JPH0565408A - Polyurethane composition - Google Patents

Abstract

PURPOSE:To obtain a polyurethane composition capable of continuously producing a molded article of polyurethane for a long period of time having excellent resistance to light and change of color, not causing bleedout phenomena. CONSTITUTION:A polyurethane is blended with (a) 0.1-2 pts.wt., preferably 0.1-1 pt. wt. hindered amine-based compound containing a group shown by formula I (A is 2-4C alkylene; R<3> to R<6> are lower alkyl), having >=1000 molecular weight, (b) 0.1-2 pts.wt., preferably 0.1-1 pt.wt. hindered phenolic compound containing a group shown by formula II (B is 2-4C alkylene; R<7> is 2-4C alkyl; R<8> is lower alkyl), having >=500 molecular weight and (C) 0.1-2 pts.wt., preferably 0.1-1 pt. wt. benzotriazole-based compound shown by formula III (R<1> and R<2> are aralkyl, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to stabilized polyurethane compositions. More particularly, the present invention relates to a polyurethane composition having excellent continuous molding processability, which gives a polyurethane molded article having excellent resistance to light discoloration.

[0002]

Polyurethanes obtained from polyisocyanates, low-molecular weight polyfunctional active hydrogen atom-containing compounds and polymeric diols have excellent mechanical properties and good processability. It is used in a wide range of applications such as, hoses, tubes, films, fibers and artificial leather. Among them, polyurethanes produced by using aromatic polyisocyanates such as 4,4′-diphenylmethane diisocyanate (MDI) are important because they have particularly excellent mechanical performance. However, a polyurethane produced using an aromatic polyisocyanate generally has a drawback that it is easily discolored by sunlight or artificial light.

As a method for solving this drawback, two methods have been mainly proposed. One is a method of using an aliphatic polyisocyanate or an alicyclic polyisocyanate instead of an aromatic polyisocyanate as a raw material of polyurethane. The second is a method of blending a light resistance improver with polyurethane.

[0004]

The former method improves the resistance to light discoloration, but has the drawback that the mechanical performance of polyurethane decreases. Further, in the latter method, stains derived from the light resistance improver during film extrusion processing such as films and tubes are likely to adhere to the die part or the metal roll surface and cause product defects, and the spinneret is soiled during fiber spinning. There is a drawback that it is easy to cause yarn breakage. Further, the latter method has a drawback that the light resistance improver is likely to bleed out on the surface of the product and impair the appearance during long-term use of the obtained polyurethane product.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies to solve these problems, and as a result, by adding a limited combination of additives to polyurethane, the photochromic resistance of polyurethane is improved. It was found that not only the above-mentioned improvement but also the continuous forming workability was remarkably improved and the bleed-out phenomenon was suppressed, and the present invention was completed.

That is, the present invention provides polyurethane with a hindered amine compound (I) having a molecular weight of 1000 or more and a hindered phenol compound (I) having a molecular weight of 500 or more.
I) and a benzotriazole compound (III) represented by Chemical formula 2

[0007]

[Chemical 2]

A polyurethane composition characterized by containing:

The polyurethane used in the present invention includes
There is no particular limitation, and known polyurethanes such as polyesters, polyethers, and polycarbonates can be used. Such a polyurethane is produced by subjecting a polymeric diol, a polyisocyanate, and optionally a low-molecular weight polyfunctional active hydrogen atom-containing compound to a urethanization reaction according to a conventional method. Examples of the polymer diol include polyester diols such as poly (tetramethylene adipate) diol and poly (3-methylpentamethylene azelate) diol; polyether diols such as polyoxypropylene glycol and polyoxytetramethylene glycol; poly ( Examples thereof include polycarbonate diols such as hexamethylene carbonate) diol. Examples of the polyisocyanate include 4,4′-diphenylmethane diisocyanate. Examples of the low molecular weight polyfunctional active hydrogen atom-containing compound include, for example, 1,4-butanediol, 1,4-bis (hydroxyethoxy) benzene, and other hydrogen atoms capable of reacting with an isocyanate in the molecule. Examples thereof include compounds having a molecular weight of 400 or less having two.

As the compound (I),

[0011]

[Chemical 3]

Compounds having a group represented by are preferred.
The alkylene group having 2 to 4 carbon atoms represented by A in Chemical Formula ³ is preferably an ethylene group, and the lower alkyl group represented by R ³ , R ⁴ , R ⁵ and R ⁶ is preferably a methyl group. When the molecular weight of the compound (I) is less than 1000, continuous molding such as occurrence of trouble due to adhesion of stain to die part or metal roll part during extrusion molding, and occurrence of trouble due to adhesion of stain to spinneret during spinning Bleed-out phenomenon is likely to occur in the obtained molded product with a decrease in workability. Compound (I)
The upper limit of the molecular weight of is not particularly limited, but is preferably 10,000 or less from the viewpoint of good compatibility with polyurethane. As the compound (I), dimethyl succinate-1- (2-hydroxyethyl) -4 represented by Chemical formula 4 is used.
-Hydroxy-2,2,6,6-tetramethylpiperidine polycondensate and the like are preferable.

[0013]

[Chemical 4]

As the compound (II),

[0015]

[Chemical 5]

Compounds having a group represented by are preferred.
The alkylene group having 2 to 4 carbon atoms represented by B in Chemical formula 5 is preferably an ethylene group or the like, and has 2 to 2 carbon atoms represented by R ^7.
The alkyl group of 4 is preferably an ethyl group, a t-butyl group or the like, and the lower alkyl group represented by R ⁸ is preferably a methyl group, an ethyl group or a t-butyl group. When the molecular weight of compound (II) is less than 500, continuous molding such as occurrence of troubles due to dirt adhered to the die part or metal roll part during extrusion molding and trouble due to dirt adhered to spinneret during spinning Bleed-out phenomenon is likely to occur in the obtained molded product with a decrease in workability. The upper limit of the molecular weight of the compound (II) is not particularly limited, but it is preferably 5000 or less from the viewpoint of good compatibility with polyurethane. Compound (I
As I), tetrakis [methylene-3- (3,5-
Di-t-butyl-4-hydroxyphenyl) propionate] methane, 3,9-bis [2- [3
-(3-t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.
5] Undecane, triethylene glycol-bis [3-
(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], etc. preferable.

[0017]

[Chemical 6]

The aralkyl groups represented by R ¹ and R ^{2 in the} chemical formula 2 representing the compound (III) are phenylmethyl group, phenethyl group, α-methylbenzyl group, 1-
C1-C1 substituted with at least one phenyl group such as methyl-1-phenylethyl group and diphenylmethyl group
Alkyl groups of 4 to 4 are preferred. As the compound (III), 2- [2-hydroxy-3,5-
Bis (α, α-dimethylbenzyl) phenyl] -2H-
Benzotriazole and the like are preferable.

[0019]

[Chemical 7]

When the compounds (I), (II) and (III) are blended into the polyurethane alone or in combination of two kinds, the discoloration preventing effect is not sufficient and satisfactory results cannot be obtained. ..

The compounding amounts of the compounds (I), (II) and (III) are preferably 0.1 to 2% by weight, and more preferably 0.1 to 1% by weight, based on the polyurethane. If the blending amount is too small, the effect of preventing light discoloration may be insufficient. On the other hand, if the amount is too large, the resulting molded product may become cloudy or the bleed-out phenomenon may easily occur.

The method for mixing the compounds (I), (II) and (III) with the polyurethane for producing the polyurethane composition of the present invention is not particularly limited, and the mixing is carried out during or after the formation of the polyurethane. It is possible to The polyurethane composition of the present invention includes a filler,
Known additives such as a reinforcing material and a coloring agent may be further blended.

The polyurethane composition of the present invention can be used for any of the known uses in conventional polyurethanes, but since it is less discolored by light, it is transparent or typified by a transparent tube film, a transparent sole member or the like. Light-colored extrusion-molded or injection-molded products, artificial leather, synthetic leather,
Alternatively, it is preferably used in the textile field.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The additives are shown by abbreviations in Examples and Comparative Examples, and the relationship between the abbreviations and compound names is as shown in Tables 1 and 2.

[0025]

[Table 1]

[0026]

[Table 2]

Reference Example: 190 parts by weight of poly (tetramethylene adipate) diol having a number average molecular weight of about 1000, 19 parts by weight of 1,4-butanediol and 100 parts by weight of 4,4'-diphenylmethane diisocyanate were melted in the absence of a solvent. A thermoplastic polyurethane was obtained by polymerization.

Examples 1 to 5 and Comparative Examples 1 to 10 The thermoplastic polyurethanes obtained in the reference examples were prepared by adding the prescribed amounts of additives shown in Table 3 and a single screw extruder of 25 mmφ and L / D = 25 (Plastic Engineering Laboratory: GT-25)
It was melt-mixed with and pelletized.

The pellets were dried at 80 ° C. for 4 hours and continuously extruded into a film by the same extruder as described above.
-Continuous molding processability was evaluated by measuring the time until the occurrence of greasy lumps at the die part and the occurrence of stains on the surface of the cooling metal roll. Incidentally, for the determination of the state of the cooling metal roll surface, based on the time until the start of the occurrence of stains by visual observation,
"A" indicates that no stain was found even after 10 hours from the start of molding, and "○" indicates that stain was found 5 hours or more and less than 10 hours after the start of molding. "," And "x" indicates that the occurrence of stains was recognized within 5 hours from the start of molding.

Using the same pellets, a disc having a thickness of 2 mm and a diameter of 120 mm was injection-molded by an injection molding machine (FS80S12ASE manufactured by Nissei Plastic Industry Co., Ltd.). A fade irradiation experiment was carried out using this disk to evaluate the resistance to light discoloration, and the bleed-out property of the disk after the irradiation experiment was evaluated. The irradiation conditions and the evaluation method are as follows.

(1) Irradiation condition Irradiation for 200 hours with a carbon lamp type light fastness tester (63 ± 2 ° C.) for dyeing fastness test of JIS L-0824

(2) Evaluation method Light discoloration resistance: Judgment was carried out according to the gray scale for discoloration of JIS L-0804. For example, "5
"No." represents "no discoloration" and "No. 1" represents "large discoloration".

Bleed-out property: It was judged by visual observation as follows. The one in which no bleed-out was observed is indicated by "A", the one in which a slight bleed-out was observed is indicated by "O", and the one in which a large amount of bleed-out was observed is indicated by "X".

The results obtained are shown in Table 4.

[0035]

[Table 3]

[0036]

[Table 4]

[0037]

EFFECTS OF THE INVENTION According to the present invention, as is clear from the above examples, there is provided a polyurethane composition which can be continuously molded into a desired molded product for a long period of time. Moreover, the molded article obtained from the polyurethane composition of the present invention has advantages that it exhibits excellent light discoloration resistance and does not cause a bleed-out phenomenon due to the polyurethane composition.

Claims (1)

[Claims] 1. A polyurethane containing a hindered amine compound (I) having a molecular weight of 1000 or more, a hindered phenol compound (II) having a molecular weight of 500 or more, and a benzotriazole compound (III) represented by Chemical Formula 1. A polyurethane composition comprising: [Chemical 1]