JPS5910688B2 - Curable polymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to curable polymer compositions that are particularly useful as casting or impregnating compositions or coating agents, and more particularly as curing agents for hydrogenated polyhydroxyptadiene polymers. The present invention relates to a curable polymer composition characterized in that it uses an isocyanate prebolymer consisting of castor oil and 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate.

Conventionally, polyurethanes obtained by a method of reacting polyglycol and polyisocyanate are well known as casting or impregnating compositions or coating agents.

The properties of these polyurethanes are influenced by the type of polyglycol and are appropriately selected depending on the intended use. For example, many elastomers use polyesters and polyethers containing hydroxyl groups, which are inferior in hydrolysis resistance, heat resistance, electrical insulation, etc.
On the other hand, polyisocyanate used as a curing agent easily reacts with a compound having active hydrogen to form a chemical bond.

For this reason, when used as a polyurethane elastomer, coating agent, adhesive, etc., it becomes a so-called two-component mixture that is mixed immediately before use, and the storage stability of the mixed solution is extremely short.

Therefore, it is suitable for applications where mixing and curing takes place in a short period of time, and applications where a cured product containing a small amount of board does not cause any problems in use.
Many problems must be solved for application to large cast or impregnated objects that require a high degree of electrical insulation. For example, if the curing speed is very fast, the curing reaction will proceed without the boards mixed in during casting or impregnation operations being completely removed, which is a major factor in causing insulation failure in electrical equipment.

Furthermore, as mentioned above, cured products using polyester or polyether as the glycol component have poor hydrolysis resistance, heat resistance, and electrical insulation properties, so it is preferable to use them as insulating materials for electrical equipment that will be used for a long time. do not have.

Therefore, as an elastic body that requires a high degree of electrical insulation,
There are almost no examples using urethane elastomer.

Butyl rubber and ethylene/propylene rubber are most often used as insulating materials that have rubber elasticity and require a high degree of electrical insulation, and have excellent heat resistance, hydrolysis resistance, electrical insulation, and mechanical properties. It also has excellent characteristics such as:

However, butyl rubber and ethylene/propylene rubber have a large molecular weight and therefore have very poor fluidity, making it impossible to manufacture various products by casting or impregnating processes like the urethane elastomers mentioned above. Generally, press molding and transfer molding are performed under high temperature and voltage, and the same is true when applying insulation treatment to electrical equipment.

When electrical equipment is insulated using the above-described molding method, the embedded material may be deformed or displaced due to the high temperature and pressure.

Furthermore, when insulating between the layers of a coil around which electric wire is wound, the fluidity of the rubber raw material is very poor, so the rubber is not completely injected into the insulating spaces between the layers of the coil, resulting in poor insulation. Therefore, it is necessary to sufficiently insulate the implant before molding, which is not a preferable method in terms of the manufacturing process. Furthermore, since molding is performed at high temperatures and pressures, expensive equipment and molds are required, and energy consumption increases. In view of the above circumstances, the present inventors have developed a thermosetting material that has significantly improved workability compared to conventional urethane elastomers and has excellent mechanical properties, electrical properties, heat resistance, and hydrolysis resistance of the cured product. In order to obtain an elastic body, the present invention was completed as a result of extensive research.

That is, the gist of the present invention is characterized in that an isocyanate prepolymer consisting of castor oil and 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate is used as a curing agent for a hydrogenated polyhydroxybutadiene polymer. The object of the present invention is to obtain a curable polymer which is excellent in workability and also has excellent hydrolysis resistance, heat resistance, and electrical insulation properties of the cured product.

The aforementioned hydrogenated polyhydroxybutadiene polymer has an average number of hydroxyl groups of 1.5 or more per molecule, preferably 1.7 to 5.0.

If the average number of hydroxyl groups per molecule is less than 1.5, only a sticky cured product will be obtained, and if it is more than 5.0, the cured product will become hard, which is not preferable.

The number of these hydroxyl groups should correspond to the number of isocyanate groups used as a curing agent. For example, for a number of hydroxyl groups of 2 or less, an isocyanate compound that can form a crosslinked structure should be selected and used according to the required characteristics. I can do it. The hydrogenated product of the polyhydroxybutadiene polymer is, for example, a homopolymer of 1,3-butadiene or a copolymer in which the content of vinyl monomer is usually 50% by weight or less, particularly preferably 40% by weight or less, based on butadiene. There are also hydrogenated products. If the content of the vinyl monomer exceeds 50% by weight, the cured product will have poor elasticity, which is not preferred. Examples of the vinyl monomer include styrene acrylonitrile, methacrylic acid, acrylic acid, vinyltoluene, vinyl acetate, etc.
and mixtures thereof.

Note that the above-mentioned homopolymer contains butadiene residues consisting of 1.4 bonds in the polymer chain, and it is known that the proportions of these butadiene residues are different. In the present invention, any homopolymer can be used, but in order to obtain a cured product with particularly excellent elasticity or heat resistance, 60% by weight of butadiene residues consisting of 1.4 bonds should be added to the polymer chain. Those that exist above are preferably used. Furthermore, among the above monomers, styrene is particularly preferably used from the viewpoint of an electrically insulating material. Specific examples of the hydrogenated polyhydroxybutadiene polymer include POlyBD, R-45M, R-45HT, and CS-15 manufactured by ARCO.
, CN-15, and NISSOPBG-10 manufactured by Nippon Soda
There are products obtained by hydrogenating polyhydroxybutadiene such as 00, PBG-2000, and PBG-3000 using a Raney catalyst, a stabilized nickel catalyst, etc., and the hydrogenation rate is preferably 50% or more. Alternatively, two or more types can be mixed and used by adjusting the number of hydroxyl groups.

If the hydrogenation rate is less than 50%, the cured product will deteriorate due to oxidation and its heat resistance will decrease, which is not preferable. The isocyanate prepolymer consisting of castor oil and 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate used as a curing agent in the present invention is usually commercially available castor oil, such as industrial castor oil or refined castor oil. , hydrogenated castor oil, etc., and refined castor oil and hydrogenated castor oil are particularly preferably used. It can be obtained by reacting cyclohexyl isocyanate in a range of 3 to 6 moles.

The first synthesis condition for the isocyanate prepolymer is preferably a method in which a predetermined amount of isocyanate is charged into a reaction vessel that is completely purged with nitrogen, and then castor oil is gradually added.

If the reverse addition method is used, the dispersion in the isocyanate equivalent of the product will increase, which is not preferable. The reaction temperature may be any temperature within the range of room temperature to 150°C, but in order to avoid side reactions, it is preferable to complete the reaction in a short time at a temperature of 80 to 100°C. If the blending ratio of 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate to castor oil is below the above range, the prepolymer will have a high viscosity and workability will be significantly reduced; if it is above the above range, free This is not preferable because the amount of isocyanate increases, resulting in decreased elasticity and increased permanent elongation of the cured product. The isocyanate prepolymer has an isocyanate group of 0.8 to 1.0% relative to the hydroxyl group of the hydrogenated polyhydroxybutadiene polymer.
An amount corresponding to 5 equivalents is preferred.

If it is outside the above range, the mechanical properties and rubber elasticity of the cured product will be extremely poor.

The hard polymer composition according to the present invention has a temperature of 60 to 150°C.
It can be easily cured by heating to , and the heating time can also be adjusted by selecting the curing temperature.

The curable polymer composition of the present invention may also be coated with commonly used reinforcing fillers such as carbon black, calcined talc, silicate, calcium carbonate, hydrated alumina, and other anti-aging fillers as necessary. It is also possible to use a mixture of agents, antioxidants, ultraviolet absorbers, antifungal agents, coupling agents, and the like. The cured product obtained by curing the composition of the present invention is a rubber-like elastic body having excellent mechanical properties such as hydrolysis resistance, heat resistance, and electrical insulation properties.

The curable polymer composition of the present invention has a long pot life during operations such as casting, and can be cured in a short time at high temperatures of 120°C or higher, so it can be used as a casting or impregnating composition or As a coating agent, adhesive, caulking agent, bottling agent for electronic parts, encapsulation agent, industrial rubber material for belts, hoses, etc.
It is used for various purposes such as anti-vibration rubber and packing, and as a special purpose, it can also be used as a binder for mouthpiece fuel, making it extremely useful industrially.

Next, the curable polymer composition of the present invention will be explained with reference to Reference Examples, Examples, and Comparative Examples, but the present invention is not limited to these Examples. Reference Example 1 Polyhydroxybutadiene polymer POlyBD8R-45M (manufactured by Arco, 1.4-cis 20 mol%, 1.2-vinyl 20 mol%, hydroxyl value 44
) 1209, Raney's solvent 109 and dioxane 1009 were placed in an autoclave of 11, and the hydrogen pressure was 10.
Hydrogenation was carried out at k9/0f11 and a reaction temperature of 80° C. to obtain a hydrogenated polyhydroxybutadiene polymer (hydrogenation rate 95%).

Reference Example 2 POlyBD8CS-15 which is a polyhydroxybutadiene polymer (manufactured by Arco Co., Ltd. 1.4-trans 60 mol%, 1.4-cis 20 mol%, 1.2-vinyl 20 mol%, hydroxyl value 42, butadiene pair Reference Example 1: Copolymer (copolymer with styrene of 75:25 (polymerization ratio)) 100'
Hydrogenation was carried out in the same manner as above to obtain a hydrogenated polyhydroxybutadiene polymer (hydrogenation rate 98%).

Reference Example 3 Polyhydroxybutadiene polymer NISSOPBG-20006 (manufactured by Nippon Soda Co., Ltd., 1
．． 2-vinyl 90 mol%, 1.4 bond 10 mol%, hydroxyl value 58) 100y was hydrogenated in the same manner as in Reference Example 1 to obtain a hydrogenated polyhydroxybutadiene polymer (hydrogenation rate 98%). Obtained.

Reference Example A nitrogen gas inlet tube, a dropping load, and a stirrer thermometer were attached to a four-tube flask of 411 to produce 333.6f of 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate! was introduced.

After flowing nitrogen gas, stirring, and raising the temperature to 80℃, castor oil 517.5f! was placed on a dropping load, and 1 dropwise addition was carried out gradually at the same temperature. After the dropwise addition was completed in about 1 hour, stirring was continued for another 1 hour at 80°C to obtain an isocyanate prepolymer. The isocyanate equivalent weight of the prepolymer was 530. Reference Example 5 A device similar to Reference Example 4 was attached to an 11-piece Yotsuro flask, and 333.69 ml of 3-isocyanate methyl 3,5,5-trimethylcyclohexyl isocyanate was taken at 80°C.
After raising the temperature to 120.degree. C., 310.59 g of castor oil was added dropwise, and the dropwise addition was carried out while being careful not to raise the reaction temperature to 120.degree. C. or higher.

After the dropwise addition was completed, the reaction temperature was maintained at 110° C. and stirring was continued for 1 hour to obtain an isocyanate prepolymer. The isocyanate equivalent weight of the prepolymer was 145. Example 1 1009 of the hydrogenated polyhydroxybutadiene polymer obtained in Reference Example 1 and 45.71 of the isocyanate prepolymer obtained in Reference Example 4 were placed in a 200CC tall beaker.
After stirring in a 0°C oil bath until a homogeneous solution was obtained, the mixture was transferred to a 100°C oil bath and stirred for 10 minutes.
From the moment it reaches 0°C (initial viscosity 35 poise), the viscosity decreases to 1
The time required to reach 000 voices was measured.

The time was 28 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 to 150°C for 1 hr, and the mold was heated to 40°C! ! l×4
0CTn×0.2C! ! 1 of cured sheets were obtained. The mechanical properties (tensile strength, elongation) and electrical properties (
Volume resistivity), the above properties after water resistance test, and mechanical properties after thermal deterioration were measured using JISK63Ol and J[SK69ll
Measured according to. The results of these measurements are shown in Table 2.
Examples 2 to 8 The isocyanate prepolymers obtained in Reference Examples 4 and 5 were used in the amounts shown in Table 1 to 100 y 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.

The measurement results are shown in Table 1. Among these, representative compositions (Examples 3, 5, 6, and 8) were selected and cured sheets having a thickness of 21E]l were obtained in the same manner as in Example 1.

In addition, the mechanical properties, electrical properties, and
Water resistance and thermal deterioration characteristics were measured in the same manner as in Example 1.

The results of these measurements are shown in Table 2. As is clear from Tables 1 and 2, since the curable polymer composition of the present invention causes a gradual increase in the viscosity of the mixed solution, it not only significantly improves casting and impregnating workability, 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, and is particularly superior in heat resistance, hydrolysis resistance, electrical insulation, etc. compared to conventional urethane elastomers. It was warm. Examples 10 to 11 The hydrogenated polyhydroxybutadiene polymer obtained in Reference Example 1, the isocyanate prepolymer 459 obtained in Reference Example 4, and hydrated alumina or calcium carbonate as a filler were combined as shown in Table 3. A cured sheet was prepared using the same amount, and its various custom orders were measured.

The filler was mixed by kneading a predetermined amount of the filler using two rolls. Further, the preparation of the cured sheet and the measurement of various properties were carried out in the same manner as in Example 1.

The measurement results are also shown in Table 3. As is clear from Table 3, the cured products obtained from the curable polymer compositions of the present invention were significantly superior in mechanical properties, electrical properties, and the like.

Comparative Example 1 Liquid 4.4'- was added to 100y of hydrogenated product obtained in Reference Example 1.
11.3 y of diphenylmethane diisocyanate (manufactured by Kasei Updition Co., Ltd., isocyanate equivalent weight 144.6) was added and mixed and dissolved at 80°C.

The mixture gelled approximately 5 minutes after dissolution and could not be used for casting. Comparative Example 2 9.0f of 2.4-toluene diisocyanate (commercial reagent first grade) was added to the hydrogenated product 1009 obtained in Reference Example 3! Add 8
The mixture was mixed and dissolved at 0°C.

This mixed solution gelled approximately 15 minutes after being dissolved, and many boards appeared on the cured sheet after casting.

Claims (1)

[Claims] 1. A hydrogenated polyhydroxybutadiene polymer, castor oil as a curing agent, and an isocyanate prepolymer consisting of 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate. A curable polymer composition characterized by: 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, characterized in that a hydrogenated polyhydroxybutadiene polymer is used in an amount of 0% by weight or more. 3 As the hydrogenated product of polyhydroxybutadiene polymer, a hydrogenated product of polyhydroxybutadiene polymer in which 60% by weight or more of butadiene residues and 50% by weight or less of styrene residues are present in the polymer chain was used. A curable polymer composition according to claim 1, characterized in that: 4 Castor oil and 3-isocyanatomethyl-3,5,5
- A patent characterized in that an isocyanate prepolymer made of trimethylcyclohexyl isocyanate is prepared by reacting 3 to 6 moles of 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate with 1 mole of castor oil. A curable polymer composition according to claim 1 or 2.