JPH0678414B2 - Polyurethane urea elastic molding method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for molding a polyurethane urea elastic body. More specifically, polytetramethylene glycol (PT
MG) and diphenylmethane-4,4'-diisocyanate (M
DI) and ethylenediamine as raw materials, and a method for reactively molding a polyurethane urea elastic body having excellent properties in the absence of a solvent to be removed during or after molding.

The composition of the elastic body in the present invention is widely used for the application of the Svandex fiber that requires the highest performance.
Usually, the molding method is to obtain a polymer by polymerizing it in a polar solvent such as dimethylacetamide and removing the solvent from the dissolved state as it is by dry spinning. However, when such a solvent is used, it is necessary to remove the solvent, so that the application is limited to thin fibers and thin films.

In the method of the present invention, there is no solvent to be removed, and it is possible to easily make thick filaments, ropes or sheets or films and nonwoven fabrics, and as a product having excellent elastic body performance in such a form, for example, automobiles, There are a wide range of fields of use such as springs and cushions for which weight reduction is important for aircraft, and non-woven tapes in miscellaneous items.

[Conventional technology]

The composition of the elastic body in the present invention is a composition adopted by most spandex fibers on the market, and its excellent properties have been proved. The soft segment PTMG is also resistant to hydrolysis and mildew. On the other hand,
Polyester diols are also known, but they are easily hydrolyzed and weak against mold. Carbonate diols are also known, but their melting points are relatively high, and when they are made into elastic bodies, their recoverability becomes weak. Regarding the MDI and the diamine constituting the hard segment, the MDI has a good reputation as a diisocyanate that gives a composition having the most excellent physical properties. Diamine has a similar reputation. Hydrazine and metaxylilediamine are also known, but the former are easily oxidized and the latter have somewhat insufficient physical properties.

In this way, the composition of the elastic body shows the best performance and is widely used for the application of spandex fiber, but the molding method is to dissolve the polymer obtained by polymerizing in a polar solvent such as dimethylacetamide as it is. The fiber is obtained by removing the solvent from the state by dry spinning or the like. As described above, the reason why the solvent is always used is that the elastic composition does not melt even at a high temperature, the polymerization reaction is very fast, and the heterogeneous polymer remains with insufficient mixing of the raw materials. Because of that. Therefore, such an elastic body composition has always been molded by using a solvent.

On the other hand, a technique is known in which the amino group of a polyamine compound is masked with ketoimine, mixed with a polyisocyanate compound, and the mixture is coated with a coating agent and cured. For example, JP-A-60-161417 discloses, as a ketoimine-containing coating composition, a low polymer containing an isocyanate group bonded to an aliphatic hydrocarbon atom, and a ketoimine reaction product of di- or polyamine and a ketone. A moisture-curable composition comprising the above is described, and an example is shown which has a long pot life even after mixing the two and gives excellent coating by coating.

Further, JP-A-53-24396 contains a prepolymer containing an isocyanate group and an amino group and a ketoimino group in a predetermined composition range in the presence of water or, if necessary, in the presence of water and a solvent. Although it is described that the composition is mixed with a curing agent mixture and used for reaction coating or Rucker coating with a pot life of 2 to 5 minutes on average, the enumerated examples always use a solvent, and a homogeneous polymerization reaction is required. This suggests that the use of a solvent is indispensable for obtaining a homogeneous reaction coating according to the present invention, which is consistent with the findings of the present inventors.

[Problems to be solved by the invention]

As can be seen from what has been described above, in the conventional technique, a solvent is used when industrially producing thick filaments, ropes, sheets, etc., which have the elastic body composition of the present invention and are thick and excellent in performance. Since there is no choice but to use it, for example, in filament, in order to secure the surface area for distilling off the solvent, the single yarn denier will be thinned to around 10 denier and several hundred or several thousand will be spun and twisted together. However, this spinning device is large and not economical. Further, the energy cost required for distilling off the solvent is high and the cost for recovering the solvent is high. The same applies to the case of manufacturing ropes and sheets, and since it takes a long time to remove the solvent, the equipment per production unit becomes large and the energy cost also becomes large. Therefore, there is little possibility of industrially producing such products.

An object of the present invention is to provide a method for easily obtaining a uniform polyurethane urea elastic body having excellent physical properties, without using an agent to be removed during or after molding.

[Means for solving problems]

The present invention is a reaction mixture of ethylenediamine and acetone, and the unreacted ethylenediamine is 25 mol% or less with respect to the ethylenediamine used as the raw material, and a compound obtained by reacting one amine of ethylenediamine with acetone is three times as much as the unreacted ethylenediamine. More than 1 mol of ethylenediamine derivative other than these is present as a reaction mixture in which both amines are reacted with acetone and polytetramethylene glycol (PTMG), or PTMG and diphenylmethane-4,4'-diisocyanate (MDI Liquid prepared by mixing with polyurethane diol prepared in (1)
And a prepolymer of both-end isocyanate obtained from PTMG and MDI (liquid B) are continuously supplied to a mixing device,
A method for molding a polyurethane-urea elastic body, characterized in that a continuously discharged mixture is obtained.

Hereinafter, the present invention will be described in detail.

In the method of the present invention, liquid A (liquid A is a reaction mixture of ethylenediamine and acetone, and unreacted ethylenediamine is 25 mol based on ethylenediamine as a raw material) is used without using a solvent to be removed during or after the molding. % Or less, a compound having one amine of ethylenediamine as a group reacted with acetone is present in an amount of 3 times or less mol of unreacted ethylenediamine, and the other raw material ethylenediamine derivatives are compounds having both amines as a group reacted with acetone. As a reaction mixture with polytetramethylene glycol (PTMG), or PTMG and diphenylmethane-4,
Liquid mixed with polyurethane diol prepared from 4'-diisocyanate (MDI). ) And B liquid (What is B liquid?
It is a prepolymer of isocyanate at both ends obtained by reacting PTMG and MDI, and this prepolymer is PTMG and
It is composed of oligomers of isocyanate at both terminals having urethane bond reacted with MDI and free MDI which is not reacted or is added after the reaction. ) And are continuously mixed and discharged by a mixing device to obtain a mixture.

The mixing device in the present invention is a device having a volume provided with a supply port for a supply liquid and a discharge port for discharging the mixed liquid,
Mixing is carried out in this volume. As means for mixing, there are mechanical stirring by a stirrer, packing by variously known packings or static mixers that disturb the flow of liquid to mix, and collision stirring by a jet flow of the feed liquid. You can choose any means or combination of means. Among such devices, a static mixer is a preferred device that is easy to adopt.

Looking at the main points in obtaining the target homogeneous molded product in the present invention, the reaction between liquid A and liquid B produces a liquid having a higher viscosity than these feed liquids. The mixing of B liquid and B liquid is slow, and the reaction progresses nonuniformly, resulting in a noticeable unevenness in the viscosity, which further deteriorates the mixing, which is not preferable.
Therefore, the mixing in the mixing device must be sufficiently fast. For example, when a static mixer is used as the mixing device, the flow rate of the feed liquid should be sufficiently high so that the mixing and stirring in the static mixer can be performed for a short time. It is necessary to do enough. As an example, when using a static mixer SMX type manufactured by SULZER, a line mixer consisting of 4 elements / unit and 2 units has a passage time of 20 seconds or more at the longest, preferably pressure loss of the pipe is acceptable. It is best to choose as short as possible, for example 2 to 10 seconds. In addition, for example, in mechanical mixing or collision stirring mixing with a jet of the supply liquid, it is relatively easy to sufficiently perform mixing and stirring in a short time, but the viscosity of the liquid increases as the reaction proceeds in the mixed liquid. Since it becomes difficult to discharge the liquid, it is preferable that the liquid which has started to be mixed is discharged within 20 seconds.

However, even if the mixing in the mixer is carried out sufficiently quickly, a homogeneous molded product cannot be obtained unless the properties of the liquids to be mixed are appropriate.

In the case of adjusting the properties of the liquid preferably, for the liquid B, that is, the prepolymer having isocyanate groups at both ends, there is a means of using a known compound for blocking the isocyanate in order to suppress the reactivity of the isocyanate, but the present inventor As a result of their investigation, it was found that the decomposition of the block structure of any known compound was troublesome and not preferable.

Therefore, the present invention has been achieved through intensive studies with the purpose of adjusting the liquid A, that is, the liquid which is a reaction mixture of ethylenediamine and ketones.

The technique of reacting an amine with a ketone to block it has been known for a long time, but in the actual examples or examples found in the literature, ethylethylene ketone or methyl isobutyl ketone is often used as the ketone. When methyl ethyl ketone is used as a result of the study conducted by the present inventors, the pipe pressure loss is high and the strength of the obtained molded product is insufficient.
In addition, when the molded product was stretched and returned, a phenomenon of white turbidity was observed. The use of methyl isobutyl ketone became more and more inconvenient, the pressure loss in the piping was still high, and the discharge was uneven. Therefore, as a result of trying acetone which has almost no use, probably because the reactivity is too high, it was possible to reach the present invention which is surprisingly satisfactory for the first time.

The larger the amount of unreacted diamine in the liquid A, the shorter the curing time at the time of discharge molding, which is preferable, but on the other hand, the pressure loss in the pipe becomes excessive. The limit is 25 mol% with respect to the raw material diamine, and it must be less than that. The ratio of a compound in which one amine of ethylenediamine is a group reacted with acetone (hereinafter referred to as ketoimineamine) to unreacted ethylenediamine (hereinafter referred to as diamine) is important. The amino group of diamine and ketoimine amine reacts very quickly with the isocyanate group of the prepolymer, but by this reaction, there is a coupling reaction by diamine and a terminal terminating reaction by ketoimine amine at the mixed contact boundary of two liquids in the line mixer. Seems to suppress the increase in polymerization degree. If ketoimine amine is used in an amount not less than 3 times the molar amount of diamine, a homogeneous molded product cannot be obtained.

Further, in order to improve the mixing of the solution A with the solution B in the mixer, the volume of the solution A is increased so that the supply amount of the solution A is about 1/20 of that of the solution B or more. It is necessary to have a means for increasing the viscosity of the liquid A to about 1/100 or more of the viscosity of the liquid B, which is usually several thousand poises. The additive for that purpose must be compatible with the solution B, and must also have such an affinity with the solution A that the two layers are not completely separated. And it is important that it does not react with the liquid B to form a substance with a high degree of polymerization. As a result of various studies on the molded products which do not adversely affect the physical properties, a polyurethane diol reacted with PTMG, or PTMG and a smaller molar amount of MDI was found as a preferred product. The number average molecular weight of this diol is
In order to maintain the affinity between the reaction product of acetone and ethylenediamine, 6000 or less is preferable. Alternatively, the addition amount of the diol depends on the addition of a pigment or the like, but the same amount or more as the reaction product of ethylenediamine and acetone is preferable.

When it reacts with an amino group and acetone, it produces water,
Since water is required when it is cured as a molded product, it is better to leave it as it is and not remove it. If removed, the atmosphere should be absorbed.

Next, the liquid B will be described. Regarding the number average molecular weight of PTMG used in the liquid B, the range which is preferably used in the spandex fiber, that is, about 1000 to 3000 shows similarly balanced physical properties.

The reaction molar ratio indicated by MDI / PTMG when synthesizing the prepolymer was 1.4, which was also the same as for the spandex fiber.
However, in the case of the present invention, it is not necessary to consider the solubility of the polymer in a solvent, and since the hard segment having a polymer structure of ethylenediamine and MDI can be enlarged, Free MDI in liquid
Can be increased, and the reaction molar ratio can be increased to a higher ratio, and MDI may be further added after the reaction.

Next, the mixing ratio of the liquid A and the liquid B will be described.

The amino group contained in the liquid A, the group obtained by reacting the amino group with acetone (hereinafter referred to as a ketoimino group), and the isocyanate group contained in the liquid B are mixed so as to be equivalent in chemical equivalent relationship. The ratio is such that the time required for the discharged mixture to stop sticking (hereinafter referred to as non-sticking time) is short,
Moreover, a molded product having good physical properties can be obtained, which is preferable. In case of deviating from equivalence in chemical equivalence relation, if the isocyanate group is increased to about 1.25 times equivalence,
It has been found that the physical properties of the molded product are excellent, although the non-sticking time tends to be long.

On the contrary, when the sum of the amino group and the ketoimino group was as large as about 1.1 times the equivalent weight, there was no significant change in the non-adhesion time, but the physical properties of the molded product tended to deteriorate, and it was found to be undesirable. .

Regarding the non-sticking time of the molded product, it is of course preferable that it is shorter, but if it is 10 minutes or less, thick filaments, tapes, sheets, films, etc. can be made to hardly stick on the moving belt. This is a rough guide. The time until the tack does not occur is shorter as the amount of unreacted diamine in the liquid A is larger, and is shorter as the number average molecular weight of the polyurethane diol in the liquid A is larger. In addition, it changes depending on various factors such as the environment in which the discharged molded product is placed, such as temperature and humidity.

Additives, that is, stabilizers, pigments, and the like are easy to add in solution A in advance, but in this case,
It should not cause undesired changes in solution A. Hereinafter, the present invention will be described with reference to some examples and comparative examples.

[Examples and Comparative Examples]

Example 1 <Reaction Method of Ethylenediamine and Acetone> A predetermined amount of ethylenediamine and acetone was placed in a reactor at 50 ° C.
Let react for 10 hours with stirring.

<Analysis method of ethylenediamine, ketoimineamine, diketoimine in the reaction product of ethylenediamine and acetone> “Quantification of (amino group + ketoimino group)” About 3 g of a sample is weighed and dissolved in tetrahydrofuran to 100 ml in a volumetric flask. 10 ml of this solution is titrated with a 1N HCI aqueous solution using bromophenol blue as an indicator to quantify the total amount of amino groups + ketoimino groups.

"Determination of diamine and ketoimine amine" 10 ml of the above sample is placed in a 100 cc. Beaker with a whole pipet, and potentiometric titration is performed with an IN phenyl isocyanate / tetrahydrofuran solution at 20 to 25 ° C to determine the concentration of free amine. Also, in this operation, the reaction product of ethylenediamine and phenylisocyanate forms a precipitate, so this is sampled with a glass filter (3G), dried and weighed to obtain the concentration of ethylenediamine, and then determined by potentiometric titration. The ethylenediamine portion is removed from the free amine value, and the ketoimine amine concentration is determined from this.

“Quantitative determination of diketoimine” Diketoimine is calculated from the value of the amino group + ketoimino group obtained first, minus the values of diamine and ketoimine amine. Since this value uses many differences in the measured values, the error is inevitably large.

As described above, various compounds having an acetone / ethylenediamine molar ratio in the range of 0.8 to 1.2 were synthesized and quantified.
The results are shown in Table 1.

<Synthesis of oligomer diol> 20 kg of PTMG having a number average molecular weight of 1750 and MDI; 1.72 kg (L1) or 1.9 kg (L2); was put into a reactor equipped with a stirrer, and 90
React at 4 ° C for 4 hours. Regarding L1, 3.84 kg of 2.6-di-tert-butyl-4-methylphenol used as a stabilizer was further added, and the mixture was stirred at 70 ° C. for 1 hour. Other than these, the number average molecular weight of the oligomer diol is 1750.
I also used PTMG itself. This is designated as (L3).

Example 2 <Solution A: Preparation of various mixed solutions> Ten kinds of mixed solutions were prepared. It shows in Table 2. Here, the acetone / ethylenediamine reactant corresponds to No. 1 in Table 1, and the oligomer diol corresponds to the symbol in the above description of synthesis. The mixing weight ratio is 3 parts for the former and 7 parts for the latter. Next, TiO ₂ was prepared by mixing 200 g of oligomer diol L1 and 100 g of tetrahydrofuran and 200 g of TiO ₂ and previously dispersing them with a homogenizer. The concentration of TiO ₂ in Solution A is 8% by weight.

The viscosity of the liquid A was measured at 30 ° C. using a B-type viscometer manufactured by Tokyo Keiki Seisakusho.

<Solution B: Synthesis of isocyanate-terminated prepolymer at both ends> 20 kg of PTMG having a number average molecular weight of 1750 and 5.15 kg of MDI are put into a reactor equipped with a stirrer, reacted at 90 ° C for 4 hours, and stored at 35 ° C.

Example 3 Sulzer mixer SMX type (unit inner diameter 12.6 mm, unit length 90 mm, 4 elements / unit * 2 unit) which is a static mixer of liquid B and various liquids A by a gear pump.
And was discharged from a nozzle having a hole diameter of 4 mm.

The discharged product was picked up on a Teflon-coated moving belt so that it became a rope with a diameter of about 2 mm without any sticking. This was left at 45 ° C. for 20 hours and used as a measurement sample.

The strength and the elongation were measured using Tensilon (UTM-III-100, manufactured by Toyo Baldwin Co., Ltd.) at a sample length of 50 mm, a pulling speed of 1000% / mim, and a temperature of 20 ° C.

ηsp / c is 0.5 g / 100 using dimethylacetamide as a solvent.
It was measured at 25 ° C. at a concentration of cc. FIG. 1 shows a schematic diagram around the mixer used in the test. Although not shown in the figure, a pressure gauge is attached near the B liquid supply port (2).

The test conditions are shown in Table 3 and the results obtained are shown in Table 4.
The equivalent ratio shown in Table 3 is the ratio of the equivalent supply rate of the amino groups and ketoimino groups in the liquid A to the equivalent supply rate of the isocyanate groups in the liquid B.

Comparative Example 1 An example in which methyl ethyl ketone (MEK) methyl isobutyl ketone (MIBK) is used instead of acetone will be shown.

<Reaction with ethylenediamine> In the case of MEK and MIBK, a mixed solution of equimolar amount to ethylenediamine was used, and the reaction was carried out with stirring at 70 ° C for 6 hours for MEK and at 100 ° C for 7 hours for MIBK.
The reaction rate of the reaction product is 1680 cm-
From the absorption of 1 ketoimine and the absorption of 1720 cm-1 ketone
66% for MEK and 74% for MIBK.

<Preparation of mixed solution> For each of them, 3 parts of the reaction solution and 7 parts of L2 of the oligomer diol described in Example 1 were mixed at a polymerization ratio to prepare each mixed solution. The viscosity of the liquid was 160 poise for MEK and 150 poise for MIBK.

<Mixing with liquid B in static mixer and discharge molded product> The same operation as in Example 3 was carried out. The results are similarly shown in Table 5.

From Table 5, when MEK is used, it takes a long time to cure and the physical properties are insufficient, and when MIBK is used, even ejection cannot be performed, and it takes a considerably long time to cure. I understand.

Comparative Example 2 Instead of ethylenediamine, 1.2 propylenediamine (PDA), metaxylylenediamine (mXDA), hexamethylenediamine (HMDA), isophoronediamine (IPDA).
An example using is shown.

<Reaction with Acetone and Preparation of Mixed Liquid> In any diamine, a mixed liquid of equimolar amount to acetone was reacted at a predetermined temperature and for a period of time with stirring. Table 6 shows these conditions and results.

For each, 3 parts of the reaction liquid and 7 parts of the oligomer diol described in Example 1 were mixed in a weight ratio to prepare each mixed liquid. These are also shown in Table 6.

<Mixing with liquid B in static mixer and discharge molded product> The same operation as in Example 3 was carried out. The results are similarly shown in Table 7.

As can be seen from the results in Table 7, any diamine species has some drawbacks such as non-uniform discharge, long non-sticking time, and insufficient physical properties. I understand.

[Effects of the Invention] As is clear from the results of the above-mentioned Examples and Comparative Examples, the present invention makes it possible to obtain a polyurethane urea elastic body having excellent physical properties without the use of a solvent. Therefore, according to the present invention, the elastic body of the composition of the present invention breaks the wall of the product field which is conventionally limited to spandex fibers or thin films because it uses a solvent, and facilitates thick filaments and ropes, or sheets, films and nonwoven fabrics. You will be able to make it.

[Brief description of drawings]

FIG. 1 is a schematic view around the mixer. Reference numeral 1 is an A liquid supply part, 2 is a B liquid supply part, 3 is a mixed liquid discharge part, and 4 is an element storage part of a Sulzer mixer.

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Claims (1)

[Claims] 1. A reaction mixture of ethylenediamine and acetone, wherein the unreacted ethylenediamine is 25 mol% or less based on the starting ethylenediamine, and a compound obtained by reacting one amine of ethylenediamine with acetone is used as unreacted ethylenediamine. With a reaction mixture that is present in a molar amount of at least 2 times, and the raw material ethylenediamine derivative other than these is present as a compound obtained by reacting both amines with acetone,
Polytetramethylene glycol (PTMG), or a mixture of PTMG and a polyurethane diol prepared from diphenylmethane-4,4'-diisocyanate (MDI) (A
Liquid) and a prepolymer of isocyanate at both ends obtained from PTMG and MDI (Liquid B) are continuously supplied to a mixing device to obtain a continuously discharged mixture. Molding method