JP2001329039A - Thermoplastic polyurethane and moldings thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic polyurethane excellent in moldability which gives moldings excellent in resistances to heat and water, in mechanical properties, etc., and to provide moldings thereof. SOLUTION: The thermoplastic polyurethane is obtained from a polyester diol which is prepared from a carboxylic acid component and a 2-10C diol component mainly comprising 2-methyl-1,3-propanediol and has terminal hydroxyl groups and a mol.wt. of 1,000-5,000; a diisocyanate compound; and a chain extender comprising a low-mol.wt. compound having at least two active hydrogen atoms. Moldings thereof are also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic polyurethane having excellent heat resistance, water resistance and mechanical properties, and a molded product thereof.

[0002]

2. Description of the Related Art Thermoplastic polyurethane is excellent in various properties such as heat resistance, water resistance, abrasion resistance, mechanical properties, solvent resistance and the like, and is applicable to ordinary thermoplastic resin moldability. In recent years, it has been widely used as a polymer material in place of conventional diene rubbers, polyolefins, and other general-purpose thermoplastic polymers for a wide range of applications.

[0003]

[Problems to be Solved by the Invention] Thermoplastic polyurethanes are characterized by various properties such as resistance and mechanical properties depending on the base polyester composition, whereas conventional thermoplastic polyurethanes have heat resistance and water resistance. It is pointed out that those having excellent flexibility are inferior in flexibility, while those having excellent flexibility are inferior in heat resistance, water resistance and the like, and it is desired to achieve both of them. Further, it is also required to have excellent moldability in obtaining various molded products.

It is an object of the present invention to provide a thermoplastic polyurethane having excellent heat resistance and water resistance while maintaining mechanical properties including flexibility represented by elongation, and a molded product thereof.

[0005]

[Means for Solving the Problems] That is, the present invention provides:
It is composed of a diol component having 2 to 10 carbon atoms, which is mainly composed of 2-methyl-1,3-propanediol, and a dicarboxylic acid component, and has a hydroxyl group-terminated molecular weight of 1,000.
The present invention provides a thermoplastic polyurethane obtained from a polyester diol of 5,000 to 5,000, a diisocyanate compound and a low-molecular compound having at least two active hydrogen atoms as a chain extender (hereinafter sometimes abbreviated as a low-molecular compound). Achieved by:

Further, the above-mentioned object is achieved by a molded article obtained from the above-mentioned thermoplastic polyurethane.

In the present invention, a polyester diol constituting a thermoplastic polyurethane is obtained by reacting a dicarboxylic acid component with a diol component having 2 to 10 carbon atoms mainly composed of 2-methyl-1,3-propanediol. Need to be a polyester diol.

In this case, it is preferable that 2-methyl-1,3-propanediol is contained in an amount of 20 to 100 mol% as a diol component constituting the polyester diol.

When the content of 2-methyl-1,3-propanediol as a diol component constituting the polyester diol is 20 mol% or less, the thermoplastic polyurethane obtained has insufficient flexibility represented by elongation, or This leads to a decrease in water resistance, and the balance of various properties cannot be maintained.

Other diol components having 2 to 10 carbon atoms include, for example, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-propylene glycol, and the like.
Butanediol, 1,3-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-
1,5-pentanediol, 1,9-nonanediol,
Examples include 2-methyl-1,8-octanediol, 1,10-decanediol, diethylene glycol, dipropylene glycol, tetraoxyethylene glycol, and the like. These diol components may be used alone or in combination of two or more.

When the number of carbon atoms of the diol component constituting the polyester diol is 11 or more, the obtained thermoplastic polyurethane has insufficient flexibility represented by elongation. , Lacks water resistance.

The dicarboxylic acid component constituting the polyester diol in the present invention is not particularly limited, and examples thereof include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and the like. And dicarboxylic acid components such as dimer acid.
These dicarboxylic acid components may be used alone,
Two or more types may be used. These dicarboxylic acid components can be used in the form of an ester derivative.

In the present invention, the polyester diol is 1
It is necessary to have a molecular weight of 000-5000.
If the molecular weight of the polyester diol is less than 1000, the thermoplastic polyurethane obtained is inferior in flexibility represented by elongation, while the molecular weight of the polyester diol is less than 50.
If the ratio is larger than 00, the obtained thermoplastic polyurethane has insufficient tensile strength and tear strength, and has reduced heat resistance and water resistance.

The method for producing the polyester diol is not particularly limited, and the polyester diol can be produced by polycondensing the above-mentioned diol component and dicarboxylic acid component by a conventionally known transesterification reaction, direct esterification reaction or the like. As a catalyst for the polycondensation reaction for producing the polyester diol, a titanium-based catalyst, a tin-based catalyst, or the like can be used.

The diisocyanate compound which is a raw material of the thermoplastic polyurethane in the present invention includes, for example,
Aliphatic diisocyanate compounds such as 1,6-hexamethylene xylylene diisocyanate; alicyclic diisocyanate compounds such as isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated xylylene diisocyanate; Aromatic diisocyanate compounds such as' -diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, xylylene diisocyanate, and 1,5-naphthalene diisocyanate. These diisocyanate compounds may be used alone or in combination of two or more.

If necessary, a mixture of a diisocyanate compound and a triisocyanate compound can be used. As such a triisocyanate compound,
For example, triphenylmethane triisocyanate, 1,
6,11-undecane triisocyanate, 1,3,6
-Hexamethylene triisocyanate.

Examples of the low molecular weight compound having at least two active hydrogen atoms as a chain extender include ethylene glycol, 1,3-propylene glycol 1,2
-Propylene glycol, 1,4-butanediol,
1,3-butanediol, 1,5-pentanediol,
2,2-dimethyl-1,3-propanediol, 2-methyl-1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9
-Nonanediol, 2-methyl-1,8-octanediol, 1,10-decanediol, diethylene glycol, dipropylene glycol, tetraoxyethylene glycol, 1,4-cyclohexanediol, 1,4-
Cyclohexanedimethanol, α, α′-dihydroxy-m-xylene, α. and bifunctional compounds such as α'-dihydroxy-p-xylene. These low molecular compounds may be used alone or in combination of two or more.

Further, as low molecular weight compounds which are chain extenders, for example, glycerin trimethylolpropane,
Trifunctional compounds such as 2,6-hexanetriol and trimethylolpropane can also be used.

The thermoplastic polyurethane of the present invention comprises:
It can be obtained by mixing the above-mentioned polyester diol, diisocyanate compound and low molecular weight compound as a chain extender in a predetermined molar ratio and reacting them. Here, the use amount of each component is as follows. That is, when a diol component is used as the low-molecular compound, the diisocyanate compound is a polyester diol and when the total molar amount of the diol component as the low-molecular compound is 1 mol,
It is preferable to use 1.0 to 1.1 mol,
If it is smaller than the mole, the obtained thermoplastic polyurethane does not increase its molecular weight sufficiently even when subjected to heat treatment after molding,
The heat resistance of the molded product decreases. On the other hand, if it is larger than 1.1 mol, the obtained thermoplastic polyurethane becomes tough,
Lack of flexibility represented by elongation.

The reaction method for obtaining the thermoplastic polyurethane of the present invention is not particularly limited, and the above-mentioned polyester diol, diisocyanate compound and chain extender can be used to form a prepolymer by a known urethanation reaction technique. And the one-shot method.

Further, if necessary, a colorant, a lubricant, a crystal nucleating agent,
Additives such as flame retardants, ultraviolet absorbers, antioxidants, weather resistance improvers, hydrolysis inhibitors, tackifiers, and fungicides
Species or two or more species may be appropriately added.

The thermoplastic polyurethane of the present invention has excellent moldability by various molding methods such as extrusion molding, injection molding, blow molding, and calendar molding, and the molded product obtained by those molding methods has heat resistance, water resistance and mechanical properties. Because of its excellent properties, for example, tubes, films, sheets, belts, hoses, various rolls, screens, casters, gears, packing materials, automobile parts, squeegees, paper feed rolls, copier cleaning blades, snow plows,
Chains, linings, solid tires, anti-vibration materials, shoe soles, sports shoes, marking materials, binders, adhesives,
It can be effectively used for a wide range of applications such as leather, elastic fibers, and mechanical parts.

As the molded article made of the thermoplastic polyurethane of the present invention, the molded article may be used directly as it is, but after molding, the molded article is heated to a temperature of 60 ° C. or more, especially 8 ° C.
Heat treatment at a temperature in the range of 0 to 110 ° C is desirable because the heat resistance of the molded product can be further improved. In that case, the heat treatment time depends on the content of the thermoplastic polyurethane,
Although it can be appropriately selected according to the size, thickness, shape and the like of the molded product, it is generally preferable to carry out for about 4 to 20 hours.

[0024]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and the like, but the present invention is not limited to these Examples. In the following examples, the mechanical properties, heat resistance, and water resistance of a molded article made of thermoplastic polyurethane were measured or evaluated by the following methods.

[Hardness] A 5 mm thick test piece was measured with a Shore A hardness meter.

[Tensile Strength] A test piece having a thickness of 5 mm was punched out into a No. 3 dumbbell shape, and was measured according to JIS K-6301 using a strograph manufactured by Toyo Seiki Seisaku-sho.

[Elongation] A test piece having a thickness of 5 mm was punched out into a No. 3 dumbbell shape, and measured according to JIS K-6301 using a strograph manufactured by Toyo Seiki Seisaku-sho.

[Tear Strength] A test piece having a thickness of 5 mm was punched out into a B-shape, and a striagraph manufactured by Toyo Seiki Seisaku-sho, Ltd.
It was measured according to SK-6301.

[Heat resistance] Using a test piece having a thickness of 5 mm,
It was left under the condition of 120 ° C. for 40 days, and the change in the value of the mechanical properties was measured and used as an index of heat resistance.

[Water resistance] Using a test piece having a thickness of 5 mm,
It was immersed in boiling water at 85 ° C. for 40 days, and the change in the value of the mechanical properties was measured and used as an index of water resistance.

The abbreviations and the contents of the compounds used in the following Reference Examples, Examples and Comparative Examples are as shown in Table 1 below.

[0032]

[Table 1]

Reference Example 1 400 g of MPG and AD600
g was charged into a reactor, and an esterification reaction was carried out under reduced pressure at 210 ° C. while distilling off water generated outside the system. The reaction was terminated when the acid value of the reactant was 1.0 or less. As a result, 850 g of a polyester diol having a molecular weight of 3000 (hereinafter, referred to as “polyester-A”) was obtained.

Reference Examples 2 to 7 The esterification reaction was carried out in the same manner as in Reference Example 1 except that the diol component used was changed, to obtain polyester diols.

The contents of the polyester diols obtained in Reference Examples 1 to 7 are summarized in Table 2 below.

[0036]

[Table 2]

[Example 1] The polyester-A obtained in Reference Example 1 and the MDI melted at 50 ° C were combined with [polyester-A] / [MDI] = [1.0] / [3.21]
(Molar ratio) and a prepolymerization reaction was carried out at 80 ° C. Subsequently, after the BD [2.0] (mol) was charged, it was immediately poured into a mold and aged at 110 ° C. for 24 hours. After cooling, it was taken out of the mold to obtain a sheet-shaped test piece having a thickness of 5 mm. After further aging at 110 ° C. for 24 hours, hardness, tensile strength, elongation, tear strength, heat resistance and water resistance were measured or evaluated by the above methods. The results are shown in Table 3 below.

[Examples 2 and 3] Compounding, reaction and preparation of test pieces were carried out in the same molar ratio as in Example 1 except that polyester diols shown in Table 3 below were used. further,
The same physical properties were measured or evaluated, and the results are shown in Table 3 below.

Comparative Examples 1-4 Compounds, reactions and test pieces were prepared in the same molar ratio as in Example 1 except that the polyester diols shown in Table 3 below were used. further,
The same physical properties were measured or evaluated, and the results are shown in Table 3 below.

[0040]

[Table 3]

From the results shown in Table 3 above, Examples 1, 2, 3
It can be seen that the thermoplastic polyurethane of the present invention is excellent in flexibility such as elongation and also excellent in heat resistance and water resistance. On the other hand, in the thermoplastic polyurethanes of Comparative Examples 1 to 4, which are different from the thermoplastic polyurethane of the present invention in the diol component, composition ratio, and molecular weight of the polyester diol, the change in mechanical properties after the heat resistance and water resistance test is generally large. A large result was obtained, and in the case of Comparative Example 4, a result that the tensile strength was clearly inferior among the initial mechanical properties was obtained.

[0042]

According to the present invention, there is provided a thermoplastic polyurethane having excellent heat resistance and water resistance and excellent mechanical properties including flexibility such as elongation. From the thermoplastic polyurethane of the present invention, various molded products can be extremely smoothly formed by utilizing the thermoplasticity by molding methods such as extrusion molding, injection molding, blow molding, casting, casting molding, and calendar molding. The resulting molded article can be used for a wide range of applications by utilizing the above-mentioned excellent properties.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Akiyama 3-8-40 Kitadamiya, Tokushima City, Tokushima Prefecture Inside the Hitachi Chemical Polymer Co., Ltd. Tokushima Plant (72) Inventor Hiroshi Hashimoto 3-8 Kitadamiya, Tokushima City, Tokushima Prefecture No. 40 Hitachi Chemical Polymer Co., Ltd. F-term in Tokushima Factory 4F071 AA53 AH03 AH08 AH11 AH12 AH17 AH19 BA01 BB04 BB05 BB06 BC01 BC03 BC04 BC05 BC06 BC07 4J034 BA03 DA01 DB04 DC50 DF01 DF16 HA01 HC07 HC08 HC11 HC HC54 HC61 HC64 JA01 QA03 QA05 QB14 QC07 QC08 QD01 QD04 RA06 RA08 RA09 RA11 RA12 RA15

Claims (3)

[Claims] 1. A polyester diol having a molecular weight of 1,000 to 5,000 and having a hydroxyl group at a terminal, comprising a diol component having 2 to 10 carbon atoms and a dicarboxylic acid component and having 2-methyl-1,3-propanediol as a main component. Thermoplastic polyurethane obtained from a diisocyanate compound and a low molecular weight compound having at least two active hydrogen atoms as a chain extender. 2. The 2-diol which is a main component of the polyester diol.
2. The thermoplastic polyurethane according to claim 1, wherein methyl-1,3-propanediol is contained in an amount of 20 to 100 mol% as a diol component. 3. A molded article comprising the thermoplastic polyurethane according to claim 1.