JPH1045701A - Production of urethodione-modified polyisocyanate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an urethodione-modified polyisocyanate suitable for producing a polyurethane resin, etc., by adding a specific catalyst to a mixed isocyanate consisting of specific different diisocyanates and performing a reaction. SOLUTION: This urethodione-modified polyisocyanate is obtained by adding 0.1-5wt.% dimerization catalyst to a mixed isocyanate consisting of 50-95wt.% polymeric-diphenylmethanediisocyanate(MDI) of the formula [(n)=0 or >=1] and 50-5wt.% organic diisocyanate and reacting the mixture. A preferable polymer MDI consists of 20-70wt.% component having (n)=0 and 80-30wt.% component having n>=1 in the formula. As the organic diisocyanate, 4,4'- diphenylmethanate-diisocyanate, 2,4-trilenediisocyanate, hexamethylenediisocyante, etc., are cited. As the dimerization catalyst, e.g. a trialkylphospine and pyrridine are cited. The isocyanate group exists in the composition obtained in this method even at a high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing a uretdione-modified polyisocyanate composition, which comprises reacting a mixed isocyanate comprising polymeric MDI and an organic diisocyanate with a dimerization catalyst.

[0002]

2. Description of the Related Art Various methods are known for modifying isocyanates. Denaturation by a uretdionization reaction is one method. For example, Japanese Patent Publication 3-49903
Discloses that the solubility of 4,4'-diphenylmethane diisocyanate (hereinafter abbreviated as 4,4'-MDI) is 5 to 5.
A uretdione-modified polyisocyanate composition is obtained using a mixed solvent of a nonpolar solvent and a moderately polar solvent of 25% by weight. In Japanese Patent Publication No. Hei 6-37475,
In a non-polar solvent as an emulsifier, finely divided liquid 4,
A complex of the uretdione-modified polyisocyanate composition and MDI is obtained by a reaction in an emulsion containing 4'-MDI. Also, US Pat.
No. 85,4,4'-MD by emulsion polymerization in water
The production of the uretdione-modified polyisocyanate composition I is carried out.

[0003]

However, if the uretdione-modified polyisocyanate composition obtained by such a conventional production method is under a high temperature condition, the existing isocyanate groups further react with each other to cause the uretdione group to react. ,
A carbodiimide group or the like is formed. As a result, the isocyanate groups decrease or disappear, so that they cannot be applied to the production of polyurethane resins.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve such conventional problems, and as a result, have found that a dimerization catalyst is added to a mixed isocyanate comprising polymeric MDI and an organic diisocyanate. The uretdione-modified polyisocyanate composition obtained by the production method characterized in that it is produced has an isocyanate group even at a high temperature, and the present invention has been completed.

That is, the present invention is a process for producing a uretdione-modified polyisocyanate composition, which comprises adding a dimerization catalyst to a mixed isocyanate comprising polymeric MDI and an organic diisocyanate.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a description will be given of polymeric MDI as an essential raw material in the present invention. In general,
Polymeric MDI is obtained by polycondensing aniline and formaldehyde, and reacting the resulting polyamine with phosgene. Polymeric MDI is represented by the following molecular formula (1). In addition, the single item of n = 0,
Pure MDI. Usually, a polymeric MDI has n
A mixture of pure MDI of = 0 and polynuclears of n = 1 or more. A preferred Polymec MDI has n = 0 components of 2
0 to 70% by weight, and the component of n ≧ 1 is 80 to 30% by weight. As such Polymec MDI, Millionate MR-100, 200, 3 manufactured by Nippon Polyurethane Industry Co., Ltd.
00, 400, etc.

[0007]

Embedded image

In the present invention, an organic diisocyanate is used in combination. As the organic diisocyanate used in combination,
4,4'-MDI, 2,4'-MDI, 2,2'-MD
I, 4,4'-dibenzyldiisocyanate, 2,4-
Aromatic diisocyanates such as tolylene diisocyanate (hereinafter abbreviated as 2,4-TDI), 2,6-TDI, 1,5-naphthylene diisocyanate, para-phenylene diisocyanate, para-xylylene diisocyanate, meta-xylylene diisocyanate, ortho-xylylene Non-yellowing diisocyanate such as diisocyanate and tetramethylxylylene diisocyanate, hexamethylene diisocyanate (hereinafter abbreviated as HDI), lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5- Diisocyanate, 2,2,4-trimethylhexaethylene-1,6-
Aliphatic diisocyanates such as diisocyanate, 2,4,4-trimethylhexahylene-1,6-diisocyanate, isophorone diisocyanate (hereinafter abbreviated as IPDI), 1,4-cyclohexyl diisocyanate,
4,4'-dicyclohexylmethane diisocyanate,
Examples include alicyclic diisocyanates such as hydrogenated xylylene diisocyanate and hydrogenated tetramethyl xylylene diisocyanate, and mixtures thereof.
DI, HDI, and IPDI.

The ratio of polymeric MDI / organic diisocyanate in the mixed isocyanate of the present invention is 9
5/5 to 50/50 (weight ratio), preferably 93/7 to
80/20 (weight ratio). 5 polymeric MDI
If the amount is less than 0% by weight or exceeds 95% by weight, the isocyanate groups of the obtained uretdione-modified polyisocyanate composition further react under high temperature conditions to form uretdione groups. As a result, the isocyanate groups decrease or disappear, so that the isocyanate groups cannot be used as a raw material such as a polyurethane resin.

As the uretdionation reaction catalyst used in the present invention, known catalysts can be used. For example, trialkyl phosphines, aromatic-aliphatic tertiary phosphines, alkyl diallyl phosphines, pyridine, dimethylamino pyridine, tri- or tetra-substituted pyridines, trialkyl phosphites, tris-dialkyl phosphites, tertiary amines, etc. A single product or a mixture of two or more types can be used.

The amount of the reaction catalyst added is 0.1 to 5% by weight, preferably 0.2 to 2% by weight, based on the total isocyanate. If the amount is less than 0.1% by weight, the uretdionation reaction hardly proceeds. If it exceeds 5% by weight, the possibility of adversely affecting the aging stability of the obtained uretdione-modified polyisocyanate composition is increased.

The reaction temperature in the present invention is from 10 to 100.
° C, preferably 20 to 80 ° C. When the temperature is lower than 10 ° C., the uretdionation reaction hardly proceeds. If the temperature exceeds 100 ° C., a side reaction occurs,
It is difficult to obtain the desired uretdione-modified polyisocyanate composition.

In the present invention, a reaction terminator can be used if necessary. Examples of the reaction terminator include peroxides such as lauryl peroxide and benzoyl peroxide, sulfonates such as methyl cyclohexanesulfonate and methyl paratoluenesulfonate, and benzyl chloride.

In the present invention, a solvent can be used if necessary. Any type of solvent can be used as long as it is inert with the isocyanate group. For example,
Toluene, xylene, aromatic solvents such as chlorobenzene, acetone, methyl ethyl ketone, ketone solvents such as cyclohexanone, methyl acetate, ester solvents such as ethyl acetate, diethyl ether, dimethyl ether, 1,4-dioxane, Ether solvents such as tetrahydrofuran, normal-hexane, aliphatic hydrocarbon solvents such as octane, gas oil, kerosene, petroleum solvents such as mineral spirits, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, methylene chloride, There is a single substance such as carbon tetrachloride or a mixed solvent of two or more kinds.

When a solvent is used, the uretdione-modified polyisocyanate composition becomes solid and precipitates as the reaction proceeds. Thereafter, the uretdione-modified polyisocyanate composition is obtained by separation and purification by a method such as filtration.

When no solvent is used, the uretdione-modified polyisocyanate composition becomes solidified as the reaction proceeds. After the reaction, the product is pulverized to obtain a powdery product.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. In Examples and Comparative Examples, “parts” and “%” are “parts by weight” and “% by weight”. In addition, the isocyanate content of the uretdione-modified isocyanate composition was calculated from the isocyanate content before the reaction and the peak intensity ratio of isocyanate group / uretdione group in solid-state NMR of the obtained uretdione-modified isocyanate composition.
The melting point is a temperature at which the obtained uretdione-modified isocyanate composition is sealed in a capillary tube, placed in a melting point flask, heated in a sulfuric acid bath, and melted.

Example 1 Millionate MR-100 was placed in a four-necked flask equipped with a stirrer, a thermometer, an Aline cooling tube, and a nitrogen gas inlet tube.
60 parts and 2,4-TDI / 2,6-TDI = 80/2
5 parts of a 0 (weight ratio) mixture were dissolved in 260 parts of toluene. To this, 0.26 parts of TBP was added and reacted at 25 ° C. for 24 hours. Thereafter, the precipitate was filtered to obtain a uretdione-modified polyisocyanate composition A-1. A
The isocyanate content of -1 was 26.7% by weight, and the melting point was 191 ° C.

Example 2 Polymeric MDI (isocyanate content = 30%, Millionate MR-20) was placed in the same reactor as in Example 1.
(0, manufactured by Nippon Polyurethane Industry Co., Ltd.) and 55 parts of HDI were dissolved in 260 parts of toluene. In addition, TBP is set to 0.
26 parts were added and reacted at 25 ° C. for 24 hours. Thereafter, the precipitate was filtered to obtain a uretdione-modified polyisocyanate composition A-2. The isocyanate content of A-2 was 26.0% by weight, and the melting point was 190 ° C.

Example 3 Polymeric MDI (isocyanate content = 30%, Millionate MR-30) was placed in the same reactor as in Example 1.
(0, manufactured by Nippon Polyurethane Industry Co., Ltd.) and 60 parts of toluene were dissolved in 260 parts of toluene. In addition, TBP is set to 0.
26 parts were added and reacted at 25 ° C. for 24 hours. Thereafter, the precipitate was filtered to obtain a uretdione-modified polyisocyanate composition A-3. A-3 had an isocyanate content of 25.8% by weight and a melting point of 188 ° C.

Example 4 Polymeric MDI (isocyanate content = 30%, Millionate MR-40) was placed in the same reactor as in Example 1.
0, manufactured by Nippon Polyurethane Industry) 60 parts and 4,4'-MD
I5 parts were dissolved in toluene 260 parts. In addition, TB
0.26 parts of P was added and reacted at 25 ° C. for 24 hours. Thereafter, the precipitate was filtered to obtain a uretdione-modified polyisocyanate composition A-4. A-4 had an isocyanate content of 25.7% by weight and a melting point of 192 ° C.

Example 5 A beaker containing 60 parts of Millionate MR-100 and 2,4
5 parts of a mixture of -TDI / 2,6-TDI = 80/20 (weight ratio) was charged, and 0.26 part of TBP was added, followed by stirring quickly and uniformly. Then cover the beaker and add 2
The reaction was performed at 5 ° C. for 24 hours. As the reaction progressed, the reaction system solidified. The obtained solid was pulverized to obtain a powdered uretdione-modified polyisocyanate composition A-5. A
The isocyanate content of -5 was 25.4% by weight, and the melting point was 190 ° C.

Comparative Example 1 In a reactor similar to that in Example 1, 65 parts of 4,4'-MDI was dissolved in 260 parts of toluene. To this, 0.26 parts of TBP was added and reacted at 25 ° C. for 24 hours. Thereafter, the precipitate was filtered to obtain a uretdione-modified polyisocyanate composition B-1. B-1 had an isocyanate content of 23.5% by weight and a melting point of 254 ° C.

Comparative Example 2 50 parts of 4,4'-MDI was put into a beaker, heated to 75 ° C., 0.5 parts of TBP was added, and the mixture was rapidly and uniformly stirred. Thereafter, the beaker was covered and reacted at 45 ° C. for 24 hours. As the reaction progressed, the reaction system solidified.
The obtained solid was pulverized to obtain a powdered uretdione-modified polyisocyanate composition B-2. B-1 had an isocyanate content of 23.3% by weight and a melting point of 255 ° C. Table 1 shows the isocyanate content and melting point of Examples 1 to 5, Comparative Examples 1 and 2, and each sample.

[0025]

[Table 1]

[Measurement of Isocyanate Group at High Temperature] A-1 to B-5 obtained in Examples 1 to 5 and Comparative Examples 1 to 2
The influence of isocyanate groups and uretdione groups upon heating 1 and 2 was measured by infrared absorption analysis (abbreviated as IR) of each sample at room temperature and 200 ° C. for 5 hours.
Was measured. The evaluation was based on the peak intensity of the isocyanate group (around 2270 cm ^-1 ) / the peak intensity of the benzene ring (1
And changes in the 600 cm ^-1 vicinity) ratio, was performed to track changes in the peak intensity (1770 cm around ^-1) / benzene ring of the peak intensity (1600 cm ^-1 vicinity) ratio of uretdione groups.
Each peak intensity was defined as a peak area. Table 2 shows the results of the IR analysis.

[0027]

[Table 2]

Table 2 shows that A-1 to A-5 have a stronger isocyanate group peak and a weaker uretdione group peak in a high-temperature atmosphere. This indicates that the uretdione group is dissociated into an isocyanate group depending on the temperature. On the other hand, in B-1 and B-2, the peak of the isocyanate group was weaker and the peak of the uretdione group was stronger in the high-temperature atmosphere, indicating that the isocyanate group was a uretdione group. This indicates that the uretdione-modified polyisocyanate composition of the present invention has an isocyanate group even at a high temperature.

Application Example 1 In a kneader, 75.3 parts of a polyester having a hydroxyl group at both ends obtained from 1,4-butanediol having a number average molecular weight of 2,000 and adipic acid and 21.3 parts of A-1 were charged. Then, 0.02 parts of dibutyltin dilaurate was added as a urethanization catalyst, and reacted at 160 ° C. for 5 hours.
Next, 3.4 parts of 1,4-butanediol was added (total isocyanate group / total hydroxyl group = 0.9 / 1.0), and the mixture was further reacted for 5 hours. (At this stage, the resin surface was bleeding. The cause of the bleeding was that the isocyanate molecules not containing the uretdione group in A-1 were liquefied due to a low melting point and reacted, but the uretdione group-containing isocyanate molecule was reacted. It is considered that the molecule is present without reacting due to its high melting point, that is, the precipitate is considered to be an isocyanate molecule containing a uretdione group.) Thereafter, at 200 ° C., 150 kgf / cm ² at 150 kgf / cm ² . The sheet was pressed into a 1 mm sheet for 1 minute. Then 105 ° C
For 24 hours to obtain a polyurethane sheet. (There was no such thing as bleeding on the sheet.) The physical properties of the obtained polyurethane sheet were as follows.
JIS A hardness 81 °, tensile strength 400kgf /
cm ² , elongation at break 520%, tear strength 70 kgf /
cm and a flow start temperature of 182 ° C.

[0030]

As described above, the uretdione-modified polyisocyanate composition obtained according to the present invention was excellent in that the isocyanate was present even at a high temperature. The uretdione-modified polyisocyanate composition obtained by the production method of the present invention can be used as a raw material for a novel polyurethane resin.

[Brief description of the drawings]

1 is an IR chart at 200 ° C. of A-1 which is a uretdione-modified polyisocyanate obtained according to the present invention. Lower: IR chart of A-1 at room temperature.

FIG. 2 is an IR chart at 200 ° C. of uretdione-modified polyisocyanate B-1 obtained in Comparative Example. Lower: IR chart of B-1 at room temperature.

Claims (1)

[Claims] 1. A uretdione-modified poly (meth) acrylate which is reacted by adding 0.1 to 5% by weight of a dimerization catalyst to a mixed isocyanate comprising 50 to 95% by weight of polymeric MDI and 50 to 5% by weight of an organic diisocyanate. Method for producing isocyanate.