JPH033657B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition that prevents crystallization of diphenylmethane diisocyanate, particularly at low temperatures. Diphenylmethane diisocyanate is a solid substance with high reactivity and excellent physical properties.
It is advantageously used as a raw material for urethane foam and elastomer, and is also frequently used for consolidating soft ground. In particular, crude diphenylmethane diisocyanate (hereinafter referred to as crude-MDI)
Because it is a liquid at room temperature, it does not need to be heated and melted like pure diphenylmethane diisocyanate before use. For this reason, crude MDI is exclusively used in cases such as insulating urethane foam at construction sites, preventing spring water in civil engineering work, and solidifying rock in coal mines because it is difficult to heat it. For these purposes, crude MDI is often stored for long periods in cold regions during the winter, or transported for long periods of time to extremely cold regions overseas. In such a case, diphenylmethane diisocyanate precipitates in the crude MDI and becomes a slurry, increasing the viscosity and making it difficult to use.If the process continues further, the entire product solidifies and becomes completely unusable. As a result of various studies to eliminate these obstacles, the present inventors succeeded in preventing the precipitation of crystals by adding and mixing esters, and arrived at the following invention. That is, the present invention is a diphenylmethane diisocyanate composition in which crystallization is prevented, which is characterized by adding an ester to diphenylmethane diisocyanate. Among the esters used in the present invention, particularly preferred compounds are those having a melting point of -20°C or lower. Specifically, examples include dibutyl phthalate (DBP), diisooctyl phthalate (DIOP), di-(2-ethylhexyl) phthalate (DOP), diisodecyl phthalate (DIDP),
Phthalate esters such as ditridecyl phthalate (DTDP) and diallyl phthalate (DAP),
Di-(2-ethylhexyl)adipate (DOA),
Di-(2-ethylhexyl) azelate (DOZ)
aliphatic dibasic acid esters such as triethylene glycol di-(2-ethylhexoate), glycol esters such as triethylene glycol di-(2-ethylhexoate), tetrahydrofurfuryl oleate, methyl acetyl ricinoleate (MAR), methyl pentachlorostearate ,
fatty acid esters such as tri-(2-ethylhexyl) phosphate (TOP), cresyl phenyl phosphate (CDP), tricresyl phosphate (TCP), tri-(2-ethylhexyl) phosphate, etc.
-ethylhexyl) trimellitate, acetyl
Compounds such as tributyl cylate (ATBC). The appropriate amount of these esters to be added is 2.5 to 20 parts by weight (hereinafter "parts") per 100 parts by weight of diphenylmethane diisocyanate. If it is below this range, the effect will be small, and if it exceeds this range, the strength of the reaction product will decrease. The present invention will be specifically explained below with reference to Examples. Example 1 Crude - MDI, 100 parts ester 10 listed in Table 1
part and mix at room temperature. This mixture was placed in a reagent bottle, the bottle was replaced with nitrogen, the bottle was sealed tightly, and the bottle was left in a constant temperature bath maintained at -30°C. The precipitation of crystals was observed. The results were as shown in Table 1. It is clear from Table 1 that crystal precipitation of diphenylmethane diisocyanate can be prevented by adding esters.

【table】

[Table] Example 2 To 100 parts of crude MDI, the amount of DOP listed in Table 2 was added and mixed. This mixture was treated in the same manner as in Example 1, and the results shown in Table 2 were obtained.

[Table] (Note) Judgment criteria were based on Table 1.
From Table 2, to prevent crystal precipitation,
It was found that more than 2.5 copies of DOP were required.

Claims (1)

[Claims] 1. A diphenylmethane diisocyanate composition which prevents crystallization and is characterized by adding an ester to diphenylmethane diisocyanate.