JPH075700B2 - Method for producing elastic urethane polymer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a urethane elastic polymer, more specifically, it has excellent heat resistance, dynamic properties and low temperature properties, and is processed in the same manner as unvulcanized natural rubber. And a method for producing a urethane elastic polymer having a high degree of elasticity that can be stored as it is without being naturally cured for a long time.

2. Description of the Related Art Conventionally, it is already known that a polyurethane elastic polymer can be obtained by reacting an organic diisocyanate with a chain compound polyol, polyester, polyether or the like having an active hydrogen atom at a terminal, and in particular, all reactions are performed. It is known that a urethane elastomer having excellent physical properties can be obtained by reacting under the condition that an isocyanate group exists in the reaction system.

Further, in recent years, urethane elasticity has become a major problem because of poor heat resistance and low temperature characteristics, particularly heat resistance and low temperature characteristics when used under dynamic conditions, especially in a compact closed room condition, and improvement thereof is earnestly desired. ing.

However, due to the large reactivity of isocyanate, the reaction product in the intermediate stage is unstable, and storage and molding operations are extremely difficult.

That is, the conventional method for producing a urethane elastic body is what is called a so-called casting method at the time of final molding of cross-linking point, in which the cross-linking reaction is not sufficiently performed, the curing is extremely fast, and the castability is poor.

These drawbacks are slightly improved by using a mixture of amino alcohol or glycol and diamine, but the reactivity of the active hydrogen atom introduced at the end of the chain compound, which is an intermediate product, and the presence of it in the middle part. Since it is difficult to balance the reactivity of the active hydrogen atoms that should form the cross-linking points, it is not easy to satisfy both processability and physical properties.

If the isocyanate residue is cross-linked with a monovalent nitrogen or a base and polymerized to saturate it, the reactivity of the terminal group will be significantly reduced, but it will be difficult to produce a stable one due to the large balance of reactivity. Due to various difficult problems, urethane elastic bodies having such a reaction system have not yet been put to practical use.

The object of the present invention is obtained by the reaction of the organic diisocyanate with a chain compound having an active hydrogen atom, which solves the above-mentioned problems of the prior art, has excellent heat resistance and dynamic properties, and has excellent low-temperature properties. It is an object to provide a method for producing a urethane elastic polymer that can be processed like natural rubber.

Another object of the present invention is that the product thus obtained has the property that it can be processed like a natural rubber that is not vulcanized through a stable intermediate that is easy to store and handle, and is natural for a long period of time. It is an object of the present invention to provide a urethane elastic polymer having a high elasticity which can be stored in the original state without being cured.

As a result of earnest research for solving the above-mentioned problems, the present inventor succeeded in achieving the object by bonding a polymer polymerization structure mechanism under specific conditions for re-crosslinking bond.

That is, the inventors have determined that an isocyanate residue is glycol, diamine, amino alcohol or monovalent nitrogen,
A urethane elastic polymer that is stable to storage is made by cross-linking addition polymerization with a base, etc. to make it stable, and an urethane elastic polymer is obtained by mixing organic polyisocyanate before final molding on a rubber mill like natural rubber to complete the reaction. Got the knowledge of the method.

Means for Solving the Problems The first invention of the present invention comprises, as a first step, at least 80
With respect to 1 equivalent of the polyol (A), which is a chain compound having a molecular weight of 0 and having an active hydrogen atom capable of reacting with an isocyanate at the terminal, an equivalent amount or more of the organic diisocyanate (B) is subjected to a chain reaction, and as a second step, at least A cross-linking agent (C) having a molecular weight of 500 and having an active hydrogen atom capable of reacting with an isocyanate at the terminal is cross-linked with the equivalent of the isocyanate residue of the chain reaction product of the first step or less to saturate it. As a three-step process, the intermediate compound obtained by the second-step reaction is a polyol (A) of a chain compound having a molecular weight of at least 800 used in the first step and having an active hydrogen atom capable of reacting with an isocyanate at the end.
The urethane elastic polymer is characterized in that the total amount of the organic diisocyanate (B) reacted with the polyol (A) is adjusted to a range of 1.0 to 1.4 equivalents per equivalent of the polyol (A). The manufacturing method is the main point.

The urethane elastic polymer thus obtained has the property that it can be processed like natural rubber that is not vulcanized, and has a high elasticity that allows it to be stored as it is without being naturally cured for a long time. I have.

Thus, the diisocyanate (B) in the above first invention
Is in the above specified range, that is, 1.0 to 10 parts by weight in the product after completion of curing with respect to 1 equivalent of the polyol (A) of the first stage component.
When it is used in an amount larger than the range of 1.4 equivalents, a tough polymer is produced, and this polymer cannot be sufficiently processed in the kneading operation, and has a property of curing during storage.

However, in this case, if the diisocyanate (B) used is made to contain 1.4 to 2.0 equivalents of NCO groups in the product after completion of curing, relative to 1 equivalent of the above-mentioned reaction component polyol (A), natural rubber is obtained. It has also been found that when processed on a rubber mill a very good cured product with excellent dynamic, heat and low temperature properties and balanced physical properties can be obtained.

A second invention of the present invention further comprises, as a fourth step, kneading the intermediate elastic polymer obtained by the reaction of the third step of the first invention with an organic diisocyanate (B) on a mill,
The total amount of the organic diisocyanate (B) reacted with the polyol (A) is 1. per equivalent of the polyol (A).
The gist is a method for producing a urethane elastic polymer, which is characterized in that the range is 4 to 2.0 equivalents.

The urethane elastic polymer thus obtained has a property that it can be processed like natural rubber that is not vulcanized, and has a high elasticity that allows it to be stored as it is without being naturally cured for a long period of time. I have.

The amount of the organic diisocyanate in the present invention is in the above specific range, that is, with respect to 1 equivalent of the polyol of the first stage component,
When used in the urethane product after curing is greater than 1.4 equivalents, a tough polymer is produced, and the urethane polymer cannot be processed satisfactorily during kneading, and also cures during storage. Has the property of However, in this case,
The organic diisocyanate to be used is 1 equivalent to 1 equivalent of the above-mentioned reaction component polyol in the urethane product after completion of curing.
An elastic polymer containing NCO groups in the range of 4 equivalents to 2.0 equivalents on a rubber mill similar to natural rubber on a rubber mill, with variables such as peroxide, dicumyl peroxide and carbon black as a polymerization initiator before final molding. By kneading and heating at 140 to 160 ° C. to complete reticulation, it was found that a urethane elastic body having excellent dynamic properties, heat resistance and low temperature properties and extremely excellent physical properties was obtained.

A third invention of the present invention further comprises, as a fourth step, kneading the intermediate elastic polymer obtained by the reaction of the third step of the first invention with a peroxide as a polymerization initiator and a filler on a mill. A method for producing a urethane elastic polymer is characterized in that a urethane elastic polymer composed of heat-insoluble macromolecules is produced by heating.

As described above, the urethane elastic body of the first invention is kneaded on the rubber mill with a variable amount of a polymerization initiator such as peroxide, dicumyl peroxide and carbon black on the rubber mill before the final molding to obtain 140 to 160. A rubber-cured urethane elastic body made by completing heating reticulation at ℃ has excellent dynamic characteristics such as heat resistance and low-temperature characteristics, and an extremely excellent elastic body with well-balanced physical properties, that is, high elasticity. However, the melting point (Tm), which is a measure of heat resistance, is high,
Loss tangent (tan
δ) is small, and the glass transition point (Tg), which is a measure of low temperature properties, is low, while elastic general properties, that is, breaking strength (T _B ), elongation (E _B ), tear energy (I), It is possible to manufacture a urethane elastic body that has excellent strain concentration factor (mr).

By the way, the diisocyanate used in the present invention is known, and it is also known to obtain a urethane elastic body produced by a combination of a polyol and a chain extender.

However, the combination of the isocyanate, the polyol, and the chain extender in the polymer polymerization structure mechanism, cross-linking point structure, and position-changing cross-linking bond has not been known.

The present invention relates to, so to speak, a polymer polymerization structure mechanism, a cross-linking point structure, a position-changing cross-linking bond combination, and it will be described below with reference to the drawings.

A: Polyol ... 3 B: Isocyanate ... 6 C: Crosslinking chain extender ... 2 When the conventional urethane elastic body has the structural formula: prepolymer-B-A-B-A-B-A-B -Free NCO group -B-, -B- The termination structural formula is as follows. (Addition 2C) B-C-B-A-B-A-B-A-B-C-B On the other hand, the structural formula of the present invention is as follows: First Invention First Stage Prepolymer-B-A-B -Free NCO group -B-, -B- Second stage (additional 2C) -B-C-B-A-B-C-B- Third stage (additional 2A) A-B-C-B-A- B-C-B-A Second Invention Fourth Stage The urethane elastic polymer obtained in the third stage of the first invention is kneaded with an organic diisocyanate (B) on a mill to prepare a polyol (A The total amount of the organic diisocyanate (B) reacted with) is set in the range of 1.4 to 2.0 equivalents per equivalent of the polyol (A).

Third Invention Fourth Step The urethane elastic polymer obtained in the third step of the first invention is kneaded with a polymerization initiator and the like on a mill to complete the reaction.

By the way, the urethane elastic body has not only a urethane bond but also various bonding groups such as ester, ether, urea, alohanate, buret, and aromatic ring in its structure, and therefore natural rubber, BR, SBR, EPT, etc. The appearance is quite different from that of hydrocarbon synthetic rubber.

There are many types of urethane elastic bodies, and it seems that various chemical structures are mixed together, but if you look closely, you can see that in all urethane elastic bodies, the soft segment and the hard segment are block polymers. The soft segment is a portion of polyester, polyesteramide or polyether, and the hard segment is a portion of a combination of an aromatic ring such as a benzene nucleus and a naphthalene nucleus and a urethane bond or a urea bond.

The soft segment can be easily changed by the type and molecular weight of the polyol, and the hard segment can be easily changed by the type of organic diisocyanate and the type of chain extender.The soft segment facilitates the free rotation of the chain, and the softening point of the polymer, It lowers the next transition point and increases the hardness, the entropy elasticity that influences the mechanical strength.

On the other hand, the hard segment has the characteristics that it constrains the freedom of the chain, raises the softening point and the second-order transition point of the polymer, improves the hardness of the polymer and the mechanical strength, and lowers the entropy elasticity. It is considered that two types of segments can be obtained by combining block structures.

Further, as the cross-linking of the urethane elastic body, in addition to the primary cross-linking, it is necessary to consider the secondary cross-linking by intermolecular hydrogen bond. First of all, the primary cross-linking of urethane elastic body is controlled properly between the rigid segments by the chemical bond of urethane, burette, alohanate, etc., which is different from the so-called vulcanized structure of natural rubber and hydrocarbon-based synthetic rubber. The urethane elastic body thus obtained has a regular mesh structure. The surprising wear resistance and other excellent properties of urethane elastomers are believed to be in this structural formula.

Next, since the urethane elastic body contains many bonds having large cohesive energy such as urea or urethane bonds, the secondary cross-linking due to intermolecular hydrogen bond becomes a big problem.

Next, referring to the cohesive energy of several kinds of bonds, As is clear from the above table, there is a marked difference in cohesive energy between natural rubber and hydrocarbon-based synthetic rubber. The fact that the urea bond has a larger cohesive energy than that of the urethane bond is sufficient because the softening point of polyurea is much higher than that of the elastic polyurethane.

For example, a urethane elastic body using a diamine as a curing agent shows a large strength due to intermolecular hydrogen bonds between urea bonds in the main chain, but if a small amount of a plasticizer or a filler such as carbon is added during curing, the strength will be It is known to drop sharply.

It is considered that this is because the additive increases the distance between molecules and weakens the hydrogen bond of the urea bond. This is because the fillers such as carbon play a reinforcing role in conventional natural rubber and hydrocarbon synthetic rubber, while the urethane elastic body acts to weaken the mechanical properties.

Furthermore, when the primary cross-linking bond is increased, the secondary cross-linking bond is weakened, the softening point of the polymerization point is increased, and the permanent set and the solvent resistance are improved, but the tensile properties are deteriorated, the tensile stress and the secondary stress are increased. The transition point becomes high. On the other hand, when the primary cross-linking bond is reduced, the secondary cross-linking bond is strengthened, and the physical properties of the polymer show a tendency opposite to the above. Therefore, when considering the crosslinking structure of the urethane elastic body, it is necessary to optimize the balance between the primary crosslinking bond and the secondary crosslinking bond.

Regarding the stability of each bonding group in the urethane elastic body, it has been found that the rheology in the stress relaxation measurement decreases in the order of ester, ether> urea, urethane> alohanate, and buret.

Moreover, since it is known that the thermal stability is also in the above-mentioned order, when deteriorating the urethane elastic body, first,
It is presumed that the bridge bonds of burette and alohanate are cleaved, and then the main chain is cleaved by the cleavage of urethane and urea bonds.

The following Table 1 shows the results obtained by synthesizing model compounds containing various bonding groups and examining the thermal stability by differential thermal analysis.

In the above, the chain compound polyol (A) having an active hydrogen atom at the terminal used in the first step of the present invention has a number average molecular weight in the range of 800 to 5000, and is preferably 1500 to 2500. Is preferable, and those having an OH value of 35 to 120 are used.
The one of ~ 80 is the best.

Here, if the number average molecular weight is less than 800, it is used for resin and loses elasticity to become leather-like, and it is difficult to obtain the elastic body of the present invention. On the other hand, when it is more than 5000, the static energy absorption is preferable, but the workability is deteriorated, and further the dynamic characteristics, heat resistance and low temperature characteristics are decreased, and it is difficult to attain the object of the present invention.

Examples of the chain compound polyol (A) include a ring-opening polymer of tetrahydrofuran, a ring-opening polymer of caprolactone, an aliphatic glycol such as ethylene glycol, propylene glycol, butylene glycol, and succinic acid.
Adipic acid, pimelic acid, polyester obtained by condensation of dimer acid, polyether obtained by polymerization of ethylene oxide, propylene oxide, etc.,
And polyester amides obtained by co-condensing an aliphatic diamine such as ethylene diamine with an amino alcohol such as 1-hydroxy-2-aminoethylene and a dicarboxylic acid, a mixture thereof, a copolymerization condensate, and the like.

Examples of the organic diisocyanate (B) include p-phenylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 1,5-naphthalene diisocyanate,
Aromatic diisocyanates such as 2,4-tolylene diisocyanate are mainly used.

Examples of the cross-linking agent (C) having a molecular weight of at least 500 and having an active hydrogen atom capable of reacting with an isocyanate at the terminal used in the second step include glycol and diamine.

Here, as the glycol, for example, phenylenedi (β
-Hydroxyethyl ether), 1,4-dimethylolcyclohexanediol, 1,4-cyclohexanediol, 1,4-butanediol and the like are used.

As the diamine, for example, 2,5-dichloro-p-
Phenylenediamine, o-dichlorobenzidine, 3,3 '
-Dichloro-4,4'-cyanodiphenylmethane and other aromatic diamines having halogen substituents, benzidine, p
-Phenyldiamine, triethylenediamine, diethanolamine and the like are also used.

In the second invention, like the natural rubber, the organic diisocyanates used in the mill kneading step include the aromatic diisocyanates mentioned in the first step, and in particular the dimer of 2,4-tolylene diisocyanate. And polyisocyanates such as dimers of 1-chloro-2,4-phenylene diisocyanate give good results.

In the third invention, as in the case of natural rubber, as the peroxide of the polymerization initiator used in the mill kneading step, for example, diphenyl peroxide, tertiary butyl peroxide, dimethyl bis (tertial butyl peroxide) hexane, benzoyl peroxide, dialkyl peroxide. , Catalperoxide, etc. give good results.

Examples Next, examples of the present invention will be described, but the present invention is not limited to them.

Further, parts in the following description represent parts by weight.

Example 1 Adipate-based polyester (trade name, Desmophen 2001, manufactured by Bayer, West Germany, hydroxyl value 56, molecular weight 2000, acid value 2) 10
Melt 00 parts by weight in a 5-vessel flask at 130-135 ° C,
The mixture was defoamed and dehydrated for about 60 minutes while stirring under a reduced pressure of 3 mmHg, and nitrogen gas was blown at a rate of 200 ml / min to make the reaction vessel a nitrogen atmosphere. To this mixture, 365 parts by weight of o-tolylene diisocyanate was added, Polymerization reaction 90-95
Performed at 90 ° C for 90 minutes.

The viscosity of this produced prepolymer at a temperature of 90 ° C. was 1370 centipoise.

The NCO / OH group equivalent weight of this prepolymer is 2.67.

Next, 0.014 parts by weight of triethylenediamine was dissolved in 1,4
-Butanediol (50 parts by weight) and adipate polyester (Desmophen2001) (1000 parts by weight) were added, and the whole was rapidly and vigorously mixed for 30 seconds with vigorous stirring, then the pressure was reduced to 3 mmHg and degassed.

Stir until the temperature of the produced polymer rises to 125-130 ° C. to form a completely uniform viscous mixture, pour it into a metal box which has been coated with a mold release agent and preheated to 110 ° C. In 100 parts by weight of a natural rubber-like urethane elastic polymer obtained by heating to 20 parts by weight of activated carbon black,
6.5 parts by weight of o-tolylene diisocyanate was kneaded with a mill roll, and the kneaded mixture was pressed at 150 ° C. for 30 minutes to obtain a urethane elastic body having the following characteristics.

Tensile strength 320kg / cm ² , elongation at break 550%, 300% modulus 1
00kg / cm ² , Shore A hardness 60 °, impact resilience (20 ℃ / 75 ℃)
57/71%.

Example 2 500 parts by weight of polytetrahydrofuran (molecular weight 3000),
500 parts by weight of polypropylene glycol ether (molecular weight 1500, hydroxyl value 62.6) in a 5-vessel flask at 130 ° C-13
The mixture was melted at 5 ° C. and defoamed and dehydrated for about 30 minutes while stirring under reduced pressure of 3 mmHg. Nitrogen gas was blown at a rate of 200 ml / min to make the reaction vessel a nitrogen atmosphere, 334 parts by weight of diphenylmethane-4,4-diisocyanate was added to this mixture, and a prepolymerization reaction was carried out at 70 ° C. for 90 minutes. The viscosity of this produced prepolymer at a temperature of 96 ° C. was 9600 centipoise.

Next, 80 parts by weight of methyldiethanolamine and 1000 parts by weight of stannas octoate were added, and the whole was rapidly and vigorously stirred and mixed for 30 seconds, then depressurized to 3 mmHg and degassed, and the polymer temperature rose to 120 ° C to 125 ° C and completely Stir until uniformly viscous mixture, apply release agent, preheat temperature 110 ℃
Pour into the metal box, and then heat the metal box at 110 ℃
6 hours by heating in an oven for 6 hours, and in the same manner as the obtained natural rubber, 15 parts by weight of activated carbon black and 8.0 parts by weight of a dimer of 2,4-tolylene diisocyanate in 100 parts by weight of the urethane elastic polymer. Knead with a rubber mill roll,
When this kneaded mixture was heated at 130 ° C. for 30 minutes, a urethane elastic body having the following physical properties was obtained.

Tensile strength 278kg / cm ² , breaking elongation 545%, 300% modulus 1
68kg / cm ² , Shore A hardness 74 °, reaction elasticity (20 ℃ / 75 ℃)
47/55%.

Comparative Example 1 1000 parts by weight of polyoxytetramethylene glycol having an average molecular weight of 2035 and a hydroxyl value of 54 was reduced under a reduced pressure of 3 mmHg of mercury.
Stir for 30 minutes at 0-135 ° C, followed by stirring
Dissolved 3,3'-dimethyldiphenyl-4,4 'kept at 80 ° C
-350 parts by weight of diisocyanate was added, the reaction was completed by stirring under nitrogen for 6 hours, and while maintaining the obtained product (prepolymer) at 80 ° C, 4,4'-methylenebis (2- 66 parts by weight of chloroaniline), and the whole mixture was rapidly and vigorously stirred and mixed for 30 seconds, then the pressure was reduced to 3 mmHg, and the reaction solution degassed for about 1 minute was coated with a release material in advance. Length: 15 cm x width: 15 cm x thickness: 2 mm It was cast in a mold, heated in an oven at 100 ° C. for 3 hours, then released, and then aged at room temperature for 7 days to obtain a urethane elastic body having the following physical properties.

Tensile strength 260kg / cm ² , elongation at break 53%, 300% modulus 93
kg / cm ² , Shore A hardness 68 °, impact resilience (20 ℃ / 75 ℃) 4
8/53%.

Comparative Example 2 Using the same method as in Comparative Example 1, but using 3,4'-dimethyldiphenyl-4,4'-diisocyanate (TODI) instead of tolylene 2,4 diisocyanate (hereinafter abbreviated as TDI) to form an elastomer molding. And tested. The results are shown in Table 2.
Also described in.

Comparative Example 3 Using the same method as in Comparative Example 1, an elastomer molded product was obtained by using methylenediphenyl 4,4 ′ diisocyanate (hereinafter abbreviated as MDI) instead of TODI and tested. The results are also shown in Table 2.

Regarding Examples 1 and 2 and Comparative Examples 1 to 3,
The results of these physical property tests are shown in Table 2. As is clear from this table, the urethane elastic bodies of Examples 1 and 2 have excellent general physical properties, a significantly higher elastic modulus and excellent dynamic properties as compared with Comparative Examples 1 to 3, and a load. The melting point below is high and the glass transition temperature (Tg) is low, so it can be seen that it has a wide range of use as a urethane elastic body and is excellent.

In Table 2, dynamic properties (loss elastic modulus, loss tangent) were measured by a high power viscoelasticity spectrometer manufactured by Iwamoto Seisakusho.

The loss modulus and loss tangent (tan
In general, the smaller the value of δ) is, the lower the heat generation is (representing a preferable elastic modulus).

The melting point (Tm) of the product is measured by a thermomechanical analyzer (TMA) according to the penetration measurement method.

That is, this is a measurement method in which a load is applied to a needle hitting a sample, the penetration is measured while increasing the temperature from room temperature, this is plotted against the temperature, and the inflection point is taken as a melting point (Tm) value.

Similarly, the glass transition temperature (Tg) was measured using TMA while gradually increasing the temperature from -150 ° C for the measurement sample.

Elastic modulus E ₁₀ (Kg / cm ² ), and general physical properties (T _B , E _B ,
I, mr) is a universal tensile tester UTMI manufactured by Toyo Baldwin Co., Ltd.
It was measured using a mold.

Here, E ₁₀ is obtained by obtaining a 10% modulus and multiplying the value by 10.

Further, the larger the numerical values of T _B , E _B , and I, the better, and the smaller mr is, the more preferable.

In Table 2, Example 2 and Comparative Examples 1, 2 and 3 use polyethers having the same molecular weight and have an isocyanate component changed.

Here, the general physical properties of the samples of Example 1 and Comparative Example 1 all have high values as urethane molded products. Example 1 has the lowest loss elastic modulus and loss tangent (tan δ).

In addition, Tg, which is a measure of low temperature characteristics, is the lowest in Example 1,
It turns out that it is excellent at -58 ° C.

Further, Table 3 shows the loss elastic modulus and loss tangent at 100 ° C. of Example 1 and Comparative Example 2.

As shown in Table 3, the loss elastic modulus and loss tangent at constant temperature of Example 1 are better than those of Comparative Example 2.

The melting point (Tm) of Example 1 is 43 ° C. higher than that of Comparative Example 2, and the glass transition temperature (Tg) thereof is 28 ° C. lower. Therefore, Example 1 is also excellent in these thermal properties.

Next, FIG. 1 shows the temperature dependence of the dynamic elastic modulus E (kg / cm ² ) and the loss tangent (tan δ) of Example 1 and the comparative example in a wide range.

It is desirable that the dynamic elastic modulus (E ') of the elastic body takes a constant value in a wide temperature range, that is, the curve is flat in FIG. 1, and the loss tangent is in a wide temperature range. Lower values are considered desirable.

From this, Example 1 is clearly superior to Comparative Example 2.

Table 2 shows the value of the phenyl group concentration per 1 mol monomer unit of each sample, but it is generally known that the value of Tm rises as the phenyl group concentration increases.

However, comparing Example 1 and Comparative Example 3, although the concentration of phenyl group was slightly lower in Example,
The value of Tm is significantly higher.

From the above, it is clear that the urethane elastic body obtained by the method of the present invention is an elastic material having a high melting point and a low heat generation.

Example 3 Adipate-based polyester (trade name, Desmophen 2001, manufactured by Bayer, West Germany, hydroxyl value 56, molecular weight 2000, acid value 2) 10
Melt 00 parts by weight in a 5-vessel flask at 130 ° C to 135 ° C, degas and dehydrate for about 60 minutes while stirring under a reduced pressure of 3 mmHg,
Nitrogen gas was blown at a rate of 200 ml / min to make the vessel a nitrogen atmosphere, 365 parts by weight of o-tolylene diisocyanate was added to this mixture, and the prepolymerization reaction was carried out at 90 ° C to 9 ° C.
Performed for 90 minutes at 5 ° C. The temperature of this prepolymer 90
The viscosity at ° C was 1370 centipoise. The NOC / OH group equivalent weight of this prepolymer is 2.67.

Next, 0.014 parts by weight of triethylenediamine was dissolved.
1.4 Butanediol 50 parts by weight and adipate polyester Desmophen 2001 1000 parts by weight were added, and the whole was rapidly and vigorously mixed for 30 seconds with stirring. Stir until it becomes a uniform viscous mixture, apply release agent, and 110 ℃
Pour into a preheated metal box,
0.5 parts by weight of stearic acid, 100 parts by weight of natural rubber-like urethane elastic polymer obtained by heating to 160 ° C for an hour, stabaxol PCD
4 parts by weight, triallyl cyanylate 1.5 parts by weight, and dicumyl peroxide D-40 4 parts by weight were kneaded with a mill roll, and the kneaded mixture was heated at 150 ° C. for 30 minutes,
A urethane elastic body having the following characteristics was obtained.

(Tensile strength 280 kg / cm ² , elongation at break 580%, Shore A hardness 74
°, impact resilience (20 ℃ / 75 ℃) 58/70%, tear strength 21kg /
cm) Example 4 500 parts by weight of polytetrahydrofuran PTG (product hydroxyl number 55.4, molecular weight 3000, product of Du. Pont, USA) and polypropylene glycol ether PPG (product of Nippon Soda Co., Ltd., hydroxyl value 120)
Molecular weight 1500) 500 parts by weight in a 5-vessel flask at 130 ° C ~
Melt at 135 ° C, degas while stirring under reduced pressure of 3 mmHg for about 30 minutes, dehydrate, and blow nitrogen gas at a rate of 200 ml / min to bring the reaction vessel into a nitrogen atmosphere, and diphenylmethane-4,4 '. 334 parts by weight of diisocyanate were added and the prepolymerization reaction was carried out at 70 ° C. for 90 minutes. The viscosity of the produced prepolymer at a temperature of 96 ° C. was 9600 centipoise. Next, 80 parts by weight of methyldiethanolamine, 0.007 parts by weight of stanos octoate, 0.014 parts by weight of triethylenediamine, and polytetrahydrofuran PTG.
Add 1000 parts by weight, mix rapidly and vigorously for 30 seconds with stirring, and immediately defoam and degas at a reduced pressure of 3 mmHg until the polymer temperature rises to 120 ° C to 125 ° C and becomes a completely homogeneous viscous mixture. Stir, apply mold release material, pour into a metal box with preheating temperature of 110 ° C, and leave the metal box for 6 hours.
Heated at 110 ° C open. Then, 100 parts by weight of the obtained natural rubber-like urethane elastic polymer was kneaded with 0.5 part by weight of stearic acid and 3 parts by weight of dicumyl peroxide D-40 in a Banbury mixer, and the kneaded mixture was kept at 150 ° C. for 30 minutes. When heated, a urethane elastic body having the following physical properties was obtained.

(Tensile strength 260kg / cm ² , elongation at break 566%, Shore A hardness 74
°, impact resilience (20 ℃ / 75 ℃) 56/71%, tear strength 20kg /
cm) Other than this, as in the examples, the results of the formulations (5) to (12) are summarized in Tables 4 to 8.

(II) Brittle point test according to ASTM 746: Do not break up to -70 ° C with formulation (6) and (8), and to -60 ° C with (10) (III) Bending test according to DIN 53359: Formulation (6): 50 at room temperature No change after 10,000 cycles, cracking after 50,000 cycles at -30 ° C It should be noted that no change was observed in the blends (3), (10) and (11) after 21 days, 28 days and 35 days.

(VI) Ozone resistance test (ozone concentration 200pphm) No change was observed after 10 days, 30% and 60% elongation in 50 days after compounding (6). From the results of the above table and the like, the urethane elastic polymer according to the present invention, compared with other natural rubber, elastomers such as synthetic rubber, high elastic modulus even in high hardness, excellent wear resistance, high tear strength, rupture It is clear that it is a urethane elastic body having great characteristics such as strength, energy absorption, oil resistance, gasoline resistance, and small permanent set.

Applications that utilize these features include seals and packings for precision rubber parts, various belts and blades for office machines, rubber rollers, solid tires, elastic belts for electrical equipment, automobile anti-vibration rubber, printing rolls, papermaking rolls, suction Used for plates, various textile parts, friction rollers, idler rolls, acoustic elastic belts, anti-vibration rubber, elastic couplings, timing belts, and silent gears.

It has a high melting point (Tm), which is a measure of heat resistance under dynamic conditions, a low loss tangent (tan δ), and a low glass transition point (Tg), which is a measure of low-temperature characteristics, while having high elasticity. From office machine scrapers, blades, paper feed rollers, conveyor belts, high elastic modulus, excellent wear resistance, high tear strength, elastic flat type for electrical machinery acoustics utilizing high energy absorption, square type, round type, T type The applications for molds, V-shaped belts, pinch rollers and various spinning machine parts are endless.

EFFECTS OF THE INVENTION As described above, the method for producing the urethane elastic polymer according to the present invention is as follows.
1 equivalent of a polyol (A), which is a chain compound having an active hydrogen atom capable of reacting with an isocyanate at the end, has a chain reaction of an equivalent amount or more of the organic diisocyanate (B), and as a second step, at least 500 A cross-linking agent (C) having an active hydrogen atom capable of reacting with an isocyanate at the terminal and having a molecular weight of 1 to less than the equivalent of the isocyanate residue of the chain reaction product of the first step is cross-linked to add to saturate the compound. As a step, at least the amount of the intermediate used in the first step was added to the intermediate obtained by the reaction of the second step.
A chain compound polyol (A) having a molecular weight of 800 and an active hydrogen atom capable of reacting with an isocyanate at the terminal is reacted, and the total amount of the organic diisocyanate (B) reacted with the polyol (A) is changed to the polyol ( 1 of A)
It is characterized in that it is in the range of 1.0 to 1.4 equivalents per equivalent, and is a reaction between an organic diisocyanate and a chain compound having an active hydrogen atom, which has excellent heat resistance and dynamic properties and excellent low-temperature properties. It is possible to produce a urethane elastic polymer which can be processed similarly to the natural rubber obtained by.

Further, the product obtained by the first invention has a property that it can be processed like natural rubber without vulcanizing the final urethane elastic body through a stable intermediate which is easy to store and handle. In addition, it is highly elastic and can be stored in its original state without being naturally cured for a long period of time.

Next, in the second invention of the present invention, the intermediate elastic polymer obtained by the reaction of the third step of the first invention is kneaded with the organic diisocyanate (B) on a mill as the fourth step, The present invention is characterized in that the total amount of the organic diisocyanate (B) reacted with the polyol (A) is kept within a range of 1.4 to 2.0 equivalents per equivalent of the polyol (A). According to the second invention, Similar to natural rubber, when processed on a rubber mill, it is possible to obtain an extremely excellent cured product having excellent dynamic properties such as heat resistance and low temperature properties and balanced physical properties.

The third invention of the present invention is further the above-mentioned first invention as a fourth stage.
The intermediate elastic polymer obtained by the reaction of the third step of the invention is kneaded with a peroxide as a polymerization initiator and a filler on a mill and heated to give a urethane elastic polymer composed of heat-insoluble macromolecules. According to the third aspect of the present invention, the urethane elastic body is treated with a variable amount of a polymerization initiator such as peroxide, dicumyl peroxide and carbon black on a rubber mill as in the case of natural rubber. By kneading before molding and completing heating reticulation at 140 ℃ ~ 160 ℃, rubber cured urethane elastic body with excellent heat resistance and low temperature characteristics of dynamic properties and extremely excellent physical properties can be obtained Has the effect.

[Brief description of drawings]

FIG. 1 is a curve diagram showing the temperature dependence of the dynamic elastic modulus E ′ and loss tangent (tan δ) of each material of Example 1 and Comparative Example 2.

Claims (3)

[Claims] 1. As a first step, with respect to 1 equivalent of a polyol (A) of a chain compound having a molecular weight of at least 800 and an active hydrogen atom capable of reacting with an isocyanate at its terminal,
A chain reaction of an equivalent amount or more of organic diisocyanate (B) is carried out, and as a second step, a chain reaction of the first step is carried out with a crosslinking agent (C) having a molecular weight of at least 500 and having an active hydrogen atom capable of reacting with isocyanate at the terminal. Cross-linking addition polymerization is carried out with an amount equal to or less than the isocyanate residue of the product to saturate, and the intermediate obtained by the reaction of the second step as the third step has a molecular weight of at least 800 used in the first step and has a terminal end. A chain compound polyol (A) having an active hydrogen atom capable of reacting with an isocyanate is reacted, and the total amount of the organic diisocyanate (B) reacted with the polyol (A) is 1.0 per 1 equivalent of the polyol (A). ~ 1.4 equivalent range, characterized in that,
Method for producing elastic urethane polymer. 2. The intermediate elastic polymer obtained by the reaction of the third step as the fourth step is kneaded with the organic diisocyanate (B) on a mill to obtain an organic diisocyanate (B) reacted with the polyol (A). 2. The process for producing a urethane elastic polymer according to claim 1, wherein the total amount of the above) is kept in the range of 1.4 to 2.0 equivalents per equivalent of the polyol (A). 3. As a fourth step, the intermediate elastic polymer obtained by the reaction in the third step is kneaded with a peroxide as a polymerization initiator and a filler on a mill and heated to obtain heat. The method for producing a urethane elastic polymer according to claim 1, wherein a urethane elastic polymer composed of insoluble macromolecules is produced.