JP2000053856A - Thermoplastic polyurethane composition excellent in heat resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having excellent heat resistance and in particular being reduced with respect to the deterioration in strength and the discoloration after a long-term heat history by mixing a thermoplastic polyurethane with a sulfur-containing antioxidant and a compound selected from among hydrotalcite compounds and ethylenediaminetetraacetic acid derivatives. SOLUTION: This composition has an especially marked effect when the thermoplastic polyurethane resin is a polyether-derived thermoplastic polyurethane. The hydrotalcite compounds are exemplified by complex salts represented by the formula: MxAly(OH)2x+3y-2z(A)2.mH2O, and is desirably the one of the formula (wherein M is Mg, and A is CO3). Usually, the composition comprises 100 pts.wt. thermoplastic polyurethane, 0.05-5 pts.wt. sulfur-containing antioxidant, and 0.05-5 pts.wt. compound selected from among hydrotalcite compounds and ethylenediaminetetraacetic acid derivatives. It is desirable that the composition additionally contains 0.05-5 pts.wt., per 100 pts.wt. thermoplastic polyurethane, a phenolic antioxidant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic polyurethane composition which is excellent in heat resistance, and in particular, has little strength reduction or discoloration with respect to a long-term heat history.

[0002]

2. Description of the Related Art Thermoplastic polyurethane is a polymer obtained by reacting a diisocyanate compound and a polyhydroxy compound. Its properties are excellent in elasticity, so that it can be used for tubes, hoses, belts, films, elastic yarns, and the like.
Widely used for various injection molded parts. But,
Thermoplastic polyurethane is susceptible to heat, oxygen, light and the like due to its structure, and has a problem that the strength is easily deteriorated or discolored during use. In order to solve such a problem, a method of stabilizing by combining a phenolic antioxidant, and a sulfur-based antioxidant and a phosphorus-based antioxidant in combination has been performed, but the heat resistance is high. Sex is not enough.

On the other hand, JP-B-57-19133 and JP-B-58-46146 disclose hydroolefin and acryl-based resin, vinyl chloride-based resin and vinyl acetate-based resin containing a halogen and / or an acidic substance. Although a method for preventing deterioration due to heat and light by including sites is disclosed, thermoplastic polyurethane is not mentioned.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation, and has a heat resistance excellent in heat resistance such that not only a decrease in strength with respect to a long-term heat history but also a little discoloration are obtained. It is an object to provide a plastic polyurethane composition.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies on a stabilizer system which is effective for improving the heat resistance of a thermoplastic polyurethane, and as a result, have found that a sulfur-based antioxidant can be added to the thermoplastic polyurethane and the following (A) to By blending a compound selected from (B), and further blending a phenolic antioxidant therewith, the heat resistance has been drastically improved, and the above-mentioned problem can be solved. That is, according to the present invention, a thermoplastic polyurethane composition excellent in heat resistance characterized in that a sulfur-based antioxidant and a compound selected from the following (A) to (B) are blended in a thermoplastic polyurethane. Is provided. (A) Hydrotalcite compounds (B) Ethylenediaminetetraacetic acid derivative Further, a thermoplastic polyurethane is mixed with a sulfur-based antioxidant, a phenol-based antioxidant, and a compound selected from the following (A) to (B). The present invention provides a thermoplastic polyurethane composition having excellent heat resistance. (A) Hydrotalcite compounds (B) Ethylenediaminetetraacetic acid derivative Further provided is a thermoplastic polyurethane composition excellent in any of the above-mentioned heat resistances, wherein the thermoplastic polyurethane is a polyether-based thermoplastic polyurethane. Is done.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic polyurethane used in the thermoplastic polyurethane composition excellent in heat resistance of the present invention is a diisocyanate compound, a polyhydroxy compound,
It can be obtained by reacting a chain extender, if necessary, and any polymer can be used as long as it is a polymer showing substantially thermoplasticity.

Examples of the diisocyanate compound used in the production of thermoplastic polyurethane include toluylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, isophorone diisocyanate, and cyclohexane diisocyanate.

The polyhydroxy compound used for the production of thermoplastic polyurethane includes polyether polyol,
And polyester polyols. As polyether polyols, ethylene glycol, diethylene glycol, propylene glycol, butanediol,
Low molecular weight polyols such as hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, neopentyl glycol and lower alkylene oxides such as ethylene oxide and propylene oxide are used alone or in combination. Examples thereof include added polyether polyols and polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran. Further, as the polyester polyol, the above-mentioned low molecular weight polyol and succinic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, condensation-based polyester polyol obtained by a dehydration condensation reaction with a dibasic acid such as isophthalic acid, ε-caprolactam Examples include lactone-based polyester polyols obtained by ring-opening polymerization, and polycarbonate polyols obtained by reacting the above-mentioned low molecular weight polyols with carbonate esters such as dimethyl carbonate and diethyl carbonate. The average molecular weight of the polyhydroxy compound is from 500 to 7000, particularly preferably from 1,000 to 5,000.

Examples of the chain extender used as necessary for the production of a thermoplastic polyurethane include the above-mentioned low molecular weight polyols and low molecular weight polyamines such as ethylenediamine and diethylenetriamine.

Thermoplastic polyurethanes are generally referred to as polyether-based thermoplastic polyurethanes using polyether polyols as polyhydroxy compounds, and polyester-based thermoplastic polyurethanes using polyester polyols. Polyether-based thermoplastic polyurethanes are generally used. Polyurethane is said to be inferior in heat resistance, and the present invention exerts a particularly remarkable effect when applied to a polyether-based thermoplastic polyurethane.

As the sulfur-based antioxidant used in the present invention, any known ones can be used. For example, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiol Dipropionate, distearyl-3,3'-thiodipropionate, pentaerythritol tetrakis (3-laurylthiopropionate) and the like. The compounding amount of the sulfur-based antioxidant is 0.05 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the thermoplastic polyurethane. If the amount is less than 0.05, sufficient heat resistance cannot be obtained, and if it exceeds 5 parts by weight, not only the effect corresponding to the added amount cannot be obtained, but also a molded article obtained from the composition. It is not preferable because it causes a decrease in physical properties and bleed-out to the surface of the molded article.

The hydrotalcite compounds used in the present invention include M _x Al _y (OH)
_{2x + 3y-2Z} (A) _z · mH ₂ O [M is Mg, C
a, or Zn, A is CO ₃ , or HPO ₄ , x,
y, z, and m are positive numbers], and hydrotalcites compounds which are double salts represented by
Those in which A is CO ₃ are preferably used.

Examples of the ethylenediaminetetraacetic acid derivative used in the present invention include ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid disodium salt, ethylenediaminetetraacetic acid tetrasodium salt, ethylenediaminetetraacetic acid dipotassium salt, and ethylenediaminetetraacetic acid tetrapotassium salt.

The hydrotalcite compound and the ethylenediaminetetraacetic acid derivative can be used alone or in combination. The amount of these is 0.01 to 5 parts by weight based on 100 parts by weight of the thermoplastic polyurethane,
Preferably it is 0.05 to 3 parts by weight. 0.0%
If less than 1, sufficient heat resistance cannot be obtained,
If the amount exceeds 5 parts by weight, not only the effect corresponding to the increase in the added amount cannot be obtained, but also the physical properties of a molded article obtained from the composition are deteriorated, which is not preferable.

The thermoplastic polyurethane composition having excellent heat resistance of the present invention exhibits a large synergistic effect by using a hydrotalcite compound or an ethylenediaminetetraacetic acid derivative as a stabilizer in combination with a sulfur-based antioxidant. ,
It has a great feature in that not only the strength is not reduced but also the discoloration is small even for a long-term heat history.

Further, in the present invention, when higher heat resistance is required, it is preferable to add a phenolic antioxidant. As the phenolic antioxidant used in the present invention, any known phenolic antioxidant can be used. For example, 2,6-di-t-butyl-4-methylphenol, n-octadecyl-3- (3 ′) , 5 '
-Di-t-butyl-4'-hydroxyphenyl) propionate, tetrakis [methylene-3- (3,5-di-
t-butyl-4-hydroxyphenyl) propionate] methane, tris [N- (3,5-di-t-butyl-
4-hydroxybenzyl) isocyanurate, 4,4 '
-Butylidenebis (3-methyl-6-t-butylphenol), triethylene glycol bis [3- (3-t-
Butyl-4-hydroxy-5-methylphenyl) propionate], 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethyl Ethyl｝ -2,4,8,
10-tetraoxaspiro [5,5] undecane and the like. The compounding amount of the phenolic antioxidant is preferably 0.05 to 5 parts by weight based on 100 parts by weight of the thermoplastic polyurethane, and the compounding amount in this range provides better heat resistance and is obtained from the composition. There is little adverse effect on the physical properties of the molded product.

The thermoplastic polyurethane composition having excellent heat resistance according to the present invention may contain, if necessary, an ultraviolet absorber, a light stabilizer, an antistatic agent, a heavy metal deactivator, a lubricant, a filler, a coloring agent, a crosslinking agent and the like. Additives may be included.

The method for producing the thermoplastic polyurethane composition having excellent heat resistance of the present invention is not particularly limited, and a predetermined compounding composition is prepared by using a roll, a kneader, a Banbury mixer, a single screw extruder, a twin screw extruder, or the like. It can be prepared by melt-kneading. Then, the thermoplastic polyurethane composition having excellent heat resistance of the present invention is molded by a known molding machine according to the form of a target molded article.

[0019]

Next, the present invention will be described in detail with reference to examples. The following components were used as the components in the examples and comparative examples. -Thermoplastic polyurethane: Polyether-based thermoplastic polyurethane [Nippon Miractran E390PFAC]-Sulfur-based antioxidant A: Pentaerythritol tetrakis (3-laurylthiopropionate) [Sumitomo Chemical Industries Sumilizer TP-D]-Sulfur-based antioxidant Agent B: dilauryl-3,3'-thiodipropionate [Sumitomo Chemical Industries Sumilizer TP
LR] ・ Phenolic antioxidant A: tetrakis [methylene-
3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane [Sumitomo Chemical Industries Sumilizer BP-101] Phenolic antioxidant B: 3,9-bis {2- [3
-(3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl {-2,4,8,10-tetraoxaspiro [5,
5] Undecane [Sumitomo Chemical Industries Sumilizer GA-
80] phosphorus-based antioxidant: tris (2,4-di-t-butylphenyl) phosphite [Sumitomo Chemical Industries Sumilizer P
-16] Hydrotalcite A: Kyowa Chemical Industry Alkamizer 1 Hydrotalcite B: Kyowa Chemical Industry DHT4A Ethylenediaminetetraacetic acid (EDTA) derivative A: Ethylenediaminetetraacetic acid Ethylenediaminetetraacetic acid (EDTA) derivative B: Ethylenediaminetetrahydrate Tetrasodium acetate

Example 1 The components shown in Table 1 were melt-kneaded at 200 ° C. using a mixing roll and pressed at 200 ° C. to form a 200 μm thick film. This film was left in an oven at 125 ° C. for 100 hours, and the tensile strength and color before and after heating were measured to determine the strength retention and the color difference (ΔE value), and the heat resistance was evaluated. Table 1 shows the results. The tensile strength was measured according to JIS K7311. Color is color difference meter (Minolta camera)
It measured using. The lower the ΔE value, the less discoloration.

Example 2 A film was prepared with the composition shown in Table 1 in the same manner as in Example 1, and the heat resistance was evaluated. Table 1 shows the results.

[Comparative Examples 1 to 6]
A film was prepared in the same manner as in Example 1, and the heat resistance was evaluated. Table 1 shows the results.

[0023]

[Table 1]

According to Table 1, the thermoplastic polyurethane composition of the present invention containing a sulfur-based antioxidant and a hydrotalcite compound or an ethylenediaminetetraacetic acid derivative shows a high strength retention, has little discoloration, and has a high heat resistance. It is clear that On the other hand, the hydrotalcites compound or ethylenediaminetetraacetic acid derivative is not blended, or in the comparative example in which the sulfur-based antioxidant is not used even if blended, the strength retention is low,
It is clear that the discoloration is also large.

[Examples 3 to 5] With the composition shown in Table 2,
A film was prepared in the same manner as in Example 1, and the heat resistance was evaluated. Table 2 shows the results.

Comparative Examples 7 to 13 Films were prepared in the same manner as in Example 1 with the composition shown in Table 2, and the heat resistance was evaluated. Table 2 shows the results.

[0027]

[Table 2]

As shown in Table 2, the thermoplastic polyurethane composition of the present invention containing a sulfur-based antioxidant, a phenol-based antioxidant, and a hydrotalcite compound or an ethylenediaminetetraacetic acid derivative shows a high strength retention rate, It is clear that there is little discoloration and high heat resistance is exhibited. On the other hand, in a comparative example in which the hydrotalcite compound or the ethylenediaminetetraacetic acid derivative is not blended, or in which the sulfur-based antioxidant is not used even if it is blended, the strength retention is low and the discoloration is large. it is obvious.

[Examples 6 to 8] With the composition shown in Table 3,
A film was prepared in the same manner as in Example 1, and the heat resistance was evaluated. Table 3 shows the results.

Comparative Example 14 A film was prepared in the same manner as in Example 1 with the composition shown in Table 3, and the heat resistance was evaluated. Table 3 shows the results.

[0031]

[Table 3]

According to Table 3, the thermoplastic polyurethane composition of the present invention containing a sulfur-based antioxidant, a phenol-based antioxidant, and a hydrotalcite compound or an ethylenediaminetetraacetic acid derivative shows a high strength retention rate, It is clear that there is little discoloration and high heat resistance is exhibited. On the other hand, in Comparative Examples in which the hydrotalcite compounds and the ethylenediaminetetraacetic acid derivative were not blended, it is clear that the strength retention was low and the discoloration was large.

[0033]

The thermoplastic polyurethane composition having excellent heat resistance of the present invention comprises a sulfur-based antioxidant and a hydrotalcite compound or an ethylenediaminetetraacetic acid derivative as heat stabilizers. A phenolic antioxidant is blended with the above, and due to the synergistic effect of these stabilizers, not only is there a small decrease in strength against long-term heat history, but also an excellent effect of little discoloration. It is.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshihiro Tange 1515 Nakatsu-cho, Marugame-shi, Kagawa Prefecture F-term in Okura Industrial Co., Ltd.

Claims (3)

[Claims] 1. A thermoplastic polyurethane composition having excellent heat resistance, comprising a thermoplastic polyurethane and a sulfur-based antioxidant and a compound selected from the following (A) to (B). (A) Hydrotalcite compounds (B) Ethylenediaminetetraacetic acid derivative 2. A thermoplastic polyurethane comprising a sulfur-based antioxidant, a phenol-based antioxidant, and the following (A):
A thermoplastic polyurethane composition having excellent heat resistance, characterized by containing a compound selected from (B). (A) Hydrotalcite compounds (B) Ethylenediaminetetraacetic acid derivative 3. The thermoplastic polyurethane according to claim 1, wherein the thermoplastic polyurethane is a polyether-based thermoplastic polyurethane.
Or a thermoplastic polyurethane composition having excellent heat resistance according to 2.