JPS5853650B2 - Curable polymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to curable polymer compositions particularly useful as casting or impregnating compositions or coatings.

More specifically, the present invention relates to a curable polymer composition comprising a hydrogenated polyhydroxybutadiene polymer and a specific incyanate compound.

Conventionally, polyurethanes obtained by reacting polyglycols and polyisocyanates are well known as casting or impregnating compositions or coating agents.

The properties of these polyurethanes are greatly influenced by the type of polyglycol used, and the type is appropriately selected and used depending on the purpose.

For example, many elastomers use polyester or polyether containing hydroxyl groups, but they have poor hydrolysis resistance and
It tends to have poor heat resistance, electrical insulation, etc.

On the other hand, polyisocyanates used as curing agents tend to react easily with compounds having active hydrogen.

For this reason, when polyurethanes are used as polyurethane elastomers, coating agents, adhesives, etc., a mixture of polyglycol and polyisocyanate has extremely poor storage stability, and these components must be mixed immediately before use. We have no choice but to adopt a so-called two-component system.

Therefore, such a liquid mixture is suitable for mixing and curing in a short time, but it is difficult to use for large-sized castings or impregnated products that require a long time, and the workability is significantly inferior.

For example, when the above-mentioned mixture, which has an extremely fast curing speed, is used in the insulation treatment of electrical equipment that requires a high degree of electrical insulation, the curing proceeds rapidly without removing voids that are introduced during processing. It is a major cause of insulation failure in electrical equipment.

As a method for improving the workability, a prepolymer having an incyanate group introduced at the end of the main chain is prepared by reacting polyester, polyether, etc. having a hydroxyl group at the end of the molecule with twice the equivalent of diisocyanate, and then A so-called prepolymer method using a glycol or diamine having hydroxyl groups at both ends as a curing agent, or a method using a phenol block isocyanate or lactam block isocyanate, which have lower reactivity than isocyanate groups, have been proposed.

However, none of these methods can be said to be a fundamental improvement method when using isocyanates.

For example, the prepolymer method requires complete sealing during storage of the prepolymer, and once the prepolymer is opened, it can become gelled due to moisture absorption or voids may be formed in the cured product, so it cannot be used repeatedly. be.

Furthermore, when using blocked isocyanates, storage stability is very good, but on the other hand, there is a drawback that high temperatures and long periods of time are required for curing, and the electrical properties of the resulting cured product are significantly reduced.

Moreover, as mentioned above, cured products obtained using polyester or polyether polyols as glycol components have poor hydrolysis resistance, heat resistance, electrical insulation properties, etc., and cannot be used as insulating materials for electrical equipment that will be used for a long time. I don't like that.

The present inventors have conducted extensive research to eliminate the above-mentioned drawbacks, significantly improve workability, and provide a curable polymer composition with significantly superior electrical properties of the cured product. As a curing agent for hydrogenated hydroxybutadiene polymer, 3-isocyanate methyl-3,5,5-
By using 4-limethyl cyclohexyl isocyanate and the 2,4-4 luene diisocyanate dimer represented by the structural formula;, it is possible to cure the cured product with excellent workability and excellent hydrolysis resistance, heat resistance, and electrical insulation properties. The present invention was completed based on the discovery that a synthetic polymer composition can be obtained.

That is, the present invention adds 3-isocyanate methyl- as a curing agent to a hydrogenated polyhydroxybutadiene polymer.
The present invention relates to a curable polymer composition comprising a combination of 3,5,5-trimethylcyclohexyl isocyanate and a 2,4-4 luene diisocyanate dimer represented by the following structural formula.

The hydrogenated product of polyhydroxybutadiene polymer is 1
The average number of hydroxyl groups per molecule is 1.5 or more, preferably 1.
, 7 to 5.0.

The number of hydroxyl groups should be used in accordance with the number of isocyanate groups used as a curing agent. For example, for a number of hydroxyl groups of 2 or less per molecule, select an isocyanate compound that can take a crosslinked structure depending on the properties to be imparted. It can be used as

As the hydrogenated product of polyhydroxybutadiene polymer, for example, 1,3-butadiene homopolymer or 1
, 3-butadiene, the vinyl monomer content is usually 50 articles (weight range, the same applies hereinafter) or less, preferably 40%.
Preferably, the copolymers present below are hydrogenated.

If the vinyl monomer content is more than 50, the cured product will have poor elasticity, which is not preferable.

Examples of the vinyl monomer include styrene, acrylonitrile, methacrylic acid, acrylic acid, vinyl acetate, vinyltoluene, and α-methylstyrene.

Note that the homopolymer contains butadiene residues consisting of 1.4 bonds and butadiene residues consisting of 1.2 bonds in the polymer chain, and it is also known that the homopolymers have different proportions of these butadiene residues.

Although any homopolymer or copolymer can be used in the present invention, one in which 60% or more of butadiene residues consisting of 1.4 bonds are present in the polymer chain is particularly preferred.

When a polyhydroxybutadiene polymer having fewer than 60 butadiene residues consisting of 1,4 bonds is used, the resulting cured product tends to have poor elasticity and heat resistance, which is not preferred.

Specific examples of the hydrogenated polyhydroxybutadiene polymer used in the present invention include Poly BD R-45M and Poly BD R- manufactured by ARCX.
45I (I'1Poly BD C8-15, Poly
BD CN-15 (all product names) or NTSSOPBGloooo, Nl5SOPBG- manufactured by Nippon Soda■
Examples include hydrogenated polyhydroxybutadiene polymers such as 20001NISSOPBG-3000 (both trade names) using a Raney catalyst, a stabilized nickel catalyst, etc., and one or more of these may be used as appropriate.

The hydrogenation rate is 50% of the unsaturated bonds in the polymer.
It is desirable that the amount is greater than that, and if it is less than that, the resulting cured product will deteriorate due to oxidation and its heat resistance will decrease, which is not preferable.

In addition, during use, the number of hydroxyl groups in the hydrogenated polyhydroxybutadiene polymer can be easily adjusted by mixing products having different numbers of hydroxyl groups.

3-incyanate methyl-3,5,5-1-limethylcyclohexyl isocyanate, which is one component of the curing agent used in the present invention, is represented by the structural formula;
It is well known that the reactivity to active hydrogen is lower than that of 4-toluene diisocyanate and 4,4'-diphenylmethane diisocyanate.

However, when heated (at 60°C or higher), a mixture containing 3-isocyanate methyl-3,5,5-1-limethylhexyl isocyanate equivalent to the hydroxyl group of the hydrogenated polyhydroxybutadiene polymer The viscosity increases extremely quickly, making it difficult to use as a casting or impregnating resin.

Therefore, 3-incyanate methyl-3,5,5-trimethylhexyl isocyanate cannot be used alone as a curing agent for hydrogenated polyhydroxybutadiene polymers, but together with 2,4-4 luene diisocyanate dimer, The object of the present invention can be achieved by using appropriate amounts of these together.

2,4- which is another component of the curing agent used in the present invention
The 4-ruene diisocyanate dimer has the above structural formula and is a white powder with a melting point of 140-150°C and a molecular weight of 348.

2.4-Toluene diisocyanate dimer reacts with a compound having active hydrogen in a dimer state up to a temperature of 130°C, but at temperatures around the melting point of 140 to 150°C, the dimer decomposes and 2. It becomes 4-toluene diisocyanate monomer.

Further, this dimer undergoes a decomposition reaction at 80 to 100'C in the presence of a secondary amine or a tertiary amine, and reacts extremely rapidly with a compound having active hydrogen.

Therefore, when 2,4-toluene diisocyanate dimer is used alone as a curing agent for hydrogenated polyhydroxybutadiene polymers, the reaction at room temperature is extremely mild, but at the temperature during casting and impregnation, i.e. ~
At 110°C, the initial viscosity increases rapidly, and the decomposition of the dimer into monomers is also promoted, and gelation progresses in a short time.

However, the present inventors will later mention 3-isocyanate methyl-3,5,5-1-limethylhexyl isocyanate and 2,4-4 luene diisocyanate dimer as curing agents for hydrogenated polyhydroxybutadiene polymers. We have discovered a new fact that when used in combination within the above range, the rate of viscosity increase at the temperature (80 to 110'C) during casting and impregnation is slower than when the dimer is used alone, As a result of further investigation based on this new fact, we determined that the hydrogenated product of polyhydroxybutadiene polymer was A, 3-isocyanate methyl-3,
5,5-trimethylcyclohexyl isocyanate B
and 2,4-toluene diisocyanate dimer at C
In this case, 3-isocyanate methyl 3,5.5
-trimethylcyclohexyl isocyanate and 2.4-
It has been discovered that the object of the present invention can be achieved only by using the 4-ruene diisocyanate dimer in combination.

Within the above range, C for 0.5 to 09 moles of B
If the number of moles of is outside the range of 0.1 to 0.3, the viscosity of the mixture increases rapidly, which is unfavorable in terms of work.

Furthermore, when the number of moles of B and C is smaller than 0.5 and 0.1 per mole of A, the viscosity of the mixture increases moderately, but the cured product becomes sticky at room temperature. It is not suitable for practical use because it cannot be changed, and when used in proportions larger than 0.9 and 0.3, respectively, the viscosity of the mixture increases relatively quickly and only a cured product with poor elasticity can be obtained. The object of the invention cannot be achieved.

It should be noted that if the isocyanate groups are in excess of the hydroxyl groups, there is a risk that the hygroscopic water of the mixture and the isocyanate groups will react during curing to generate voids, which is not preferable.

Therefore, in carrying out the present invention, the ratio of each component used is (0.6+0.1/1 to 0.9+0.271,1
It is effective to keep it within this range, and the workability during casting and impregnation can be significantly improved.

The curable polymer composition of the present invention can be easily cured by heating to 90 to 150°C, and the heating time can also be adjusted by selecting the curing temperature.

In addition, the curable polymer composition of the present invention may optionally contain commonly used reinforcing dimers such as carbon black, talc, calcined clay, silicate, calcium carbonate, water-containing alumina, and other anti-aging agents as necessary. , an antioxidant, a radiation absorber, a fungicide, a coupling agent, etc. may be used in combination.

The cured product obtained by curing the composition of the present invention is a rubber-like elastic body with excellent mechanical properties, hydrolysis resistance, heat resistance, electrical insulation properties, and the like.

The curable polymer composition of the present invention can be used as a casting or impregnating composition or coating agent, and as a potting agent for adhesives, caulking agents, electronic components, encabbing agent, binder for rocket fuel, industrial It is used as a rubber material for belts, hoses, anti-vibration rubber, packing, etc., and is extremely useful in industry.

Next, the curable polymer composition of the present invention will be explained in detail with reference to Reference Examples, Examples, and Comparative Examples, but the present invention is not limited to these Examples.

Reference example 1 PolyBDR which is a polyhydroxybutadiene polymer
-45M (manufactured by ARCO, product name, 1.4-
60 moles of trans, 20 moles of 1,4-cis, 1.2
- 20 mol of vinyl, 120 g of hydroxyl value 44), Raney nickel catalyst ICB1' and 100 g of dioxane
1 and hydrogenated at a hydrogen pressure of 10 kg/d and a reaction temperature of 80° C. to obtain a hydrogenated polyhydroxybutadiene polymer (hydrogenation rate of 95%).

Reference example 2 Po1yBD which is a polyhydroxybutadiene polymer
C8-15 (manufactured by ARCO, product name, 1,4
-trans 60 mol φ, 1,4-cis 20 mol φ, 1.
Hydrogenation of 100 g of a copolymer (2-vinyl 20 mole ratio, hydroxyl value 42, butadiene:styrene (weight ratio) of 75:25 (weight ratio)) was carried out in the same manner as in Reference Example 1 to hydrogenate the polyhydroxybutadiene polymer. (hydrogenation rate 98%).

Reference example 3 Nl5SOPB which is a polyhydroxybutadiene polymer
G-2000 (manufactured by Nippon Soda ■, trade name, 1,2-vinyl 90 mol%, 1.4-bond 10 mol%, hydroxyl value 58)
100 g was hydrogenated in the same manner as in Reference Example 1 to obtain a hydrogenated polyhydroxybutadiene polymer (hydrogenation rate: 98 tons).

Example 1 100g of the hydrogenated polyhydroxybutadiene polymer obtained in Reference Example 1 was placed in a 200CC tall beaker.
Heating was carried out to 80°C, and to this were added 3-indianate methyl-3,5,5-trimethylcyclohexyl isocyanate 6.97.9 and 2.4-, toluene diisocyanate dimer 1.3. l! and mixed.

The mixture was a slightly opaque suspension.

This liquid mixture was heated in an oil bath at 100° C., and the time from when the temperature reached 100° C. (initial viscosity, 35 poise) until the viscosity reached 1000 poise was measured.

The time was 40 minutes. Then, a mixed solution separately prepared in the same amount as above was defoamed at 80° C. and poured into a mold made of polypropylene.

After injection, the mold was heated at 130°C for 2 hours to form 40CrfLX.
A cured sheet of 40 crfLX 0.2 cm was obtained.

The mechanical properties (tensile strength, elongation), electrical properties (volume resistivity), water resistance, and properties after thermal deterioration of this cured sheet were determined according to JIS K 6301 and JIS K.
Measured according to 6911.

The results of these measurements are shown in Table 1.

As is clear from Table 1, the cured products obtained from the curable polymer compositions of the present invention were extremely excellent in both normal state and post-deterioration properties.

Examples 2 to 11 3-isocyanate methyl-3,5,5-)limethylcyclohexyl isocyanate and 2,4-toluene diisocyanate were added to 100 g of the hydrogenated polyhydroxybutadiene polymer obtained in Reference Examples 1 to 3. The viscosity of the mixed liquid was measured in the same manner as in Example 1 using the dimer in the amount shown in Table 2.

The measurement results are shown in Table 2. Among these, typical blended compositions (Examples 2.4.7 and 11) were selected and cured sheets of two thicknesses were obtained in the same manner as in Example 1.

In addition, the mechanical properties, electrical properties, water resistance, and the above-mentioned properties after thermal deterioration of the obtained cured sheet were measured in the same manner as in Example 1.

The measurement results are shown in Table 3. As is clear from Tables 2 and 3, since the curable polymer composition of the present invention causes a gradual increase in the viscosity of the mixed liquid, it not only significantly improves the workability of casting and impregnating, but also improves the cured product. It provides a cured product with excellent mechanical and electrical properties, as well as heat resistance and hydrolysis resistance, especially compared to conventional urethane elastomers.
It had outstanding electrical insulation properties.

Examples 12 to 13 Hydrogenated product of the polyhydroxybutadiene polymer obtained in Reference Example 1, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 2,4-4 luene diisocyanate dimer, and water-containing alumina as a filler. Alternatively, a cured sheet obtained by using calcium carbonate in the amount shown in Table 4 As is clear from Table 4, the cured product obtained from the curable 1 combined composition of the present invention has mechanical properties, electrical properties, etc. It was extremely good.

Comparative Example 1 Liquid 4,4-diphenylmethane diisocyanate (manufactured by Kasei Upjohn Co., Ltd., Isonate 143 L, trade name Incyanate equivalent weight 144.6) was added to 100 g of the hydrogenated product obtained in Reference Example 1, and mixed and dissolved at 80°C. .

This mixed solution gelled approximately 5 minutes after dissolution and could not be used for casting.

Comparative Example 2 9.1 of 2.4-toluene diisocyanate (commercially available reagent grade 1) was added to the hydrogenated products ioo and p obtained in Reference Example 3.
'c to mix and dissolve.

This liquid mixture gelled approximately 15 minutes after being dissolved, and many voids were generated in the cured sheet after casting.

Comparative Example 3 In order to investigate the hydrolysis resistance of a urethane elastomer manufactured from polyester or polyether, PTMG-2000 (manufactured by Kasei Upjohn Co., Ltd., trade name, hydroxyl value 56.9) was used as a polyether type polyol.
Niraporan 40 as a polyester type polyol
42 (manufactured by Nippon Polyurethane Industries ■, product name, hydroxyl value 5
6.1) and 2,4 toluene diisocyanate (commercially available first class reagent) as a curing agent, a mixed solution with a molar ratio of OH groups of the polyol to NCO groups of the curing agent of 1.0 was prepared at room temperature. A cured sheet with a thickness of between 2 and 2 was obtained in the same manner as in Example 1.

When the hydrolyzability of the resulting cured sheet was examined at 80°C and 95% RH, it was found that a white sticky substance precipitated on the surface of the cured sheet after about 80 hours in the case of the one using polyester type polyol. However, when a polyether type polyol was used, a similar phenomenon occurred after about 150 hours.

When this test was continued for up to 500 hours, the entire surface of both cured sheets turned into a white adhesive substance, and the original shape before the test could not be maintained.

It goes without saying that the use of the curable polymer composition of the present invention is not limited to the above-mentioned cured sheet.

As described above, the curable polymer composition of the present invention not only significantly improves workability compared to conventional urethane elastomers, but also improves the mechanical properties, electrical properties, and hydrolysis resistance of the resulting cured product. It has excellent properties such as durability and heat resistance.
Its industrial value is extremely poor.

Claims (1)

[Claims] 1. A hydrogenated product of polyhydroxybutadiene polymer,
3-Isocyanatomethyl-3,5,5- as a curing agent
A curable polymer composition comprising a combination of trimethylcyclohexyl isocyanate and a 2,4-toluene diisocyanate dimer represented by the following structural formula. 2 As a hydrogenated product of polyhydroxybutadiene polymer, there are 6 butadiene residues consisting of 1,4 bonds in the polymer chain.
The curable polymer composition according to claim 1, which is a hydrogenated product of a polyhydroxybutadiene polymer present on a zero weight plate. 3 As a hydrogenated product of a polyhydroxybutadiene polymer, a hydrogenated product of a polyhydroxybutadiene polymer in which butadiene residues are present in the polymer chain at 60 weight φ or more and styrene residues are present at 40 weight φ or less A curable polymer composition according to claim 1, characterized in that: 4 A hydrogenated product of polyhydroxybutadiene polymer
, 3-isocyanate methyl-3,5,5-1-limethylcyclohexyl isocyanate as B and 2.4-1
-If the luene diisocyanate dimer is C,
The curable polymer composition according to claim 1, 2, or 3, characterized in that the mixing ratio of each component is within the following range.