JPS61215397A - Block polyisocyanate - Google Patents

Abstract

PURPOSE:The titled substance having an active isocyanate group which is protected with a hindering agent free from toxicity, obtained by reacting an organic isocyanate compound with a silanol compound having an aryl group directly bonded to Si. CONSTITUTION:For example, a silanol compound having at least one aryl group directly bonded to Si, such as a compound (e.g., triphenylsilanol, etc.) shown by the formula I (R1-R6 are H, CH3, Cl, Br, CF3, etc.; m is 0-2; n is 1-3), a compound (e.g., compound shown by the formula III, etc.) shown by the formula II (R7-R9 are alkyl such as CH3, C2H5, etc.); l and m are 1 or 2), etc. is reacted with an organic isocyanate compound (e.g., tolylene diisocyanate, etc.) in such a way that the amount of the silanol compound is equivalent to NCO, at 70 deg.C for about 10hr, to give the aimed substance having 0.3wt% NCO content.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to block polyisocyanate compounds capable of forming thermally active isocyanate groups.

[Technical background of the invention and its problems]

Conventional polyurethane resins are resins with urethane bonds formed by the reaction between polyisocyanate compounds and hydroxyl groups, and have excellent gloss, hardness, abrasion resistance, purity, etc., and are used as coatings, coatings, film impregnations, insulation materials (forms), etc. It is used in a wide range of molded products, and its uses are expanding further.

In general, polyurethane sealants are two-component and have a short pot life, so there are practical problems in that they must be mixed immediately before use and stored at low temperatures. For this reason, research into making polyurethane resins into a single component has been actively carried out.Blocked isocyanates, which are temporarily stabilized with a compound having a wide range of active hydrogens to act as a blocking agent for trapping isocyanate groups, have been developed and put into practical use. Those that are thermally dissociated by heating and regenerated as active isocyanate groups are widely used.

As such a sequestering agent, “Erogress in Or
ganicCOatings"Vol, 3.p, 73
(1975) and “polyurethane resin” plastic material R
Lecture 2. As shown in Keiji Iwata 1), 51, phenol, diethyl malonate, acetoacetate, acetylacetone, hydrocyanic acid, sodium acid salivary sulfate, methanol, 1-butanol, benzenethiol,
Phthalimide, imidazole, caprolactam, alpha-pyrrolidone, ketoxime, ethyl carbamate, polysuccinic acid.

etc. are known. However, some of these have problems such as solubility in organic solvents and toxicity when thermally dissociated. In addition, Bayer's "AP Stable" is currently the most widely used phenol-block polyitecyanate compound. has a boiling point of iso'a, which evaporates as soon as it dissociates, has a characteristic odor, and is also toxic. Furthermore, there are physical problems such as foaming due to evaporated matter, coating film, and deterioration of electrical properties due to phenol retained in the molded product.

Furthermore, in some products, the regeneration rate of isocyanate groups during heating is low, and side reactions such as amine formation occur. For example, when a methylene group-containing isocyanate is used as a blocking agent in combination with a polyhydroxy compound,
It has poor chemical resistance and water resistance, and when baked at temperatures between 71 and 150°C, the paint film discolors significantly.As such, various proposals have been made as blocked isocyanates, but none have yet been found that are satisfactory. 0 [Object of the Invention] This invention improves the above-mentioned drawbacks, and improves the stability of blocked isocyanate, the high regeneration rate of active isocyanate by thermal dissociation, and the excellent effect of non-toxicity of the blocking agent after dissociation. The purpose of the present invention is to provide a novel blocked isocyanate with high properties.

[Summary of the invention]

In view of the above-mentioned circumstances, the present inventors conducted intensive research on the regeneration rate of active isocyanate through thermal dissociation and on non-toxic blocking agents. We have discovered that this is the case and have completed the present invention. That is, the present invention provides a block polyisocyanate compound obtained from an organic isocyanate compound and an active hydroxyl compound as a blocking agent for the active isocyanate base layer, in which the active hydroxyl compound is a silanol in which at least one aryl group is directly bonded to silicon. It is characterized by using a compound.

As the silicon compound as the active hydroxyl compound as the capping agent used in the present invention, (in the formula, R1-R6 are H2 country 3. CI, Br, CF3
These groups may be the same or different. Further, m represents 1 or 2, and n represents an integer of 1 to 3. ) ((II l, in the formula R7~R9cG(3,a(zHs
fk represents a O7k + group. Moreover, l and m represent 1 or 2, and m represents an integer of 1 to 3. ) Examples include silanol compounds in which at least one aryl group is directly bonded to silicon, such as.

Specific examples of such silicon compounds include the following formula: Fa Examples include compounds shown in the following.

Organic isocyanates that can be used in the present invention include 1,6-hexamethylene diisocyanate, 1,8
-octamethylene diisocyanate, 1,12-) decamethylene diisocyanate, 2.2.4-) alkylene diisocyanate such as dimethylhexamethylene diisocyanate, 3.3'-diisocyanate dipropyl ether, 3-isocyanate methyl-3,5, 5-) Dimethylcyclohexyl isocyanate, cyclohexylene-1,3-diisocyanate, cyclohexylene-1
Unsaturated isocyanates such as 4-diisocyanate, methyl-2,6-diisocyanate caproate, bis(2-isocyanate ethyl) fumarate, 4-methyl-1,3-diisocyanate cyclohexane, transvinylene diisocyanate, 4,4-methylene −Bis(
carbonates of diisocyanates such as cyclohexylic anate), methane diisocyanate% NtN'tN"-tris(6-isocyanatehexamethylene)biuret, bis(2-isocyanateethyl)carbonate, and other well-known carbonates derived from aliphatic polyamines. Isocyanates, toluene diisocyanate, xylylene diisocyanate, dianisidine diisocyanate, -4
, 4'-diphenylmethane diisocyanate, 1-ethoxy-2,4-diisocyanatebenzene, 1-chloro-2,4-diisocyanatebenzene, tris(4-isocyanatephenyl)methane, naphthalene diisocyanate, phleolein diisocyanate, 4.4'- Aromatic isocyanates such as biphenyl diisocyanate, phenylene diisocyanate, 3,3'-dimethyl-
4,4'-biphenyl diisocyanate, p-isocyanate benzyl isocyanate, tetrachloro-1,3
-phenylene diisocyanate, 2.4.6-dribromo 1.3-phenylene diisocyanate, bis(2-
Polyisocyanates such as prepolymers such as polyether or polyester polyols with benzene, 3-isocyanate methyl-3,3,5-trimethylcyclohexyl isocyanate, and even 2-isocyanate ethyl-6-isocyanate cabroate, etc. and a polyhydroxy compound or a polyamine compound.

Block compounds of various diisocyanate monomers as described above can be used as the organic isocyanate compound, and the technique of the present invention can also be applied to partially blocked blocked isocyanate compounds.

The blocked isocyanate compound of the present invention can be obtained by reacting each of the above-mentioned organic isocyanate compounds with a silanol compound in which at least one aryl group is directly bonded to silicon, but such a reaction can be carried out according to a conventional method. does not require any means.

〔Effect of the invention〕

As outlined above, by blocking the active isocyanate of an organic isocyanate compound with a silanol compound in which at least one ester group is directly bonded to silicon, it is possible to improve odor and toxicity caused by thermal dissociation. At the same time, the thermally dissociated silanol compound acts as a two-way catalyst through interaction with M thylate, and also acts as a curing catalyst for epoxy, etc., so it plays a large role in practical use.

[Embodiments of the invention]

Example 1 TDI-80/20 (2
, 4-tolylene diisocyanate, 2.6-)lylene diisocyanate), 2 mol of triphenylsilanol dissolved in MEK was added dropwise to 1 mol of the mixture. The temperature was gradually increased, and when it reached 70°C, the reaction started υ At that point, the temperature was fixed 1 Due to an exothermic reaction, the solution rose to 82°C. The reaction was carried out at 70°C for 10 hours and stopped when the NCO content reached 0.30. Thereafter, the MEK was transferred to a vat and desolvated under a vacuum of less than 1 wHg at 70° C. for 5 hours to obtain a white powder product. When the thermal dissociation temperature was examined with B8C, it was 150-170'O.

Example 2 A polyisocyanate prepared by adding 3 moles of diitecyanate to 1 mole of trimethylol probath, such as Olestar P49-758 (Mitsui Chemicals, Inc.), was mixed with 3 moles of triphenylsilanol at 70°C for 10 hours. A reaction NCO content of 0.5% was obtained. The same vacuum desolvation as in Example 1 was performed to obtain a white powder product. The thermal dissociation temperature measured by DSC was 150-170'O.

Example 3゜Examples shown in Table 1 and triphenylsilanol, and for comparison, AP stable (manufactured by Bayer AG) in which the polyisocyanate was the same as in Example 2 and was blocked with phenol.
When the gel time on a hot iron plate was measured using the method, it was found that the system containing triphenylsilanol exhibits catalytic function when combined with the Al complex. Moreover, it has become clear that active NGO promotes even faster curing due to its active reactivity with epoxy groups.

Agent: Patent Attorney Noriyuki Chika (1 other person)

Claims (1)

[Claims] A blocked polyisocyanate, which is stabilized by reacting an organic isocyanate compound with a silanol compound in which at least one aryl group is directly bonded to silicon as a blocking agent for active isocyanate groups in the isocyanate compound.