JPS6322216B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyurethane-based curable composition using a specific modified castor oil. The chemical composition of castor oil is a triglyceride whose main component is ricinoleic acid (12-hydroxyoleic acid), and about 90% by weight of its constituent fatty acids are ricinoleic acid, and most of the remaining fatty acids do not have hydroxyl groups. Therefore, castor oil has about 2.7 hydroxyl groups in its molecule, and the hydroxyl groups are located far apart from each other, with most of them connected by methylene groups. Due to this chemical structure, castor oil can be said to be a material that provides flexibility with superior water resistance and electrical properties compared to polyether polyols and polyester polyols, which are common polyols. Because castor oil has the above-mentioned properties, it is used as a polyol component in the production of polyurethane resin for encapsulating electronic components, but as the development of ultra-miniaturization technology for electronic components progresses, castor oil The required properties of resins have become stricter, and there is a demand for higher extensibility. In addition, castor oil is a relatively low-viscosity material that is used as a valuable material in high-concentration systems and solvent-free systems for urethane paints and adhesives, but it is necessary to use a lower viscosity in terms of pot life and workability. It is requested to do so. Similar improvements in properties are also required for other insulating materials. Against this background, attempts have been made to improve the extensibility of cured resins for use in electronic component encapsulants, and to lower the viscosity for use in paints and adhesives, without losing the advantages of castor oil. The intended purpose has not yet been fully achieved. That is, it has been proposed to incorporate a plasticizer such as a phthalate ester into the urethane system for the above-mentioned applications, but this has the disadvantage of lowering the performance of the cured resin. In addition, ricinoleic acid esters of dihydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol are used in place of castor oil or in partial substitution of castor oil. It has also been proposed that ricinoleic acid ester, a dihydric alcohol, can be used by first hydrolyzing castor oil.
It is obtained by esterifying the obtained castor oil fatty acid with a dihydric alcohol, or by transesterifying the methyl ester of castor oil fatty acid or the castor oil and a dihydric alcohol. However, the by-product of glycerin cannot be avoided, and as a result, it is necessary to treat the glycerin water (high BOD) generated in the step of washing and removing the by-product glycerin, which is also disadvantageous in terms of yield. Castor oil is also known to be effective as a modifier that lowers the viscosity and lengthens the pot life in the production of polyurethane resins whose polyol components are high-viscosity hydrocarbon polyols such as polyhydroxypolybutadiene. , castor oil has limited compatibility with polyols with large hydroxyl equivalents such as high viscosity hydrocarbon polyols,
In particular, there are problems in that it is limited in use at low temperatures, and its viscosity lowering effect is not necessarily sufficient. The present invention aims to solve the above problems of castor oil in urethane systems by using a specific transesterification product of castor oil. The curable composition of the present invention contains a hydroxyl group-containing compound
and a curable composition consisting of polyisocyanate Y, characterized in that at least a part of the hydroxyl group-containing compound X is a transesterification product X ₁ of castor oil a and a natural fat or oil b that does not substantially have hydroxyl groups. It is. The transesterification product X ₁ has a reduced number of functional groups compared to castor oil (approximately 2.7 functional groups), and thus exhibits excellent effects as listed below. (1) The resulting cured urethane has the water resistance expected when castor oil is used as a polyol;
Advantages such as electrical properties, tensile and tear strength are not compromised. (2) The extensibility of the resulting cured urethane product can be increased to a desirable level. (3) In urethane systems, the viscosity of the system can be greatly reduced, the pot life can be extended, and workability is significantly improved, so it can be used as an insulating material for electronic parts, electrical equipment parts, electrical equipment parts, and communication parts. Injection and impregnation are improved. In addition, it plays the same role as an organic solvent in high-concentration systems and solvent-free systems for urethane paints and urethane adhesives, and is also ideal as a reactive diluent that reacts to become a resin component. (4) It has good compatibility even when used in combination with a high viscosity hydrocarbon polyol with a high hydroxyl equivalent, and its combination reduces the viscosity of the system and lengthens the pot life, and its combination also improves the physical properties of the cured urethane. Not only does it not reduce the properties, but it can even improve its physical properties. Therefore, when used in combination with a high viscosity hydrocarbon polyol, the electrical properties, particularly the dielectric constant and dielectric loss tangent, are improved, making it possible to impregnate and cast coils, for example flyback transformers for televisions. (5) Since the transesterification product of castor oil and natural fats and oils can be easily obtained in terms of process, and natural fats and oils can also be selected from inexpensive ones, it is extremely industrially possible to use this transesterification product as a urethane polyol. rich in The curable composition of the present invention contains a hydroxyl group-containing compound
and polyisocyanate Y. In the present invention, as at least a part of the hydroxyl group-containing compound X, a transesterification product X ₁ of castor oil a and a natural fat or oil b that does not substantially have a hydroxyl group is used. Here, the natural oils and fats B to be transesterified with castor oil A include linseed oil, tung oil, rapeseed oil, soybean oil, coconut oil, palm oil, edible oil, walnut oil, rice bran oil, cottonseed oil, camellia oil, Examples include vegetable oils such as olive oil and horsetail oil, and animal oils such as beef tallow, lard, fish oil, liver oil, and whale oil. For transesterification of (a) and (b) above, a commonly used transesterification reaction is used, for example, using an alkali catalyst such as alkali hydroxide, alkali metal alcoholate, or sodium carbonate, or a catalyst such as litharge.
Transesterification is carried out under reaction conditions of 260°C and 15 minutes to 6 hours. Although the reaction ratios of (a) and (b) above can be varied widely, (a)
It is particularly preferable to select from the range of 90 to 30% by weight and (b) 10 to 70% by weight. If the proportion of (b) is too small, the object of the present invention cannot be fully achieved;
When the proportion of (b) is too high, it cannot contribute to the urethanization reaction and becomes a mere compound, which tends to have a negative effect on the physical properties of the cured product. In the above transesterification reaction, other polyols c, For example, ethylene glycol
Diethylene glycol, 1,2- or 1,3-propylene glycol, 1,3-, 1,4- or 2,3-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin, trimethylolpropane, etc. are used. can. In the present invention, the transesterification product X ₁ can be used alone as the polyol X, but the transesterification product X ₁ can be used in combination with other general urethane polyols. In particular, polyethers with large hydroxyl equivalents such as high viscosity hydrocarbon polyols X ₂ such as polyhydroxy polybutadiene and polyhydroxy polyolefins are generally too viscous and _difficult to handle; In addition to being compatible with polyisocyanate Y even at low temperatures, the combined use of X ₁ lowers the viscosity and makes it easier to handle.Furthermore, the combined use of polyisocyanate Y does not reduce the physical properties of the cured product, but rather improves its physical properties. It has the effect of causing When the transesterification reaction product X ₁ and the high viscosity hydrocarbon polyol X ₂ are used together, the blending ratio of the two can be varied widely, but the weight ratio of X ₁ and X ₂ is 8:2.
It is preferable to select from a range of 1:9 to 1:9, particularly 7:3 to 2:8. In the present invention, polyisocyanate Y is used as a curing agent for the hydroxyl group-containing compound X. As such polyisocyanate Y,
Tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate,
xylylene diisocyanate, diphenyl sulfone diisocyanate, triphenylmethane diisocyanate, hexamethylene diisocyanate,
3-Isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 3-isocyanate ethyl-3,5,5-trimethylcyclohexyl isocyanate, 3-isocyanate ethyl-3,5,5-triethylcyclohexyl isocyanate, diphenylpropane diisocyanate, Examples include phenylene diisocyanate, cyclohexylylene diisocyanate, 3,3'-diisocyanate dipropyl ether, diphenyl ether-4,4'-diisocyanate, and isophorone diisocyanate. Prepolymers with terminal isocyanate groups derived from these polyisocyanates can be used as well. The blending ratio of the hydroxyl group-containing compound
It is preferable to adjust the amount to 0.8 to 1.4 equivalents because sufficient curing can be achieved. Curing may be carried out slowly at low temperatures or may be accelerated by heating. The composition of the present invention contains fillers or pigments such as talc, clay, calcium carbonate, baryta powder, silica powder, alumina, carbon black, titanium oxide, iron oxide, phosphorus compounds, halogen compounds, antimony oxide, etc. Various additives such as flame retardants, antioxidants, anti-aging agents, and ultraviolet absorbers may be added as necessary. The composition of the present invention includes a casting composition, an impregnating composition, a coating agent, an adhesive, a paint, a caulking material, a potting material, a sealant, a foam, an encabbing material, a lining material, a packing material, It is useful for applications such as industrial rubber materials and rocket fuel binders. Next, the curable composition of the present invention will be further explained with reference to Examples. Synthesis example of transesterification reaction product X ₁ 1 Castor oil a (hydroxyl value 160, viscosity 700 cps/25°C)
170 g, 30 g of coconut oil B (hydroxyl value 0.2), and 0.6 g of soda carbonate were placed in a 500 ml four-necked flask, and the temperature was raised with stirring while blowing in nitrogen gas.After 20 minutes, the temperature was 180℃, and after another 10 minutes, it was 230℃. ℃ and at this temperature
Stirring was continued for 90 minutes and then cooled to room temperature to complete the reaction. The reaction mixture was neutralized with phosphoric acid, dehydrated under reduced pressure, and treated with clay. This transesterification reaction resulted in a hydroxyl value of 137,
An oily substance X ₁ was obtained with a water content of 0.01% and a viscosity of 484 cps/25°C. Synthesis example 2 Castor oil a (hydroxyl value 160, viscosity 700cps/25℃)
A flask was charged with 100 g of rapeseed oil B (hydroxyl value almost 0) and 2 g of a 28% methanol solution of sodium methylate, and a transesterification reaction was carried out in the same manner as in Synthesis Example 1.
Oil X ₁ was obtained at 172 cps/25°C. Synthesis example 3 Castor oil a (hydroxyl value 160, viscosity 700cps/25℃)
84 g, 116 g of linseed oil B (hydroxyl value almost 0), and 0.4 g of soda carbonate were charged into a flask, and a transesterification reaction was carried out in the same manner as in Synthesis Example 1.
68, moisture 0.01%, viscosity 141cps/25℃ oily substance x ₁
I got it. Synthesis example 4 Castor oil a (hydroxyl value 160, viscosity 700cps25℃)
142 g, lard b (hydroxyl value almost 0), 58 g, and 0.6 g of soda carbonate were charged into a flask, and a transesterification reaction was carried out in the same manner as in Synthesis Example 1, resulting in a hydroxyl value of 115,
An oily substance X ₁ with a water content of 0.01% and a viscosity of 302 cps/25°C was obtained. Synthesis example 5 Castor oil a 93g, rapeseed oil b 90g, trimethylolpropane c 13.4g and sodium methylate 28g
% methanol solution was charged into a flask and transesterification was carried out in the same manner as in Synthesis Example 1 to obtain an oily substance X ₁ having a hydroxyl value of 156 and a viscosity of 210 cps at 25°C. The above synthesis examples are summarized in Table 1 below.

[Table] Compatibility test test example between transesterification product X ₁ and high viscosity hydrocarbon polyol X ₂ 1 Oily transesterification product obtained in Synthesis Example 2 X ₁
and “PB R- _45HT ” manufactured by Idemitsu Petrochemical Co., Ltd.
were mixed at various ratios under various temperature conditions, and then left to stand at the same temperature to examine compatibility. Here, “PB R-
45HT" has a number average molecular weight of 2800 and a functional group number of 2.2~
It is a polyhydroxypolybutadiene with characteristic values of 2.4, iodine value of 398, and hydroxyl value of 46. The results are shown in Table 2. Comparative Test Example 1 The compatibility between castor oil and polyhydroxypolybutadiene "PB R-45HT" X ₂ was investigated in the same manner as in Test Example 1. The results are also shown in Table 2.

【table】

[Table] Two-layer separation)
Test Example 2 Oily transesterification product obtained in Synthesis Example 3 X ₁
The compatibility between this and polyhydroxypolybutadiene "PB R-45HT" X ₂ manufactured by Idemitsu Petrochemical Co., Ltd. was investigated in the same manner as in Test Example 1. The results are shown in Table 3.

[Table] Test Example 3, Control Test Example 2 Oily transesterification product obtained in Synthesis Example 2 X ₁
and polyhydroxypolyolefin "Polytail HA" manufactured by Mitsubishi Chemical Corporation (hydroxyl value ₄₈ , viscosity 1000ps or more/25℃) The solution remained clearly dissolved, and the compatibility was extremely good. (Test Example 3) On the other hand, an attempt was made to blend castor oil into the above-mentioned "Polytail HA" X ₂ , but "Polytail HA" and castor oil were hardly compatible. (“Politaire
HA and castor oil are incompatible even at a weight ratio of 9:1. ) (Comparative Test Example 2) Reaction Example 1 between Hydroxyl Group-Containing Compound X and Polyisocyanate Y This Example 1 is an example in which the transesterification product X ₁ was used alone as the hydroxyl group-containing compound X. Oily transesterification product obtained in Synthesis Example ₁
and hexamethylene diisocyanate Y
After mixing thoroughly at a ratio such that the NCO/OH equivalent ratio was 1.05, the mixture was vacuum degassed in a desiccator, and then poured into a mold with a thickness of 3 mm and cured at 120° C. for 1 hour. Since the viscosity of the system was low, mixing of X ₁ and Y, defoaming of this mixture, and further injection into a mold could be carried out extremely smoothly and in a short time. The physical properties of the obtained cured sheet are shown in Table 4, and the extensibility was greatly improved compared to when castor oil was used as the urethane polyol (Comparative Example 1 described later), and the tensile strength, tear strength, and volume specific properties were greatly improved. Resistance was maintained. Control Example 1 A cured sheet was obtained in the same manner as in Example 1, except that 100 g of castor oil and 25 g of hexamethylene diisocyanate were used. The results are also shown in Table 4.

【table】

[Table] Examples 2 to 9 Examples 2 to 9 are examples in which the transesterification product X ₁ and the high viscosity hydrocarbon polyol X ₂ were used together as the hydroxyl group-containing compound X. Example 2 Oily transesterification product obtained in Synthesis Example 2 X ₁
and polyhydroxypolybutadiene "PB R-45HT" manufactured by Idemitsu Petrochemical Co., Ltd. X ₂ at a weight ratio of 1:
Then, to this mixture, carbodiimide-modified 4,4'-diphenylmethane diisocyanate ("Millionate MTL" manufactured by Nippon Polyurethane Industries Co., Ltd.) Y was added to the mixture at a NCO/OH equivalent ratio.
1.05, and after stirring for 2 minutes, it was immediately poured into a mold and cured at a temperature of 120°C for 1 hour to obtain a cured sheet with a thickness of 3 mm. Table 5 shows the viscosity reducing effect of the above formulation and the physical properties of the cured urethane product. Example 3 Oily transesterification product obtained in Synthesis Example 3 X ₁
and polyhydroxypolybutadiene "PB R-45HT" manufactured by Idemitsu Petrochemical Co., Ltd. X ₂ at a weight ratio of 3:
"Millionate MTL" Y was blended, poured, and cured in the same manner as in Example 2 to obtain a cured sheet. The results are shown in Table 5. Example 4 Oily transesterification product obtained in Synthesis Example 4 X ₁
and polyhydroxypolybutadiene "PB R-45HT" manufactured by Idemitsu Petrochemical Co., Ltd. X ₂ at a weight ratio of 4:
"Millionate MTL" Y was blended, poured, and cured in the same manner as in Example 2 to obtain a cured sheet. The results are shown in Table 5. Control Example 2 Using polyhydroxypolybutadiene "PB R-45HT" X ₂ manufactured by Idemitsu Petrochemical Co., Ltd. alone as the urethane polyol, "Millionate MTL" Y was blended and poured in the same manner as in Example 2.
Curing was performed to obtain a cured sheet. The results are also shown in Table 5.

[Table] Examples 5 to 7 Oily transesterification product obtained in Synthesis Example 5 X ₁
and polyhydroxypolybutadiene "PB R-45HT" manufactured by Idemitsu Petrochemical Co., Ltd. X ₂ at a weight ratio of 3:
7 (Example 5), 1:1 (Example 6), and 7:3 (Example 7), and then blended and poured "Millionate MTL" Y in the same manner as in Example 2.
Curing was performed to obtain a cured sheet. The results are shown in Table 6.

[Table] Example 8 Oily transesterification product obtained in Synthesis Example 2 X ₁
and polyhydroxypolyolefin "Polytail HA" manufactured by Mitsubishi Chemical Corporation (hydroxyl value 48, viscosity 1000 ps or _more /25°C) , 4′-diphenylmethane diisocyanate (“Millionate MTL” manufactured by Nippon Polyurethane Industries Co., Ltd.) was added so that the NCO/OH equivalent ratio was 1.05, and after stirring for 2 minutes, it was immediately poured into a mold and cured at a temperature of 120°C for 1 hour. A cured sheet with a thickness of 3 mm was obtained.The results are shown in Table 7.The viscosity of "Polytail HA" was 25℃.
The viscosity is over 1000 ps, which is so high that it is difficult to handle as a two-component urethane polyol at room temperature. I also tried to mix castor oil with "Polytail HA", but as mentioned in Control Test Example 2, "Polytail HA" and castor oil were hardly compatible.
No effective viscosity reduction can be expected during work. Control example 3 Dioctyl phthalate was mixed with ₂ "Polytail HA" X at a weight ratio of 7:3, and then "Millionate MTL" Y was mixed in the same manner as in Example 8.
A cured sheet was obtained by pouring and curing. The results are also shown in Table 7.

[Table] Example 9 Oily transesterification product obtained in Synthesis Example 5 X ₁
and polyhydroxypolybutadiene "G-1000" manufactured by Mitsui Nisso Urethane Co., Ltd. (hydroxyl value 73.3, viscosity 800 ps or _more / 25 ° C.) "Millionate MTL" Y was mixed, poured, and a cured sheet was obtained. The results are shown in Table 8. Control Example 4 Polyhydroxypolybutadiene "G-1000" X ₂ manufactured by Mitsui Nisso Urethane Co., Ltd. was used alone as the urethane polyol, and "Millionate MTL" Y was blended and poured in the same manner as in Example 8.
Although it was cured, the workability was poor due to the high viscosity. The results are also shown in Table 8.

【table】

Claims (1)

[Scope of Claims] 1. A curable composition comprising a hydroxyl group-containing compound X and a polyisocyanate Y, wherein at least a part of the hydroxyl group-containing compound A curable composition that is transesterification reactant _X1 . 2 Transesterification reaction product X ₁ is castor oil A90-30
Weight% and natural fats and oils with virtually no hydroxyl groups b10~
The curable composition according to claim 1, which is a transesterification product with 70% by weight. 3. Claim 1, characterized in that the hydroxyl group-containing compound X is comprised of a transesterification product X ₁ of castor oil a and a natural oil b having substantially no hydroxyl groups, and a high viscosity hydrocarbon polyol X ₂ The curable composition described in .