Mn is preferably 1.5 to 4.0.
It is more preferably 5 to 3.5. The density of the olefin copolymer (B) is 0.85 to 0.92 g / cm.
It is preferably from ^3, more preferably from 0.85~0.91g / cm ^3. By using the olefin copolymer (B) having Mn, Mw / Mn, and a density within the above range, the compatibility is good, and the thermal properties are excellent due to mechanical properties, wear resistance, flexibility, etc. A plastic polyurethane composition is obtained. The Mn and Mw of the olefin copolymer (B) referred to in the present specification are values obtained from a standard polystyrene calibration curve by the gel permeation chromatography (GPC) method.

The method for producing the olefin-based copolymer (B) is not particularly limited, and the above-mentioned monomers are usually prepared by, for example, a solution polymerization method, a bulk polymerization method or a gas phase polymerization method.
Normal pressure to 1000 atm (100M
It is obtained by polymerizing in Pa). At that time, it is preferable to use a single-site catalyst having uniform polymerization active points, since a polymer having a narrow molecular weight distribution and a narrow copolymer composition distribution can be easily obtained. Among the single-site catalysts, a metallocene compound containing a tetravalent transition metal is particularly preferable, and examples thereof include cyclopentadienyl titanium tris (dimethylamide), methylcyclopentadienyl titanium tris (dimethylamide), and bis (cyclo Pentadienyl) titanium dichloride, dimethylsilyltetramethylcyclopentadienyl-t-butylamide zirconium dichloride, dimethylsilyltetramethylcyclopentadienyl-t-butylamide hafnium dichloride, dimethylsilyltetramethylcyclopentadienyl-p- n-butylphenylamide zirconium dichloride, methylphenylsilyl tetramethylcyclopentadienyl-t-butylamide hafnium dichloride,
(T-butylamido) (tetramethyl-cyclopentadienyl) -1,2-ethanediyl titanium dichloride,
Indenyl titanium tris (dimethylamide), indenyl titanium tris (diethylamide), indenyl titanium bis (di-n-butylamide) (di-n-
Propylamide) and the like. When a metallocene compound is used as a polymerization catalyst, it does not exhibit polymerization activity by itself. Therefore, a cocatalyst such as methylaluminoxane or a non-coordinating boron-based compound is added to the metallocene compound in an amount of 2 to 1,000, It is used in a proportion of 000 mol, preferably 50 to 5,000 mol.

The thermoplastic polyurethane composition of the present invention comprises
It is composed of the thermoplastic polyurethane (A) and the olefin copolymer (B). The weight ratio of component (A) / component (B) is 50/50 to 95/5, and 55 /
It is preferably 45 to 85/15. When the weight ratio of component (A) / component (B) exceeds 95/5 [component (B)
When the blending ratio is too small], the thermoplastic polyurethane composition is inferior in low water absorption and moldability. On the other hand, when the weight ratio of component (A) / component (B) is less than 50/50 [when the blending ratio of component (B) is too large],
The compatibility is lowered, and the mechanical properties, abrasion resistance, flexibility, etc. of the thermoplastic polyurethane composition are inferior.

Further, if desired, an ultraviolet absorber, an antioxidant, and an ultraviolet absorber within a range that does not adversely affect the effects of the present invention.
Additives such as a plasticizer, an antistatic agent, and a hydrolysis inhibitor can be used in combination.

The thermoplastic polyurethane composition of the present invention comprises
It can be produced by mixing the above-mentioned thermoplastic polyurethane (A), olefin-based copolymer (B) and, if necessary, an additive by a desired method. For example, a thermoplastic polyurethane (A) and an olefin-based copolymer (B) are pre-mixed at a predetermined ratio using a vertical or horizontal mixer that is usually used for mixing resin materials, It can be produced by melt-kneading under heating in a batch system or a continuous system using a single-screw or twin-screw extruder, a mixing roll, a Banbury mixer and the like. In addition, the olefin copolymer (B) may be blended in the latter stage of the polymerization when the thermoplastic polyurethane (A) is produced.

The thermoplastic polyurethane composition of the present invention comprises
Hot-melt molding and heat processing are possible, and various molded products can be smoothly molded by any molding method such as extrusion molding, injection molding, blow molding, calender molding, and casting.

The thermoplastic polyurethane composition of the present invention comprises
It is useful as a material for a wide variety of applications such as automobile parts, machine parts, shoe soles, watch bands, packing materials, films, sheets, belts, hoses and tubes.

[0028]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In Examples and Comparative Examples, the tensile strength / elongation, specific gravity, hot water resistance, abrasion resistance and flexibility of the thermoplastic polyurethane compositions were measured or evaluated by the following methods.

[Tensile Strength and Elongation] A punching test piece was prepared from a disc-shaped material with dumbbell No. 3, and the tensile strength and the tensile elongation were measured according to JIS K 7311.

[Specific gravity] It was measured at 24 ° C. by the buoyancy method.

[Hot water resistance] A test piece was punched out from a disc-shaped material with dumbbell No. 3, and the test piece was immersed in hot water at 100 ° C. for 4 days, and then the tensile strength was measured according to JIS K 7311. It was measured and the retention rate of tensile strength after hot water treatment was determined.

[Abrasion resistance] In accordance with JIS K 7311 (load 1 kg, 1000 revolutions, wear wheel H-22),
The amount of wear was measured.

[Flexibility] A disc-shaped material is bent, and the bent portion is observed with the naked eye. When surface peeling or delamination is observed, x is given, and when a slight whitening phenomenon is seen at the bent portion, o is given. Those that did not change are indicated by ⊚.

Abbreviations for the resins used in the following examples and comparative examples are shown in Table 1 below. The Mn and Mw of the olefin polymer are GPC method (using "150C" manufactured by WATERS, column: "Shodex A" manufactured by Showa Denko KK
"T-807 / S" and "Shodex AT-80MIS", column temperature: 1
40 ° C., solvent: o-dichlorobenzene), and is a value obtained from a standard polystyrene calibration curve, and the density is JIS
It is a value measured according to K7112. Furthermore, the JIS A hardness of thermoplastic polyurethane is JISK 731.
It is a value measured according to 1.

[0035]

[Table 1]

Examples 1 to 7 thermoplastic polyurethane and olefinic copolymer
What was blended in the blending ratio shown in Table 2 below was a single screw extruder (25 mmφ, cylinder temperature: 170 to 200).
C., die temperature: 190.degree. C.), and melt-kneaded to produce pellets of the thermoplastic polyurethane composition. A disk-shaped product (diameter 120 mm, thickness 2 mm) obtained by subjecting the pellets to dehumidification drying at 80 ° C. for 2 hours or more and then injection molding (cylinder temperature: 180 to 200 ° C., mold temperature 30 ° C.) By using the above method, tensile strength and elongation, specific gravity,
The hot water resistance, abrasion resistance and flexibility were evaluated. The results are shown in Table 2 below.

[0037]

[Table 2]

Comparative Examples 1 to 5 A thermoplastic polyurethane and an olefin polymer were blended at the compounding ratios shown in Table 3 below to obtain a single screw extruder (25 mmφ, cylinder temperature: 170 to 200).
C., die temperature: 190.degree. C.), and melt-kneaded to produce pellets of the thermoplastic polyurethane composition. A disk-shaped product (diameter 120 mm, thickness 2 mm) obtained by subjecting the pellets to dehumidification drying at 80 ° C. for 2 hours or more and then injection molding (cylinder temperature: 180 to 200 ° C., mold temperature 30 ° C.) By using the above method, tensile strength and elongation, specific gravity,
The hot water resistance, abrasion resistance and flexibility were evaluated. The results are shown in Table 3 below.

[0039]

[Table 3]

[0040]

The thermoplastic polyurethane composition of the present invention is excellent not only in mechanical properties, abrasion resistance, hot water resistance and flexibility but also in light weight and excellent in moldability.
It is useful as a material for extrusion molded products and injection molded products.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-55-110141 (JP, A) JP-A-4-255712 (JP, A) JP-A-7-133323 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08L 1/00-101/16

Claims (4)

(57) [Claims] 1. A thermoplastic polyurethane composition comprising a thermoplastic polyurethane (A) and an olefin copolymer (B) and having a weight ratio of component (A) / component (B) of 50/50 to 95/5. Which is a thermoplastic polyurethane
Tan (A) has a high number average molecular weight of 500 to 8,000
Child diol, organic diisocyanate and chain extender
Thermoplastic with JIS A hardness of 55-98
And the olefinic copolymer (B) is composed of an ethylene unit (I) and a 1-octene unit position (II), and has a molar ratio of structural unit (I) / structural unit (II). A thermoplastic polyurethane composition, characterized in that the ratio is 75/25 to 95/5. 2. The number average molecular weight of the olefin copolymer (B) is 10,000 to 180,000, and the ratio Mw / Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn).
Is 1.5 to 4.0, and the density is 0.85 to 0.9.
2 g / cm ³ and is claim 1 the thermoplastic polyurethane composition. 3. A single olefinic copolymer (B)
The thermoplastic polyurethane composition according to claim 1 or 2 , which is a polymer produced using a site catalyst . 4. A molded article made of the thermoplastic polyurethane composition according to claim 1.