JPH09136932A - Preparation of polyurethane resin and yellowing preventive composition for polyurethane resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a polyurethane resin which is excellent in the effect of inhibiting initial yellowing. SOLUTION: In the preparation of a polyurethane resin from an isocyanate compd. and a compd. contg. an active hydrogen, a phosphorous acid compd. and a tertiary amino alcohol represented by the formula are added in the system in any stage of the preparation of polyurethane resin. In the formula, R1 represents a straight-chain or branched 1-20C alkyl group or the like, R2 represents a straight-chain or branched 2-20C alkylene group or the like, and n represents the average degree of polymn. and is a number of 2 to 50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a stabilized polyurethane resin, and more particularly to a method for producing a polyurethane resin in which natural fading (yellowing) is reduced for a few days immediately after molding. . The present invention also provides
The present invention relates to an anti-yellowing agent composition for polyurethane resin, which exhibits such effects.

[0002]

2. Description of the Related Art Polyurethane has impact resistance, chemical resistance,
Since it is a polymer having excellent wear resistance and cold resistance, it is a material that has been conventionally used in various fields.
However, on the other hand, polyurethane is also susceptible to external factors such as light, heat, moisture, oxygen, etc., and these external factors cause the quality of polyurethane such as surface gloss and hue change. An unfavorable phenomenon occurs.

Therefore, various stabilizers have been developed for the purpose of improving the poor weather resistance of polyurethane against these external factors. For example, in JP-A-56-100848, a phenylenediamine compound and a sterically hindered phenol compound, a phenylenediamine compound and a phosphite compound, a phenylenediamine compound and a quinoline compound, a phenylenediamine compound and a benzotriazole compound are disclosed. A phenylenediamine compound and a thiourea-based compound, a phenylenediamine compound and a piperidine-based compound, or a phenylenediamine compound and a metal oxide are used as stabilizers for polyurethane. In JP-A-57-49653, a hindered phenol compound and a phosphite are used to improve the weather resistance of a polyurethane resin.

[0004]

However, the stabilizers for polyurethanes that have been developed so far are a measure against obvious visible yellowing in long-term use, and the fading immediately after molding (hereinafter referred to as initial yellowing). In some cases) is not considered. That is, for example, JP-A-57-496
The polyurethane resin containing the additive disclosed in Japanese Patent No. 53 shows relatively excellent light resistance in an exposure acceleration test (evaluation of long-term yellowing) by a weather sunshine meter, etc. Not effective in natural fading (evaluation of initial yellowing) when left indoors,
On the contrary, yellowing was sometimes accelerated. Yellowing of the urethane resin for several days after molding is a problem especially when coating the surface. Generally, after molding, the coating is allowed to take several days to cure, but if the yellowing during that period is severe, the base will stand out and the color will become uneven even if the coating is performed, resulting in a decrease in commercial value. In addition, even if the surface coating is not applied, product storage,
If yellowing occurs during transfer, the product value will decrease.

[0005]

In order to solve the above-mentioned problems, the present inventors have added a phosphite compound and a tertiary amino alcohol having a specific structure to a polyurethane resin to allow it to be used for several days immediately after molding. It was found that the natural fading (initial yellowing) can be remarkably suppressed, and the present invention has been completed.

That is, according to the present invention, when a polyurethane resin is produced by using an isocyanate compound and an active hydrogen-containing compound, (a) a phosphorous acid compound and (b) a tertiary amino compound represented by the following general formula (I): A method for producing a polyurethane resin, which comprises adding alcohol to the system at any stage of the production process, and preventing yellowing of the polyurethane resin containing the components (a) and (b) as essential components. An agent composition is provided.

[0007]

Embedded image

[In the formula, R ₁ represents a linear or branched alkyl group having 1 to 20 carbon atoms or an aralkyl group, and R ₂ represents a linear or branched alkylene group having 2 to 20 carbon atoms, an alicyclic alkylene group, Aralkylene group or-(CH ₂ CH ₂ O) _p- (CH ₂ CH ₂ ) _q
Group (wherein p is 0 or a positive number and q is a positive number), and the average degree of polymerization n is 2 to 50. ].

Specific examples of the phosphite compound which is the component (a) of the present invention include distearyl pentaerythritol diphosphite, tetraphenyl tetra (tridecyl) pentaerythritol tetraphosphite, tetraphenyl dipropylene glycol diphosphite, Examples thereof include bis (nonylphenyl) pentaerythritol diphosphite and tetraphenyl tetratridecyl pentaerythritol phosphite. Further, a compound represented by the following general formula (II) is preferable.

[0010]

Embedded image

[In the formula, R ₃ , R ₄ and R ₅ may be the same or different and each is hydrogen, an alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms and 6 carbon atoms. Represents an aryl group having 18 to 18 carbon atoms, an alkylaryl group having 7 to 30 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms. However, not all are hydrogen. Examples of the phosphorous acid compound represented by the general formula (II) include diphenyl-nonylphenyl phosphite, triphenyl phosphite, tri (nonylphenyl) phosphite,
Triethyl phosphite, tri (2-ethylhexyl)
Phosphite, tridecyl phosphite, diphenyl-
2-ethylhexyl phosphite, diphenyl hydrogen phosphite, dilauryl hydrogen phosphite and the like can be mentioned. Of these, diphenyl-nonylphenyl phosphite is particularly preferable. The above phosphorous acid compounds can be used alone or as a mixture of two or more kinds.

Further, as the tertiary amino alcohol which is the component (b) of the present invention, any of those having the structure represented by the above general formula (I) and satisfying the condition can be used. When the carbon number of R ₁ and R _{2 in} the general formula (I) or the average degree of polymerization n exceeds the upper limit of the range specified in the present invention, the viscosity becomes high and it becomes difficult to use. Preferably, R ₁ is a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₂ is a linear or branched alkylene group having 6 to 9 carbon atoms,
It is a tertiary amino alcohol having an average degree of polymerization n of 3 to 18. Particularly, the average degree of polymerization n is preferably larger than 3. R ₁
When is an aralkyl group, the total number of carbon atoms is 7-20. When R ₂ is an alicyclic alkylene group or an aralkylene group, the total number of carbon atoms is 3-20.

The method for producing the polyurethane resin of the present invention comprises:
It can be applied to a conventionally known method for producing various polyurethane resins using an isocyanate compound and an active hydrogen-containing compound.

In the present invention, examples of the polyisocyanate compound used for producing polyurethane include toluene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate and hexamethylene. Diisocyanate, isophorone diisocyanate, polymethylene polyphenyl diisocyanate, 3,3'-dimethyl 4,4'-biphenylene diisocyanate, 3,3'-dimethyl 4,4'-diphenylmethane diisocyanate, 3,3-dichloro 4,
Examples thereof include polyisocyanate compounds such as 4'-biphenylene diisocyanate and 1,5-naphthalene diisocyanate, mixtures thereof, modified products thereof, and prepolymers thereof, which can be used in the production of polyurethane.

Examples of the active hydrogen-containing compound used in producing the polyurethane in the present invention include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, glycerin and trimethylol. propane,
Low molecular weight polyols such as 1,2,6-hexanetriol and pentaerythritol, ethylenediamine, 4,4'-
Examples thereof include amine compounds such as methylenebis2-chloroaniline, or polyether polyols and polytetramethylene glycol obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to low molecular weight polyols. Polycondensation products with polybasic acids such as phthalic acid, maleic acid, malonic acid, succinic acid, adipic acid, terephthalic acid, etc. Polyester polyols having a hydroxyl group at the terminal, polycaprolactone polyols, polycarbonate polyols, acrylic polyols, castor oil , Tall oil, and the like.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The production method of the present invention can be carried out according to known methods as long as it is a method for producing a polyurethane resin using an isocyanate compound and an active hydrogen-containing compound. At that time, the component (a) and the component (b) are
It may be added at any stage of charging the raw materials, during the polyurethane reaction or after the polyurethane reaction, but it is particularly preferable to add it in the raw materials in advance. In particular, the phosphorous acid compound as the component (a) is used by adding it to the isocyanate component, and the tertiary amino alcohol as the component (b) is used by adding it in the active hydrogen-containing compound (polyol component).

The components (a) and (b) are preferably used in a weight ratio of (a) / (b) = 1 / 0.25 to 1/4 from the viewpoint of the effect of suppressing initial yellowing. In addition, the total of the components (a) and (b) is the final polyurethane resin 100.
It is added so as to be 0.5 to 4 parts by weight in parts by weight.

An example of the production method of the present invention will be described. First, a polyester polyol which is an active hydrogen-containing compound and a tertiary amino alcohol as the component (b) are mixed and heated under heating (about 60 to 80 ° C.) for 2 to 2. Stir for 6 hours to dissolve. Further, optional components such as a foaming agent, a catalyst and a foam stabilizer are added to prepare a polyol component. Further, an isocyanate and a polyester polyol are reacted under heating, and a predetermined amount of the phosphorous acid compound of the component (a) is added to the obtained polyurethane prepolymer to prepare an isocyanate component. After thoroughly mixing the polyol component and the isocyanate, they are poured into a desired mold to obtain the target polyurethane resin (molded product). The ratio of the polyol component and the isocyanate component is not limited.

Examples of the foaming agent used in the present invention include diols such as ethylene glycol and diethylene glycol, triols such as glycerin, diamines such as hexamethylenediamine, and components other than the component (b) of the present invention such as diethanolamine. Amino alcohol etc. are mentioned. Examples of the reaction catalyst used in the present invention include triethylenediamine, tetramethylethylenediamine,
Examples thereof include amine compounds such as tetramethylhexanediamine, salts thereof, organometallic compounds such as dibutyltin dilaurate, tin octylate, lead octylate and lead octylate, and mixtures thereof. Also,
Examples of the foam stabilizer used in the present invention include silicon-based foam stabilizers. As other additives, a chain extender, a crosslinking agent, a flame retardant, a filler and the like can be used. These amounts may be selected according to the target polyurethane resin.

The present invention also provides a yellowing inhibitor composition for a polyurethane resin, which contains the component (a) and the component (b) in the above weight ratio. The amount of the polyurethane resin used in this case is as described above. The anti-yellowing agent composition of the present invention is excellent in the effect of suppressing the initial yellowing of the polyurethane resin, but a known anti-yellowing agent may be used in combination in order to impart a long-term yellowing effect. Known anti-yellowing agents include di-t-butylhydroxytoluene, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 1,6-hexamethylenebis (N, N-dimethylsemicarbazide), etc. Is mentioned. In this case, the weight ratio of the total amount (a) of the components (a) and (b) to the other anti-yellowing agent (b) in the anti-yellowing agent composition of the present invention is (a) /
(B) = 2/1 to 1/2 is preferable.

According to the present invention, the initial yellowing of the polyurethane resin can be significantly suppressed. Therefore, resinification,
It is useful as a method for producing a polyurethane resin in which a curing step is performed for several days after molding.

[0022]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Moreover, all "parts" in the examples are parts by weight.

Examples 1 to 4 and Comparative Examples 1 to 5 (1) Production of Polyurethane Resin Polyester polyol (hydroxyl value 51, average molecular weight 220)
0) To 100 parts, a predetermined amount of components other than the phosphite compound among the anti-yellowing agents shown in Table 1 was added (the addition amount in Table 1 is the amount based on 100 parts by weight of the final polyurethane resin), and 60 to 80
The mixture was heated and stirred at 2 ° C. for 2 to 6 hours to be dissolved. Furthermore, 11 parts of ethylene glycol, 1.65 parts of water, 0.8 parts of triethylenediamine, and 1 part of a silicon foam stabilizer were added to and mixed with this polyol component, and this was used as the polyol component. Also, 100 parts of 4,4'-diphenylmethane diisocyanate and 66.5 parts of polyester polyol (hydroxyl value 56, average molecular weight 2000) were used as 60 parts.
The resulting polyurethane prepolymer (NCO% 18.5%) was allowed to react for 2 hours at a temperature of the predetermined amount of the phosphorous acid compound among the yellowing inhibitors shown in Table 1 (the addition amount in Table 1 is 100% by weight of the final polyurethane resin). This is the isocyanate component. The above polyol component 10
After thoroughly mixing 0 parts and 71 parts of isocyanate, the mixture was poured into a mold of 45 to 50 ° C. coated with a silicone type release agent, and after 5 minutes, it was taken out and a white cured product sheet (specific gravity 0.65, thickness 5 mm (1
50 mm × 150 mm) was obtained. The tertiary amino alcohol used here has the following structure.

[0024]

[Chemical 6]

(2) Evaluation of the effect of suppressing the initial yellowing The above-obtained polyurethane sheet was left for 3 days immediately after molding in a room using a fluorescent lamp that was not exposed to direct sunlight as a light source, and the yellowing of the test piece was performed. Degree colorimeter (Suga Test Instruments Co., Ltd.)
Manufactured by SM Color Computer SM-3), and indicated by a yellow index (YI value). The results are shown in Table 1. In Table 1, if the difference in yellowing degree is 0.2, the difference will be easily identifiable visually.

[0026]

[Table 1]

(Note) The addition amount in the table is the amount (part by weight) in 100 parts by weight of the final polyurethane resin (the same applies hereinafter).

Comparing Comparative Examples 1 to 3 with Examples 1 to 4, it can be seen that the combined system of the tertiary amino alcohol and the phosphorous acid compound (Example 1) is excellent in the effect of preventing the initial yellowing of the polyurethane resin. Recognize. Further, Comparative Examples 4 and 5 are examples in which known anti-yellowing agents were used, but it can be seen that these are rather adverse effects for the prevention of initial yellowing.

Example 6 Using the polyurethane sheets obtained in Examples 2 and 4 and Comparative Examples 1 to 5, long-term yellowing prevention was evaluated. That is,
Each polyurethane sheet was irradiated for 30 hours with a carbon arc type sunshine weather meter (Suga Test Instruments Co., Ltd., Ducycle sunshine super long life weather meter WEL-SUN-DC type), and then the test piece turned yellow. The degree was measured with a colorimeter and indicated by a yellow index (YI value). The results are shown in Table 2.

[0030]

[Table 2]

It can be seen that Comparative Examples 4 and 5 have a relatively long-term yellowing prevention effect, but Examples 2 and 4 also have a sufficient long-term yellowing prevention effect.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazushige Takemura 1334 Minato Minato, Wakayama City, Wakayama Prefecture Kao Co., Ltd. (72) Inventor Shoichiro Harada 1334 Minato Minato, Wakayama City, Wakayama Lab.

Claims (7)

[Claims] 1. When a polyurethane resin is produced using an isocyanate compound and an active hydrogen-containing compound,
A process for producing a polyurethane resin, which comprises adding (a) a phosphite compound and (b) a tertiary amino alcohol represented by the following general formula (I) to the system at any stage of the production process. Embedded image [In the formula, R ₁ represents a linear or branched alkyl group having 1 to 20 carbon atoms or an aralkyl group, and R ₂ represents a linear or branched alkylene group having 2 to 20 carbon atoms, an alicyclic alkylene group, an aralkylene group or -(CH ₂ CH ₂ O) _p- (CH ₂ CH ₂ ) _q -group (however,
p is 0 or a positive number, and q is a positive number), and the average degree of polymerization n is a number of 2 to 50. ] 2. In the general formula (I), R ₁ is a linear or branched alkyl group having 1 to 4 carbon atoms, R ² is a linear or branched alkylene group having 6 to 9 carbon atoms, and the average degree of polymerization n is 3 The method according to claim 1, wherein the number is -18. 3. The process according to claim 1, wherein the phosphorous acid compound is a compound represented by the following general formula (II). Embedded image [In the formula, R ₃ , R ₄ and R ₅ may be the same or different,
Each represents hydrogen, an alkyl group, a cycloalkyl group, an aryl group, an alkylaryl group or an aralkyl group.
However, not all are hydrogen. ] 4. The component (a) and the component (b) are replaced by (a) /
(B) = 1 / 0.25 to 1/4, and the total of the components (a) and (b) is the final polyurethane resin 100.
The method according to any one of claims 1 to 3, wherein the amount is 0.5 to 4 parts by weight in parts by weight. 5. A yellowing inhibitor composition for a polyurethane resin, which comprises (a) a phosphorous acid compound and (b) a tertiary amino alcohol represented by the following general formula (I). Embedded image [In the formula, R ₁ represents a linear or branched alkyl group having 1 to 20 carbon atoms or an aralkyl group, and R ₂ represents a linear or branched alkylene group having 2 to 20 carbon atoms, an alicyclic alkylene group, an aralkylene group or -(CH ₂ CH ₂ O) _p- (CH ₂ CH ₂ ) _q -group (however,
p is 0 or a positive number, and q is a positive number), and the average degree of polymerization n is a number of 2 to 50. ] 6. The weight ratio of component (a) and component (b) is
(A) / (b) = 1 / 0.25-1 / 4, The anti-yellowing agent composition for polyurethane resins of Claim 5. 7. The anti-yellowing composition according to claim 5 or 6, further comprising an anti-yellowing agent other than the components (a) and (b).