KR790001437B1 - Curing agents for polyurethane foams - Google Patents

Abstract

Polyurethane curing agents with high solubility of solvent and low m.p. of the general formala (n = o or positive integer) were manufd. by condensation of 4,4'-methylenebis(2-chloroaniline) with formaldehyde without catalyst. The title composition has general formula >=2, m.p. 110<= and applied to sealant, water proofing material, flooring material etc.

Description

Curing agent composition for polyurethane

1 and 2 are NMR spectral diagrams of the curing agent of the present invention.

3 is an NMR spectrum diagram of a raw material compound.

The present invention relates to a method for producing a novel curing agent for polyurethane.

It is well known that 4,4'-methylenebis (2-chloroaniline) obtained by condensing 0-chloroaniline and formaldehyde in the presence of an acid catalyst is used as a curing agent for polyurethane. However, due to the recent rapid development of the polyurethane industry, the demand for 4,4'-methylenebis (2-chloroaniline) is rapidly increased, and at the industrial scale, high workability and It is desired to be able to achieve the improvement of molded article physical properties. Usually, 4,4'- methylenebis (2-chloroaniline) can provide the outstanding molded article physical property compared with the other hardening | curing agents for polyurethanes, but since it has a high melting point, there exists a fault which is inferior to workability.

For example, in the case of using this curing agent, there is a concern that it is hardened and precipitated while sufficient mixing is not performed in the liquid polyurethane prepolymer, so that the curing agent is melted and preheated poly It is necessary to add in a urethane prepolymer and to mix completely. If the crystallization of this curing agent occurs too quickly, it will not be cured or will result in a molded article having poor physical properties even if cured. Therefore, various methods have been proposed so far in order to obtain a low melting point curing agent.

For example, a method is known in which a mixture of two or more kinds of mononuclear aromatic amines is used as a raw material and condensed with amines to obtain a low melting point or liquid polyurethane curing agent. 37 － 9, 484, 特 公 昭 46 0 19, 062, 特 公 63 49 97 63, 797, etc.) However, this method is the result of using a variety of amines, and the manufacturing process. It is disadvantageous in that it becomes complicated, or it is difficult to adjust reaction conditions, and it is difficult to obtain a certain quality thing.

On the other hand, it is also known to react an excess amount of aldehyde with a raw material amine to obtain a low melting point or liquid curing composition. However, in this case, too, the progress of reaction to multinucleation is uneven, and there is a tendency to excessively multinucleate, resulting in deterioration of the physical properties of the molded article and difficulty in quality control. There is a drawback which causes a back. MEANS TO SOLVE THE PROBLEM The present inventors earnestly researched in order to overcome the fault which these conventional hardening | curing agents have, and to develop a low-melting-point hardening | curing agent with high product stability, and mole ratio of 4,4'-methylenebis (2-chloroaniline) and formaldehyde By dehydrating and condensing within the range of 1: 0.01 to 1: 0.50, it was found that a curing agent for polyurethane of low melting point without deteriorating the physical properties of the molded article was obtained, and thus, the present invention was completed based on this knowledge. .

That is, this invention is a general formula obtained by dehydrating condensation of 4,4'-methylenebis (2-chloroaniline) and formaldehyde in the range of molar ratio 1: 0.01 to 1: 0.50.

(N in the formula is 0 or a positive integer.)

It provides at least 2 types of compounds represented by the following, and provides the hardening | curing agent for polyurethanes which becomes a compound which has melting | fusing point of 110 degrees C or less. The present invention also provides a method by which the above-mentioned curing agent can be used to produce polyurethane elastomers and polyurethane forms with high workability.

The curing agent of the present invention is a mixture of several kinds of compounds represented by the general formula (I), has a low freezing point, can work at low temperatures, has a high solubility in solvents, and can be used as a high concentration solution. .

The hardening | curing agent of the polynuclear compound obtained by reaction of the conventional raw material amine with excess formaldehyde is a general formula

(Wherein X is an arbitrary substituent and m is an arbitrary integer.)

The hardener of the present invention is a polyfunctional compound in which the aromatic nucleus is linked via a secondary amino group and a methylene group, while the aromatic nucleus is linked via a methylene chain. Because of this, it exhibits very specific properties.

The hardening | curing agent of this invention is manufactured by heating 4, 4- methylene bis (2-chloro aniline) and formaldehyde in the ratio of molar ratio 1: 0.01-1: 0.50 in the absence of a catalyst. More specifically, this curing agent heat-dissolves 4,4'-methylenebis (2-chloroaniline) at 95-150 ° C, and while stirring, a predetermined amount of formalin or formaldehyde-generating substance, for example, para After adding formaldehyde and making it react for 10 minutes-3 hours, it can manufacture by distilling water under reduced pressure.

The curing agent prepared in this way has a low melting point and can be operated at a low temperature, so that it can maintain a long pot life and has high solubility in a solvent. It can be used for applications such as waterproofing material and flooring material.

Production of the polyurethane elastomer using the curing agent of the present invention is sufficient by adding the curing agent in a molten state to a reaction mixture of a heated polyisocyanate and a poly or a polyurethane prepolymer having a terminal isocyanate group. It is made by injecting into a mold and stirring after stirring. Examples of the polyisocyanate used at this time include hexamethylene diisocyanate (HMDI), cyclohexane diisocyanate, 2,4-trilene diisocyanate (2,4-TDI), and 2,6-triylene diisocyanate (2,6-TDI ) And mixtures of these 2,4-TDI and 2,6-TDI, dimers and trimers of 2,4-trilene diisocyanate, xylene diisocyanate (XDI) , Methaxylene diisocyanate (MXDI), m-phenylene diisocyanate, 4,4'-biphenyl diisocyanate, diphenyl ether-4,4'-diisocyanate, 3,3'-ditolluene-4,4'-di Isocyanate (TODI), dianisidine diisocyanate (DADI), 4,4'-diphenylmethane diisocyanate (MDI), 3,3'-dimethyl 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate (NDI), toriphenylmethane diisocyanate (TTI), etc. That there can be any polyisocyanate.

Moreover, as a polyol, aliphatic forester glycol, ethylene oxide, propylene oxide, tetra, such as polyethylene adipate, polybutylene adipate, and polypropylene adipate obtained by condensing aliphatic glycol with dicarboxylic acid and extending chain length The hydroxyl group of the polyalkyl ether ether glycol obtained by ring-opening polymerization, such as hydrofuran, the tetramethylene ether glycol, polyester glycol obtained by ring-opening polymerization of (epsilon) -caprolactone, and the terminal group of polybutadiene Long chain diols, such as a copolymer of two or more alkylene oxides, a copolymer of two or more glycols with dicarboxylic acids, and a mixture of aromatic glycols, glycerin, and trimethol; Obtained by cocondensing polyol with aliphatic glycol and dicarboxylic acid Is the number of the polyester polyol, or glycerine, to a storage methoxy polrieul such as methylol propane as an initiator (開始 劑), by ring-opening polymerization of ethylene oxide, propylene oxide, such as tetrahydro Francisco obtained polyether polyol.

Moreover, as a polyurethane prepolymer which has a terminal isocyanate group, it was manufactured by making said polyol react with an excess amount of polyisocyanate, Usually, terminal isocyanate prepolymer which concerns on either of polyether or polyester glycol is mentioned. And prepolymers (trade name: Adipurene: DuPont) made from polytetra methylene glycol and excess tolylene diisocyanate, for example. The curing agent used for these varies depending on the polyol and polyisocyanate or polyurethane prepolymer used, but usually the sum of the primary and secondary amino groups of the curing agent is about 0.8 to 1.2, preferably 1 equivalent of the isocyanate group. The following is used in proportions ranging from 0.9 to 1.1 equivalents.

Next, in order to produce the polyurethane form using the curing agent of the present invention, a production method of a generally known polyurethane form, that is, a polyether polyol or a polyester polyol and a polyisocyanate may be prepared using a foam stabilizer, a foaming agent and a catalyst. In the general method for producing a urethane form by reacting in the presence of a semi-prepolymer and one-shot method by substituting a part of the active hydrogen supplied by the polyol with the curing agent (polyamine) of the present invention. The form can be manufactured by (one-shotmethod), and workability can be improved by using the hardening | curing agent of this invention. Thus, using the curing agent of the present invention, it is possible to obtain a high quality polyurethane elastomer and a polyurethane form in a very simple operation.

The invention is further illustrated by the following examples.

Example 1

300 g (1.12 mol) of 4, 4'- methylenebis (2-chloroaniline) was put into 500 ml of Pulasco, and it heated and melted at 100-120 degreeC, stirring in an oil bath.

Next, 13.9 g (0.373 mol) of paraformaldehyde having a purity of 81% was added thereto while stirring at that temperature and allowed to react for 1 hour. Paraformaldehyde dispersed at the same time as the reaction proceeds is lost.

After completion | finish of reaction, dehydration was carried out by depressurizing to 20-30 mmHg, heating for 1 hour, stirring, maintaining the said temperature. Thus, 304 g of liquid condensation products were obtained at the room temperature of 7.9% of primary amino group content, 11.8% of total amino group content, and 439 KOHmg / g of hydroxyl value. The nuclear magnetic resonance spectrum of this condensation product is shown in FIG. 1 of the accompanying drawings.

The position of each proton which appears in this spectrum is as showing in the following structural formula.

FIG. 2 is a spectrum of heavy water treatment and loss of absorption of the primary amino group and the secondary amino group.

3 is the nuclear magnetic resonance spectrum of 4,4'-methylenebis (2-chloroamine) for comparison.

The position of each proton in this case is as showing in the following structural formula.

The results of the above nuclear magnetic resonance measurement are analyzed and shown in the first table.

[Table 1]

EXAMPLES 2-7

The molar ratio between 4,4-methylenebis (2-chloroaniline) and paraformaldehyde was changed between 1: 0.026 and 1: 0.50 in various ways, and the rest was reacted under the same conditions as in Example 1.

The physical properties of each condensation product thus obtained are shown in the second table.

[Table 2]

Example 8

250 g (0.936 mol) of 4,4'-methylenebis (2-chloroaniline) was put into Pulasco, and it heated and melted at 100-120 degreeC, stirring in an oil bath. Subsequently, 3.8 g (0.0468 mol) of formalin with a formaldehyde content of 37% was dripped over 25 minutes, maintaining this temperature, and reaction was carried out at the same temperature for 1 hour. At this time, crystals precipitated at the same time as the dropping, but disappeared as the reaction proceeded. After the completion of the reaction, while maintaining the same temperature, depressurization to 20-30mmHg, dehydration while stirring for 1 hour.

The resulting condensation product was 250 g, exhibited a melting point of 80 to 103 ° C., a solidification point of 57 ° C., a primary amino group content of 11.4%, a total amino group content of 12.8%, and a hydroxyl value of 445 KOHmg / g. This structural determination is carried out using nuclear magnetic resonance, and the results are shown in the third table.

For comparison, the results for 4,4'-methylenebis (2-chloroaniline) were also included.

[Table 3]

The position of each proton is as above.

Moreover, although the absorption positions of protons b and c overlap, the ratio was calculated | required by deuterium exchange.

As a result, as for the condensation product in each Example of this invention, formaldehyde dehydrates condensation with each 4,4'- methylenebis (2-chloroaniline), and forms the bridge | crosslinking between these amino groups. Is clearly recognized.

In addition, almost the same result was obtained when formalin was used as a formaldehyde source and when paraformaldehyde was used.

[Reference Example]

When urethane resin is used as a flooring material, for example, it is necessary to melt | dissolve a hardening | curing material in a solvent.

Therefore, 4,4 as the hardening | curing material and control of this invention with respect to polyethyleneglycol dibenzoate EB-200 which is the most general use as a floor flooring solvent, and an average molecular weight of about 200 of glycol). The solubility test of '-methylenebis (2-chloroaniline) was done, and the result is shown in the 4th table | surface.

[Table 4]

As is clear from this table, the curing agent of the present invention shows a solubility as high as 10-20% compared to 4,4'-methylenebis (2-chloroaniline), and thus can be used as a higher concentration solution.

Next, the application example demonstrates the method of using various hardening condensation compositions manufactured according to the manufacturing examples of the said hardening composition as a hardening | curing agent of a urethane prepolymer.

[Application Example 1]

Adiprene L-100 (made by the brand name DuPont) was used as a urethane prepolymer.

This prepolymer is a linear polymer made from polytetra methylene glycol and tolylene diisocyanate, contains 4.21% of active isocyanate groups, and has an average molecular weight of about 2,000.

The usage-amount of the prepolymer of various hardening condensation compositions was computed from the content of the total amino group of the hardening condensation composition.

That is, the usage-amount was computed from the amine number of various hardening compositions so that the total amine equivalent of a hardening condensation composition might be 0.95 equivalent with respect to 1 equivalent of adiprene L-100.

17.8 parts by weight of a curing agent was used per 140 parts by weight of adiprene L-100, and the prepolymer was heated to 100 ° C and mixed by adding a curing agent melted at 100 ° C and stirring for 2 minutes.

The mixture was poured into a mold (15 cm x 20 cm x 2 mm) and then cured at 100 ° C for 1 hour.

After mold release, curing was performed at 80 ° C. for 15 hours.

The remainder of the mixture was placed in an air bath at 100 ° C, and after mixing, the time until the mixture could be cast was measured to determine the pot life.

As a result of measuring the physical properties of the cured elastic sheet, tensile strength was 152 kg / cm 2 elongation 280%, 100% elastic modulus 28 kg / cm 2, Shore A hardness 70, tear strength 13 kg / cm and repulsive elasticity 24%.

The pot life was 23 minutes.

Next, the urethane elastomer was produced as mentioned above using the condensation composition for hardening obtained in Examples 2-8 as a hardening | curing agent.

The physical properties and fore life of the obtained urethane elastomer seed are shown in Table 5.

[Table 5]

[Application Example 2]

The amount of the curing agent was used in the same manner as in Application Example 1, using a primary amino group of 0.95 equivalents relative to the isocyanate equivalents.

That is, a urethane elastomer was prepared in the same manner as in Application Example 1 using 25.1 parts by weight of a curing agent based on 140 parts by weight of adiprene L-100.

The physical properties of the urethane elastomer obtained were tensile strength 384 kg / cm 2, elongation 380%, 100% elastic modulus 106 kg / cm 2, Shore A hardness 73, tear strength 24 kg / cm and repulsive elasticity 20%.

The pot life was 19 minutes.

Moreover, the urethane elastomer was produced as mentioned above using the condensation composition for hardening prepared in Examples 2-6.

The physical properties and pot life of the obtained urethane elastomer sheet are shown in Table 6.

[Table 6]

Comparative Example 1

This comparative example uses 4,4'- methylenebis (2-chloroaniline) as a hardening | curing agent in manufacture of a urethane elastomer.

That is, a urethane elastomer was prepared in the same manner as in Application Example 1 by using 17.8 parts by weight of 4,4'-methylenebis (2, chloroaniline) based on 140 parts by weight of adiprene L-100.

The physical properties of the obtained urethane elastomer were 436 kg / cm 2 of tensile strength, 450% of elongation, 79 kg / cm 2 of 100% elasticity, 157 kg / cm 2 of 300% elasticity, Shore A hardness 95, 56 kg / cm of tear strength and 55% repulsive elasticity.

Forth life was 12 minutes.

[Application Example 3]

This example is a manufacture example of the urethane form by the one-shot method using the composition for hardening of this invention.

The condensation composition for hardening prepared in Example 3 was used as a hardening | curing agent, and the form by the one-shot method was manufactured by the two-component automatic molding machine.

The composition of each solution is as follows.

[A amount]

Component weight part

Polyethylene adipide with average molecular weight of 1,000

(OH value 106-118 KOHmg / g) 100

Synthesis composition for elapse of Example 3 16.9

Silicon Oryl 2.0

Stanas Octanoate 0.1

Triethylenediamine 0.7

0.25 in water

[B amount]

MDI 45.2 parts by weight

Both solutions were mixed with an isocyanate index of 1.05.

Physical properties

Hardness (Shore A) 40

Density (g / cm 3) 0.48

Tensile Strength (㎏ / ㎠) 24

Elongation (%) 210

Tear strength (㎏ / ㎝) 17

A urethane form was prepared as described above except that 18 parts by weight of the curing condensation composition prepared in Example 4 was used as the curing agent.

The physical property of the obtained form is shown next.

Hardness (Shore A) 32

Density (g / cm 3) 0.51

Tensile Strength (㎏ / ㎠) 20

Elongation (%) 210

Tear strength (㎏ / ㎝) 18

Comparative Example 2

Except for using 15.9 parts by weight of 4,4'- methylene bis (2-chloroaniline) as a curing agent, a urea form was prepared in the same manner as in Application Example 3 of the form.

The physical property of the obtained form is shown next.

Hardness (Shore A) 38

Density (g / cm 3) 0.43

Tensile Strength (㎏ / ㎠) 26

Elongation (%) 230

Tear Strength (㎏ / ㎝) 19

Claims (1)

4,4'- methylenebis (2-chloroaniline) and formaldehyde are dehydrated and condensed in the range of molar ratio 1: 0.01-1: 0.05, General formula

(Where n is 0 or a positive integer) The hardening | curing agent composition for polyurethane containing at least 2 type of compound represented by this, and becoming a mixture which has a melting point of 110 degrees C or less.

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