JPS6065018A - Polyisocyanate compound - Google Patents

Abstract

PURPOSE:To obtain a high-MW polyisocyanate compound without causing gelation, by reacting a chemical species having two active-hydrogen-containing functional groups in the molecule with a specified triisocyanate compound. CONSTITUTION:A polyisocyanate compound having at least four isocyanato groups in the molecule is obtained by reacting a chemical species having two active-hydrogen-containing functional groups in the molecule with a triisocyanate compound having three isocyanato groups in the molecule one of which is less reactive than the other two at a molar ratio of the isocyanato groups to the functional groups, M, in the range of 1.5<M<=3. When used as a curing agent for a paint such as a magnetic paint, the polyisocyanate compound can improve the strength, durability, and solvent resistance of a cured film, because it is possible to increase the number and concentration of isocyanato groups even when its MW is high. It is also advantageous, for example, in that the toxicity problem during application can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyisocyanate compounds. Hitherto, polyisocyanate compounds have been widely used as curing agents for paints and adhesives. Polyisocyanate compounds are
Since diisocyanate monomers are toxic and easily volatile, they are often used in the form of polyurethane prepolymers obtained by adding diisocyanates to polyhydric alcohols. A typical example is trimethylolpropane tris (tolylene diisocyanate), which is obtained by reacting trimethylolpropane i mo/ with 3 mo/tolylene diisocyanate, and is known under trade names such as Coronate L (Japan Polyurethane ■). Such polyisocyanate compounds themselves have low volatility and low toxicity, but because diisocyanate is used in excess of polyhydric alcohol during synthesis,
It is inevitable that free diisocyanate will be mixed into the polyisocyanate compound. It is extremely difficult to completely remove this diisocyanate. When a polyisocyanate compound containing a small amount of diisocyanate is used, for example, as a curing agent for a paint, there are problems in terms of safety and health during the coating process. Further, when obtaining a high molecular weight polyisocyanate compound, a similar problem occurs because an excessive amount of diisocyanate is reacted with a high molecular weight acrylic polyol or the like. On the other hand, attempts have also been made to do C). However, in this case 6
If the reactivities of the two isocyanate groups are equivalent, each inocyanate group will participate in this reaction.
The branched chains grow to produce a gel-like polyisocyanate compound. However, such gel-like polyisocyanate compounds are unsuitable for applications such as paints.

JP-A-53-155931 discloses triisocyanate compounds with low toxicity and low viscosity. The present inventor found that among the three isocyanate groups of this triisocyanate compound, the reactivity of one incyanate group is only a fraction of that of the other two.

As a result of intensive research focusing on this difference in reactivity, we found that by using such triisocyanates, high molecular weight polyfunctional incyanate compounds can be synthesized without gelling. Successful.

Therefore, the present invention uses a chemical species having two functional groups containing active hydrogen atoms in the molecule and an isocyanesocyanate compound having three incyanate groups in the molecule, A reaction product obtained by the reaction with a molar ratio M of isocyanate groups to the containing functional groups being 1.5<M≦3, which provides a polyisocyanate compound having at least 4 isocyanate groups in the molecule. be.

The polyisocyanate compound of the present invention is obtained by reacting a chemical type having two functional groups containing active hydrogen atoms in the molecule with a triisocyanate compound.
The active hydrogen atom herein refers to a hydrogen atom that can form an intermolecular bond by attacking the two incyanate groups with greater reactivity among the three incyanate groups of the triisocyanate compound. Therefore, the activity level of this active hydrogen atom is selected by controlling the reaction conditions as necessary to such an extent that the active hydrogen atom hardly reacts with the least reactive isocyanate group remaining in the triisocyanate compound. . As chemical species having two functional groups containing active hydrogen atoms, compounds having two hydroxyl groups that react with incyanate groups to form urethane bonds are preferable, such as ethylene glycol, propylene glycol, β, β '-Dihydroxy diethyl ether (diethylene glycol), cyfropylene glycol, 1,4-butylene glycol, 1,3-butylene glycol and other low molecular weight dihydric alcohols, and polyesters and polyethers having two hydroxyl groups (hereinafter referred to as polyester diols, respectively) Examples include polymers such as polyether diol (referred to as polyether diol) and mixtures thereof.

As the polyether diol, polyethylene glycol, polypropylene glycol, polypropylene-polyethylene glycol, polybutylene glycol, polyoxymethylene, etc. can be used.

In addition, the above polyester diol contains terephthalic acid, isophthalic acid, orthophthalic acid,
1.5-Aromatic dicarboxylic acids such as naphthalic acid, dicarboxylic acids such as aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, p-oxybenzoic acid, p-(2- They may be synthesized using aromatic oxycarboxylic acids such as hydroxyethoxybenzoic acid, tricarboxylic acids and tetracarboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid, etc. Among these, particularly preferred carboxylic acids Acid components include terephthalic acid, isophthalic acid, adipic acid,
Such as sebacic acid.

Further, as polyhydric alcohol components which are another component of polyester diol, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-bentanediol, neopentyl glycol, 1, 6-hexanediol, 2.2.4
- aliphatic diols such as trimethyl-1,6-pentanediol or their substituted salt conductors, diols such as polyalkylene glycols such as alicyclic 9-diols such as 1,4-cyclohexane dimetatool;
Ethylene oxide adduct or propylene oxide adduct of bisphenol A, hydrogenated bisphenol A
Examples of ethylene oxide adducts include oxides such as alkylene oxide adducts of aromatic diols such as propylene oxide adducts.

Further, the triisocyanate compound has three isocyanate groups, and in this invention, it is important that one of the isocyanate groups is inferior in reactivity to the other two isocyanate groups.

As such a triisocyanate compound, a triisocyanate compound represented by the general formula: % formula % (1) (wherein R represents a divalent hydrocarbon residue having 2 or 3 carbon atoms) can be used. In this general formula, in order to distinguish between the six isocyanate groups, each is conveniently replaced with XlY%Z, and X-(L'H2)4-CH-Y C=0... ......(2) -R-Z If you compare the reactivity of the isocyanate group, you will find that X(Y, Z Y?Z...Song...(3) To be more specific, Y and 2 are X at room temperature.
This difference in reactivity becomes even larger as the temperature increases.

The specific name of the compound represented by the general formula (1) is:
2-incyanatoethyl 2,6-dicyanatohexanoate, 6-incyanatopropyl 2,6-dicyanatohexanoate, 2-methylethyl 2-incyanato-2,6-dicyanatohexanoate It is. All of these can be produced by phosgenating an ester of lysine and an amino alcohol.

In the general formula (1), it is difficult to synthesize a compound in which the number of carbon atoms is 1, and if the number of carbon atoms is 4 or more, the reactivity of the incyanate group Z decreases. become unsuitable.

As mentioned above, when a triisocyanate compound and a chemical species having an active hydrogen atom are reacted, depending on the molar ratio, two of the more reactive incyanate groups of the three incyanate groups of the triisocyanate compound react with each other. groups preferentially participate in the reaction. In other words, the triisocyanate compound behaves as if it were a trifunctional isocyanate compound. As a result, a chain-like polyisocyanate compound in which a compound having an active hydrogen atom is chain-extended by the triisocyanate compound and an incyanate group that does not participate in one reaction remains in the side chain is obtained. Furthermore, if the triisocyanate compound is used in excess, the polyisocyanate compound will have incyanate groups at both ends. When the triisocyanate compound represented by the above general formula is used, the resulting polyincyanate compound is schematically represented by formula (4).

(n is a positive integer) The polyincyanate compound in this invention has a molar ratio M of the incyanate group to the functional group containing an active hydrogen atom of 1.5 < M ≦ 3, and a chemical species having an active hydrogen atom and a tri-incyanate compound. It is obtained by reacting with a cyanate compound. When this molar ratio M is 1.5 or less,
This is not suitable because no isocyanate group remains at the end. Furthermore, since M=3 when n=0 in equation (4), M being larger than 3 deviates from the spirit of the invention. However, it is possible to carry out the synthesis in a system in which M is greater than 6, in which case an excess of the triisocyanate compound remains in the system.

The polyisocyanate compound according to the present invention can cure resins by thermal crosslinking, and is therefore useful as a curing agent for paints and adhesives. In that case, the incyanate group concentration of the polyisocyanate compound is 2% or more, and the molecular weight is 20.0%.
It is preferable that it is 00 or less. That is, if the incyanate group concentration is less than 2, the crosslinking density will be low, resulting in insufficient hardness of the cured film and slow curing speed. The molecular weight is 20. If it is larger than ODD, the curing performance will similarly deteriorate, which is not preferable. The incyanate group concentration here is defined by formula (5), but the molecular weight and incyanate group concentration of the polyisocyanate compound can be determined arbitrarily by appropriately selecting the molecular weight of the chemical species having active hydrogen atoms. It can be done. In addition, as shown in Table 1, these also depend on the value of M, so
Polyisocyanate compounds with various physical properties can be obtained depending on various chemical compounding ratios of triisocyanate compounds and active hydrogen atoms during synthesis. In addition, Table 1 shows polyester diol (molecular weight 1,500) as a chemical species having an active hydrogen atom, and a compound represented by the above general formula (R-CH2-CH) as a triisocyanate compound.
2-, molecular weight 267) The polyisocyanate compound of the present invention can be used alone or in a mixed state with other resins as a curing agent for paints, adhesives, and the like. Previously, resins contained in paints and adhesives and cured by this polyisocyanate compound include vinyl chloride-vinyl acetate copolymer,
vinyl chloride-vinyl acetate-vinyl alcohol copolymer,
Vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-vinyritine chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylic ester-acrylonitrile copolymer, acrylic ester ~ Table 1: Polyisocyanate compound vinylidene chloride Copolymer, methacrylic acid ester-vinylidene chloride copolymer, methacrylic acid ester-styrene copolymer, thermoplastic polyurethane resin, phenoxy resin, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer acrylonitrile-butadiene-acrylic acid copolymer, acrylonitrile-butadiene-methacrylic acid copolymer,
Polyvinyl butyral, cellulose derivatives, styrene
Examples include butadiene copolymers, polyester resins, phenol resins, epoxy resins, thermosetting polyurethane resins, urea resins, melamine resins, alkyd resins, urea-formaldehyde resins, and mixtures thereof. Among these, resins having a hydroxyl group at the terminal and/or side chain are particularly preferable because they form a urethane bond with the triisocyanate compound, and a mixture of a resin having a hydroxyl group and a resin not having a hydroxyl group is also effective. It is true.

The polyisocyanate compound according to the present invention can be used as a hardening agent for paints and adhesives as described above, but is particularly suitable for use as a hardening agent for magnetic paints in the production of magnetic recording media.

Any of the resins mentioned above can also be used as a binder for magnetic recording media.

In addition to the binder, magnetic paints also contain ferromagnetic powder and other basic constituent materials. j: Contains solvent. As this ferromagnetic powder, any of the commonly used ferromagnetic iron oxide particles, ferromagnetic chromium dioxide, ferromagnetic alloy powder, etc. can be used. As ferromagnetic iron oxide particles, when expressed by the general formula FeOx, the value of X is in the range of 1.33≦X≦150, that is, magnetite (r -Fe203
1.50), magnetite (Fe504X=1.3
3), and solid solutions thereof (FeOx 1.33<X
< 1.50) can be used. Cobalt may be added to these ferromagnetic iron oxides for the purpose of increasing coercive force.

There are two types of cobalt-containing magnetic iron oxide: doped type and coated type, and either type may be used. As ferromagnetic chromium dioxide, CrO2 or Ru s Sn, Te e Sb @ for the purpose of improving Hc
Fe e Ti @ V * Mn, etc., can be used with a small amount added. As the ferromagnetic alloy powder, Fe %Co %Ni %Fe-Co, Pe-Ni
Also, Fe-Co-Ni, etc. can be used, and I'J, 8i%Ti%, etc. can be used to improve various properties of these materials.
There are those to which metal components such as Cr%Mn, Cu, Zn, etc. are added.

Examples of organic solvents include ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, and glycol monoethyl acetate; ether, glycol dimethyl ether,
Glycol ethers such as glycol monoethyl ether and dioxane; Tars (aromatic hydrocarbons) such as benzene, toluene, and xylene; methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chloride, °/L- < y-v 7
and other chlorinated hydrocarbons can be selected and used.

Furthermore, abrasives such as aluminum oxide, chromium oxide, and silicon oxide, antistatic agents such as carbon black, and lubricants such as molybdenum disulfide, graphite, silicone oil, and olive oil may be added to the magnetic paint. can.

Accordingly, a magnetic paint is applied to a non-magnetic carrier. Materials for this non-magnetic carrier include polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate; polyolefins such as polyethylene and polypropylene; cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, cellulose acetate propionate, etc. Cellulose derivatives; vinyl resins such as polyvinyl chloride and polyvinylidene chloride; plastics such as polycarbonate, polyimide, and polyamideimide, as well as non-magnetic materials such as aluminum, copper, tin, zinc, or non-magnetic alloys containing these, depending on the application. Metals;
Ceramics such as glass, earthenware, and porcelain; paper, baryta, or paper coated or laminated with α-polyolefins having 2 to 10 carbon atoms such as polyethylene, polypropylene, and ethylene-butene copolymers can also be used.

These nonmagnetic carriers may be transparent or opaque depending on the intended use. In addition, the form of the non-magnetic carrier is a film,
It may be a tape, a sheet, a disk, a card, a drum, etc. (various materials may be used depending on the form), depending on the requirements. The thickness of these non-magnetic carriers is about 1 to 50 μm, preferably 1 to 30 μm when they are in the form of a film, tape, or sheet. Further, in the case of a disk or card shape, the diameter is about 05 to 10 mm, and in the case of a drum shape, it is cylindrical, and the shape is determined depending on the recorder used.

A magnetic recording medium is completed through various processes such as surface treatment, orientation, thermosetting, and cutting.

The characteristics of the polyisocyanate compound of this invention are summarized as follows.

(2) A triisocyanate compound, which is less toxic than diisocyanate, is used during synthesis, and this triisocyanate compound can also be synthesized without using diisocyanate.

(3) From a low molecular weight to a high molecular weight, it does not have any molecular weight and has a chain structure.

In particular, when used as a hardening agent for paints such as magnetic paints,
The following advantages can be obtained for each of the above-mentioned items 1ζ.

(1) Since the number and concentration of incyanate groups can be increased even in the case of high molecular weight, a cured film with a high crosslinking density is formed, and the cured film has good strength, durability, and solvent resistance.

(2) It is possible to avoid concerns about the toxicity of diisocyanate during the coating process.

(3) Those with high molecular weight are advantageous in terms of surface smoothness and gloss of the cured film.

(4) It dissolves well in the solvents used in paints.

The present invention will be explained below with reference to Examples.

Example 1: Synthesis of a polyisocyanate compound In a reaction vessel equipped with a thermometer, a stirrer and a partial reflux condenser, methyl ethyl ketone 753i 11 parts toluene 7'6 # polyester diol 50 ll 50 mol propylene glycol 5 ml and dibutyltin dilaurate [Add 1.0[J5〃,
The reaction was carried out at 70-90r for 3 hours. The produced polyisocyanate compound had a number average molecular weight of 10.900, an incyanate group concentration of 6.5%, and a number of incyanate groups of 9.

Example 2 and Comparative Example 1: Formation of a cured film 20 parts by weight of the polyisocyanate compound obtained in Example 1 and 80 parts by weight of polyester polyurethane (Parabrene 225, manufactured by Nippon Polyurethane Industries) were mixed with 5 parts by weight of methyl ethyl ketone and 50 parts by weight of toluene. It was dissolved in parts by weight of a mixed solvent. Then, this solution was applied onto a glass plate using a doctor blade to form a film. After naturally drying at room temperature for one day, 80
It was placed in a tll' vacuum dryer for 48 hours and cured (
Example 2].

For comparison, 20 parts by weight of Coronate L (a polyisocyanate compound manufactured by Nippon Polyurethane Kogyo ■) and 80 parts by weight of polyester polyurethane were dissolved in a mixed solvent of 50 parts by weight of methyl ethyl ketone and 50 parts by weight of toluene. A cured film was obtained in the same manner as in Example 2 (Comparative Example 1)
].

Table 2 shows the results of measuring the lead bale hardness, gloss, and solvent resistance of the cured films obtained in Example 2 and Comparative Example 1.

Table 2: Cured film 1) Gloss was measured using a gloss meter, with an incident angle of 75° and a reflection angle of 75°.
The reflectance was measured.

2) Solvent resistance was investigated for methyl ethyl ketone.

As shown in Table 2, the glue incyanate compound of the present invention, when used as a curing agent, had performance equivalent to or better than that of the conventionally used curing agent (Coronet L).

Example 6 and Comparative Example 2: Preparation of magnetic tape and after dissolving lecithin 2 in a mixed solvent of 80 parts by weight of methyl ethyl ketone and 80 parts by weight of toluene, r-1i'e2U3
A magnetic paint was prepared by adding 25 layers of the mixture and mixing in a ball mill for 24 hours. Example 1 of this magnetic paint
Add 20 parts by weight of the polyisocyanate compound obtained in 6.
Mixed for 0 minutes. Next, a magnetic paint was applied onto the polyester film using a doctor blade method, the magnetic powder was oriented in a parallel magnetic field of 900 oersted for about 1 second at rv3pm, and left open in a hot air dryer at 90C for about 30 minutes. , to remove the solvent, and then cure the coating film at 80C for 48 hours. Finally, the film was cut to obtain a magnetic tape (Example 6).

For comparison, a magnetic tape was produced in the same manner as in Example 6 except that 20 parts of Coronate L was added in place of the polyisocyanate compound obtained in Example 1 (Comparative Example 2).

Table 6 shows the results of measuring the powder shedding and solvent resistance of the magnetic tapes of Example 3 and Comparative Example 2.

Table 6 = Magnetic tape 6) The amount of powder falling off is the amount of falling powder on the head drum, guide, etc. after running the shuttle 100 times for 60 minutes, with 0 point being the layer temperature, -
The lowest score was 5 points.

4) Solvent resistance was expressed by the number of times the coating film was rubbed with gauze containing methyl ethyl ketone until the coating film was completely removed.

From Table 3, it is clear that the polyisocyanate compound of the present invention, when used as a hardening agent for magnetic t-n, has a property F equivalent to or higher than that of conventionally used hardening agents.

Agent Masaru Doyo Yoshio always Toshiki Sugiura

Claims (1)

[Claims] A chemical species with two functional groups containing active hydrogen atoms in the molecule, and a \functional group with three inocyanate groups in the molecule and one of the six isocyanate groups containing the active hydrogen atom. The molar ratio M of incyanate groups to
．． A polyisocyanate compound which is a reaction product obtained by a reaction where 5<M≦3 and has at least 4 incyanate groups in the molecule.