阅读说明：本技术 一种异氰酸酯稳定剂及其制备方法 (Isocyanate stabilizer and preparation method thereof ) 是由 朱付林 李建峰 尚永华 陈浩 刘照 郑兵 吴谦 宋国毅 黎源 于 2018-08-31 设计创作，主要内容包括：本发明涉及一种异氰酸酯稳定剂及其制备方法。所述异氰酸酯稳定剂结构如通式(Ⅰ)所示,<Image he="333" wi="305" file="DDA0001784143530000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>本发明稳定剂通过一步反应合成,经分离纯化即可得到,制备方法简单,适用于提高异氰酸酯特别是XDI存储稳定性,延长异氰酸酯存储时间,添加该类稳定剂的异氰酸酯可用于光学树脂合成。(The invention relates to an isocyanate stabilizer and a preparation method thereof. The isocyanate stabilizer has a structure shown as a general formula (I), the stabilizer is synthesized by one-step reaction, can be obtained by separation and purification, has simple preparation method, is suitable for improving the storage stability of isocyanate, particularly XDI, and prolonging the storage time of isocyanate, and the isocyanate added with the stabilizer can be used for synthesizing optical resin.)

1. An isocyanate stabilizer having the structure shown in formula (I):

wherein n is more than or equal to 1 and less than or equal to 3, preferably 1, 2 or 3;

x is chlorine or bromine;

r is selected from C1-C12 alkyl, C3-C12 cycloalkyl, C3-C12 cycloalkyl with substituent, phenyl with substituent, and five-membered or six-membered heterocyclic aromatic group containing at least one atom selected from oxygen, sulfur and nitrogen, preferably C1-C6 alkyl, C5-C6 cycloalkyl, C5-C6 cycloalkyl with substituent, phenyl and phenyl with substituent;

the substituent on the C3-C12 cycloalkyl with substituent and the substituent on the phenyl with substituent are respectively at least one of C1-C12 alkyl, C1-C12 alkoxy, halogen, nitro, ester group and cyano, and preferably at least one of C1-C4 alkyl and C1-C4 alkoxy.

2. The isocyanate stabilizer according to claim 1, characterized in that: at least one compound of the following structure:

3. the isocyanate stabilizer according to claim 1, characterized in that: the concentration of the isocyanate is 1 to 2000ppm, preferably 5 to 500 ppm.

4. The isocyanate stabilizer according to any one of claims 1 to 3, wherein: the isocyanate is mixed with the existing isocyanate stabilizer for use, and the mixing mass ratio is preferably 1: 1; the existing isocyanate stabilizer is preferably a hindered phenol stabilizer, a phosphite stabilizer, a benzoyl chloride stabilizer or phenol, most preferably phenol.

5. The isocyanate stabilizer according to any one of claims 1 to 4, wherein: the isocyanate stabilizer, suitable isocyanate include monoisocyanate, and diisocyanate containing formula (II)

OCN-R′-NCO

(Ⅱ)

Wherein R' is selected from C2-C18 alkyl, C3-C12 cycloalkyl, C3-C12 cycloalkyl with substituent, phenyl with substituent, naphthyl and naphthyl with substituent;

the substituent on the C3-C12 naphthenic base with the substituent, the substituent on the phenyl with the substituent and the substituent on the naphthyl with the substituent are respectively at least one of C1-C12 alkyl, alkoxy of C1-C12, halogen, nitro, ester group and cyano.

6. The isocyanate stabilizer according to claim 5, characterized in that: the monoisocyanate is methyl isocyanate, butyl isocyanate, phenyl isocyanate and benzyl isocyanate; the diisocyanate is toluene diisocyanate, 4 '-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4' -dicyclohexylmethane diisocyanate, and m-xylylene diisocyanate.

7. The isocyanate stabilizer according to claim 5, characterized in that: the isocyanate is m-xylylene diisocyanate.

8. A method for preparing the isocyanate stabilizer according to any one of claims 1 to 7, comprising the steps of:

a) dissolving a compound of a general formula (III) in an inert organic solvent, and introducing hydrogen chloride or hydrogen bromide gas for reaction;

wherein n and R are the same as formula (I);

b) separating the reaction system in the step a) to obtain the isocyanate stabilizer.

9. The method of claim 8, wherein: the inert organic solvent is at least one of aromatic hydrocarbon, halogenated aromatic hydrocarbon, alkane and halogenated alkane, and preferably at least one of chlorobenzene, dichlorobenzene, toluene and xylene.

10. The method of claim 8, wherein: the mass ratio of the compound of the general formula (III) to the inert organic solvent is 1: 10-100, preferably 1: 20-50; the molar ratio of the compound of the general formula (III) to hydrogen chloride or hydrogen bromide is 1: 2.2-20, preferably 1: 2.5-10.

Technical Field

The invention belongs to the technical field of isocyanate, and relates to an isocyanate stabilizer and a preparation method thereof.

Background

Among isocyanate compounds, since isocyanate groups have high reactivity and they tend to yellow or self-polymerize during storage, affecting downstream applications, it is essential to suppress the yellowing and self-polymerization of isocyanates by adding a stabilizer.

Currently, isocyanate compound stabilizers are typically hindered phenolic compounds, for example, U.S. Pat. No. 3,182,81 discloses 2, 6-di-tert-butyl-4-methylphenol (BHT) as an isocyanate stabilizer, and Japanese patent publication No. JP33438/1970 reports that phosphite esters such as triphenyl phosphite antioxidants have good effects, and are still widely used at present.

In addition, many other stabilizers are known, such as japanese patent JPS5036546 which discloses substituted ureas as stabilizers that can prevent yellowing of isocyanates due to sunlight or ultraviolet light; german patent DE2837770 discloses acidic substances such as perchloric acid and trifluoromethanesulfonic acid as stabilizers; US3247236 discloses the same stabilization of carbon dioxide and sulphur dioxide; japanese patent JPS 50101344A discloses organic tertiary amines as MDI stabilizers which are effective in preventing color numbers from increasing; also patent CN104718215 discloses that acyl chloride species are used as stabilizers for silicon-containing isocyanates to improve their storage stability.

However, the stability effect of the above stabilizers such as acid stabilizer perchloric acid, trifluoromethanesulfonic acid, carbon dioxide or acid chloride on m-Xylylene Diisocyanate (XDI) is poor, it is known that XDI tends to become turbid by forming a nylon-1 type polymer by self-polymerization, and it is difficult to stably store XDI at room temperature for 1 month or more with the currently used isocyanate stabilizers and the stabilizers disclosed in the above patents.

In the aspect of isocyanate application, the isocyanate compound raw material for preparing the optical resin has strict requirements on stability, and the raw material is required not to have yellowing or turbidity, so that isocyanates such as XDI (X double hydroxides) serving as the raw material of the optical resin have higher requirements on additives.

Therefore, there is an urgent need for a stabilizer capable of suppressing yellowing and clouding of isocyanate compounds, particularly XDI, due to long-term storage.

Disclosure of Invention

The present invention has been made in view of the above-mentioned disadvantages of the prior art, and an object of the present invention is to provide an isocyanate stabilizer which can prevent yellowing and clouding of isocyanate-based compounds during long-term storage and can inhibit self-polymerization of isocyanates, particularly m-Xylylene Diisocyanate (XDI). The isocyanate compound to which the stabilizer of the present invention is added can be used as a raw material for an optical polyurethane resin such as a plastic lens.

It is another object of the present invention to provide a method for preparing the isocyanate stabilizer.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an isocyanate stabilizer having the structure shown in formula (I):

wherein n is more than or equal to 1 and less than or equal to 3; e.g., n can be 1, 2, or 3;

x is chlorine or bromine;

r is selected from C1-C12 alkyl, C3-C12 cycloalkyl, C3-C12 cycloalkyl with substituent, phenyl with substituent, and five-membered or six-membered heterocyclic aromatic group containing at least one atom selected from oxygen, sulfur and nitrogen, preferably C1-C6 alkyl, C5-C6 cycloalkyl, C5-C6 cycloalkyl with substituent, phenyl and phenyl with substituent;

the substituent on the C3-C12 cycloalkyl with substituent and the substituent on the phenyl with substituent are respectively at least one of C1-C12 alkyl, C1-C12 alkoxy, halogen, nitro, ester group and cyano, and preferably at least one of C1-C4 alkyl and C1-C4 alkoxy.

The isocyanate stabilizer is preferably at least one of compounds of the following structures:

the isocyanate stabilizer is added to the isocyanate at a concentration of 1 to 2000ppm, preferably 5 to 500 ppm.

The isocyanate stabilizer is preferably mixed with the existing isocyanate stabilizer for use, and the mixing mass ratio is preferably 1: 1; the prior isocyanate stabilizer is preferably hindered phenol stabilizer, phosphite stabilizer, benzoyl chloride stabilizer, phenol, most preferably phenol.

Suitable isocyanates include monoisocyanates, and diisocyanates containing the structure of formula (II)

OCN-R′-NCO

(Ⅱ)

Wherein R' is selected from C2-C18 alkyl, C3-C12 cycloalkyl, C3-C12 cycloalkyl with substituent, phenyl with substituent, naphthyl and naphthyl with substituent;

the substituent on the C3-C12 naphthenic base with the substituent, the substituent on the phenyl with the substituent and the substituent on the naphthyl with the substituent are respectively at least one of C1-C12 alkyl, alkoxy of C1-C12, halogen, nitro, ester group and cyano.

The monoisocyanate is preferably methyl isocyanate, butyl isocyanate, phenyl isocyanate or benzyl isocyanate;

the diisocyanate is preferably toluene diisocyanate, 4 '-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4' -dicyclohexylmethane diisocyanate, or m-xylylene diisocyanate.

The isocyanate is most preferably m-Xylylene Diisocyanate (XDI).

The preparation method of the isocyanate stabilizer comprises the following steps:

a) dissolving a compound of a general formula (III) in an inert organic solvent, and introducing hydrogen chloride or hydrogen bromide gas for reaction;

wherein n and R are the same as formula (I);

b) and a) carrying out filter pressing separation on the reaction system in the step a) by using nitrogen to obtain the isocyanate stabilizer.

The preparation method of the isocyanate stabilizer has the following reaction formula:

wherein n, X and R are the same as those in formula (I).

The inert organic solvent is at least one of aromatic hydrocarbon, halogenated aromatic hydrocarbon, alkane and halogenated alkane, and preferably at least one of chlorobenzene, dichlorobenzene, toluene and xylene.

The mass ratio of the compound of the general formula (III) to the inert organic solvent is 1: 10-100, preferably 1: 20-50; the molar ratio of the compound of the general formula (III) to hydrogen chloride or hydrogen bromide is 1: 2.2-20, preferably 1: 2.5-10.

The reaction temperature is controlled below 30 ℃, the flow of hydrogen chloride or hydrogen bromide is 1-20L/h per 20g of the compound of the formula (III), preferably 10L/h per 20g of the compound of the formula (III), and the reaction is completed after the hydrogen chloride is introduced.

The isocyanate to which the stabilizer of the present invention is added can inhibit self-polymerization of isocyanate itself, and is useful as a raw material for optical polyurethane resins such as plastic lenses. Effectively solves the yellowing and turbidity phenomena of the isocyanate in the long-term storage process and effectively improves the stability of the isocyanate.

Compared with the prior art, the invention has the following positive effects:

1. the isocyanate stabilizer is a compound with a carbamyl chloride or bromine structure, wherein a hindered amine structure contained in the compound can capture free radicals, so that the stability is improved; meanwhile, the structure reacts in isocyanate to release hydrogen chloride or hydrogen bromide, so that isocyanate polymerization is inhibited, a stabilizing effect is further achieved, and turbidity caused by increase of polymers is prevented.

2. The isocyanate stabilizer disclosed by the invention is simple in preparation method, is suitable for improving the long-term storage stability of isocyanate, particularly XDI, inhibiting a long-chain homopolymerized compound generated by XDI due to free radicals, preventing the isocyanate from becoming turbid after long-term storage, and prolonging the storage time to more than six months. XDI added with the stabilizing agent can obtain lens resin without optical deformation and white turbidity when used for preparing the lens resin.

Detailed Description

The invention will now be further illustrated with reference to the following examples, but is not limited thereto.

The embodiment of the invention and the comparative example have the following main raw material sources:

1. isocyanates such as XDI, MDI, HDI and the like are self-made by a conventional method;

2. the hydrogen chloride or hydrogen bromide gas comes from cigarette-table Shuangfeng gas company;

3. other reagents were obtained from Sigma Aldrich.

The performance test method of the embodiment and the comparative example comprises the following steps:

1. isocyanate color number: measured according to the method of GB/T3143-1982;

2. nuclear magnetic analyses were tested using Bruker 400 MHz.

Preparation of isocyanate stabilizer