JP3187900B2 - Method for producing polyurethane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing polyurethane. Specifically, the present invention relates to a method for producing a polyurethane having excellent heat resistance, weather resistance, discoloration resistance, and the like.

[0002]

2. Description of the Related Art Polyurethane is widely used for various molded articles, artificial leather, elastic fibers, paints, adhesives, etc. because of its excellent mechanical properties and easy molding and processing. However, as the polyurethane after manufacturing time has elapsed, sunlight, NO _x gas, outdoor exposure, such as exhaust gas of an automobile, gradually yellowed by such contact with chemicals such as chlorine bleach or solvents, strength and elongation It has drawbacks such as a decrease in mechanical properties such as degree, and is greatly restricted in use.

In order to improve the above-mentioned disadvantages of polyurethane, a hindered amine compound having a piperidine ring substituted at each of the 2- and 6-positions with two alkyl groups, ie, a hindered piperidine ring, is added to the polyurethane polymer. Has been done in the past. However, in this method, there were problems such as blooming of the hindered amine compound on the surface of the polyurethane product, low compatibility with the polyurethane, and falling off the polyurethane by washing with water or dry cleaning.

[0004] In order to solve the above problems, a method has been proposed in which a hindered amine compound having a hindered piperidine ring is chemically bonded to polyurethane. As a conventionally proposed method of chemically bonding a hindered amine compound, a method of using a hindered amine compound as a terminal terminator during polyurethane production,
There is a method in which a hindered piperidine ring is introduced in a side chain form into the hard segment portion of the polyurethane using a hindered amine compound as a chain extender, and a method in which the hindered piperidine ring itself is introduced into the main chain of the polyurethane. The method is described in JP-A-53-39395.
And the above method is described in JP-A-53-1294.

[0005] However, in the case of the above method, the hindered amine compound acts as a terminal terminator, which hinders the enhancement of the degree of polymerization of the polyurethane.
In particular, when a large amount of a hindered amine compound is used in order to further improve the weather resistance and discoloration resistance of the polyurethane, the polyurethane is terminated at an extremely low degree of polymerization and a polyurethane having a desired degree of polymerization cannot be produced. There are disadvantages, and the amount of hindered amine compound used is limited.

In the above method, since a bulky hindered piperidine ring is present as a side chain in the hard segment, the formation of a crosslinked structure by hydrogen bonding between the hard segments is inhibited. However, they have the drawbacks that they tend to cause excellent mechanical properties such as elastic recovery, tensile strength and the like, and that heat resistance is easily lost.

In the case of the above-mentioned method, the polyurethane main chain is cleaved at the nitrogen atom of the piperidine ring in the polyurethane main chain by light, similarly to the radical scavenging mechanism known as the photostable mechanism of the hindered amine compound. Therefore, the polyurethane has a drawback that the light resistance of the polyurethane is not improved, and when exposed to light, the main chain is more likely to be cut and the mechanical strength is liable to be reduced.

[0008]

SUMMARY OF THE INVENTION In view of the above, the present inventors have obtained the above-mentioned conventional technology without causing the problems described above.
Research has been conducted in search of a method for chemically bonding a hindered amine compound to a polyurethane molecule. As a result, without using the hindered amine compound containing a hindered piperidine ring as a terminal terminator or a chain extender,
The present invention was completed by finding that the above object can be achieved by incorporating the hindered amine compound into a prepolymer type organic polyisocyanate having a molecular weight equal to or more than a predetermined value as a side chain in a pendant form and using the prepolymer at the time of polyurethane production. did.

Accordingly, the present invention is a polymer polyol, in the production of polyurethane by using a chain elongation agent, if organic polyisocyanate and optionally, as at least part of the organic polyisocyanate, the following pre
Special use of polymer organic polyisocyanate
This is a method for producing polyurethane . [ Organic Poly
Prepoly used as at least part of the cyanate
Mer type organic polyisocyanate ] The active hydrogen atom number F is 2
<F <4 high molecular weight polyol, organic polyiso
The cyanate is reacted so that the average number of isocyanate groups is 2
Produces larger isocyanate-terminated prepolymers
And the isocyanate-terminated prepolymer is
2- and 6-positions with one active hydrogen atom reactive to the salt
A piperidine ring wherein each is substituted with two alkyl groups
A hindered amine compound containing
Less than the isocyanate group equivalent of the end prepolymer
More than one unreacted isocyanate obtained by reacting
Leaving a nate group and two at each of the 2 and 6 positions
Group containing a piperidine ring substituted with an alkyl group of
The average molecular weight of the pendant side chain is 1500
The above prepolymer type organic polyisocyanate.

In the present invention, the above-mentioned “positions 2 and 6”
A prepolymer-type organic polyisocyanate having an average molecular weight of 1500 or more having a group containing a piperidine ring substituted at each position with two alkyl groups in a side chain in a pendant form (hereinafter referred to as "piperidine side chain containing prepolymer"). "Polymer") has an average molecular weight of 1500 or more, preferably 200
The prepolymer obtained by the above method, having an average molecular weight of 0 to 10,000 and having a hindered piperidine ring pendant as a side chain in the prepolymer.
Any type of organic polyisocyanate may be used .
In order for the piperidine side chain-containing prepolymer to function as a polyisocyanate prepolymer, it must have more than one isocyanate group, and typically has an average of about 1.8 to 3 isocyanate groups. It is preferable to have an isocyanate group per molecule.

As long as the above requirements are satisfied, specific conditions for obtaining a prepolymer containing a piperidine side chain are not particularly limited.
Although not described, an example of a preferred method for producing the piperidine side chain-containing prepolymer used in the present invention is described below in order to facilitate understanding.

Production Example of Piperidine Side Chain-Containing Prepolymer (1) In addition to relatively high molecular weight polyols such as polyester polyols and polyether polyols wherein the number of active hydrogen atoms F such as hydroxyl groups is 2 <F <4, organic poly The isocyanate (e.g., organic diisocyanate) is reacted to produce an isocyanate-terminated prepolymer having an average number of isocyanate groups greater than 2, preferably 2.2 to 3.8. (2) A hindered amine compound containing a piperidine ring having one isocyanate-reactive active hydrogen atom and each of which is substituted with two alkyl groups in the isocyanate-terminated prepolymer prepared in (1) above. To
Reacting in an amount less than the isocyanate group equivalent of the isocyanate-terminated prepolymer, having more than one, preferably on average about 1.8 to 3 unreacted isocyanate groups remaining and hindered The piperidine side chain-containing prepolymer having an average molecular weight of 1500 or more, in which a piperidine ring is pendant to the prepolymer as a side chain, is produced.

The polyol of 2 <F <4 used in the above step (1) may be a polyol having at least one low molecular polyol having three or more hydroxyl groups such as glycerin, trimethylolpropane, and pentaerythritol. A polyester polyol of 2 <F <4 produced by reacting an organic dicarboxylic acid and a low molecular weight diol, a low molecular weight polyol having three or more hydroxyl groups such as glycerin, trimethylolpropane, and pentaerythritol; The compound may optionally be reacted with a glycol to produce a 2 <F <4 polyester polyol, glycerin, trimethylolpropane, pentaerythritol, etc., at least one of low molecular polyols having three or more hydroxyl groups, ethylene oxide, propylene Oxa By reacting an alkylene oxide such as de may be mentioned 2 <F <4 polyether polyol produced by. And those polyester polyols and polyether polyols are usually about 300 to
It is desirable to have an average molecular weight of 5000, especially about 500-3000.

The organic polyisocyanate used in the above step (1) is preferably an organic diisocyanate. Such organic diisocyanates include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, , 5-naphthalenediisocyanate, xylylenediisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and the like. One or more of these organic diisocyanates are preferably used.

The "hindered amine compound having a piperidine ring having one isocyanate-reactive active hydrogen atom and substituted at each of the 2- and 6-positions by two alkyl groups" used in the above step (2) is used. As long as a total of four alkyl groups are bonded to the 2- and 6-positions of the piperidine ring and has one isocyanate-reactive active hydrogen atom, it is known in the art. Any of the hindered amine compounds can be used. Typical examples of the compound include a compound represented by the following formula (I).

[0016]

Embedded image Wherein R ¹ , R ² , R ³ and R ⁴ are each an alkyl group, R ⁵ is a direct bond or a divalent group, A and B are each a monovalent group, and A and B Only has one isocyanate-reactive active hydrogen atom, and m is 1
(The above is the number)

In the compound of the above formula (I), R ¹ ,
R ² , R ³ and R ⁴ are each preferably a lower alkyl group having 1 to 4 carbon atoms, and particularly preferably all of the 4 alkyl groups are methyl groups. When R ⁵ is a divalent group, it may be a divalent hydrocarbon group such as an alkylene group or an arylene group or a divalent group having an ester bond, an ether bond, a thioether bond, an amide bond, or the like. . Further, one of A and B is a monovalent group having an isocyanate-reactive active hydrogen atom, and is preferably an amino group, a hydroxyl group, a carboxyl group, or another monovalent group having a hydroxyl group, an amino group or a carboxyl group.
Valent groups (eg, aminomethyl, hydroxymethyl,
And the other one of A and B is a monovalent group having no isocyanate-reactive active hydrogen atom such as an alkyl group, an aryl group, an alkoxy group, an aryloxy group. Further, m is preferably 1 to 20.

Specific examples of the hindered amine compound contained in the compound represented by the formula (I) include the following formula (II)
1-methyl-2,2,6,6-tetramethyl-4-hydroxypiperidine represented by the formula: 1-methyl-2,2,6,6-tetramethyl-4- represented by the following formula (III)
Examples thereof include aminopiperidine and a compound represented by the following formula (IV).

[0019]

Embedded image

[0020]

Embedded image

[0021]

Embedded image (Wherein, n represents a number of 2 to 20)

Among the above hindered amine compounds, the compound represented by the formula (IV) is preferable because a plurality of hindered piperidine rings can be introduced into the piperidine side chain-containing prepolymer molecule.

In the piperidine side chain-containing prepolymer used in the present invention, the ratio of the hindered amine compound is about 5 to 70%, preferably about 10 to 60%, based on the weight of the piperidine side chain containing prepolymer. It is preferable from the viewpoints of improving the weather resistance, light resistance, discoloration resistance, heat resistance and the like of the polyurethane, maintaining good mechanical properties, and the like. The reaction (2) for producing a piperidine side chain-containing prepolymer is usually carried out at a temperature of about 50 to 200 ° C, preferably about 70 to 160 ° C.

In producing a polyurethane using the piperidine side chain-containing prepolymer in the present invention, the polyurethane may be produced by a one-shot method or a prepolymer method in the presence of a piperidine side chain-containing prepolymer, or may be optionally prepared. After producing a polyurethane having no piperidine side chain by the method described above, a piperidine side chain-containing prepolymer may be added and reacted to bind to the polyurethane molecule.

In the case of the one-shot method, a polyurethane is produced by simultaneously reacting a polymer polyol, an organic polyisocyanate and, if necessary, a chain extender.
In that case, on average, more than one, preferably from 1.8 to 3, as at least part of the organic polyisocyanate
The above-mentioned piperidine side chain-containing prepolymer having 1.9, more preferably 1.9 to 2.8 isocyanate groups is used. The ratio of the piperidine side chain-containing prepolymer in the organic polyisocyanate may vary depending on the molecular weight of the piperidine side chain-containing prepolymer, the amount of hindered piperidine rings bonded thereto, the type of other organic polyisocyanate, and the like. However, it is usually desirable to set the amount to about 0.5 to 60% based on the total weight of the organic polyisocyanate including the piperidine side chain-containing prepolymer. In this case, the molar ratio of active hydrogen atoms such as isocyanate groups to hydroxyl groups in the one-shot raw material mixture is desirably in the range of 0.9: 1 to 1.2: 1.

When a polyurethane is produced by the prepolymer method, an isocyanate-terminated prepolymer is produced from a high molecular polyol and an ordinary organic polyisocyanate, and then the above-mentioned piperidine side chain-containing prepolymer is added to the isocyanate-terminated prepolymer. It is preferable to add polyurethane and a chain extender and react to produce polyurethane. Also in this case, the ratio of (isocyanate group obtained by summing the isocyanate-terminated prepolymer and the piperidine side chain-containing prepolymer) :( active hydrogen atom in a chain extender or the like) is 0.9: 1 to 1.2 in molar ratio. : 1 is desirable.

Further, in the case of producing a polyurethane containing a hindered piperidine side chain by adding the above-mentioned piperidine side chain-containing prepolymer after producing the polyurethane and reacting, for example, a conventional one-shot method or a prepolymer method is used. After producing a thermoplastic polyurethane by the above, the piperidine side chain-containing prepolymer is added to the thermoplastic polyurethane and heated and melted to react an isocyanate group of the piperidine side chain-containing prepolymer with active hydrogen atoms in the polyurethane molecule, A group containing a hindered piperidine ring is pendantly bonded to a side chain of the polyurethane.

The high molecular polyol used in the one-shot method or the prepolymer method described above has an average molecular weight of 500 to 5,000, preferably 1,000 to 300.
It is preferred to use one of zero. As the polymer polyol, it is preferable to use at least one kind of polyester diol, polycarbonate diol, polyether diol, polyether ester diol, and the like. In addition, a polymer polyol such as a polymer triol and a polymer tetraol can be used alone or in combination with a polymer diol.

For example, the polyester diols described above include at least one of dicarboxylic acids (eg, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc.) and low molecular diols (eg, ethylene glycol, propylene). Glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 1,9-
Nonanediol, 1,10-decanediol, etc.), and polylactone diols such as polycaprolactone diol and polymethylvalerolactone diol obtained by ring-opening polymerization of a lactone compound. .

Examples of the polycarbonate diol include, for example, at least one of dialkyl carbonates (dimethyl carbonate, diethyl carbonate, ethylene carbonate, etc.) and a low molecular weight diol (for example, ethylene glycol, propylene glycol,
4-butanediol, neopentyl glycol, 1,6
-Hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 1,
9-nonanediol, 1,10-decanediol, etc.).

Further, polyether diols include polyether diols obtained by ring-opening polymerization of cyclic ethers (polyethylene oxide, polypropylene oxide, trimethylene oxide, tetrahydrofuran, etc.) and glycols (ethylene glycol, propylene glycol, 1,4- Butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5
-Pentanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, etc.) are preferred.

As the polyetherester diol, those prepared by reacting the above-described polyester diol with the above-mentioned cyclic ether, those obtained by reacting the above-described polyester diol with polyether diol, and the like can be used. Can be.

As the organic polyisocyanate other than the piperidine side chain-containing prepolymer used for producing the polyurethane, an organic diisocyanate, an organic triisocyanate or the like can be used, and an organic diisocyanate is preferably used. As the organic diisocyanate in that case, 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, 1,5-naphthalenediisocyanate, xylylene diisocyanate,
Examples thereof include isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate. These organic diisocyanates may be used alone or in combination of two or more.

In the present invention, a chain extender can be used, if necessary. As the chain extender, ethylene glycol, propylene glycol,
1,4-butanediol, 1,6-hexanediol,
Diols such as 1,9-nonanediol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol, xylylene glycol, ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, 4,4 One or more diamines such as' -diaminodiphenylmethane, tolylenediamine, and 4,4'-diaminodicyclohexylmethane can be used.

In any of the above methods,
The bonding ratio of the hindered piperidine ring in the finally obtained polyurethane is not particularly limited.However, in consideration of the effect of improving light resistance and weather resistance and economic efficiency, it is usually based on the total weight of the raw material for polyurethane. The proportion of the piperidine side chain-containing prepolymer is about 0.1 to 20%.
It is desirable to produce the polyurethane in such a way that

The above-mentioned reaction for producing the polyurethane of the present invention can be carried out by various known methods depending on the properties of the obtained polyurethane. For example, in the case of producing a thermoplastic polyurethane, a thermoplastic polyurethane is produced using a batch-type or continuous-type reactor, and the thermoplastic polyurethane obtained there is further subjected to various molding processes and treatments. Various molded products (films, sheets, other molded products, etc.), fibers, synthetic leather, paints, adhesives, etc., or polymerization and molding performed simultaneously using a mold or other molding equipment Good. In the case of thermosetting polyurethane, even if polymerization and molding are performed simultaneously using various molding equipment, or the raw material mixture for polyurethane is kept in a state before polymerization (for example, a multi-liquid mixture) and It may be used for various applications such as molding, paints, adhesives and sealants.

In the production of the polyurethane of the present invention, catalysts, activators, foaming agents, defoamers, other stabilizers, coloring agents such as dyes and pigments, fillers and the like, which are usually used in the production of polyurethane, are used. Optional components such as agents, flame retardants, and lubricants can be used as needed.

Hereinafter, the present invention will be described specifically with reference to Examples and the like, but the present invention is not limited thereto. Parts in the following examples represent parts by weight. Further, in the following examples, the light resistance test, the evaluation of the solvent extractability, and the quantification of the isocyanate group of the produced prepolymer were performed by the following methods.

<Light resistance test> A carbon arc type fade meter FAL manufactured by Suga Test Instruments Co., Ltd. was applied to the polyurethane film (0.1 mm thick) manufactured in each of the following examples.
Ultraviolet rays were irradiated at a temperature of 83 ° C. for 20 hours using a -5 type mold, and its light fastness and strength retention were examined. The light fastness was evaluated by the following five-grade evaluation of the degree of browning. Criteria for light fastness evaluation 5: No discoloration (colorless) 4: Discoloration slightly yellow 3: Discoloration yellow 2: Discoloration yellow to brown 1: Discoloration brown The ratio was calculated from the following formula 1 by measuring the strength of the polyurethane film using an autograph manufactured by Shimadzu Corporation.

[0040]

## EQU1 ## Strength retention (%) = (strength after ultraviolet irradiation / strength before ultraviolet irradiation) × 100

<Solvent Extractability> The polyurethane film (0.1 mm in thickness) produced in each example was immersed in 70 ° C. perchren for 5 hours at a bath ratio of 1: 1000, and dried at 50 ° C. for 1 hour. A light fastness test was conducted by the above method, and the light fastness and strength retention were determined.

<Quantification of Isocyanate Group> 0.1 g of the reaction solution containing the prepolymer was added to 0.01 N di-n-
After butylamine was added to and dissolved in 40 ml of a dimethylformamide solution, the solution was quantified by neutralization titration with a solution of 0.01 N hydrochloric acid in methanol using bromophenol blue as an indicator.

The compounds used in each example are as indicated by the following abbreviations. PES-X : 3-methyl-1,5-pentanediol,
Polyester polyol having an average number of hydroxyl groups of 3 obtained by reacting trimethylolpropane and adipic acid (average molecular weight: 1000) PES-Y : 3-methyl-1,5-pentanediol,
Polyester polyol having an average hydroxyl number of 3 obtained by reacting trimethylolpropane and adipic acid (average molecular weight: 2,000) P-312 : polycaprolactone polyol having an average hydroxyl number of 3 (manufactured by Daicel Chemical Industries, Ltd .; Plaxel -312 ,
Average molecular weight 1250) P-2010 : poly (3-methyltylpentane adipate) diol [manufactured by Kuraray Co., Ltd .; Kurapol P-201]
0, average molecular weight 2000) PCL : polycaprolactone diol (average molecular weight 20)
00) BD : 1,4-butanediol MDI : 4,4′-diphenylmethane diisocyanate 622LD : Hindered amine compound represented by the above formula (IV) (light stabilizer, Ciba Geigy; Tinuvin 62)
2LD, average molecular weight 3400) LS-765 : Hindered amine compound having no isocyanate group and no active hydrogen atom represented by the following formula (V) [Sanol LS-765 manufactured by Sankyo Co., Ltd.]

[0044]

Embedded image

Reference Example 1 [Production of Piperidine Side Chain-Containing Prepolymer] 100 parts of PES-X was placed in a nitrogen-sealed reaction vessel, and 75 parts of MDI was added while keeping the temperature at 80 ° C., followed by a reaction for 40 minutes. Thereafter, the remaining amount of the isocyanate groups was determined by the above-mentioned quantitative method, and was 49.9 mol%. Next, 113 parts of 622LD was added and reacted for 1 hour.
A piperidine side chain-containing prepolymer (prepolymer A) was obtained. The residual amount of the isocyanate group of the prepolymer A is 2
6.5 mol%, an average number of functional groups (average number of isocyanate groups) of 2.65, and 62 in prepolymer A.
The binding amount (content) of 2LD was 39.2% by weight.

Reference Examples 2 to 5 [Production of polyisocyanate prepolymer] Instead of PES-X, the polyols shown in Table 1 below were used in the amounts shown in Table 1, and the amounts shown in Table 1 were used. MDI
In the same manner as in Reference Example 1 with or without 622LD, and with or without 622LD, the piperidine side chain-containing prepolymers (prepolymers B to D) and the piperidine side chain-free prepolymers (prepolymers) shown in Table 1 were used. Polymer E) was prepared. The average number of isocyanate groups and the content of 622 LD of these prepolymers were as shown in Table 1.

[0047]

[Table 1]  Reference Example 1 Reference Example 2 Reference Example 3 Reference Example 4 Reference Example 5 Raw material for prepolymer  Type of polyol PES-X PES-Y PES-Y P-312 PES-Y / P-2010 Polyol usage (parts) 100 200 200 125 130/70 MDI usage (parts) 75 75 75 75 66.3 622 LD usage ( Part) 113 113 226 68 0Generated prepolymer  Type ABCDE Average number of NCO groups 2.65 2.65 2.33 2.80 2.65 622 LD content 39.2 29.1 45.1 25.4 0(weight%)

Example 1 [Production of Polyurethane] In a reaction vessel, 32 parts of P-2010 and 2.9 parts of BD were placed, and while maintaining the temperature at 80 ° C., 12.1 parts of MDI and 0.61 part were added.
After adding and stirring part of prepolymer A, the mixture was transferred to a kneader maintained at 220 ° C. and reacted for 10 minutes. The obtained reaction product was hot-pressed at 230 ° C. to produce a 0.1 mm-thick polyurethane film. The light fastness test and the light fastness test after solvent extraction of this polyurethane film were performed by the methods described above, and the light fastness and strength retention were examined. The results are shown in Table 2 below.

<< Examples 2 to 4 >> [Production of Polyurethane] Instead of prepolymer A, the prepolymers produced in Reference Examples 2 to 4 were used. In Example 4, P-2010 was further used.
Polyurethane and polyurethane film were produced in the same manner as in Example 1 except that PCL was used instead of PCL, and the light resistance test of the polyurethane film obtained in each example was performed in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 1 [Production of Polyurethane] In a reaction vessel, 32 parts of P-2010 and 2.9 parts of BD were added, and while maintaining the temperature at 80 ° C., 12.0 parts of MDI and 0.96 were added.
After adding and stirring part of prepolymer E, the mixture was transferred to a kneader kept at 220 ° C. and reacted for 10 minutes. The obtained reaction product was hot-pressed at 230 ° C. to produce a 0.1 mm-thick polyurethane film. The light resistance test of this polyurethane film was performed in the same manner as in Example 1. The results are shown in Table 2 below.

Comparative Example 2 [Production of Polyurethane] 32 parts of P-2010 and 2.9 parts of BD were placed in a reaction vessel, and 12.1 parts of MDI and 0.47 parts were maintained at 80 ° C.
Of LS-765 was added and stirred, then transferred to a kneader kept at 220 ° C. and reacted for 10 minutes. The obtained reaction product was hot-pressed at 230 ° C. to produce a 0.1 mm-thick polyurethane film. The light resistance test of this polyurethane film was performed in the same manner as in Example 1. The results are shown in Table 2 below.

[0052]

[Table 2]  Example Comparative example  1 2 3 4 1 2 Raw materials for polyurethane  Type of polyol P-2010 P-2010 P-2010 PCL P-2010 P-2010 Polyol usage (parts) 32 32 32 32 32 32 Butanediol usage (parts) 2.9 2.9 2.9 2.9 2.9 2.9 MDI usage (parts) 12.0 12.0 12.1 12.0 12.0 12.1 Prepolymer Type ABCDE-Amount used (parts) 1.22 1.66 1.06 1.92 0.96-622 LD content (% by weight) 1.0 1.0 1.0 1.0 0-LS-765 content (% by weight) ) 0 0 0 0 0 1.0Light fastness test  Before solvent extraction  Light fastness 4 4 4 4 1 4 Strength retention (%) 80 81 85 79 35 80After solvent extraction  Light fastness 4 4 4 4 1 2 Strength retention (%) 79 79 84 76 30 50

From the results in Table 2 above, it can be seen that Examples 1 to 4 of the present invention in which a polyurethane was produced using a piperidine side chain-containing prepolymer as a part of an organic polyisocyanate.
In No. 4, a polyurethane having excellent light resistance was obtained,
It can be seen that the excellent light fastness hardly decreases even after the solvent extraction treatment. In contrast, the polyurethane of Comparative Example 1 to which no hindered amine compound was added was inferior in light resistance from the beginning, and a polyurethane containing a non-reactive hindered amine compound having no isocyanate group or active hydrogen atom. In Example 2, although light resistance was initially exhibited, the light resistance was lost by the solvent extraction treatment.

[0054]

The method of the present invention, sunlight, NO _x gas,
It is possible to obtain a stabilized polyurethane which has very little yellowing due to outdoor exposure to automobile exhaust gas or the like or contact with a chemical substance such as a chlorine bleach. In the case of the present invention, by obtaining a polyurethane in which a hindered amine compound is chemically bonded to the polyurethane, blooming on the surface of the polyurethane product, low compatibility with the polyurethane, separation from the polyurethane by washing or cleaning, etc. are obtained. Problem does not occur. Furthermore, in the case of the method of the present invention, the end blocking of the polymer in a low polymerization degree state,
The introduction of the hindered piperidine ring into the hard segment portion of the polyurethane and the introduction of the piperidine ring into the polyurethane main chain do not occur, and the hindered piperidine ring is pendantly bonded to the soft segment of the polyurethane as a side chain. Polyurethane having high physical properties such as elastic recovery, tensile strength and heat resistance can be produced.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Koji Hirai 1621 Sazu, Kurashiki-shi, Okayama Prefecture Kuraray Co., Ltd. (56) References JP-A-60-86116 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) C08G 18/00-18/87

Claims (1)

(57) [Claims] When producing a polyurethane using a polymer polyol, an organic polyisocyanate and, if necessary, a chain extender, at least a part of the organic polyisocyanate described below is used as a prepolymer type organic polyisocyanate.
Polyurethane characterized by using cyanate
Production method; [ Use as at least a part of organic polyisocyanate
Prepolymer type organic polyisocyanate ] High-molecular-weight polyol having an active hydrogen atom number F of 2 <F <4
Reaction with an organic polyisocyanate,
Isocyanate terminal having more than 2 cyanate groups
Producing a prepolymer, the isocyanate-terminated prepolymer
Has one active hydrogen atom reactive with isocyanate
2 and 6 are each substituted by two alkyl groups
Hindered amine compound containing a piperidine ring,
Isocyanate groups of the isocyanate-terminated prepolymer
Less than one obtained by reacting in an amount smaller than the equivalent
It has many unreacted isocyanate groups and
And 6-position pipettes each substituted by two alkyl groups
A pendant side chain containing a group containing a lysine ring
Prepolymer type organic polyiso having an average molecular weight of 1500 or more
Cyanate.