JP2617738B2 - Polyester polyol composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyester polyol composition useful for urethane polyols and other uses, in particular, has a viscosity that is easy to handle, has a low water absorption, and has excellent electrical insulation properties. The present invention relates to a polyol composition capable of giving a polyurethane.

2. Description of the Related Art Conventionally, an epoxy resin or a silicone resin has been used as a sealant for electric insulation to protect electric and electronic components from vibration or shock, or an atmosphere containing moisture and dust, and to sufficiently exert the functions of the components. Used.

However, the epoxy resin is inferior in flexibility and has large internal stress and heat shrinkage during curing, so that there is a possibility that disconnection may occur or electrolytic corrosion may occur due to chlorine ions contained as impurities in the curing agent or the epoxy resin. .

Since the silicone resin has a high moisture permeability, its use in an electronic part whose characteristics change depending on the humidity is limited, and the silicone resin has poor adhesion to metals and plastics, and is disadvantageous in that it is expensive.

Polyurethane is also used as a material replacing the above-mentioned epoxy resin and silicone resin. Polyurethane is
Since it is highly flexible, if it has water resistance, low-temperature characteristics, and electric characteristics, it can be used for electrical insulation, and can be used for various purposes including civil engineering.

In order for polyurethane to have the above-mentioned properties, it is important to select a polyol component to be reacted with an orisocyanate component, that is, urethane polyol. From this viewpoint, various studies have been made on urethane polyols.

Examples of urethane polyols include (a) those using polybutadiene polyol or a hydrogenated product thereof (Abstracts of the Institute of Electrical Engineers of Japan, p. 211 [1978]), and (b) those using castor oil or a derivative thereof (Japanese Unexamined Patent Publication No.
No. 57-85816, JP-A-57-87417, U.S. Pat.
No. 3,362,921), and (c) a combination of polybutadiene polyol or a hydrogenated product thereof and castor oil or a derivative thereof (JP-A-55-139422, JP-A-56-57818, and JP-A-56-57818). Five
No. 8-93717).

The present applicant also discloses (i) a transesterification reaction product of castor oil (A) and a natural fat / oil (B) having substantially no hydroxyl group, or a combination use of the transesterification reaction product and a high-viscosity hydrocarbon polyol (particularly, JP-A-59-226016), (ii) an ester polyol having 1.5 to 3 functional groups obtained by reacting a high-viscosity hydrocarbon-based polyol (A) with a polyhydric alcohol and a monobasic acid or a dibasic acid ( A patent application has been filed for use in combination with B) (JP-A-60-215012). In the above description, a typical example of the high-viscosity hydrocarbon polyol is polybutadiene polyol.

In addition, Japanese Patent Application Laid-Open No. 54-61295 discloses a urethane foam which is foamed by mixing a dimer acid derivative polyol or a castor oil derivative polyol, a hydrocarbon substance, a foaming agent and a polyisocyanate. JP-A-54-160495 discloses dimer acid derivative polyol, castor oil derivative polyol or castor oil,
Alternatively, a polyurethane foam sealing agent obtained from a mixture thereof and a polyisocyanate compound is disclosed.

Problems to be Solved by the Invention Among the above, the method using polybutadiene polyol as the urethane polyol has excellent electrical insulation properties, water resistance and low temperature properties, but has high viscosity due to high casting, defoaming, impregnation. Are inferior in workability, and also have a high degree of unsaturation, so that they are susceptible to oxidative deterioration and have poor heat resistance. Further, there is also a problem that a peculiar rubber smell is generated at the time of casting and the like, and the working environment is deteriorated.

In order to improve workability in a urethane system using polybutadiene polyol, it is necessary to reduce the viscosity by using a plasticizer in combination, but the blending of the plasticizer may cause aging or damage to electronic components due to bleed. There is
This leads to a decrease in physical properties of the cured product.

The use of a reactive diluent in place of the plasticizer has also been proposed, but commercially available reactive diluents have a high OH value, which impairs the characteristics of polybutadiene polyol.

Further, the defect based on the degree of unsaturation of the polybutadiene polyol remains even when the plasticizer and the reactive diluent are added. Hydrogenated polybutadiene polyol to reduce the degree of unsaturation has higher viscosity,
General usage cannot be adopted.

Castor oil has a low viscosity, good water resistance, and good electrical properties, but it has a high OH value of about 160 mgKOH / g, so that a low-hardness cured product with good low-temperature properties cannot be obtained.

The transesterification reaction product of castor oil and natural fats and oils having substantially no hydroxyl group is required to be bifunctional (OH value of about 120 mgKOH / g) or more in order to be used as urethane polyol. Cannot be modified to obtain a cured product having low-temperature characteristics and low hardness. The same applies to other castor oil derivatives.

As castor oil derivatives, esterified products of castor oil fatty acid and polyether polyol, and alkylene oxide adducts of castor oil are also known, but those containing these ether bonds are poor in water resistance and electric insulation. There is a disadvantage that.

Polybutadiene polyol or a hydrogenated product thereof,
The method of using castor oil or a derivative thereof in combination has restrictions on the compatibility of the two, and the polyurethane after curing shows only intermediate properties between the two, and is not an essential improvement.

Dimer acid derivative polyols (typically polyester polyols synthesized from dimer acid and ethylene glycol) generally have extremely high viscosities, which limits their application. Even when a dimer acid derivative polyol and a castor oil derivative polyol are used in combination, it is impossible to lower the viscosity while keeping the OH value low.

Japanese Patent Application Laid-Open No. 54-61295 mentions "a dimer acid polyester which is a reaction product of a dimer acid and a long-chain polyol, for example, castor oil" as a dimer acid derivative polyol. Left column 8-11
According to the study of the present inventors, this has a viscosity as high as that of polybutadiene polyol, and it is impossible to lower the viscosity while keeping the HO value low.

The present invention provides a urethane polyol that solves the above-mentioned problems, that is, provides a urethane polyol having a viscosity that is easy to handle, a small water absorption rate, and a polyurethane having excellent electrical insulation properties. It was made for the purpose.

Means to solve the problems Synthesizing various compounds to solve the above problems,
As a result of examining its usefulness as a urethane polyol,
1 mole of dimer acid (X) and 2.5 functional groups per molecule
Castor oil-based polyol (Y) 1 below (especially 1.3 to 2.4)
Mol or 2 mol and the castor oil-based polyol (Y)
The inventors have found that a polyester polyol composition comprising an esterified product with 1 mol or 0 mol of a polyol (Z) other than the above is useful for this purpose, and have completed the present invention.

 Hereinafter, the present invention will be described in detail.

The dimer acid (X) refers to a dimer obtained by polymerization of unsaturated fatty acids such as linoleic acid, oleic acid, elaidic acid, and tall oil fatty acid. In general, a fatty acid having 18 carbon atoms is used as a raw material, and the main component is a dicarboxylic acid having 36 carbon atoms. However, industrially produced dicarboxylic acids partially include a trimer and a monomer.

Examples of the castor oil-based polyol (Y) to be reacted with the dimer acid (X) include partially dehydrated castor oil, partially acylated castor oil, a transesterification product of castor oil with a natural fat or oil having substantially no OH group, and An ester of a castor oil fatty acid with a low molecular weight polyol is dissolved therein.

Partially dehydrated castor oil is the sulfuric acid, phosphoric acid, p-
It is obtained by heating in the presence of an acidic catalyst such as toluenesulfonic acid.

Partially acylated castor oil is obtained by partially acylating castor oil. Acetylation is the most important of the acylations, and is practically limited to this acetylation in industry. As the acetylation method, a method of reacting ketene and a method of reacting glacial acetic acid can be adopted,
Acetylation with acetic anhydride is most advantageous industrially.

As a transesterification reaction product between castor oil and a natural fat / oil having substantially no OH group, a transesterification reaction which is usually carried out for both, for example, an alkali catalyst such as alkali hydroxide, alkali metal alcoholate, sodium carbonate or litharge, etc. In the presence of the above catalyst, a method of transesterifying under a reaction condition of 180 to 260 ° C. for 15 minutes to 6 hours is employed.

In addition, as the above-mentioned natural fats and oils having substantially no OH, linseed oil, drill oil, rapeseed oil, soybean oil, coconut oil, palm oil, enamel oil, walnut oil, rice bran oil, cottonseed oil,
Vegetable oils such as camellia oil, olive oil and raccoon oil, and animal properties such as beef tallow, lard, fish fat, liver fat, and whale fat can be exemplified.

Examples of the ester of castor oil fatty acid with low molecular weight polyol include esterified product of castor oil and low molecular weight polyol, esterified product of castor oil fatty acid or its alkyl ester and low molecular weight polyol, and the like.

Here, as the low molecular weight polyol, ethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, neaptyl glycol,
Polyols such as 1,6-hexane glycol, polypropylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and polyfunctional polyols, or alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) addition of these polyols Things can be exemplified.

Regarding the above castor oil-based polyol (Y), those having a number of functional groups of 2.5 or less, particularly 2.4 or less, per molecule are used in either case. 1
When the number of functional groups per molecule exceeds 2.5, the viscosity of the ester with dimer acid (X) becomes substantially equal to that of castor oil, and the object of the present invention cannot be sufficiently achieved. On the other hand, when the number of functional groups per molecule becomes extremely small, the compound substantially becomes a monool. Therefore, the lower limit is naturally limited, and is usually 1.3 or more, especially 1.4 or more.

By the way, castor oil is a triglyceride containing ricinoleic acid as a main component, and about 90% by weight of its constituent fatty acids.
Is ricinoleic acid, and most of the remaining fatty acids do not have OH groups, so the number of functional groups in castor oil is about 2.
7 (OH number is about 160 mg KOH / g).

Examples of the polyol (Z) other than the castor oil-based polyol (Y) include castor oil, ethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexane glycol, and polypropylene. Examples thereof include polyols such as glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol and polyfunctional polyether polyols, and alkylene oxide (ethylene oxide, propylene oxide, butylene oxide and the like) adducts of these polyols.

The polyester polyol composition of the present invention comprises 1 mol of dimer acid (X) and the above castor oil-based polyol (Y)
It consists of 1 mol or 2 mol and 1 mol or 0 mol of the polyol (Z) other than the castor oil-based polyol (Y) and the esterified product. Among them, particularly important is an esterified product of 1 mol of dimer acid (X) and 2 mol of castor oil-based polyol (Y).

The esterification reaction can be achieved by heating and reacting each of the above components in an inert gas atmosphere without a catalyst or in the presence of a metal catalyst or an acidic catalyst. Reaction temperature is 160-2
The temperature is set to 50 ° C, particularly 180 to 240 ° C, and the reaction time is often set to about 2 to 24 hours.

The amount of the castor oil-based polyol (Y) to be used per 1 mol of the dimer acid (X) is equivalent to 1 mol or 2 mol, but a width of about 0.5 to 2.5 mol is acceptable. Similarly,
The amount of the polyol (Z) other than the castor oil-based polyol (Y) to be used per mole of the dahamic acid (X) is equivalent to 1 mol or 0 mol, but a width of about 1.5 to 0 mol is acceptable. . In such a range, a by-product or an unreacted product is generated, but a required amount of the desired polyester polyol composition is generated.

The ester polyol composition of the present invention comprising the above esterified product can be used for various applications, but is particularly useful as a polyol component (that is, urethane polyol) for reacting with a polyisocyanate component in a two-part urethane system. It is. In this case, other known urethane polyols such as castor oil can be used together with the polyester polyol composition of the present invention.

Polyisocyanate components in the urethane system include diphenylmethane diisocyanate (MDI),
Polymerized MDI, carbodiimide-modified MDI, tolylene diisocyanate, naphthalene diisocyanate, xylene diisocyanate, diphenylsulfone diisocyanate, triphenylmethane diisocyanate, hexamethylene diisocyanate, 3-isocyanatomethylcyclohexyl diisocyanate, diphenylpropane diisocyanate, phenylene diisocyanate, cyclohexylene diisocyanate, 3, 3'-diisocyanate dipropyl ether, triphenylmethane triisocyanate, isophorone diisocyanate, diphenyl-4,4'-diisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, etc., or a polyisocyanate thereof and a polyol or monool Obtained by reacting Such end isocyanate prepolymer is used.

The mixing ratio of the polyol and the polyisocyanate at the time of the urethanization reaction should be set so that the ratio of the OH group in the polyol to the NCO group in the polyisocyanate NCO / OH is in the range of 0.8 to 1.4, and sufficient curing is performed. Is preferred. Curing may be performed at room temperature or under heating.

During the urethanization reaction, if necessary, fillers or pigments, flame retardants, curing accelerators, crosslinking agents, catalysts, defoamers, thixotropic agents, plasticizers, solvents, antioxidants, ultraviolet absorbers, leveling An additive such as an agent can be blended.

The two-part urethane system using the polyester polyol composition of the present invention alone or in combination with other known polyols as a urethane polyol has electrical insulation,
It is useful for various applications including bonding, paints, sealants, sealants, lining agents, flooring, molding, and the like.

Action As described above, the polyester polyol composition of the present invention comprises 1 mol of dimer acid (X), 1 mol or 2 mol of a castor oil-based polyol (Y) having 2.5 or less functional groups per molecule, and It consists of an esterified product with 1 mol or 0 mol of the polyol (Z) other than the castor oil-based polyol (Y).

Typical examples are HOOC-R-COOH for dimer acid (X), HO-R'-OH for castor oil-based polyol (Y), and HO-R for polyol (Z) other than castor oil-based polyol (Y). When "-OH" and 2 moles of (Y) react with 1 mole of (X), a polyester polyol HO-R'-OOC-R-COO-R'-OH is obtained, and 1 mole of (X) When 1 mole of (Y) and 1 mole of (Z) react, polyester polyol HO-R'-OOC-R-COO-R "-OH is obtained.

During urethanization, the terminal OH groups react with the NCO groups of the polyisocyanate compound.

EXAMPLES Next, the present invention will be further described with reference to Examples. Hereinafter, “parts” and “%” are shown on a weight basis.

Dimer acid As dimer acid, 75% dimer and 20 trimer
%, A monomer having a composition of 5%, a commercially available dimer acid having an acid value of 193 mgKOH / g, a specific gravity of 0.95 / 25 ° C, and a viscosity of 9000 cps / 25 ° C.

Castor oil-based polyol The following were prepared as castor oil-based polyols.

(Y-1) Partially dehydrated castor oil 600 parts of castor oil and 0.9 parts of sodium acid sulfite were charged into a flask equipped with a thermometer and a stirrer, and heated under reduced pressure. The dehydration reaction started at 165-190 ° C., and then gradually increased in temperature. The reaction is completed at 190-250 ° C for 1 hour, and after cooling
At 150 ° C., acid clay was added, followed by filtration and purification. This allows O
A partially dehydrated castor oil having an H value of 120 mgKOH / g and a viscosity of 450 cps / 25 ° C. was obtained.

(Y-1 ′) Partially dehydrated castor oil In Example 1, only the reaction time was changed, and the OH value was 140 mgK.
A partially dehydrated castor oil having an OH / g and a viscosity of 580 cps / 25 ° C. was obtained.

(Y-2) Partially acylated castor oil 600 parts of castor oil and 35 parts of acetic anhydride were charged into a flask equipped with a thermometer, a stirrer and a reflux condenser, and then heated to 120-1.
The reaction was continued for about 2.5 hours by heating at 50 ° C. Then, the reflux condenser was replaced with a distillation condenser and the temperature was gradually raised, and acetic acid produced as a by-product and unreacted acetic anhydride were recovered by distillation. During this time, the degree of vacuum was gradually increased with an aspirator. Since the temperature of the system reached 230 ° C. after one hour, the temperature was maintained for one hour and then cooled. As a result, a partially acetylated castor oil having an OH value of 125 mgKOH / g and a viscosity of 400 cps / 25 ° C. was obtained.

(Y-3) Transesterification reaction product of castor oil with a natural fat or oil having substantially no OH group 200 parts of castor oil and rapeseed oil (acid value 0.1, pour point -17.5
C.) with 0.6 part of a 28% methanol solution of sodium methylate at 230-240.degree. C. for 4 hours, cooled, neutralized with phosphoric acid (first grade reagent),
Activated clay was added at ℃ ° C., followed by filtration and purification. This gives the OH value
A castor oil-rapeseed oil transesterification product with 107 mg KOH / g and a viscosity of 242 cps / 25 ° C. was obtained.

(Y-4) Ester of Castor Oil Fatty Acid with Low Molecular Weight Polyol 300 parts of castor oil fatty acid and 61 parts of ethylene glycol
After reacting at 50 to 200 ° C. for 8 hours at 150 to 200 ° C., the mixture was cooled, and then activated clay was added at 120 ° C. for filtration and purification. As a result, ethylene glycol monoricinoleate having an OH value of 265 mgKOH / g and a viscosity of 265 cps / 25 ° C. was obtained.

(Y ′) Castor oil Castor oil having an OH value of 161.1 mg KOH / g and a viscosity of 680 cps / 25 ° C. was used.

Example 1 582 g (1 mol) of the above dimer acid, 120 mgK of the above OH value
1860 g (2 mol) of OH / g partially dehydrated castor oil (Y-1) and 2.4 g (0.1% based on the system) of a tin-based catalyst were charged into a three-necked flask equipped with a thermometer and a stirrer, and charged at 220 ° C. for 8 hours.
The reaction was allowed to proceed for an hour, and after cooling, acid clay was added at 120 ° C., followed by filtration and purification. By this reaction, acid value 2.6 mg KOH / g, OH value 44.5 mg
A polyester polyol composition having a KOH / g and a viscosity of 5080 cps / 25 ° C. was obtained.

Example 2 582 g (1 mol) of the above dimer acid, 140 mgK of the above OH value
1860 g (2 mol) of partially dehydrated castor oil (Y-1 ') of OH / g
And 2.4 g of tin-based catalyst (0.1 g with respect to the system) was charged into a flask, reacted at 220 ° C. for 12 hours, cooled, and added with acid clay at 120 ° C., followed by filtration and purification. By this reaction, the acid value 1.8 mgK
A polyester polyol composition having an OH / g, an OH value of 48.8 mgKOH / g, and a viscosity of 6380 cps / 25 ° C. was obtained.

Example 3 582 g (1 mol) of the dimer acid described above, OH value of 125 mgK described above
1860 g (2 mol) of OH / g partially acetylated castor oil (Y-2) and 2.4 g (0.1% based on the system) of a tin-based catalyst were charged into a flask, reacted at 220 ° C. for 16 hours, cooled, and cooled at 120 ° C. Acid clay was added and the mixture was purified by filtration. By this reaction, the acid value
A polyester polyol composition having 4.3 mg KOH / g, an OH value of 42.2 mg KOH / g, and a viscosity of 4880 cps / 25 ° C. was obtained.

Example 4 582 g (1 mol) of the above dimer acid and the above OH value of 265 mgK
OH / g ethylene glycol monoricinoleate (Y-4)
832 g (2 mol) was charged into a flask and reacted at 220 ° C. for 15 hours. After cooling, acidic clay was added at 120 ° C. for filtration and purification. By this reaction, acid value 2.3mgKOH / g, HO value 79.0mg
A polyester polyol composition having a KOH / g and a viscosity of 3100 cps / 25 ° C. was obtained.

Example 5 582 g (1 mol) of the above dimer acid, 107 mgK of the above OH value
OH / g castor oil-rapeseed oil transesterification product (Y-
3) 1840 g (2 mol) and 1.4 g (0.1% based on the system) of a tin-based catalyst were charged into a flask, reacted at 220 ° C. for 15 hours, cooled, and added with acid clay at 120 ° C., followed by filtration and purification. By this reaction, acid value 2.8mgKOH / g, OH value 45.0mgKOH / g,
A polyester polyol composition having a viscosity of 4300 cps / 25 ° C. was obtained.

Example 6 1160 g (2 mol) of the above dimer acid, 120 mg of the above OH value
1830 g (2 mol) of partially dehydrated castor oil (Y-1) of KOH / g and 236 g (2 mol) of hexanediol were charged into a flask, reacted in the same manner as in Example 1, and purified to obtain an acid value of 2.3 mg KOH / g. g, OH value 42.1mgKOH / g, viscosity 6100cps / 2
A polyester polyol composition at 5 ° C. was obtained.

Comparative Example 1 582 g (1 mol) of the above-mentioned dimer acid and 800 g (2 mol) of polypropylene glycol having a molecular weight of 400 were charged into a flask and reacted at 220 ° C. for 6 hours. After cooling, acid clay was added at 120 ° C., followed by filtration and purification. . By this reaction, acid value 2.8mgK
A polyester polyol composition having an OH / g, an OH value of 80.2 mg KOH / g, and a viscosity of 1530 cps / 25 ° C. was obtained.

Comparative Example 2 1746 g (3 mol) of the above dimer acid, 248 g (4 mol) of ethylene glycol and 2.0 g of a tin catalyst (based on the system)
0.1%) was charged into a flask and reacted at 220 ° C. for 8 hours. The viscosity of the reaction product was 100000 cps / 25 ° C or more.

Comparative Example 3 582 g (1 mol) of the above dimer acid, 124 g (2 mol) of etalene glycol and 0.7 g of a tin-based catalyst (based on the system)
0.1%) was charged into a flask and reacted at 220 ° C. for 8 hours. The viscosity of the reaction product was 100000 cps / 25 ° C or more.

Comparative Example 4 582 g (1 mol) of the above dimer acid and 76.6 mg of the above OH value
A flask was charged with 1860 g (2 mol) of KOH / g castor oil (B '), reacted at 220 ° C. for 12 hours, cooled, and added with acid clay at 120 ° C. for filtration and purification. Due to this reaction, the acid value 2.
As a result, a polyester polyol composition having an OH value of 76.6 mgKOH / g and a viscosity of 7620 cps / 25 ° C. was obtained.

Comparative Example 5 A commercially available polybutadiene polyol was prepared. The acid value is
0.1mgKOH / g or less, OH value 46.0mgKOH / g, viscosity 7800cps / 2
5 ° C.

Table 1 collectively shows the characteristic values of the polyester polyol compositions or the polyols obtained in Examples 1 to 6 and Comparative Examples 1 to 5.

As in Examples 1 to 6, the polyester polyol composition of the present invention has a viscosity that can be easily handled as urethane polyol.

<Urethanation reaction> The polyester polyol compositions or polyols obtained in Examples 1 to 6 and Comparative Examples 1, 4 and 5 were combined with carbodiimide-modified diphenylmethane diisocyanate (Millionate MTL manufactured by Nippon Polyurethane Industry Co., Ltd.) in NCO / OH.
= 1.05, mixed, stirred, defoamed, poured into a mold, and cured at 120 ° C for 1 hour to obtain a cured sheet having a thickness of 3 mm.

 The physical properties of this urethane cured product are shown in Table 2 below.

Effect of the Invention The polyester polyol composition of the present invention has a viscosity that is easy to handle, and a urethane system using this as a urethane polyol provides a polyurethane having a low water absorption and excellent electrical insulation. Further, no unpleasant odor is generated in the heating step.

Further, the hardness of the obtained polyurethane can be reduced, and even when a plasticizer is blended, the amount thereof can be reduced, so that disadvantages due to the blending of the plasticizer can be minimized.

Claims (4)

(57) [Claims] 1. A mol of dimer acid (X), 1 mol or 2 mol of castor oil-based polyol (Y) having 2.5 or less functional groups per molecule, and a polyol (Z) other than castor oil-based polyol (Y) A polyester polyol composition comprising an esterified product with 1 mol or 0 mol. 2. The polyester polyol composition according to claim 1, wherein the number of functional groups of the castor oil-based polyol (Y) is 1.3 to 2.4 per molecule. 3. The polyester polyol composition according to claim 1, comprising an esterified product of 1 mole of dimer acid (X) and 2 moles of castor oil-based polyol (Y) having 2.5 or less functional groups per molecule. . 4. A castor oil-based polyol (Y) comprising a partially dehydrated castor oil, a partially acylated castor oil, a transesterification product of a castor oil with a natural fat or oil having substantially no OH group, and a castor oil fatty acid. 2. The polyester polyol composition according to claim 1, which is a compound selected from the group consisting of an ester with a low molecular weight polyol.