JPS5995259A - Organic polyisocyanate and preparation thereof - Google Patents

Abstract

NEW MATERIAL:A compound of formula I [either one of X1 and X2 is a group of formula II, and the other is H; R is partially a bifunctional residue of formula III, and the rest is hexamethylene; n is an integer 1-5]. USE:A non-yellowing organic polyisocyanate, useful as molded expanded molded articles, paints, adhesives, etc., and having improved initial drying property and physical properties of coating films. PROCESS:At least 5mol diisocyanate component consisting of a mixture of isophorone diisocyanate with hexamethylene diisocyanate is added to one mole biuret forming agent and reacted therewith at 70-200 deg.C. The unreacted diisocyanates are then removed from the reaction mixture to give the aimed compound of formula I . The molar ratio between the isophorone diisocyanate and the hexamethylene diisocyanate in the mixed diisocyanate is preferably within (1:9)-(9:1) range. Water, tert-butyl alcohol or an aliphatic primary amine, etc. is used as the biuret forming agent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel quick-drying organic polyinsyanate capable of forming a coating film with excellent weather resistance, and a method for producing the same. More specifically, the present invention relates to a biuret-type polyisocyanate containing residues derived from hexamethylene/isophyte and inphoron diiso/iso-1 in its molecular structure, and a method for producing the same. be.

Organic polyisocyanate obtained by the reaction of organic cyinoneanate with water, trimethylolpropane, etc.
Utilizing its property of forming polyurethane with a three-dimensional structure together with active hydrogen-containing compounds, it is widely used in foamed molded products, paints, adhesives, etc. In particular, polyurethane paints made from this material form coating films with excellent wear distribution, adhesion, chemical resistance, solvent resistance, flexibility, electrical insulation, etc., and therefore have high utility value.

Among these organic polyisocyanates, polyinocyanates derived from aliphatic and alicyclic polyisocyanates are non-yellowing and are suitably used as outdoor paints. Polyisocyanate derived from methylene diisonoanate (hereinafter abbreviated as HDI) forms a urethane coating film with extremely excellent physical properties, but it has poor initial drying properties during application, and therefore requires repeated coating, masking, or taping. The required color separation is extremely inconvenient for work such as painting, and has the drawback of significantly reducing work efficiency. In addition, alicyclic diisocyanates such as inphorone diisocyanate (hereinafter referred to as PD)
Polyinsyanates derived from polyinsyanates (abbreviated as I) have excellent initial drying properties of urethane paints using them, but
The disadvantage is that the resulting coating film is hard and brittle, and has poor adhesion to the substrate. Therefore, the reality is that polyisocyanates having different advantages and disadvantages are usually blended and used to compensate for their respective disadvantages, depending on the use and application conditions.

For example, HD
It is commonly used to improve the drying properties of polyurethane by blending a portion of polyisocyanate derived from polyisocyanate with polyino/anate derived from PD. A decline is inevitable.

In short, urethane-based polyisocyanate derived from engineered PDI, and urethane-based polyisocyanate derived from HDI.
It is also known to improve the properties of the coating film by blending it with anate (Japanese Patent Publication No. 55-19723).

However, in general, polyisocyanates derived from PD process, such as urethane polyiso7ane 1. However, this requires equipment equipped with a special heating means and is accompanied by the risk of denaturation due to heating, and it is difficult to obtain polyinocyanate with a low content of yn7anate groups. This causes undesirable problems such as On the other hand, incyanurate-based polyiso7
For anate, a special catalyst must be used to prevent trimerization, but in general, the use of a catalyst is complicated, and there are problems with the use of polymerization terminators, filtration of spent catalysts, and problems with polymerization. There is instability in quality due to the difficulty of quantitative control, the risk of abnormal runaway reactions due to excessive polymerization, and even when the obtained polyisocyanate is made into a paint, the paint film is brittle and tends to stick. It is criticized for its shortcomings, such as lacking in sex. Regarding biuret polyisocyanate, the reaction from urea bond to biuret bond is difficult to proceed completely, and the content of the intermediate urea isonanate is very high, which is thought to be due to the effect of steric hindrance of the IPD engineered molecule. The characteristics of polyincyanate, such as high innoanate group content, high number of functional groups, and low viscosity, cannot be utilized.

Unfortunately, it is difficult to remove unreacted IPDI monomer from the various types of polyisocyanates that are solely based on the IP'D process, and usually 2 to 0% of IPD monomer remains in the polyisocyanate. .

The present inventors have developed the first non-yellowing type of polyino7anate.
In order to develop polyinosiaite, which has excellent drying properties, good coating film properties, and a simple manufacturing process with little variation in quality, we have carried out extensive research to develop polyinosyaite, which has a unique structure in its molecular structure. It was discovered that the object could be achieved by forming a polyisocyanate containing residues derived from both HDI and PD, and based on this finding, the present invention was accomplished.

That is, the present invention is based on the general formula % (1) (where one of xl and x2 is a residue represented by the general formula -C-NH-R-NCO・(II) 1 , and the other is a hydrogen atom) A part of each R present in the formula is a divalent residue represented by the formula, and the rest is a hexamethylene group represented by the formula → CH2-iq~, where n is 1 to 5. is an integer).

Residues R derived from the diynone agate used as a raw material in the molecule of the organic polyisocyanate of the present invention
Some of these are residues from which two inocyanate groups have been removed from PD, and the rest are residues from which two isocyanate groups have been removed from HDI. The proportion of these residues is
The molar ratio is preferably in the range of 1:9 to 9:1.

Such an organic polyisocyanate can be prepared, for example, by adding at least 5 moles of a mixed diisocyanate component consisting of a mixture of engineered PDI and HDI to 1 mole of the biuret forming agent and reacting at a temperature of 70 to 200°C. It can be produced by removing unreacted zoisone anate components. At this time, the molar ratio of PDI and HDI in the mixed isocyanate component was 1=9.
It is desirable to select a ratio within the range of 9:1 to 9:1. When the proportion of PD is higher than this, a large amount of IPDI urea dimer will be contained in the polyisocyanate after removing unreacted components, and the incyanate group content will increase.
It cannot be crushed, and the residual rate of unreacted components can be reduced to 1.
It becomes difficult to reduce the amount to less than % by weight.

On the other hand, if the ratio of J(D) is higher than this, it becomes impossible to obtain a polyinsyanate with the desired initial drying properties.A particularly suitable molar ratio range of PD and HDI is from 1:4 to 1:4. The ratio is 4:1. In actual reactions, it is advantageous to use slightly more IPD because HDI has a higher reaction rate with the biuret forming agent than PD.

As the biuret-forming agent in the method of the present invention, a compound capable of forming a biuret structure by reacting with an isonoanate group, such as water, tertiary butyl alcohol, aliphatic primary amine, etc., is used.

In the method of the present invention, for 1 mole of biuret forming agent,
At least 5 moles of mixed diisocyanate component, usually 5
~40 mol, preferably 8 to 30 mol. If this amount is less than 5 moles, the viscosity of the reaction product increases markedly, or the reaction product tends to become resinous, making it difficult to separate unreacted components. Moreover, if this amount exceeds 40 moles, the amount of diinthate recovered in the reaction mixture increases, which is economically disadvantageous.

The reaction temperature in the method of the present invention must be selected within the range of 70 to 200°C. If the temperature is lower than 70°C, the reaction rate will be too low and the reaction from the urea compound to the biuret compound will not proceed, and if the temperature is still higher than 200°C, polymerization of the polyinsoate will occur and coloration will be significant. It becomes brighter.

In the method of the present invention, the reaction can be carried out without a solvent, but a solvent can also be used if desired. Preferred examples of such solvents include hydrophilic solvents such as ethylene glycol monoalkyl acetate and phosphorus trialkyl ester.

Particularly suitable solvents are ethylene glycol monomethyl ether acetate and phosphoric acid trimethyl ester.

These may be used alone or in combination of two or more. When water is used as a biuret forming agent, the IPD process produces less polyurea and less solid precipitate than HDI in the water reaction, so there is no need to use a solvent.

In other cases, considering the economic efficiency of the collection process, there will be no (6
Although a medium is desirable, in order to allow the reaction to proceed smoothly, it is generally advantageous to use a solvent that uniformly dissolves the IPD, HDI, and water components.

When excess diisocyanate components and 6 medium are used, unreacted components and solvent are removed and recovered after the reaction is completed.

This operation can be easily carried out using, for example, a scraped thin film distillation apparatus. In this way, according to the method of the present invention, compared to the case of a biuret polyisocyanate based solely on polypropylene, the viscosity is lower, the inocyanate group content is higher, and the remaining unreacted polyisocyanate is less than 0.7% by weight. Component quantities of polyinsyanate can be obtained.

By the way, when producing biuret polyincyane-1 by reacting TPD alone with a biuret forming agent, it was possible to avoid the formation of a large amount of TPD urea dimer. Regardless, when the diincyanate component consisting of PDI and HDI is reacted with a biuret forming agent according to the method of the present invention, the amount of IPDI urea dimer in the reaction mixture is significantly reduced, and the amount of IPDI urea dimer is significantly reduced after the reaction is completed. It was completely unexpected that unreacted components could be easily recovered and the amount of residual unreacted components in the polyisocyanate could be reduced to as low as 1% by weight.

To explain these facts with reference to the attached drawings, Figure 1 shows the urea dimer of poly-PDI when a diisocyanate component consisting of poly-PD and HDI is reacted with a biuret forming agent at a molar ratio of 15:1. 2 is a graph showing the relationship between the production amount of and the amount of PD in the diisocyanate (mol%). IP
In D, the amount of mer is shown as the peak area ratio (PA, %) of the Kervermeation chromatogram. From this graph, it can be seen that HDI is incorporated into the poly-PDI biuret polyinsyanate, and the content of poly-PD-urea dimer is significantly reduced.

The organic polyisocyanate according to the present invention has extremely low unreacted diisocyanate content and IPDI urea dimer content, high No○ content, and high number of functional groups,
When this is used as a paint component, for example, good initial drying properties are obtained, and the trench polyisocyanate itself has a relatively low viscosity and good fluidity, making it a material with excellent handling and workability.

The organic polyiso/anate of the present invention can be used alone or in combination with other organic polyisocyanates as a curing agent for two-component polyurethane paints, and can not only provide excellent paint films but also The incyane-1 group can be blocked with a suitable blocking agent such as methyl ethyl ketone oxime, ε-caglolactam, phenol, etc., and can be effectively used as a crosslinking agent for powder coatings and water-based coatings, so it is extremely useful in practice. It is a substance.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Engineering PD engineering 1066? (9.8 mol), HD Engineering 202
f (1,2 mol), water as biuretizing agent 7.2
′? (0.4 mol) was added to 5852, a mixed solvent of methyl cellosolve acetate and trimethyl phosphate at a ratio of 1:1 (weight ratio), and the mixture was reacted at a reaction temperature of 160° C. for 1.5 hours. Initially, the reaction solution was prepared in 1. using a thin film evaporator. OmmHg/
Under pressure of 160℃ then 0.1+nynHg/20
A two-step treatment was performed under pressure at 0 °C to remove unreacted PD.
The solution, HDI, and solvent were distilled off and collected.

The obtained polyincyanate is free from residual unreacted components.
:oF): 1. owt% 1, HDI 0.1wt%
The NC◯ content was 19.6% by weight (corrected value excluding residual unreacted components; the same applies hereinafter). -! In addition, this material has fluidity at a temperature of 65°C or higher, and the viscosity of a 75% by weight ethyl acetate solution at a temperature of 25°C (the same applies hereinafter) is 2.
It was rare at 60 cp.

Examples 2 to 5 Reactions were carried out under the same reaction conditions as in Example 1 with various changes in the mixing ratio of IPD and HDI as shown in the first column. The reaction solution was treated in the same manner as in Example 1 using a thin film evaporator,
The solvent and unreacted HDI and IPD were removed to obtain each polyinocyanate as a bottom liquid. The physical properties of each polyinocyanate obtained are shown in the first layer.

Comparison 1 da] 1 1(T)I 504 Y (3 mol), water 3.69
(0.2 mol) and a mixed solvent 2527 of methyl cellosolve acetate and trimethyl phosphate in a ratio of 1:1 (weight ratio) were mixed and reacted at a reaction temperature of 160° C. for 1.5 hours. The reaction solution was treated in two stages using a thin film evaporator. First 0.9+nm
Most of the solvent and unreacted HDH were recovered under a reduced pressure of Hg at 160°C, and then residual HDI was removed and recovered at 160°C under a reduced pressure of 0.091 mochi Hg. About 80f! Polyisocyanate-1 was obtained, with a viscosity of 900 cp/25°C, NC
The O content was 24.4%, and the remaining unreacted components were 0.2%.

Comparative example 2 IPD engineering 666? (3 mol), water 3.6 f (0,2
mol) and a mixed solvent 3337 of methyl cellosolve acetate and trimethyl phosphate in a ratio of 1=1 (weight ratio) were mixed and reacted at a reaction temperature of 160° C. for 1.5 hours. The reaction solution was treated in two stages using a thin film evaporator. First, 1.0+nmHg
, 160°C, then 0. O8mmHg, 200
Unreacted PD and solvent were removed and recovered under conditions of .degree.

In the second stage of operation, the removal part of the bottom liquid of the can is heated to 120 to 1
By heating to 30°C, it was finally possible to remove the fluid polyisocyanate.

This polyin7anate is a brittle solid at room temperature;
At 0°C, it was a slightly sticky substance.

The remaining work PD work was measured by gas chromatography.
．． 9%, NCO content 18.4%, viscosity 950cp/
25°C (diluted to 75% solids concentration with ethyl acetate) and Kölpermeation chromatography (OP).
The compositional analysis based on c) was as follows.

Unreacted components 5. OPA% Dimer 29.5 Dimer 40.0 Large amount 1 bottle 25.5 (PA% is the peak area ratio.) Figures 2 and 3 show the above Example 1 and Figure 3, respectively. An OPC chart of the polyisocyanate obtained in Comparative Example 2 is shown. From this chart, it can be seen that the product obtained by the method of the present invention has much less content of unreacted components of PI)I and PD dimer than that of Comparative Example 2.

Table 1 shows the physical properties of the polyisocyanates obtained in Examples 1-5 as well as the physical properties ki of the polyisocyanates obtained in Comparative Examples 1-2.

Reference Examples Examples 1 to 5. A coating test was conducted using the polyisocyanates obtained in Comparative Examples 1 and 2.

All paint formulations use 1vco of acrylic polyol, Acrydic A-801 manufactured by Dainippon Ink Co., Ltd. as a polyol.
Used at a ratio of 10H = 1.0, diluted with a mixed solvent (toluene/butyl acetate/ethyl acetate/xylene/cellosolve acetate - 30/30/20/1515), and controlled at 25°C for 15 seconds with a Fort Cup +4. and painted it. Curing drying time and impact resistance values are at a temperature of 20°C and a humidity of 65°C.
Measurement or evaluation was performed in accordance with JIS-5400 under constant temperature and humidity conditions of 5%.

The results are summarized together with the pot life in Table 2.

[Brief explanation of drawings]

Figure 1 shows the PD emole% and polyiso/
FIG. 2 is a graph showing the relationship between the amount of poly-PD-urea dimer (PA%) in anate, and FIGS. [) This is a PC chart. Patent amount head person Asahi Kasei Industries Co., Ltd. agent Akira Agata

Claims (1)

[Claims] 1 general formula % formula % (in which one of Xl and A part of each H present is a divalent residue represented by the formula, and the remainder is a hexamethylene group represented by the formula -(-aH2, where n is an integer from 1 to 5). At least 5 moles of a diinnoate component consisting of a mixture of isophorone diisocyanate and hexamethylene diisocyanate is added to 1 mole of the polyisocyanate-forming agent, and after stirring at 70 to 200°C, unreacted fins are removed. / anate component is removed, the general formula (in the formula, one of Xl and X2 is a residue represented by the general formula -C-NH-R-NC0 j , the other is a hydrogen atom, A part of the valleys R present in is a divalent residue represented by the formula, and the rest is a hexamethylene group represented by the formula (-CH2-)-, where n is an extra number from 1 to 5). A method for producing the organic polyisocyanate.