CN1335302A

CN1335302A - Biuret polyisocyanic acid ester and its producing process

Info

Publication number: CN1335302A
Application number: CN 00121728
Authority: CN
Inventors: 朝比奈芳幸; 片川洋德; 安川敦
Original assignee: Asahi Kasei Kogyo KK
Current assignee: Asahi Kasei Corp
Priority date: 2000-07-20
Filing date: 2000-07-20
Publication date: 2002-02-13
Anticipated expiration: 2020-07-20
Also published as: CN1163476C

Abstract

The biuret polyisocyanate is obtained through the reaction between at least one kind of diisocyanate, selected from aliphatic diisocyanate and alicyclic diisocyanate, and biuret. The biuret polyisocyanate contains carbamide linkage compounds as intermediate product of the reaction between diisocyanate and biuret including urea dimer. The urea dimer content is less than 0.5 wt% of the total product weight. Said biuret polyisocyanate which is measured by using sample cell with length of 2 cm at 430 nm has at least 90 % light transmittivity. The said biuret polyisocyanat preparing process is also disclosed.

Description

Biuret polyisocyanate and its method of preparation

The present invention relates to biuret polyisocyanate.More particularly, the present invention relates to by the biuret polyisocyanate that at least a vulcabond and biuretized reagent react obtained that is selected from aliphatic vulcabond and alicyclic diisocyanate, wherein the biuret polyisocyanate of gained has a kind of undesirable urea dimer of intermediate very low levels, that belong to above-mentioned reaction and demonstrates high-transmission rate.Biuret polyisocyanate of the present invention not only demonstrates excellent stability at low temperatures, and is not with color.In view of these performances, biuret polyisocyanate of the present invention can be used to produce coating composition, tackiness agent, fibre finish, sealing agent, water-resisting agent, foams and elastomerics or the like ideally.For example, when biuret polyisocyanate of the present invention was used to prepare coating composition, the coating composition that is obtained can form a kind of coating that demonstrates excellent binding property and resistance to deflection energy.The invention still further relates to that preparation not only demonstrates excellent low-temperature stability but also not with the high-efficiency method for producing of the biuret polyisocyanate of look.By method of the present invention, might produce excellent biuret polyisocyanate with high yield.

The polyisocyanates that is substantially free of vulcabond has been widely used in producing coating composition, tackiness agent, sealing agent, water-resisting agent, foams, elastomerics, fibre finish etc.The representative example that is used for the polyisocyanates of this purposes is the polyisocyanates (being biuret polyisocyanate) with biuret structure.Biuret polyisocyanate can be from vulcabond (as main raw material) and biuretized reagent such as water, the monobasic tertiary alcohol, formic acid, hydrogen sulfide and organic primary amine and organic secondary amine production.The someone has advised the method for several production biuret polyisocyanates.For example, following patent literature discloses the method for producing biuret polyisocyanate: not substantive examination Japanese Patent Application Publication specification sheets No.49-134629 is (corresponding to US patent No.3,976,622), not substantive examination Japanese Patent Application Publication specification sheets No.63-174961 is (corresponding to US patent No.4,837,359), the Japanese patent application notification number No.61-60093 that has examined, the Japanese patent application notification number No.61-26778 that has examined is (corresponding to US patent No.4,176,132) the Japanese patent application notification number No.62-41496 that, has examined is (corresponding to US patent No.4,290,969), the Japanese patent application notification number No.2-62545 that has examined is (corresponding to US patent No.4,983,762), Japanese patent application notification number No.5-17222 that has examined and unexamined Japanese Patent Application Publication specification sheets No.8-225511 (corresponding to US patent No.5,641,851).

In the production of biuret polyisocyanate, at first, thereby the isocyanate groups of initial compounds such as vulcabond and biuretized reagent react form a kind of compound (for example, " the urea dimer " that obtains from two diisocyanate monomers) that contains the urea key as intermediate.Then, containing urea key in the compound of urea key and isocyanate groups reacts to each other and has formed biuret polyisocyanate.Be known that this reaction various types of compounds that contain the urea key of having followed by-product, therefore seem muddy because of the urea key compound that contains that has by-product in the polyisocyanates that is obtained.For example, when the polyisocyanates of muddiness was used for coating composition, the physicals of the coating that obtains from this coating composition just may become unsatisfactory.Prevent that polyisocyanates from becoming muddy a kind of method is that maintenance at high temperature with reaction mixture (it is obtained by vulcabond and biuretized reagent react).For example, this method is described in the Japanese patent application notification number No.62-41496 that examined (corresponding to US patent No.4,290,969) and the Japanese patent application notification number No.63-6544 that has examined (corresponding to US patent No.4,264,519) in, wherein each piece all discloses the continuation method of producing polyisocyanates; The Japanese patent application notification number No.5-17222 that has examined, the Japanese patent application notification number No.2-62545 that has examined is (corresponding to US patent No.4,983,762) and unexamined Japanese Patent Application Publication specification sheets No.8-225511 (corresponding to US patent No.5,641,851) in, wherein each piece all discloses a kind of discontinuous method of producing polyisocyanates.Yet when keeping polyisocyanates at high temperature, polyisocyanates is sometimes painted easily.And prevent that polyisocyanates from becoming these muddy class methods and also having following problem: this method causes poor efficiency and expensive (for example the needing to drop into substantial contribution on plant and equipment) of polyisocyanates.

At the above-mentioned Japanese patent application notification number No.62-41496 that examined (corresponding to US patent No.4,290,969) in the disclosed method, in order to prevent that urea dimer and/or other compound that contains the urea key are incorporated in the polyisocyanates, to in tubular reactor, handle by the reaction mixture that reaction obtained of producing polyisocyanates, and allow vulcabond and urea dimer and other compound that contains the urea key react efficiently in view of the above.Yet in the method, the processing in tubular reactor is that vulcabond concentration is up to carrying out under the condition of about 77-89wt% therein, and therefore, the minimizing degree of urea dimer content is lower.So, store the muddiness that becomes afterwards at low temperatures by the polyisocyanates that this method is produced.

Examined in the disclosed method of Japanese patent application notification number No.61-60093 above-described, in order to be suppressed at the raising of the vulcabond concentration in the biuret polyisocyanate in the long storage process, biuret polyisocyanate was heat-treated before storing.Specifically, in the method, polyisocyanates heated to impel improve its vulcabond concentration (its objective is that elimination will cause those materials that form vulcabond in the storage process of polyisocyanates), remove vulcabond subsequently.Yet this patent documentation is not only done any description to urea dimer itself, and causes that for urea dimer contained in the polyisocyanates polyisocyanates becomes muddy understanding at low temperatures and all do not have to describe.In addition, about a kind of method that not only can reduce the urea dimer content in the polyisocyanates and prevent the polyisocyanates variable color, this patent documentation does not provide any instruction or suggestion.

In general, polyisocyanates is to produce from excessive vulcabond.So in order to obtain the polyisocyanates as final product, the purification step that is used to remove the unreacted vulcabond with high-vapor-pressure is necessary.For the method for removing unreacted vulcabond, having of can mentioning uses the Weak solvent of polyisocyanates to carry out extractive method, as low polar solvent or the fluid under criticality; Yet, in most of the cases, use and change the film method of evaporating.Utilizing changes the film evaporation, and the thermal history that polyisocyanates stood can be suppressed, and has therefore suppressed the thermally denature of polyisocyanates.So, change the film method of evaporating and be suitable for from have full-bodied polyisocyanates, removing vulcabond (it is a low-boiling point material).

By change that the film method of evaporation is evaporated from the mixture of polyisocyanates and vulcabond and a kind of method of producing polyisocyanates of isolating low-boiling point material (as vulcabond) in, change film when evaporation in the vaporizer when a large amount of said mixtures is added into, then in the isolated low-boiling point material of institute, also can contain polyisocyanates (it is a high boiling substance).This phenomenon is known as " carrying secretly ".It is very disadvantageous carrying secretly, and this productive rate that not only is final product can reduce, but also is that the viscosity of polyisocyanates becomes too high, to such an extent as to the essential condition of producing polyisocyanates that changes when when the vulcabond that reclaimed is produced polyisocyanates.

In this case, the inventor be develop a kind of nondiscoloration and become muddy, especially the biuret polyisocyanate of constant muddiness has carried out extensive research in the low tempertaure storage process.The result is surprised to find that, when the content of urea dimer in the biuret polyisocyanate (a kind of compound that contains the urea key) is reduced to the level that is not higher than 0.5wt%, might prevent in the low tempertaure storage process that then polyisocyanates from becoming muddy.

In addition, the inventor also finds, when adopting following this method to produce biuret polyisocyanate, the amplitude that the urea dimer reduces is improved, at first carry out the first set reaction between vulcabond and the biuretized reagent in the method, obtain first reaction mixture in view of the above, then, after the level of unreacted vulcabond concentration in regulating first reaction mixture in the 3-20wt% scope, make this first reaction mixture carry out second time and react.

Also have, the inventor finds that also the existence that is dissolved in the gas in the reaction mixture is to cause the root of carrying secretly.

Based on these new discoveries, finished the present invention.

Therefore, the purpose of this invention is to provide a kind of nondiscoloration and constant muddiness and demonstrate the biuret polyisocyanate of high stability at low temperatures.

Another object of the present invention provides a kind of nondiscoloration of production efficiently and constant muddiness and demonstrates the method for the biuret polyisocyanate of high stability at low temperatures.

Aforementioned and other purpose of the present invention, feature and advantage, from following being described in detail and claim, more in conjunction with the accompanying drawings, it is clearer to become.

In the accompanying drawings,

Fig. 1 shown in embodiment 4 and 5, and the synoptic diagram that is used to produce the system of biuret polyisocyanate in reference example 1 and 2.The description of each label among the figure

1: the ingress pipe of biuretized reagent

2: the ingress pipe of raw material

3,6: agitator

3A, 6A: heating jacket

4: the first reactors

5,8,12: pipe

7: the second reactors

9,10,11: tubular reactor

9A, 10A, 11A: chuck

13,15,17: vapor pipe

14,16,18: condenser

19: the intermediate basin

20: de-gassing vessel

21,24: Rota-film evaporator

22,25,26: waste pipe

23: heating container

According to the present invention, provide the biuret polyisocyanate that is obtained by at least a vulcabond that is selected from aliphatic vulcabond and alicyclic diisocyanate and biuretized reagent reacting.

This biuret polyisocyanate has following characteristic (1) and (2):

(1) this biuret polyisocyanate contain comprise the midbody product urea dimer, that belong to the reaction of between described vulcabond and biuretized reagent, carrying out contain the urea key compound, wherein the urea dimer is to be represented by following formula (I):

Wherein each R represent independently the aliphatic group of deriving from described vulcabond and alicyclic group and

Based on this biuret polyisocyanate and the gross weight that contains the urea key compound that comprises the urea dimer, this biuret polyisocyanate has the urea dimer content that is not higher than 0.5wt%, wherein the urea dimer content is defined as: in the gel permeation chromatography figure that contains unreacted vulcabond and this biuret polyisocyanate that contains the urea key compound, based among this gel permeation chromatography figure after having got rid of the peak that belongs to the unreacted vulcabond gross area at all peaks, belong to the area % at the dimeric peak of urea; With

(2) this biuret polyisocyanate records under 430nm by the sample cell that uses 2cm length and has at least 90% light transmission.

In order to be more readily understood the present invention, now principal character of the present invention and various embodiment are summarized as follows:

1, by the biuret polyisocyanate that at least a vulcabond and biuretized reagent react obtained that is selected from aliphatic vulcabond and alicyclic diisocyanate.

This biuret polyisocyanate has following characteristic (1) and (2):

Wherein each R represent independently from described vulcabond deutero-aliphatic group and alicyclic group and

Based on this biuret polyisocyanate and the gross weight that contains the urea key compound that comprises the urea dimer, this biuret polyisocyanate has the urea dimer content that is not higher than 0.5wt%, wherein the urea dimer content is defined as: in the gel permeation chromatography figure that contains unreacted vulcabond and this biuret polyisocyanate that contains the urea key compound, based among this gel permeation chromatography figure after having got rid of the peak that belongs to the unreacted vulcabond total area at all peaks, belong to the area % at the dimeric peak of urea; With

(2) this biuret polyisocyanate records under 430nm by the sample pool that uses 2cm length and has at least 90% optical transmittance.

2, produce the method for biuret polyisocyanate, it comprises:

(a) at first carry out between at least a vulcabond that is selected from aliphatic vulcabond and alicyclic diisocyanate and biuretized reagent first the reaction, wherein the mol ratio of vulcabond and biuretized reagent is 4-40, thereby has obtained to contain first reaction mixture of unreacted vulcabond and biuret polyisocyanate;

(b) based on the gross weight of unreacted vulcabond and biuret polyisocyanate, with the concentration adjustment of unreacted vulcabond in first reaction mixture level in the 3-20wt% scope;

(c) under 110 ℃-160 ℃ temperature, will in step (b), regulate first reaction mixture heating of unreacted vulcabond concentration, carry out second reaction in view of the above, therefore produce biuret polyisocyanate with following feature (1) and (2):

(1) this biuret polyisocyanate contain comprise the urea dimer, belong to

The midbody product of one reaction contain the urea key compound, wherein the urea dimer is by following formula (I)

Expression:

Wherein each R represents independently from described vulcabond deutero-aliphatic group and alicyclic ring

Family's base and

Based on this biuret polyisocyanate and comprise the urea dimer contain urea key chemical combination

The gross weight of thing, this biuret polyisocyanate have the urea dimerization that is not higher than 0.5wt%

Body burden, wherein the urea dimer content is defined as: containing the unreacted vulcabond

In the gel permeation chromatography figure of this biuret polyisocyanate that contains the urea key compound, base

After in this gel permeation chromatography figure, having got rid of the peak that belongs to the unreacted vulcabond

The total area at all peaks belongs to the area % at the dimeric peak of urea; With

(2) this biuret polyisocyanate exists by the sample pool that uses 2cm length

Record under the 430nm and have at least 90% optical transmittance; With

(d) from second reaction mixture that step (c) is obtained, isolate biuret polyisocyanate.

3, according to above-mentioned the 2nd method, wherein in step (d), the separation of biuret polyisocyanate is undertaken by remove the unreacted vulcabond from second reaction mixture.

4, according to above-mentioned the 2nd or 3 method, wherein said at least a vulcabond is a hexa-methylene-1, the 6-vulcabond.

5, according to any one method among the above-mentioned 2-4, wherein biuretized reagent is water.

6,, in step (a), be to carry out in the presence of at least a solvent of compound of representing from following formula (II) and alkyl phosphate, selecting wherein in the reaction of first between vulcabond and the water according to above-mentioned the 5th method:

R wherein ¹And R ²Expression independently of one another has the alkyl or the acyl group of 1-4 carbon atom, R ³Expression methyl or hydrogen atom and n represent

integer

1 or 2.

7,, wherein in step (b), the adjusting of the unreacted vulcabond concentration in first reaction mixture is undertaken by changeing the film evaporation according to any one method among the above-mentioned 2-6.

8, according to above-mentioned the 7th method, wherein to the processing that before changeing film evaporation, outgases of first reaction mixture.

9,, wherein in step (d), from second reaction mixture, remove the operation of unreacted vulcabond and undertaken by changeing the film evaporation according to any one method among the above-mentioned 3-8.

10, according to above-mentioned the 9th method, wherein to the processing that before changeing film evaporation, outgases of second reaction mixture.

11, according to any one method among the above-mentioned 2-10, wherein step (a) comprises and carries out following substep (i) and (ii) continuously:

(i) mixture that stirs vulcabond and biuretized reagent obtains the intermediate reaction mixture in view of the above to carry out the reaction between vulcabond and the biuretized reagent in the homogeneous system of mixture; With

(ii) the intermediate reaction mixture is joined in the tubular reactor with piston stream mode and further carry out reaction between vulcabond and the biuretized reagent, thereby obtain first reaction mixture.

The present invention will be described in detail belows.

Polyisocyanates of the present invention is the polyisocyanates by the biuret-containing structure that at least a vulcabond and biuretized reagent react obtained that is selected from aliphatic vulcabond and alicyclic diisocyanate.For instance, polyisocyanates of the present invention is the polyisocyanates that contains biuret structure that is expressed from the next:

In the present invention, the polyisocyanates that contains biuret structure is known as " biuret polyisocyanate ".Comprise the reaction of reaction formation urea key between two isocyanate groups and the biuretized reagent between vulcabond and the biuretized reagent for the reaction that obtains biuret polyisocyanate, and react the reaction that forms biuret structure between formed urea key and the isocyanate groups.Have no particular limits for the reaction that forms the urea key.As the example of this reaction, can lift the reaction of following reaction formula (α 1) to (α 5):

Shown in above in the reaction dimer that contains the urea key that produce, vulcabond by with following formula (I) expression " urea dimer ".Urea key and the isocyanic ester radical reaction that forms like this, thus biuret structure formed.For the reaction that forms biuret structure without any particular restriction.As an example of this reaction, can mention reaction by following reaction formula (β) expression:

The method of producing biuret polyisocyanate not only comprises and forms the dimeric reaction of urea, and the reaction shown in above reaction formula (α 1)-(α 5), and comprise various side reactions, these side reactions form except that the urea dimer other and contain the urea key compound.This type of example that contains urea key compound (except that the urea dimer) comprises the compound that is expressed from the next:

Wherein n is the integer more than 2 or 2,

With the compound with a kind of like this structure: promptly, be converted to the urea key with in the middle of the end isocyanate group of the biuret polyisocyanate shown in the following formula (β) at least one.

Be known that, the existence of urea dimer in biuret polyisocyanate is that biuret polyisocyanate becomes a muddy reason, but the inventor finds for the first time, by reducing the urea dimer content in the biuret polyisocyanate, might prevent that biuret polyisocyanate from becoming muddy (muddiness takes place, be considered to because the raising of the concentration of vulcabond in the biuret polyisocyanate) in the low tempertaure storage process in the low tempertaure storage process.Based on biuret polyisocyanate and the gross weight that comprises the compound that contains the urea key of urea dimer, the urea dimer content in the biuret polyisocyanate of the present invention is reduced to and is not higher than 0.5wt%, the preferred level that is not higher than 0.3wt%.When the urea dimer content in the biuret polyisocyanate surpasses 0.5wt%, when it about 5 ℃ or when more storing under the low temperature this biuret polyisocyanate become muddy.

Urea dimer content in the biuret polyisocyanate is defined as: in the gel permeation chromatography that contains unreacted vulcabond and the biuret polyisocyanate that contains the urea key compound, based on getting rid of peak (when using reaction solvent, also should get rid of the peak that belongs to reaction solvent) the whole total area at peaks afterwards belong to the unreacted vulcabond in the gel permeation chromatography, belong to the area % at the dimeric peak of urea.In the present invention, the gel permeation chromatography that is used to measure the urea dimer content is to allow carry out the gel permeation chromatography figure that gel osmoticing chromatogram analysis obtained under the condition described in the biuret polyisocyanate embodiment in this manual.

In addition, biuret polyisocyanate of the present invention demonstrates at least 90% optical transmittance according to the result who uses 2cm length sample pool to measure under 430nm.It is painted that high optical transmittance like this means that biuret polyisocyanate does not have.In the usual way of producing biuret polyisocyanate, biuret polyisocyanate is heated to prevent polyisocyanates (especially in the low tempertaure storage process) change in storage process muddy for a long time, but polyisocyanates is painted easily.On the other hand, in the production of biuret polyisocyanate of the present invention, need not this polyisocyanates of long-time heating and just can eliminate the urea dimer (it causes that biuret polyisocyanate becomes muddy) that in biuret polyisocyanate, contains, like this, biuret polyisocyanate of the present invention demonstrates high-transmission rate.

For the method for producing biuret polyisocyanate of the present invention, preferably use method of the present invention.Might produce a kind of biuret polyisocyanate by method of the present invention, it neither contains the urea dimer basically and does not also contain other and contain the urea key compound but also demonstrate high-transmission rate.This biuret polyisocyanate shows excellent stability and can be painted and become muddy at low temperatures.

Method of the present invention may further comprise the steps (a) and (b), (c) and (d):

(a) at first carry out between at least a vulcabond that is selected from aliphatic vulcabond and alicyclic diisocyanate and biuretized reagent first the reaction, wherein the mol ratio of vulcabond and biuretized reagent is 4-40, obtains to contain first reaction mixture of unreacted vulcabond and biuret polyisocyanate in view of the above;

(b) based on the gross weight of unreacted vulcabond and biuret vulcabond, with the concentration adjustment of unreacted vulcabond in first reaction mixture level in the 3-20wt% scope;

(c) first reaction mixture that will regulate unreacted vulcabond concentration under 110 ℃-160 ℃ temperature in step (b) heats, and carries out second reaction in view of the above, thereby produces biuret polyisocyanate of the present invention; With

Vulcabond as raw material is at least a vulcabond that is selected from aliphatic vulcabond and alicyclic diisocyanate in the method for the invention.As aliphatic vulcabond, C ₄-C ₃₀Aliphatic vulcabond is preferred; As alicyclic diisocyanate, C ₈-C ₃₀Alicyclic diisocyanate is preferred.The object lesson of vulcabond comprises tetramethylene-1,4-vulcabond, pentamethylene-1, the 5-vulcabond, hexa-methylene-1,6-vulcabond, 2,2,4-tri-methyl hexamethylene-1, the 6-vulcabond, lysinediisocyanate, isophorone diisocyanate, 1, two (isocyanic ester the methyl)-hexanaphthenes and 4,4 of 3-'-dicyclohexyl methane diisocyanate.This type of vulcabond can use separately or be used in combination.In the middle of them, the hexa-methylene-1 that can extensively in industry, use, 6-vulcabond (hereinafter often being called for short " HMDI ") and isophorone diisocyanate (following usually be called for short " IPDI ") they are preferred, and HMDI is most preferred.

The example of the biuretized reagent of Shi Yonging comprises water in the method for the invention, the monobasic tertiary alcohol, formic acid, hydrogen sulfide, organic uncle's monoamine and organic uncle's diamine.In the middle of them, water is preferred because make water not only can produce low viscous polyisocyanates, and can not cause the by-product flammable gas, poisonous gas and monoisocyanates etc.

In the step (a) of method of the present invention, the vulcabond and the biuretized reagent that carry out first reaction are with at least 4, preferably at least 5 and be not higher than 40, preferably be not higher than 30 and use more preferably no higher than 20 (vulcabond and biuretized reagent) mol ratio.When the mol ratio of vulcabond and biuretized reagent was lower than 4, it is too high that the viscosity of the polyisocyanates of being produced becomes, and full-bodied polyisocyanates like this can not be used to obtain excellent coating composition, or the like.For instance, the consistency of full-bodied polyisocyanates and polyvalent alcohol (it is to use the main agents of polyisocyanates as the coating composition of solidifying agent) is relatively poor, like this, when using the high viscosity polyisocyanates to prepare coating composition, the solids content step-down of coating composition.When the mol ratio of vulcabond and biuretized reagent was higher than 40, the productive rate of polyisocyanates reduced, and this considers it is disadvantageous from productivity and economy.

In the method for the invention, when water is used as biuretized reagent, preferably in the presence of solvent, carry out the reaction of first between vulcabond and the water.Preferably use the reaction solvent that can dissolve vulcabond and water simultaneously, therefore can obtain homogeneous reaction system down by employed in the method for the invention reaction conditions, can suppress by product like this as containing the formation of urea key compound.So when using solvent in step (a), preferably the consumption of solvent is enough to form homogeneous reaction system.

For the solvent that uses in the step (a), preferably the solubleness of water (as biuretized reagent) in this solvent is 0.5wt% or higher.When the solubleness of water is lower than 0.5wt%, a large amount of solvents must be joined in the reaction system.The use of a large amount of solvents need spend in the fringe cost that reaction separates and reclaim solvent afterwards, is disadvantageous economically therefore.Also have, from separating and reclaim the difficulty or ease angle consideration of unreacted vulcabond, preferably the boiling point of solvent for use is lower than the boiling point of vulcabond.Specifically, the preferred solvent that uses in the present invention is at least a solvent of selecting from the compound of following formula (II) expression and alkyl phosphate:

integer

1 or 2.

By with the compound of following formula (II) expression and alkyl phosphate neither with the isocyanic ester radical reaction.Also have, above-mentioned two compounds are hydrophilic, like this their reaction systems that can be used for wherein biuretized reagent very easily be water.

Example by the compound of representing with following formula (II) comprises compound that is used as glycol based solvent and the compound that is used as propylene glycol type solvent.The example of glycol based solvent comprises ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, glycol monomethyl n-propyl ether acetic ester, glycol monomethyl isopropyl ether acetic ester, glycol monomethyl n-butyl ether acetic ester, glycol diacetate, glycol dimethyl ether, the ethylene glycol bisthioglycolate ethyl ether, the ethylene glycol bisthioglycolate n-propyl ether, the ethylene glycol bisthioglycolate isopropyl ether, the ethylene glycol bisthioglycolate n-butyl ether, Ethylene Glycol Methyl ethyl ether, Ethylene Glycol Methyl isopropyl ether, the Ethylene Glycol Methyl n-butyl ether, ethylene glycol ethyl n-propyl ether, ethylene glycol ethyl isopropyl ether, ethylene glycol ethyl n-butyl ether, ethylene glycol n-propyl n-butyl ether, ethylene glycol sec.-propyl n-butyl ether, glycol ether monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diglycol monotertiary n-propyl ether acetic ester, diglycol monotertiary isopropyl ether acetic ester, diglycol monotertiary n-butyl ether acetic ester, diethylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, glycol ether di ether, glycol ether Di Iso Propyl Ether, the glycol ether di-n-butyl ether, the glycol ether methyl ethyl ether, glycol ether methyl isopropyl ether, glycol ether methyl n-propyl ether, glycol ether methyl n-butyl ether, glycol ether ethyl isopropyl ether, glycol ether ethyl n-propyl ether, glycol ether ethyl n-butyl ether, glycol ether n-propyl n-butyl ether and glycol ether sec.-propyl n-butyl ether.In the middle of these compounds, preferably ethylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, glycol diacetate and diethylene glycol dimethyl ether.

The example of propylene glycol type solvent comprises propylene glycol monomethyl ether, propylene glycol list ethyl ether acetic ester, propylene glycol list n-propyl ether acetic ester, propylene glycol monoisopropyl ether acetic ester, propylene glycol list n-butyl ether acetic ester, propylene-glycol diacetate, the propylene glycol dimethyl ether, the propylene glycol Anaesthetie Ether, propylene glycol di ether, the propylene glycol Di Iso Propyl Ether, the propylene glycol di-n-butyl ether, the propylene glycol methyl ethyl ether, the propylene glycol methyl isopropyl ether, propylene glycol methyl n-butyl ether, propylene glycol ethyl n-propyl ether, propylene glycol ethyl isopropyl ether, propylene glycol ethyl n-butyl ether, propylene glycol n-propyl n-butyl ether, propylene glycol sec.-propyl n-butyl ether, the DPGME acetic ester, dihydroxypropane single-ethyl ether acetic ester, dipropylene glycol list n-propyl ether acetic ester, dipropylene glycol monoisopropyl ether acetic ester, dipropylene glycol list n-butyl ether acetic ester, dipropylene glycol diacetate esters, dipropylene glycol dimethyl ether, the dipropylene glycol Anaesthetie Ether, dipropylene glycol di ether, dipropylene glycol Di Iso Propyl Ether, dipropylene glycol di-n-butyl ether, the dipropylene glycol methyl ethyl ether, the dipropylene glycol methyl isopropyl ether, dipropylene glycol methyl n-propyl ether, dipropylene glycol methyl n-butyl ether, dipropylene glycol ethyl isopropyl ether, dipropylene glycol ethyl n-propyl ether, dipropylene glycol ethyl n-butyl ether, dipropylene glycol n-propyl n-butyl ether and dipropylene glycol sec.-propyl n-butyl ether.In the middle of these compounds, propylene glycol monomethyl ether preferably, propylene glycol list ethyl ether acetic ester, propylene-glycol diacetate and dipropylene glycol dimethyl ether.

The example of alkyl phosphate comprises tricresyl phosphate methyl ester, tricresyl phosphate ethyl ester, tricresyl phosphate propyl diester and tricresyl phosphate butyl ester.In the middle of these alkyl phosphates, preferably tricresyl phosphate methyl ester and tricresyl phosphate ethyl ester.

Above-mentioned solvent can use separately or be used in combination.The polyisocyanates that obtains in order to suppress its vulcabond concentration in long storage process improves, and preferably uses mixed solvent in the method for the invention.Specifically, when glycol based solvent and alkyl phosphate were used in combination, preferably the weight ratio of glycol based solvent and alkyl phosphate was in the 3/7-9/1 scope.Based on the gross weight as the vulcabond and the mixed solvent of raw material, preferably the consumption of above-mentioned mixed solvent is 20-50wt%.

In the method for the invention, the OH-acidic cpd as not examining di(2-ethylhexyl)phosphate (2-ethylhexyl) ester of describing among the Japanese Patent Application Publication specification sheets No.8-225511 (corresponding to US patent No.5,641,851), can join in the reaction system.When the OH-acidic cpd was added in the reaction system, the speed of biuretized reaction had improved, and therefore might suppress the raising of polyisocyanates vulcabond concentration in its long storage process.

In the step (a) of the inventive method, what carry out is first reaction between vulcabond and biuretized reagent, obtains to contain first reaction mixture of unreacted vulcabond and biuret polyisocyanate in view of the above.In this first reaction, the urea key compound that contains that comprises the urea dimer is to be formed by the isocyanate group of vulcabond and the reaction between the biuretized reagent, and then, the urea key that contains in the urea key compound changes into biuret structure by the reaction that contains between urea key compound and the isocyanate group, has obtained biuret polyisocyanate in view of the above.Preferably first be reflected at 70-200 ℃, more preferably carry out under the temperature between 90-180 ℃.Be reflected at when carrying out under the temperature that is lower than 70 ℃ when first, be difficult to carry out above-mentioned reaction.On the other hand, be reflected at when carrying out under the temperature that is higher than 200 ℃ when first, the polyisocyanates of being produced is painted easily.

First reaction in step (a) between vulcabond and biuretized reagent can be carried out with intermittent mode or continuous mode.Yet,, preferably carry out first reaction in a continuous manner from the considerations such as angle of productivity.Specifically, preferably, step (a) is to be undertaken by the continuation method of describing in examining Japanese patent application notification number No.62-41496, and this method comprises carries out following substep (i) and (ii) continuously:

(ii) the intermediate reaction mixture is joined in the tubular reactor, further carry out reaction between vulcabond and the biuretized reagent with piston stream mode in view of the above, thereby obtain first reaction mixture.When using tubular reactor to react with piston stream mode, the entire reaction mixture is trapped in the tubular reactor, therefore, contains the easy and isocyanic ester radical reaction of urea key compound.As a result, the content that contains the urea key compound can reduce significantly.

Reaction in substep (i) can be used and for example stir the type reactor and carry out under for the described reaction conditions of step (a) above.The substep that in tubular reactor, carries out (ii) in, reaction generally under atmospheric pressure and under 80-180 ℃, preferred 90-160 ℃ is carried out.Reaction times (being the residence time) generally is 30-240 minute, and the flow velocity of preferred 30-120 minute and reaction mixture generally is 0.5-5m/hr, preferred 0.5-2m/hr.

In the step (b) of the inventive method, with the concentration adjustment of unreacted vulcabond in first reaction mixture that obtains in the step (a) to specific level.Unreacted vulcabond concentration is the amount (wt%) based on the unreacted vulcabond of the gross weight of unreacted vulcabond and polyisocyanates (it contain comprise the urea dimer contain the urea key compound).Carry out step (b) with the concentration of regulating the unreacted vulcabond in first reaction mixture to 3-20wt%, preferred 3-15wt%, the more preferably level in the 3-10wt% scope.When vulcabond concentration deflects away from above-mentioned scope, lower in second reaction that the dimeric minimizing speed of urea is carried out in later step (c).Develop method of the present invention based on following surprised discovery: when carrying out second reaction in unreacted vulcabond concentration therein is in reaction system in the above-mentioned specified range, the dimeric minimizing speed of urea can improve.As above explain in detail, urea key in the urea dimer and isocyanic ester radical reaction and the urea key is changed into biuret linkage have been eliminated the contained urea dimer of polyisocyanates in view of the above.Generally can think, isocyanate group concentration in the reaction system is high more, the minimizing speed of urea dimer content is fast more, and therefore the urea dimer content of polyisocyanates can reduce apace when carrying out above-mentioned reaction in the reaction system of the unreacted vulcabond with high density.Yet, research according to the inventor has been found that, with have Comparatively speaking above the reaction system of the high density unreacted vulcabond of 20wt%, in the reaction system with this lower unreacted vulcabond concentration of 3-20wt%, the dimeric minimizing speed of urea is high.

In general, because first reaction mixture contains a large amount of unreacted vulcabond, need from first reaction mixture, to remove excessive unreacted vulcabond.Yet, when the unreacted vulcabond concentration in first reaction mixture is lower than above-mentioned scope, vulcabond should be joined in first reaction mixture, thus with the unreacted vulcabond concentration adjustment in the reaction mixture to desired level.Remove the unreacted vulcabond to regulate the process of the unreacted vulcabond concentration in first reaction mixture, can use the Weak solvent such as the low polar solvent of polyisocyanates the liquid under criticality is undertaken by extracting or by the distillation carry out.Yet in the method for the invention, preferably removing of unreacted vulcabond is by utilizing the distillation procedure that changes the film evaporation to carry out.In changeing the film evaporation operation, the content in the vaporizer is carried out the compulsory type processing with the formation film, thereby help the evaporation of vulcabond (it has lower boiling), vulcabond just can be separated from polyisocyanates efficiently like this.

In the method for the invention, the processing that preferably before changeing film evaporation, first reaction mixture outgased.When making water produce polyisocyanates as biuretized reagent, carbonic acid gas (CO ₂) will produce as by-product gas.Usually, CO ₂Gas is considered to be insoluble in the reaction mixture basically, but in fact, the by-product carbon dioxide of a part is dissolved in the reaction mixture.The amount that is dissolved in this gas in the reaction mixture will change according to reaction conditions, but generally be in the 0.05-0.4Nml/ml scope (wherein " Nml " is meant the ml that measures under normal temperature and condition (0 ℃, 1 normal atmosphere)).When the gas dissolving first reaction pressure mixture therein was added in the Rota-film evaporator of operating under vacuum condition, following disadvantageous phenomenon can take place.Be dissolved in diffusing the sprinkling of first reaction mixture that the gas in first reaction mixture volatilizees and expands and causes a part to refrigerating unit (being used for the steam that condensation is made up of the unreacted vulcabond) in Rota-film evaporator.First reaction mixture that sprinkles that so looses adheres on the refrigerating unit.When using this type of refrigerating unit to carry out the separation of unreacted vulcabond and reclaiming, just cause adherent first reaction mixture mix with the unreacted vulcabond that is reclaimed.This phenomenon can take place when big in the amount of first reaction mixture in joining Rota-film evaporator significantly, thereby causes economically unfavorable, because reduced the productive rate of biuret polyisocyanate.Also have, the biuret polyisocyanate that contains in the vulcabond that is reclaimed causes the concrete too high viscosity of polyisocyanates that makes from the vulcabond that reclaims, thereby has influenced the physicals of polyisocyanates.

When employed biuretized reagent (as water) is that above-mentioned disadvantageous phenomenon also can occur in the reaction of producing biuret polyisocyanate significantly when producing the compound of byproduct gas (as carbonic acid gas).Yet the amount of the biuret polyisocyanate that contains in the vulcabond that reclaims changes with the difference of reaction bar, but sometimes can account for percentum of the vulcabond weight that reclaims.

In the preference pattern of method of the present invention, the above-mentioned discovery of the phenomenon that causes in view of relevant byproduct gas, first reaction mixture before changeing film evaporation by the degassing removing wherein institute's dissolved gases, thereby prevent that polyisocyanates is incorporated in the vulcabond that is reclaimed.The degassing to first reaction mixture can be undertaken by for example following method.Provide the de-gassing vessel that same vacuum tightness is arranged with Rota-film evaporator in the system that is used for producing polyisocyanates.First reaction mixture is added in the de-gassing vessel on the top of de-gassing vessel, and such first reaction mixture is outgased the process of landing from the top of de-gassing vessel.When first reaction mixture arrived on the surface of the liquid phase be positioned at the de-gassing vessel bottom, still incomplete as the degassing of first reaction mixture, then liquid phase can be bubbled in its surface, and such first reaction mixture is outgased.In this method, it is not preferred first reaction mixture directly being joined in the bottom of containing liquid phase of de-gassing vessel, because like this, it is incomplete that the degassing of first reaction mixture can become.This agitator that is equipped with of this degassing.Yet,, when agitator is housed, make the structure of de-gassing vessel become too complicated because de-gassing vessel is to operate under vacuum condition.So the use of this complex appts can increase cost.

The temperature of preferably changeing first reaction mixture of film evaporation is not higher than the boiling point of first reaction mixture.When the temperature of first reaction mixture is higher than the boiling point of first reaction mixture, when joining it in the Rota-film evaporator, carry phenomenon easily secretly.

Removing the operation of vulcabond from first reaction mixture can be undertaken or by using placed in-line two Rota-film evaporators to carry out in two stages by the single phase of using single Rota-film evaporator.When the evaporation of commentaries on classics film is carried out in two stages, before each stage, can carry out the degassing to first reaction mixture.

In the step (c) of the inventive method, first reaction mixture is heated to carry out second reaction, to reduce the urea dimer content in the biuret polyisocyanate, therefore obtains biuret polyisocyanate of the present invention.In second reaction, the urea dimer that forms in first reaction changes into biuret structure with the isocyanic ester radical reaction with the urea key, thus elimination urea dimer.In step (c), first reaction mixture of adjusted unreacted vulcabond concentration is 110-160 ℃, preferred 110-140 ℃ of heating down.When temperature of reaction was lower than 110 ℃, the dimeric minimizing speed of urea had then very reduced unfriendly.When temperature of reaction was higher than 160 ℃, biuret polyisocyanate was painted easily.In step (c), heat so that the urea dimer content that is obtained in the biuret polyisocyanate is not higher than 0.5wt%, but should make biuret polyisocyanate also demonstrate at least 90% transmissivity (using 2cm length sample pool under 430nm, to measure) when importantly, heating.When transmissivity is lower than 90%, this means that final polyisocyanates is painted.In order to obtain to demonstrate the biuret polyisocyanate of at least 90% transmissivity, in the said temperature scope, heated 5-90 minute, preferred 5-60 minute, more preferably 5-30 minute.When be shorter than above-mentioned scope heat-up time, the dimeric minimizing degree of urea was not satisfied.When being longer than above-mentioned scope heat-up time, the transmissivity of biuret polyisocyanate can reduce, so biuret polyisocyanate can be painted.

Step (c) can be carried out with intermittence or continuous mode.Because the dimeric minimizing process of urea is carried out as zeroth order reaction, can be substantially the same in the reaction times (residence time) of reaction of step (c) discontinuous and successive reaction.The preferably 5-90 minute reaction times of in step (c), carrying out, more preferably 5-60 minute, most preferably 5-30 minute.

In step (d), the biuret polyisocyanate that will obtain in step (c) is separated from second reaction mixture.Preferably, the separation of biuret polyisocyanate is undertaken by remove the unreacted vulcabond from second reaction mixture.The operation of in the step (d) the unreacted vulcabond being removed can use the Weak solvent (as low polar solvent or the liquid under criticality) of polyisocyanates to be undertaken by extracting, or undertaken by evaporation, but preferably according to step (b) in regulate the described same way as of unreacted vulcabond concentration and evaporate and remove unreacted vulcabond by changeing film.Also have, the same with situation in the step (b), processing preferably outgased second reaction mixture before changeing the film evaporation.

Describe the inventive method of producing biuret polyisocyanate in a continuous manner in detail below with reference to the system shown in Fig. 1.

When using the system shown in Fig. 1 to produce biuret polyisocyanate, the raw material vulcabond is joined in first reactor 4 with constant flow rate continuously by ingress pipe 2.In the raw material feeding, biuretized reagent is joined in the reactor 4 with constant rate of speed continuously by ingress pipe 1.First reactor 4 is complete mixed type stirred reactors that agitator 3 and heating jacket 3A are housed.In first reactor 4, carry out the reaction between vulcabond and the biuretized reagent, thereby obtain the first intermediate reaction mixture.The gas that produces in reaction process is removed by vapor pipe 13 and condenser 14.The first intermediate reaction mixture joins in second reactor 7 by pipeline 5.Second reactor 7 also is the complete mixed type stirred reactor that agitator 6 and heating jacket 6A are housed.Further react in second reactor 7, thereby obtain the second intermediate reaction mixture, the gas that produces in this reaction process is removed (corresponding to the substep (i) of step (a)) by vapor pipe 15 and condenser 16.The second intermediate reaction mixture is added in placed in-line tubular reactor 9,10 and 11 by pipeline 8.Tubular reactor 9,10 and 11 is equipped with chuck 9A, 10A and 11A respectively.In tubular reactor, further react again, thereby obtain first reaction mixture ((ii)) corresponding to the substep of step (a).The a small amount of gas that produces in this reaction is removed by vapor pipe 17 and condenser 18.First reaction mixture is discharged from tubular reactor continuously and is incorporated in the intermediate basin 19 by pipeline 12.Then, first reaction mixture is added into and makes the degassing of first reaction mixture in the de-gassing vessel 20.First reaction mixture after the degassing is added in the Rota-film evaporator 21, regulates the concentration (corresponding to step (b)) of unreacted vulcabond in first reaction mixture therein.The unreacted vulcabond that is removed for the unreacted vulcabond concentration of regulating in first reaction mixture is to reclaim by waste pipe 22, and first reaction mixture of adjusted unreacted vulcabond concentration is added in the heating container 23.In heating container 23, first reaction mixture is heated to carry out second and reacts, thereby obtains second reaction mixture (corresponding to step (c)).Subsequently, second reaction mixture is added in the Rota-film evaporator 24, and wherein the unreacted vulcabond in second reaction mixture is removed by waste pipe 25, thereby isolates biuret polyisocyanate from second reaction mixture.Isolated biuret polyisocyanate is discharged (corresponding to step (d)) from waste pipe 26.

The biuret polyisocyanate that is obtained by the inventive method not only has low-down urea dimer content (it is that biuret polyisocyanate becomes muddy cause, takes place) in the low tempertaure storage process, and is colourless, transparent.Specifically, the urea dimer content in the biuret polyisocyanate of the present invention is not higher than 0.5wt%, and the transmissivity that preferably is not higher than 0.3wt% and biuret polyisocyanate is at least 90%.Also have, the biuret polyisocyanate that is obtained by the inventive method is substantially free of vulcabond, and in general, have be not higher than 5wt%, preferably be not higher than 2wt%, more preferably no higher than the unreacted vulcabond concentration of 1wt%.For biuret polyisocyanate of the present invention, its isocyanate group content generally is 3-25wt%; Number-average molecular weight generally is 550-1000; With the viscosity under 25 ℃ generally be 500-50,000mPa.s.

Implement best mode of the present invention

Below, describe the present invention in more detail in conjunction with the following examples, comparative example and reference example, but they should not think the scope of the present invention that limited.

In embodiment below, comparative example and the reference example, the various performances of following mensuration.

(1) urea dimer content

Urea dimer content in the biuret polyisocyanate is defined as: by the dimeric amount of urea of above general formula (I) expression, account for biuret polyisocyanate and comprise the dimeric percentage ratio (wt%) that contains the gross weight of urea key compound of urea.

The sample that is used for measuring the biuret polyisocyanate of its urea dimer content is by biuret polyisocyanate being dissolved in tetrahydrofuran (THF) (THF) so that the ultimate density of biuret polyisocyanate in THF becomes 0.5wt% makes.In order to measure the urea dimer content of biuret polyisocyanate in reaction mixture, the reaction mixture former state is as sample.

Measure carrying out gel permeation chromatography (GPC) under the mentioned below condition of the sample of biuret polyisocyanate, thereby obtained spectrogram.The urea dimer content is that (promptly working as polyisocyanates is hexa-methylene-1 as belonging to the dimeric peak of urea, the residence time is corresponding to the peak of molecular weight 310 during 6-vulcabond (HMDI)) area % measure, it is that the total area with whole peaks in the obtained spectrogram peak of unreacted vulcabond (belong to except) is a benchmark.

GPC carries out under the following conditions:

Chromatography machine: HLC-8120 GPC (by Japanese TOSOH company's manufacturing and sale),

Chromatographic column: placed in-line TSKgel Super H1000, TSKgel Super H2000 and TSKgel Super H3000 (separately by Japanese TOSOH company produce and market),

Carrier: THF (flow velocity: 0.6ml/min) and

Detector: refractive index detector.

(2) transmissivity

The transmissivity of biuret polyisocyanate is to use the sample pool of 2cm length to measure under 430nm by means of visible light and UV spectrophotometer (" UV-160 " is by the Shimadzu company produce and market of Japan).

(3) unreacted vulcabond concentration

Unreacted vulcabond concentration in reaction mixture or the biuret polyisocyanate is defined as the amount of unreacted vulcabond, accounts for the percentage ratio (wt%) of the gross weight of unreacted vulcabond and biuret polyisocyanate (contain and comprise the dimeric urea key compound that contains of urea).

The sample of reaction mixture or biuret polyisocyanate is according to preparing with mode identical described in above above-mentioned (1).The sample of reaction mixture or biuret polyisocyanate carries out GPC under the condition described in above above-mentioned (1), thereby obtains color atlas.Vulcabond concentration is the area % mensuration as the peak (promptly when vulcabond is HMDI the residence time corresponding to the peak of molecular weight 168) that belongs to vulcabond, and it is that the total area with all peaks in the obtained color atlas is a benchmark.

(4) number-average molecular weight

The sample that is used for measuring the polyisocyanates of its number-average molecular weight is by polyisocyanates being dissolved in tetrahydrofuran (THF) (THF) so that the ultimate density of polyisocyanates in THF becomes 0.25wt% prepares.Prepared sample is carried out gpc analysis to measure its number-average molecular weight.GPC be with above above-mentioned (1) described identical condition under carry out.

(5) isocyanate group content

Isocyanate group content is defined as the content (wt%) of isocyanate groups in the biuret polyisocyanate.

In order to measure isocyanate group content, accurately take by weighing the biuret polyisocyanate of 5-10g and be used as sample.The toluene solution of the di-n-butyl amine of 20ml toluene and 20ml 2N is joined in the biuret polyisocyanate.The mixture that is obtained is at room temperature placed 15 minutes to react.

Reaction mixture utilizes automatic titration device (model APB-410 is by Japanese KYOTO DENSI Co., Ltd. produce and market) to carry out back titration by using the 1N hydrochloric acid soln.Be determined as the volume (being the titrating titer of sample) of the needed 1N hydrochloric acid of unreacted di-n-butyl amine in the neutralization reaction mixture.

Also have,, carry out titration according to identical with the above basically mode except not using biuret polyisocyanate.

Be determined as the volume (being the titrating titer of blank sample) of the needed 1N hydrochloric acid of unreacted di-n-butyl amine in the neutralization reaction mixture.

Measure the amount of isocyanate group according to following formula:

Isocyanate group content (wt%)=[(the titrating titer of blank sample (ml))-(the titrating titer of sample (ml))] * 42/[example weight (g) * 1,000] * 100

(6) viscosity:

Use E-type viscometer (model VISCONIC ED is by Japanese TOKIMEC Co., Ltd. produce and market) 25 ℃ of viscosity of measuring biuret polyisocyanates down.

(7) package stability of biuret polyisocyanate under 5 ℃

Biuret polyisocyanate is placed in colourless, the transparent Glass Containers and after with nitrogen purging container and is sealed.Then this Glass Containers was deposited under 5 ℃ 1 day.With the naked eye check the biuret polyisocyanate in the Glass Containers, whether become muddy to determine polyisocyanates.

Embodiment 1

To the flask nitrogen purging of agitator, thermometer, reflux exchanger and nitrogen service pipe be housed.Hexa-methylene-1 with 700 weight parts, 6-vulcabond (HMDI), the water of the biuretized reagent of conduct of the mixed solvent of the methylcellosolve acetate of the trimethyl phosphite 99 of 150 weight parts and 150 weight parts and 15 weight parts (mol ratio of HMDI/ water=5/1) joins in the flask.The mixture that is obtained is stirred 1 hour, keeps the flask temperature at 160 ℃ simultaneously, carries out first reaction in view of the above.Unreacted diisocyanate content in first reaction mixture is 65wt%.

In order to regulate the unreacted vulcabond concentration in first reaction mixture, with the feeding rate of 500g/hr first reaction mixture is joined in the Rota-film evaporator, under 160 ℃ and vacuum tightness, change the film evaporation then at 655pa.As a result, the unreacted vulcabond concentration in first reaction mixture becomes 5wt%.The transmissivity of urea dimer content and biuret polyisocyanate is respectively 1.5wt% and 94% in first reaction mixture.

First reaction mixture that has carried out regulating at unreacted vulcabond concentration heated 30 minutes under 140 ℃ of temperature in nitrogen atmosphere, carried out second reaction in view of the above.For the biuret polyisocyanate in second reaction mixture, the urea dimer content is not higher than 0.2wt% and transmissivity is 93%.

Subsequently, second reaction mixture is joined Rota-film evaporator (vacuum tightness: 67Pa; Temperature: 160 ℃) therefrom isolates biuret polyisocyanate by removing in second reaction mixture unreacted vulcabond in.For isolated biuret polyisocyanate, its number-average molecular weight is 690; Isocyanate group content is 22.9wt%; Unreacted vulcabond concentration is 0.3wt%; Be not higher than 0.2wt% with the urea dimer content.The transmissivity of biuret polyisocyanate and viscosity are respectively 93% and 3700mPas (25 ℃).In addition, biuret polyisocyanate in addition under 5 ℃, accept storage stability test after also become muddy.

Embodiment 2

Carry out first reaction according to identical with embodiment 1 basically mode, just the amount that is added into the water in the flask as biuretized reagent is 9.4 weight parts (mol ratio of HMDI/ water=8/1).Unreacted vulcabond concentration in first reaction mixture is 70wt%.

In order to regulate the unreacted vulcabond concentration in first reaction mixture, first reaction mixture is being changeed the film evaporation under the identical condition basically with among the embodiment 1.As a result, the unreacted vulcabond concentration in first reaction mixture becomes 4wt%.The transmissivity of urea dimer content and biuret polyisocyanate is respectively 1.1wt% and 95% in first reaction mixture.

The content of unreacted vulcabond is carried out the heating 60 minutes under 110 ℃ temperature in nitrogen atmosphere of first reaction mixture regulated, carried out second reaction in view of the above.For the biuret polyisocyanate in second reaction mixture, its urea dimer concentration is not higher than 0.2wt% and transmissivity is 95%.

Subsequently, second reaction mixture is changeed the film evaporation, separate biuret polyisocyanate by the unreacted vulcabond of removing in second reaction mixture.For isolated biuret polyisocyanate, its number-average molecular weight is 635; Isocyanate group content is 23.8wt%; Unreacted vulcabond concentration is 0.3wt%; Be not higher than 0.2wt% with the urea dimer content.The transmissivity of biuret polyisocyanate and viscosity are respectively 94% and 1600mPa.s (25 ℃).In addition, biuret polyisocyanate in addition under 5 ℃, accept storage stability test after also become muddy.

Embodiment 3

Basically according to embodiment 2 in identical mode carry out first reaction.Unreacted vulcabond concentration in first reaction mixture is 70wt%.

First reaction mixture changeing the film evaporation under the identical condition basically with among the embodiment 2, is joined HMDI in first reaction mixture subsequently, regulate unreacted vulcabond concentration in first reaction mixture in view of the above to 10wt%.

First reaction mixture that unreacted vulcabond concentration has been carried out regulating heated 30 minutes under 125 ℃ temperature in nitrogen atmosphere, carried out second reaction in view of the above.For the biuret polyisocyanate in second reaction mixture, its urea dimer content is not higher than 0.2wt% and transmissivity is 95%.

Subsequently, second reaction mixture is changeed the film evaporation, therefrom isolate biuret polyisocyanate by the unreacted vulcabond of removing in second reaction mixture.For isolated biuret polyisocyanate, its number-average molecular weight is 635; Isocyanate group content is that 23.7wt% unreacted vulcabond concentration is 0.3wt%; Be not higher than 0.2wt% with the urea dimer content.The transmissivity of biuret polyisocyanate and viscosity are respectively 94% and 1,600mPa.s (25 ℃).In addition, biuret polyisocyanate even under 5 ℃, carry out still becoming after the storage stability test muddy.The comparative example 1

According to basically with embodiment 2 in identical mode carry out first reaction.Unreacted vulcabond concentration in first reaction mixture is 70wt%.

First reaction mixture changeing the film evaporation under the identical condition basically with among the embodiment 2, is joined HMDI in first reaction mixture subsequently, in view of the above with the unreacted vulcabond concentration adjustment in first reaction mixture to 50wt%.

First reaction mixture that unreacted vulcabond concentration has been carried out regulating heated 30 minutes under 125 ℃ temperature in nitrogen atmosphere, carried out second reaction in view of the above.For the biuret polyisocyanate in second reaction mixture, its urea dimer content is that 0.5wt% and transmissivity are 95%.

Subsequently, second reaction mixture is changeed the film evaporation, therefrom isolate biuret polyisocyanate by the unreacted vulcabond of removing in second reaction mixture.For isolated biuret polyisocyanate, its number-average molecular weight is 635; Isocyanate group content is 23.8wt%; Unreacted vulcabond concentration is 0.3wt%; With the urea dimer content be 1.0wt%.The transmissivity of biuret polyisocyanate and viscosity are respectively 92% and 1,600mPa.s (25 ℃).Yet, become muddy this biuret polyisocyanate is accepted storage stability test under 5 ℃ after.The comparative example 2

In order to regulate the unreacted vulcabond concentration in first reaction mixture, first reaction mixture is being changeed the film evaporation under the identical condition basically with among the embodiment 2.

First reaction mixture that unreacted vulcabond concentration has been carried out regulating heated 15 minutes under 100 ℃ temperature in nitrogen atmosphere, carried out second reaction in view of the above.For the biuret polyisocyanate in second reaction mixture, its urea dimer content is that 0.8wt% and transmissivity are 95%.

Subsequently, second reaction mixture is changeed the film evaporation, therefrom isolate biuret polyisocyanate by the unreacted vulcabond of removing in second reaction mixture.For isolated biuret polyisocyanate, its number-average molecular weight is 635; Isocyanate group content is 23.8wt%; Unreacted vulcabond concentration is 0.3wt%; With the urea dimer content be 0.8wt%.The transmissivity of biuret polyisocyanate and viscosity are respectively 95% and 1,600mPa.s (25 ℃).Yet, become muddy after the storage stability test of this biuret polyisocyanate under 5 ℃.The comparative example 3

First reaction mixture that unreacted vulcabond concentration has been carried out regulating heated 120 minutes under 150 ℃ temperature in nitrogen atmosphere, carried out second reaction in view of the above.For the biuret polyisocyanate in second reaction mixture, its urea dimer content is not higher than 0.2wt% and transmissivity is 88%.

Subsequently, second reaction mixture is changeed the film evaporation, therefrom isolate biuret polyisocyanate by the unreacted vulcabond of removing in second reaction mixture.For isolated biuret polyisocyanate, its number-average molecular weight is 635; Isocyanate group content is that 23.8wt% unreacted vulcabond concentration is 0.3wt%; Be not higher than 0.2wt% with the urea dimer content.The viscosity of biuret polyisocyanate is 1,600mPa.s (25 ℃).In addition, this biuret polyisocyanate in addition under 5 ℃, accept storage stability test after also become muddy.Yet the transmissivity of this biuret polyisocyanate is 87%, and promptly there is discoloration problem in biuret polyisocyanate.The comparative example 4

To the flask nitrogen purging of agitator, thermometer, reflux exchanger and nitrogen service pipe be housed.With the HMDI of 700 weight parts, the water (mol ratio of HMDI/ water=5/1) of the mixed solvent of the methylcellosolve acetate of the trimethyl phosphite 99 of 150 weight parts and 150 weight parts and the biuretized reagent of conduct of 15 weight parts joins in the flask.The mixture that is obtained is stirred 1 hour, and the temperature that meanwhile keeps flask is carried out first reaction in view of the above at 160 ℃.Unreacted vulcabond concentration in first reaction mixture is 65wt%.

In order to regulate the unreacted vulcabond concentration in first reaction mixture, first reaction mixture is added in the Rota-film evaporator with the rate of feed of 500g/hr, under 160 ℃ and vacuum tightness, change the film evaporation then, then down and changeing the film evaporation under the vacuum tightness at 67Pa again at 160 ℃ at 655Pa.As a result, the unreacted vulcabond concentration in first reaction mixture becomes 0.5wt%.The transmissivity of urea dimer content and biuret polyisocyanate is respectively 1.5wt% and 94% in first reaction mixture.

First reaction mixture that unreacted vulcabond concentration has been carried out regulating heated 30 minutes under 110 ℃ temperature in nitrogen atmosphere, carried out second reaction in view of the above.For the biuret polyisocyanate in second reaction mixture, its number-average molecular weight is 690; Isocyanate group content is 22.9wt%; Unreacted vulcabond concentration is 0.5wt%; With the urea dimer content be 1.2wt%.The transmissivity of biuret polyisocyanate and viscosity are respectively 94% and 3,700mPa.s (25 ℃).Yet, become muddy this biuret polyisocyanate is accepted storage stability test under 5 ℃ after.

Embodiment 4

Use the system shown in Fig. 1 to carry out embodiment 4.Unless otherwise specified, all programs are to carry out in nitrogen atmosphere.

With hexa-methylene-1,6-vulcabond (HMDI) and reaction solvent (1: 1 mixed solvent of methylcellosolve acetate and trimethyl phosphite 99) respectively with 1,000 weight part/hour and 500 weight parts/hour flow velocity join continuously in first reactor 4 by ingress pipe 2.As biuretized reagent, water with 7.1 weight parts/hour flow velocity join (mol ratio of HMDI/ water=15/1) in first reactor 4 continuously by ingress pipe 1.First reaction is carried out in first reactor 4, second reactor 7 and

tubular reactor

9,10 and 11 in succession continuously.For instance, the reaction in first reactor 4 is at 120 ℃ and carries out under 90 minutes the residence time; Reaction in second reactor 7 is at 150 ℃ and carries out under 60 minutes the residence time; Reaction in

tubular reactor

9,10 and 11 is at 160 ℃ and carries out in 60 minutes the residence time, therefore obtains first reaction mixture.

(gas dissolving amount therein: 0.25Nml/ml) top (gas phase) via de-gassing vessel 20 joins in the de-gassing vessel with first reaction mixture that obtained, wherein de-gassing vessel 20 remains under the vacuum tightness of 30 ℃ and 655Pa, thereby makes the degassing of first reaction mixture.First reaction mixture after the degassing is discharged from the lower position (liquid phase) of de-gassing vessel 20.The content of unreacted vulcabond is 83wt% in first reaction mixture.

First reaction mixture after the degassing is added into Rota-film evaporator 21 (vacuum tightness: 655Pa; Temperature: 160 ℃) in, unreacted vulcabond concentration is regulated by Rota-film evaporator in first reaction mixture, and the vulcabond concentration in such first reaction mixture becomes 5wt%.The transmissivity of urea dimer content and biuret polyisocyanate is respectively 1.0wt% and 93% in first reaction mixture.Unreacted vulcabond and reaction solvent are recovered by waste pipe 22 with its form of mixtures.The amount of the biuret polyisocyanate that is contained in the mixture that is reclaimed is not higher than 0.5wt%.

First reaction mixture that unreacted vulcabond concentration has been carried out regulating is added in the heating container 23, and heats 30 minutes down at 130 ℃, carries out second reaction in view of the above.For the biuret polyisocyanate in second reaction mixture that is obtained, its urea dimer content is not higher than 0.2wt% and transmissivity is 91%.

Subsequently, second reaction mixture is joined Rota-film evaporator 24 (vacuum tightness: 67Pa, temperature: 160 ℃) in, the unreacted vulcabond in second reaction mixture is discharged by waste pipe 25, thereby isolates biuret polyisocyanate from second reaction mixture.Isolated biuret polyisocyanate is discharged from waste pipe 26.

For the biuret polyisocyanate that is obtained, its number-average molecular weight is 600; Isocyanate group content is 24.7wt%; Unreacted vulcabond concentration is 0.5wt%; Be not higher than 0.2wt% with the urea dimer content.The transmissivity of biuret polyisocyanate and viscosity are respectively 91% and 900mPa.s (25 ℃).In addition, this biuret polyisocyanate in addition under 5 ℃, accept storage stability test after also become muddy.

Embodiment 5

According to basically with embodiment 4 in identical mode carry out first reaction continuously, just the flow velocity of water is 10.7 weight parts/hour (mol ratio of HMDI/ water=10/1).The content of unreacted vulcabond is 73wt% in first reaction mixture that is obtained.

With first reaction mixture changeing the film evaporation under the identical condition basically with among the embodiment 4, to regulate the unreacted vulcabond concentration in first reaction mixture.Then, with basically with embodiment 4 in identical mode carry out second reaction.For the biuret polyisocyanate in second reaction mixture, its urea dimer content is not higher than 0.2wt% and transmissivity is 94%.

Subsequently, the unreacted vulcabond in second reaction mixture according to basically with embodiment 4 in identical mode be removed, thereby from second reaction mixture, isolate biuret polyisocyanate.For the biuret polyisocyanate that is obtained, its number-average molecular weight is 615; Isocyanate group content is that 24.4wt% unreacted vulcabond concentration is 0.4wt%; With the urea dimer content be not to be higher than 0.2wt%.The transmissivity of this biuret polyisocyanate and viscosity are respectively 94% and 1,700mPa.s (25 ℃).In addition, this biuret polyisocyanate in addition under 5 ℃, accept storage stability test after also become muddy.

For the mixture of unreacted vulcabond and the reaction solvent that reclaimed in changeing for the first time the film evaporation, the amount of wherein contained biuret polyisocyanate is not higher than 0.5wt%.Reference example 1

According to basically with embodiment 5 in identical mode produce biuret polyisocyanate, step does not just outgas.For the biuret polyisocyanate of being produced, its number-average molecular weight is 615; Isocyanate group content is 24.4wt%; With unreacted vulcabond concentration be 0.5wt%.The viscosity of gained biuret polyisocyanate is 1,700mPa.s (25 ℃).

For the mixture of unreacted vulcabond and the reaction solvent that reclaimed in changeing for the first time the film evaporation, the amount of wherein contained biuret polyisocyanate is up to 4wt%.Reference example 2

According to basically with reference example 1 in identical mode (promptly not using de-gassing vessel) produce biuret polyisocyanate, just will be at the unreacted vulcabond in the reference example 1 and the mixture that change the reaction solvent that is reclaimed in the film evaporation for the first time as vulcabond (raw material).For the biuret polyisocyanate of being produced, its number-average molecular weight is 665; Isocyanate group content is 23.6wt%; With unreacted vulcabond concentration be 0.5wt%.The viscosity of gained biuret polyisocyanate is 2,010mPa.s (25 ℃).

For the mixture of unreacted vulcabond and the reaction solvent that reclaimed in changeing for the first time the film evaporation, the amount of wherein contained biuret polyisocyanate is up to 4wt%.

Biuret polyisocyanate of the present invention not only has excellent stability at low temperatures, and its constant muddiness is not painted yet.Owing to have these character, biuret polyisocyanate of the present invention can be used for preparing coating composition, tackiness agent, fibre finish, sealing agent, water-resisting agent, foams and elastomerics or the like.For example, when biuret polyisocyanate of the present invention was used to prepare coating composition, the coating composition that is obtained can form a kind of coating that demonstrates excellent binding property and resistance to deflection energy.In addition, can also prepare efficiently by method of the present invention and not only demonstrate excellent low-temperature stability but also constant muddiness not with the biuret polyisocyanate of look.And the method for the application of the invention might reclaim unreacted vulcabond after the reaction of producing polyisocyanates.

Claims

1. biuret polyisocyanate, it is obtained by at least a vulcabond and the biuretized reagent react that is selected from aliphatic vulcabond and alicyclic diisocyanate, and this biuret polyisocyanate has following feature (1) and (2):

(1) this biuret polyisocyanate contain comprise the midbody product urea dimer, that belong to described vulcabond and biuretized reagent react contain the urea key compound, wherein said urea dimer is to be represented by following formula (I):

Based on this biuret polyisocyanate and the gross weight that contains the urea key compound that comprises the urea dimer, this biuret polyisocyanate has the urea dimer content that is not higher than 0.5wt%, wherein this urea dimer content is defined as: in the gel permeation chromatography figure that contains unreacted vulcabond and the described described biuret polyisocyanate that contains the urea key compound, the area at the dimeric peak of described urea accounts among this gel permeation chromatography figure the percentage ratio of the total area at all peaks after having got rid of the peak that belongs to described unreacted vulcabond; With

2. produce the method for biuret polyisocyanate, it comprises:

(a) carry out between at least a vulcabond that is selected from aliphatic vulcabond and alicyclic diisocyanate and biuretized reagent first the reaction, the mol ratio of wherein said vulcabond and biuretized reagent is 4-40, thereby obtains to contain first reaction mixture of unreacted vulcabond and biuret polyisocyanate;

(c) described first reaction mixture that will regulate unreacted vulcabond concentration under 110 ℃-160 ℃ temperature in step (b) heats, carry out second reaction in view of the above, therefore produce biuret polyisocyanate with following feature (1) and (2):

(1) this biuret polyisocyanate contain comprise the midbody product urea dimer, that belong to above-mentioned first reaction contain the urea key compound, wherein said urea dimer is to be represented by following formula (I):

Based on this biuret polyisocyanate and the gross weight that contains the urea key compound that comprises described urea dimer, this biuret polyisocyanate has the urea dimer content that is not higher than 0.5wt%, wherein this urea dimer content is defined as: containing the unreacted vulcabond and containing among the gel permeation chromatography figure of described biuret polyisocyanate of urea key compound, the area at the dimeric peak of described urea accounts among this gel permeation chromatography figure the percentage ratio of the total area at all peaks after having got rid of the peak that belongs to described unreacted vulcabond; With

(2) this biuret polyisocyanate records under 430nm by the sample pool that uses 2cm length and has at least 90% optical transmittance; With

(d) from second reaction mixture that step (c) is obtained, isolate described biuret polyisocyanate.

3. according to the method for claim 2, wherein in step (d), the separation of described biuret polyisocyanate is undertaken by remove unreacted vulcabond from described second reaction mixture.

4. according to the method for claim 2, wherein said at least a vulcabond is a hexa-methylene-1, the 6-vulcabond.

5. according to the method for claim 2, wherein said biuretized reagent is water.

6. according to the method for claim 5, in step (a), be to carry out in the presence of at least a solvent of compound of representing from following formula (II) and alkyl phosphate, selecting wherein in the reaction of first between described vulcabond and the water:

R wherein ¹And R ²Expression independently of one another has the alkyl or the acyl group of 1-4 carbon atom, R ³Expression methyl or hydrogen atom, n represents integer 1 or 2.

7. according to the method for claim 2, wherein in step (b), the adjusting of the unreacted vulcabond concentration in first reaction mixture is undertaken by changeing the film method of evaporating.

8. according to the method for claim 7, wherein to the processing that before changeing the film evaporation, outgases of described first reaction mixture.

9. according to the method for claim 3, wherein in step (d), from described second reaction mixture, remove the operation of unreacted vulcabond and undertaken by changeing the film method of evaporating.

10. according to the method for claim 9, wherein to the processing that before changeing the film evaporation, outgases of described second reaction mixture.

11. according to the method for claim 2, wherein step (a) comprises and carries out following substep (i) and (ii) continuously:

(i) mixture that stirs vulcabond and biuretized reagent obtains the intermediate reaction mixture in view of the above to carry out the reaction between described vulcabond and the biuretized reagent in the homogeneous system of gained mixture; With

(ii) described intermediate reaction mixture is joined in the tubular reactor, further carry out reaction between described vulcabond and the biuretized reagent with piston stream mode, thereby obtain first reaction mixture.