JPH09255663A - Production of diphenylmethane-type polyisocyanate dimer having low decomposition point - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for the production of a diphenylmethane-type polyisocyanate dimer having low decomposition point. SOLUTION: This diphenylmethane-type polyisocyanate dimer having low decomposition point is produced by incorporating a diphenylmethane-type polyisocyanate composed of 40-90 pts.wt. of 4,4'-diphenylmethanediisocyanate and 60-10 pts.wt. of a diphenylmethanediisocyanate isomer other than 4,4'- diphenylmethanediisocyanate, an MDI modified compound or a polymeric MDI with 0.1-5 pts.wt. (based on the polyisocyanate) of a dimerization catalyst and reacting the polyisocyanate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a diphenylmethane polyisocyanate dimer having a low decomposition point by using a specific diphenylmethane polyisocyanate.

[0002]

2. Description of the Related Art Conventionally, a method for producing a dimer of diphenylmethane diisocyanate (hereinafter abbreviated as MDI) has been known and is disclosed in JP-B-3-49903 and JP-B-6-37475.
Et al. Describe a process for dimerizing MDI in a solvent. Further, in BP1134285, a dimer is produced by emulsion polymerization in water. All of the MDI dimers obtained by these production methods have high decomposition points,
It does not decompose to regenerate isocyanate groups in a practical heating range. Since the dimer of tolylene diisocyanate is decomposed by heating to regenerate the isocyanate group, it may be used for crosslinking an elastomer or the like. However,
The dimer of MDI synthesized from 4,4′-MDI has a high decomposition point and is not decomposed to regenerate the isocyanate group in a practical heating range, so that improvement has been required.

[0003]

DISCLOSURE OF THE INVENTION As a result of diligent research and study to solve the above-mentioned conventional problems, the present inventors have found that the raw material diphenylmethane-based polyisocyanate is
By using 2,4'-MDI, which is an isomer of 4'-MDI, and polyphenylene polymethylene polyisocyanate (hereinafter, referred to as polymeric MDI), it is possible to obtain an MDI dimer having a low decomposition point. The present invention was started and the present invention was completed.

[0004]

That is, the present invention provides, as diphenylmethane type polyisocyanate, 40 to 90 parts by weight of 4,4'-MDI and 60 to 10 parts by weight of 4,4.
Dimerization catalysts for MDI isomers other than'-MDI
It is a method for producing an MDI dimer having a low decomposition point, which is characterized by adding 0.1 to 5 parts by weight to the above and reacting.

The present invention relates to 40 to 100 parts by weight of 4,4'-MD as a diphenylmethane type polyisocyanate.
The method for producing an MDI dimer having a low decomposition point according to claim 1, wherein a modified product of a mixture of I and 60 parts by weight or less of an MDI isomer other than 4,4'-MDI is used. Is.

The present invention has a low decomposition point characterized by using a polymeric MDI as the diphenylmethane type polyisocyanate and adding 0.1 to 5 parts by weight of a dimerization catalyst to the polyisocyanate to react. It is a method for producing a polymeric MDI dimer.

The present invention uses 40 to 90 parts by weight of polymeric MD as a diphenylmethane type polyisocyanate.
I and M other than 60 to 10 parts by weight of 4,4'-MDI
For DI isomer, dimerization catalyst from 0.1 to 5 relative to MDI
It is a method for producing a polymeric MDI dimer having a low decomposition point, which is characterized by adding a part by weight and reacting.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The diphenylmethane type polyisocyanate used in the present invention includes MDI and polymeric MDI. Among these, as isomers other than 4,4'-MDI, 2,2'-MDI, 2,3'-MDI,
There are 2,4'-MDI, 3,4'-MDI and the like. 4,4
The'-MDI is industrially produced with a purity of 98% or more, for example, Millionate MT manufactured by Nippon Polyurethane Industry. As the modified MDI, a carbodiimide compound of MDI, methanol, ethanol, diethylene glycol, dipropylene glycol or the like having a molecular weight of 32
Examples thereof include urethane compounds modified with about 1000 alcohols. Examples of the polymeric MDI include Millionate MR manufactured by Nippon Polyurethane Industry. Such MDI is an MDI isomer other than 4,4'-MDI or MD relative to 40 to 90 parts by weight of 4,4'-MDI.
It is preferable to use 10 to 60 parts by weight of modified I. M
As the DI modified product, a modified product obtained by mixing MDI other than 4,4′-MDI can be used. If the amount is less than 10 parts by weight, the effect of lowering the decomposition point cannot be expected.
If it is more than 1 part by weight, the reactivity will decrease. For the MDI mixture of the present invention, an MDI isomer mixture containing 10% or more of 2,4'-MDI can be used as it is.
Polymeric MDI can be used alone or as Polymeric MDI.
Medium MDI isomers other than 4,4'-MDI 10-60%
It can be contained and used.

The dimerization catalyst used in the present invention includes trialkylphosphine, aromatic-aliphatic tertiary phosphine, alkyldiallylphosphine, pyridine, dimethylaminopyridine, tri- or tetra-substituted pyridine,
Examples thereof include trialkyl phosphite, tris-dialkyl phosphite, tertiary amine and the like. The amount of the dimerization catalyst used is 0.1 to 5 parts by weight based on MDI. In the production method of the present invention, a solvent can be used if necessary. The reaction solvent is generally a solvent inert to isocyanate, for example, benzene, toluene, xylene, chlorobenzene, nitrobenzene, acetone, methyl ethyl ketone, acetic ester, dioxane, tetrahydrofuran, aliphatic hydrocarbon, dimethylformamide, dimethylacetamide, methylene chloride. Etc. It can also be produced without a solvent. The MDI dimer obtained in the present invention preferably contains 20% or more of the dimer component. When it is 20% or less, the characteristics as a dimer cannot be exhibited, which is not preferable. The MDI dimer obtained by the present invention may be added with other substances such as an antioxidant, if necessary.

Aromatic diisocyanate dimers and their production are known. The production method of the present invention is 40 to 90.
10 parts by weight of 4,4'-MDI and 60 to 10 parts by weight of a mixture of MDI isomers other than 4,4'-MDI, MDI multimers, and MDI modified products in an amount of 10 to 10 parts by weight in a reaction solvent.
50 parts by weight is dissolved, and 0.1 to 5 parts by weight of the dimerization catalyst is added to the raw material MDI. In order to allow the reaction to proceed efficiently, heating is carried out in the temperature range of 30 to 100 ° C if necessary. The MDI dimer precipitates out of solution in solid form. The produced MDI dimer is separated from the reaction system by a suitable method such as filtration. When the reaction is carried out without a solvent, the raw material MDI is melted by heating, and 0.1 to 5 parts by weight of a dimerization catalyst is added thereto. MDI solidifies by dimerization. The solid dimerized MDI is ground to give a powdered product. The MDI dimer obtained in the present invention has a decomposition point of 220 ° C. or lower. The decomposition point can be evaluated by a differential thermal analyzer or a visual method.

[0011]

According to the present invention, the temperature (2
It is possible to synthesize an MDI dimer that decomposes at 20 ° C. or less) and regenerates an isocyanate group in a practical heating range.

[0012]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In Examples and Comparative Examples,
All "parts" mean "parts by weight" and all "%" mean "% by weight".

Example 1 4,4'-MDI 81%, 2,4'-MDI 19%
A fractional distillation of an MDI isomer mixture consisting of 4,4'-
An MDI isomer mixture of MDI 50%, 2,4'-MDI 50% was prepared. This MDI was dissolved in 65 g of toluene and 260 g of toluene, and 0.26 g of tri-n-butylphosphine was added thereto, and the mixture was allowed to stand at room temperature (20 to 25 hours) for 24 hours.
After stirring at (° C.), the precipitated solid MDI dimer was removed by filtration. The yield of MDI dimer was 14 g. As a result of IR measurement, the produced MDI dimer was
Peak derived from dimer to 1780 cm ^-1 and 1400 cm ^-1 were observed. The produced dimer was enclosed in a capillary tube and visually measured with a melting point measuring instrument in a sulfuric acid bath. As a result, the dimer decomposed at 198 ° C. and became liquid. Infrared absorption spectrum (hereinafter IR) of this liquefied sample
As a result of the measurement, no peak derived from the dimer was observed,
In addition, the peak derived from the isocyanate group at 2275 cm ^-1 was large.

Example 2 PTG-50 was added to 900 g of melted Millionate MT.
100 g of 0 (polyether polyol, molecular weight 500, manufactured by Hodogaya Chemical Industry Co., Ltd.) was added and reacted at 60 ° C. for 2 hours to synthesize a modified MDI. As a result of IR measurement, it was found that the obtained modified MDI consisted of 86% 4,4′-MDI and 14% modified MDI. This modified MDI is 6
5 g, dissolved in 260 g of toluene, and added with tri-n
-Butylphosphine (0.26 g) was added, and the mixture was stirred at room temperature (20 to 25 ° C) for 24 hours, and then precipitated solid MD
The I dimer was removed by filtration. The yield of MDI dimer was 42 g. MD generated as a result of IR measurement
In the I dimer, peaks derived from the dimer were observed at 1780 cm ^-1 and 1400 cm ^-1 . As a result of visual measurement using a melting point measuring device, the dimer decomposed at 177 ° C. and became liquid. As a result of IR measurement of this liquefied sample, a peak derived from a dimer was not recognized, and a peak derived from an isocyanate group at 2275 cm ⁻¹ was large.

Example 3 65 g of Millionate MR100 (Polymeric MDI manufactured by Nippon Polyurethane Industry Co., Ltd.) was dissolved in 260 g of toluene, and 0.2 g of tri-n-butylphosphine was dissolved therein.
After adding 6 g and stirring at room temperature (20 to 25 ° C.) for 24 hours, the precipitated solid MDI dimer was taken out by filtration. The yield of MDI dimer was 12 g. As a result of IR measurement, in the produced MDI dimer, peaks derived from the dimer were observed at 1780 cm ^-1 and 1400 cm ^-1 .
When visually measured using a melting point measuring device, the dimer decomposed at 189 ° C. and became liquid. As a result of IR measurement of this liquefied sample, a peak derived from a dimer was not recognized, and a peak derived from an isocyanate group at 2275 cm ⁻¹ was large.

Comparative Example 1 To a solution of 65 g of Millionate MT (manufactured by Nippon Polyurethane Industry Co., Ltd., 4,4'-MDI, purity 99.5% or more) in 260 g of toluene was added tri-n-butylphosphine (Japan). When 0.26 g of Hishicholine P-4 manufactured by Kagaku Kogyo Co., Ltd., purity 98%) was added, a white solid MDI dimer was immediately precipitated. This reaction mixture was stirred for 24 hours at room temperature (20 to 25 ° C.), and then the precipitated solid MD was used.
The I dimer was removed by filtration. The yield of MDI dimer was 52 g. MD generated as a result of IR measurement
In the I dimer, peaks derived from the dimer were confirmed at 1780 cm ^-1 and 1400 cm ^-1 . As a result of visual measurement using a melting point measuring device, the dimer decomposed at 252 ° C. and became liquid. As a result of IR measurement of this liquefied sample, a peak derived from a dimer was not recognized, and a peak derived from an isocyanate group at 2275 cm ⁻¹ was large.

Example 4 4,4'-MDI 81%, 2,4 'melted at 75 ° C
-MDI isomer mixture 26g consisting of -MDI 19% and Millionate MT 24g were mixed and 4,4'-MDI
50 g of 90% 2,4'-MDI 10% liquid MDI isomer mixture was prepared. This liquid MD at 75 ° C
To 50 g of the mixture of I isomers, 500 μl of tri-n-butylphosphine was added, and immediately after dimerization, M was added.
The DT isomer mixture solidified. The solid dimer was ground in a mortar. As a result of IR measurement, in the produced MDI dimer, peaks derived from the dimer were observed at 1780 cm ^-1 and 1400 cm ^-1 . When visually measured using a melting point measuring device, the dimer decomposed at 154 ° C. to be liquid. As a result of IR measurement of this liquefied sample, no peak derived from a dimer was observed, and 227
The peak derived from the isocyanate group at 5 cm ^-1 was large.

Example 5 To 50 g of Millionate MR100 (Polymeric MDI manufactured by Nippon Polyurethane Industry Co., Ltd.) heated to 75 ° C.
When 500 μl of n-butylphosphine was added, it solidified immediately by dimerization. As a result of IR measurement, in the produced MDI dimer, peaks derived from the dimer were observed at 1780 cm ^-1 and 1400 cm ^-1 . Visual measurement using a melting point meter showed that the dimer was 163
It decomposed at ℃ and became liquid. As a result of IR measurement of this liquefied sample, a peak derived from a dimer was not recognized, and a peak derived from an isocyanate group at 2275 cm ⁻¹ was large.

Example 6 To 30 g of Millionate MR100 (manufactured by Nippon Polyurethane Industry Co., Ltd., Polymeric MDI) heated to 75 ° C., 4,4
20 g of a mixture of MDI isomers consisting of 81% of'-MDI and 19% of 2,4'-MDI was added to the mixture.
When 500 μl of n-butylphosphine was added, it solidified immediately by dimerization. As a result of IR measurement, in the produced MDI dimer, peaks derived from the dimer were observed at 1780 cm ^-1 and 1400 cm ^-1 . The dimer was 16 when visually measured using a melting point measuring device.
It decomposed and became liquid at 3 ° C. As a result of IR measurement of this liquefied sample, a peak derived from a dimer was not recognized, and a peak derived from an isocyanate group at 2275 cm ⁻¹ was large.

Comparative Example 2 50 g of Millionate MT was heated and melted at 75 ° C., and 500 μl of tri-n-butylphosphine was added to the mixture to effect dimerization. The reaction system was solidified by the dimerization. Solid dimerized MDI was ground in a mortar. As a result of IR measurement, the MDI dimer produced had a density of 1780 cm ^-1 and 1
A peak derived from a dimer was observed at 400 cm ^-1 . When visually measured using a melting point measuring device,
The dimer decomposed into a liquid at 249 ° C. As a result of IR measurement of this liquefied sample, a peak derived from the dimer was not recognized, and a peak derived from the 2275 cm ⁻¹ isocyanate group was large.

Application Example 1 A polybutylene adipate having a molecular weight of 2000 and the MDI dimer prepared in Example 1 were charged into Laboplast mill at an isocyanate group / hydroxyl group equivalent ratio of 2.0 together with 20 ppm of dibutyltin dilaurate at 160 ° C. Prepolymerization is carried out by stirring for 30 minutes, and then 1,4-butanediol is added so that the isocyanate group / hydroxyl group equivalent ratio becomes 1.0 in the total amount charged, and the mixture is stirred at the same temperature for 3 minutes.
Knead for 0 minutes and remove, then at 200 ℃, 150Kg / cm ² 1
Press-molded into 1mm sheet per minute, then at 105 ℃ for 4
When cured for 8 hours, hardness (JIS A) 81, tensile strength (kgf / cm ² ) 400, elongation at break (%) 520,
Tear strength (kgf / cm) 70, flow start temperature (℃) 18
A polyurethane resin of 2 was obtained.

Application Comparative Example 1 Polybutylene adipate having a molecular weight of 2000 and the MDI dimer prepared in Comparative Example 1 were introduced into a Laboplast mill at an isocyanate group / hydroxyl group equivalent ratio of 2.0 together with 20 ppm of dibutyltin dilaurate, and the mixture was heated at 160 ° C. Prepolymerization is carried out by stirring for 30 minutes, and then 1,4-butanediol is added so that the isocyanate group / hydroxyl group equivalent ratio becomes 1.0 in the total amount charged, and the mixture is stirred at the same temperature for 30 minutes.
After kneading and taking out, the mixture was press-molded into a 1 mm sheet at 200 ° C and 150 kg / cm ² for 1 minute, and then at 105 ° C for 48 minutes.
Polyurethane with hardness (JIS A) 72, tensile strength (kgf / cm ² ) 357, elongation at break (%) 535, tear strength (kgf / cm) 59, flow starting temperature (° C) 184 when cured for a period of time A resin was obtained.

Application Example 2 A polybutylene adipate having a molecular weight of 2000 and the MDI dimer prepared in Example 1 were charged into a Laboplast mill at an isocyanate group / hydroxyl group equivalent ratio of 2.0 together with 20 ppm of dibutyltin dilaurate at 160 ° C. Prepolymerization is carried out by stirring for 30 minutes, and then 1,4-butanediol is added so that the isocyanate group / hydroxyl group equivalent ratio becomes 1.0 in the total amount charged, and the mixture is stirred at the same temperature for 30 minutes.
After kneading and taking out, it is press-molded into a 1 mm sheet at 150 ° C and 150 kg / cm ² for 1 minute, and then at 105 ° C for 48 minutes.
Polyurethane with hardness (JIS A) 79, tensile strength (kgf / cm ² ) 352, elongation at break (%) 230, tear strength (kgf / cm) 77, flow starting temperature (° C) 183 when cured for a period of time A resin was obtained.

Application Comparative Example 2 Polybutylene adipate having a molecular weight of 2000 and the MDI dimer prepared in Comparative Example 1 were charged into a Laboplast mill at an isocyanate group / hydroxyl group equivalent ratio of 2.0 together with 20 ppm of dibutyltin dilaurate and heated at 160 ° C. Prepolymerization is carried out by stirring for 30 minutes, and then 1,4-butanediol is added so that the isocyanate group / hydroxyl group equivalent ratio becomes 1.0 in the total amount charged, and the mixture is stirred at the same temperature for 30 minutes.
After kneading and taking out, it is press-molded into a 1 mm sheet at 150 ° C and 150 kg / cm ² for 1 minute, and then at 105 ° C for 48 minutes.
Polyurethane with hardness (JIS A) 69, tensile strength (kgf / cm ² ) 190, elongation at break (%) 200, tear strength (kgf / cm) 55, flow starting temperature (° C) 185 when cured for a period of time A resin was obtained.

Claims (4)

[Claims] 1. As diphenylmethane-based polyisocyanate, 40 to 90 parts by weight of 4,4'-diphenylmethane diisocyanate and 60 to 10 parts by weight of 4,4 '.
A method for producing a diphenylmethane diisocyanate dimer having a low decomposition point, characterized by adding 0.1 to 5 parts by weight of a dimerization catalyst to a diphenylmethane diisocyanate isomer other than diphenylmethane diisocyanate and reacting the dimerization catalyst. . 2. A modified product of a mixture of 40 to 100 parts by weight of 4,4'-diphenylmethane diisocyanate and 60 parts by weight or less of diphenylmethane diisocyanate isomers other than 4,4'-diphenylmethane diisocyanate as the diphenylmethane polyisocyanate. The method for producing a diphenylmethane diisocyanate dimer having a low decomposition point according to claim 1, which is used. 3. A low decomposition point characterized by using polyphenylene polymethylene polyisocyanate as the diphenylmethane-based polyisocyanate and adding 0.1 to 5 parts by weight of a dimerization catalyst to the polyisocyanate to cause a reaction. A method for producing a polyphenylene polymethylene polyisocyanate dimer having the same. 4. A diphenylmethane-based polyisocyanate comprising 40 to 90 parts by weight of polyphenylene polymethylene polyisocyanate and 60 to 10 parts by weight of 4,4.
Polyphenylene polymethylene polyisocyanate dimer having a low decomposition point, characterized by adding 0.1 to 5 parts by weight of a dimerization catalyst to diphenylmethane diisocyanate isomers other than ′ -diphenylmethane diisocyanate and reacting the dimerization catalyst. Body manufacturing method.