JP6845653B2 - Method for producing polyisocyanate composition - Google Patents

Description

The present invention relates to a method for producing a polyisocyanate composition.

A polyurethane resin containing a polyisocyanate composed of an aliphatic diisocyanate or an alicyclic diisocyanate as a curing agent is excellent in chemical resistance, flexibility, weather resistance and the like. When this polyisocyanate is used as a curing agent for polyurethane paints, a wide variety of substrates are applied. This is the case when the product is intentionally deformed after being applied to a deformable base material such as a thin plate, plastic film, cloth, leather, or rubber, or after being applied to a hard base material such as an aluminum plate, iron plate, copper plate, or stainless steel plate. In order to follow the deformation, the coating film is required to have extensibility. Examples of the method for imparting this extensibility include a method in which a polyol is used as an auxiliary raw material and the polyisocyanate is modified in advance.
For example, Patent Document 1 proposes a polyisocyanate composition using a polycarbonate diol as the polyol.

International Publication No. 2014/208567 Pamphlet

The polyisocyanate composition described in Patent Document 1 exhibits excellent drying property, heat resistance, and water resistance in addition to extensibility.
However, further drying properties, hardness, and high yield point stress may be required, and further improvement is required in order to achieve both of these performances.
Therefore, an object of the present invention is to provide a method for producing a polyisocyanate composition, which further improves the drying property when formed into a coating film and is also excellent in hardness and yield point stress.

As a result of diligent studies to solve the above-mentioned problems of the prior art, the present inventors have made a urethanization reaction of a polyisocyanate precursor and a polycarbonate diol in the first step, and an allophanate reaction in the second step. It has been found that the above-mentioned problems can be solved by the manufacturing method to be used, and the present invention has been completed.

That is, the present invention is as follows.
[1] Obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and selected from the group consisting of a polyisocyanate precursor having an isocyanurate group and a diol having 2 to 20 carbon atoms. A poly having a first step of subjecting a polycarbonate diol obtained by polymerizing at least one diol and a carbonate compound to a urethanization reaction, and a second step of subjecting a urethane group in the obtained reaction product to an allophanate reaction. A method for producing an isocyanate composition , wherein the molar ratio of allophanate group to urethane group of the polyisocyanate composition is 10:90 or more and 90:10 or less, and the average number of isocyanate functional groups of the polyisocyanate composition is 4.0. A manufacturing method of more than 9.0 or less .
[ 2 ] The method for producing a polyisocyanate composition according to [1], wherein the diisocyanate contains hexamethylene diisocyanate.

According to the present invention, it is possible to provide a method for producing a polyisocyanate composition, which further improves the drying property when formed into a coating film and is also excellent in hardness and yield point stress.

Hereinafter, embodiments for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be modified in various ways without departing from the gist thereof. In the present specification, the amount of a specific functional group contained in the composition or compound can be expressed as a "molar ratio". That is, the dimension of the value obtained by dividing the number of specific functional groups of the composition or compound by the Avogadro's number is defined as mole. Thereby, the amount of the specific functional group is expressed as a "molar ratio" with respect to the amount of other specific functional groups. The specific functional group contained in the composition means a specific functional group contained in the compound contained in the composition.

As used herein, the term "polyisocyanate" refers to a polymer in which a plurality of monomers having one or more isocyanate groups (-NCO) are bonded.
As used herein, the term "polypoly" refers to a compound having two or more hydroxy groups (-OH).

<Manufacturing method of polyisocyanate composition>
In the method for producing a polyisocyanate composition of the present embodiment, a first step of urethanizing a polyisocyanate precursor and a polycarbonate diol, and a first step of urelating the urethane group in the obtained reaction product are performed. It has two steps.
In the method for producing a polyisocyanate composition of the present embodiment, first, a urethane group is generated between the polyisocyanate precursor and the polycarbonate diol in the first step. Next, in the second step, the urethane group between the polyisocyanate precursor produced in the first step and the polycarbonate diol is allophanated. In the present embodiment, a high proportion of allophanate groups between the polyisocyanate precursor and the polycarbonate diol is produced by combining the first step of producing urethane groups and the second step of allophanating the produced urethane groups. Can be introduced at.

The polyisocyanate precursor used in the method for producing the polyisocyanate composition of the present embodiment is a polyisocyanate precursor obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates. Further, the polycarbonate diol used in the method for producing the polyisocyanate composition of the present embodiment is a polycarbonate diol obtained by polymerizing at least one diol selected from the group consisting of diols having 2 to 20 carbon atoms and a carbonate compound. ..
Hereinafter, each step of the method for producing the polyisocyanate composition of the present embodiment will be described.

[First step]
The first step is a step of urethanizing the polyisocyanate precursor and the polycarbonate diol.
In the first step, the reaction may be carried out under solvent-free conditions, and if necessary, the reaction may be carried out in an organic solvent which does not have reactivity with a compound having an isocyanate group. Examples of such organic solvents include aliphatic hydrocarbon solvents such as hexane, heptane, and octane; alicyclic hydrocarbon solvents such as cyclohexane and methylcyclohexane; and ketone solvents such as acetone, methylethylketone, methylisobutylketone, and cyclohexanone. Ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, methyl lactate, ethyl lactate; aromatic solvents such as toluene, xylene, diethylbenzene, mesitylene, anisole, benzyl alcohol, phenylglycol, chlorobenzene; ethylene glycol Glycol solvents such as monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate, dipropylene glycol monomethyl ether and propylene glycol monomethyl ether; ether solvents such as diethyl ether, tetrahydrofuran and dioxane; dichloromethane, 1,2-dichloroethane , Halogenated hydrocarbon solvent such as chloroform; Pyrrolidone solvent such as N-methyl-2-pyrrolidone; Amid solvent such as N, N-dimethylacetamide, N, N-dimethylformamide; Lactone-based solvents such as γ-butyrolactone; amine-based solvents such as morpholin; mixtures thereof. These solvents may be used alone or in combination of two or more.

The reaction temperature in the first step is preferably −20 ° C. or higher and 150 ° C. or lower, and more preferably 30 ° C. or higher and 120 ° C. or lower, from the viewpoint of suppressing side reactions and manufacturing efficiency. Further, in the reaction, an organometallic salt such as tin, zinc or lead; a tertiary amine compound; an alkali metal alcoholate such as sodium may be used as a catalyst.

In the first step, the mass ratio of the polyisocyanate precursor to the polycarbonate diol is preferably 95: 5 or more and 30:70 or less, more preferably 90:10 or more and 50:50 or less, and 80:20 or more and 60:40 or less. More preferred. When these mass ratios are in such a range, the coating film tends to have a high yield point stress and excellent hardness.

[Second step]
The second step is a step of allophanizing the urethane group between the polyisocyanate precursor obtained by the first step and the polycarbonate diol.
In the second step, the reaction may be carried out under solvent-free conditions, and if necessary, the reaction may be carried out in an organic solvent which is not reactive with the compound having an isocyanate group. Such an organic solvent is not particularly limited, and examples thereof include an organic solvent that can be used in the first step described above. This organic solvent can also be removed after the reaction.
The reaction temperature in the second step is preferably 50 ° C. or higher and 180 ° C. or lower, and more preferably 80 ° C. or higher and 150 ° C. or lower, from the viewpoint of suppressing side reactions and manufacturing efficiency.

The second step is carried out in the presence of an allophanation catalyst. Examples of the allophanation catalyst used in the second step include lead, zinc, bismuth, tin, zirconyl, zirconium carboxylate and the like. The amount of the allophanation catalyst used is preferably 0.005 part by mass or more and 0.1 part by mass or less with respect to 100 parts by mass of the product obtained in the first step. By setting the amount of the allophanation catalyst used in the above range, the urethane group between the polyisocyanate precursor produced in the first step and the polycarbonate diol can be efficiently converted into an allophanate group.

In the second step, the molar ratio of the allophanate group to the urethane group of the obtained polyisocyanate composition is preferably 10:90 or more and 90:10 or less, more preferably 10:90 or more and 50:50 or less, and 20:80 or more. 50:50 or less is more preferable, and 20:80 or more and 30:70 or less is particularly preferable. Within such a range, the balance between dryness, hardness, yield stress, and extensibility tends to be excellent, and workability tends to be excellent.

Further, in the second step, the average number of isocyanate functional groups of the obtained polyisocyanate composition is preferably 4.0 or more and 9.0 or less, and more preferably 4.0 or more and 6.0 or less. Within such a range, the balance between drying property and yield point stress tends to be excellent, and workability tends to be excellent.

In the present embodiment, the first step of forming a urethane group between the polyisocyanate precursor and the polycarbonate diol and the second step of allofanating the urethane group between the produced polyisocyanate precursor and the polycarbonate diol. By combining with, the allophanate group between the polyisocyanate precursor and the polycarbonate diol can be introduced in a high proportion. Since the polyisocyanate composition produced by the present embodiment has a large amount of allophanate groups introduced between the polyisocyanate precursor and the polycarbonate diol, the drying property when formed into a coating film is further improved, and in addition, the hardness is improved. It can also be excellent in yield point stress.

In the present embodiment, the urethanization reaction (first step) is carried out for a predetermined time in the absence of the allophanation catalyst, and then the allophanization catalyst is added to carry out the allophanization reaction (second step). preferable.
Further, in the present embodiment, the first step and the second step may be performed at the same time.
When the first step and the second step are performed at the same time, the urethanization reaction (first step) and the allophanization reaction (second step) are carried out for a predetermined time in the presence of an allophanization catalyst. Just do it.

Hereinafter, each material used in the method for producing the polyisocyanate composition of the present embodiment will be described.

≪Polyisocyanate precursor≫
The polyisocyanate precursor used in the present embodiment is obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates. Aliphatic diisocyanates and alicyclic diisocyanates refer to compounds that do not contain a benzene ring in their structure.

The aliphatic diisocyanate preferably has 4 to 30 carbon atoms, and specifically, tetramethylene-1,4-diisocyanate, pentamethylene-1,5-diisocyanate, and hexamethylene diisocyanate (hereinafter, also referred to as “HDI”). ), 2,2,4-trimethyl-hexamethylene-1,6-diisocyanate, and lysine diisocyanate. The alicyclic diisocyanate preferably has 8 or more carbon atoms and 30 or less carbon atoms, and specifically, isophorone diisocyanate (hereinafter, also referred to as “IPDI”), hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,4. -Cyclohexane diisocyanate can be mentioned.

Among the above aliphatic diisocyanates and alicyclic diisocyanates, HDI, IPDI, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate are more preferable, and HDI is further preferable, because they are easily available industrially. By using HDI, the weather resistance and flexibility when the polyisocyanate composition is used as a coating film tend to be more excellent. The aliphatic diisocyanate and the alicyclic diisocyanate may be used alone or in combination of two or more.
The diisocyanate preferably contains hexamethylene diisocyanate (HDI). As a result, the weather resistance and flexibility when the polyisocyanate composition is used as a coating film tend to be more excellent.

The polyisocyanate precursor may be obtained from the above-mentioned diisocyanate and alcohols having a valence of 1 or more and 6 or less. Examples of monohydric or higher and hexavalent or lower alcohols include non-polymerized polyols and polymerized polyols. The non-polymerized polyol is a polyol that does not have a history of polymerization, and the polymerized polyol is a polyol obtained by polymerizing a monomer.

Specific examples of the non-polymerized polyol include monoalcohols, diols, triols and tetraols. Examples of monoalcohols include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, n-pentanol, n-hexanol, n-octanol, n-nonanol, and 2-ethyl. Examples thereof include butanol, 2,2-dimethylhexanol, 2-ethylhexanol, cyclohexanol, methylcyclohexanol and ethylcyclohexanol. Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, and 1,3-. Butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,2-propanediol, 1,5-pentanediol, 2-methyl-2,3-butanediol, 1,6- Hexanediol, 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,3-dimethyl-2,3-butanediol, 2-ethyl-hexanediol, 1, 2-octanediol, 1,2-decanediol, 2,2,4-trimethylpentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol Can be mentioned. Examples of triols include glycerin and trimethylolpropane. Examples of tetraols include pentaerythritol.

Specific examples of the polymerized polyol include polyester polyol, polyether polyol, acrylic polyol, and polyolefin polyol.

Specific examples of the polyester polyol include dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid, and ethylene glycol, propylene glycol, and the like. Polyester polyol obtained by condensation reaction with a polyvalent alcohol such as diethylene glycol, neopentyl glycol, trimethylolpropane, glycerin, etc. alone or in a mixture; a poly obtained by ring-opening polymerization of ε-caprolactone using a polyhydric alcohol. Caprolactones can be mentioned.

Specifically, as the polyether polyol, a hydroxide such as lithium, sodium and potassium, a strong basic catalyst such as alcoholate and alkylamine, and a composite metal cyan compound complex such as a metal porphyrin and a zinc hexacyanocobalate complex are used. Polyether polyols obtained by randomly and / or blocking addition of an alkylene oxide alone or a mixture such as ethylenediamine, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide to a polyvalent hydroxy compound alone or a mixture. Polyether polyols obtained by reacting a polyamine compound such as ethylenediamine with an alkylene oxide; so-called polymer polyols obtained by polymerizing acrylamide or the like using these polyether polyols as a medium can be mentioned.

As the acrylic polyol, specifically, an ethylenically unsaturated bond-containing monomer having a hydroxyl group alone or a mixture thereof, and another ethylenically unsaturated bond-containing monomer copolymerizable therewith alone or a mixture thereof. Can be mentioned as a copolymer of the above. Specific examples of the ethylenically unsaturated bond-containing monomer having a hydroxyl group include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate and the like. Can be mentioned. Among these, hydroxyethyl acrylate and hydroxyethyl methacrylate are preferable.

Specific examples of the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.
The polyisocyanate precursor preferably contains a component obtained by polymerizing two or more diisocyanates (for example, a dimer), and more preferably contains a component obtained by polymerizing three or more diisocyanates (for example, a trimer). As a result, the weather resistance, dryness, hardness, and yield point stress of the coating film tend to be more excellent.

The polyisocyanate precursor containing a component obtained by polymerizing two or more diisocyanates includes an isocyanurate group, a biuret group, a uretdione group, an oxadiazine trione group, an iminooxadiazine dione group, an allophanate group, a urethane group, and a urea group. Can have at the same time. Among these, by having an isocyanurate group, the weather resistance, drying property, hardness, and yield point stress when the polyisocyanate composition is used as a coating film tend to be more excellent.

As a method for producing a polyisocyanate precursor having an isocyanurate group, for example, a diisocyanate is subjected to an isocyanurate conversion reaction using a catalyst or the like, and when a predetermined conversion rate is reached, the reaction is stopped to obtain an unreacted diisocyanate. There is a method of removing it.

The catalyst used in the above isocyanurate-forming reaction is preferably one showing basicity, and specifically, a hydroxide of tetraalkylammonium such as tetramethylammonium and tetraethylammonium, and an organic such as acetic acid and capric acid. Weak salts; hydroxyalkylammonium hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium and triethylhydroxyethylammonium, and organic weak salts such as acetic acid and capric acid; acetic acid, caproic acid and octyl acid. , Alkali metal salts of alkylcarboxylic acids such as myristic acid such as tin, zinc and lead; metal alcoholates such as sodium and potassium; aminosilyl group-containing compounds such as hexamethyldisilazane; Mannig bases; tertiary amines and epoxy Combined use with a compound; Examples thereof include phosphorus compounds such as tributylphosphine. The amount of these catalysts used is preferably 10 ppm or more and 1% or less with respect to the total amount of the raw materials, diisocyanate and alcohol. Further, in order to terminate the isocyanurate-forming reaction, the catalyst may be inactivated by addition of an acidic substance such as phosphoric acid or acidic phosphoric acid ester, which neutralizes the catalyst, thermal decomposition, or chemical decomposition.

The yield of the polyisocyanate precursor usually tends to be 10% by mass or more and 70% by mass or less. Polyisocyanate precursors obtained in higher yields tend to be more viscous. The yield is measured by the method described in Examples described later.

The reaction temperature of the isocyanurate-forming reaction is preferably 50 ° C. or higher and 200 ° C. or lower, and more preferably 50 ° C. or higher and 150 ° C. or lower. When the reaction temperature is 50 ° C. or higher, the reaction tends to proceed easily, and when the reaction temperature is 200 ° C. or lower, side reactions that cause coloring tend to be suppressed.

After completion of the isocyanurate-forming reaction, it is preferable to remove the unreacted diisocyanate monomer by a thin film evaporator, extraction or the like. Even when the polyisocyanate precursor contains unreacted diisocyanate, it preferably contains 3% by mass or less of diisocyanate, more preferably 1% by mass or less, and further preferably 0.5% by mass or less. so. When the residual unreacted diisocyanate monomer concentration is within the above range, the curability and hardness tend to be excellent.

The viscosity of the polyisocyanate precursor is preferably 100 mPa · s or more and 50,000 mPa · s or less, more preferably 200 mPa · s or more and 4000 mPa · s or less, and 200 mPa · s or more and 2000 mPa · s or less at 25 ° C. It is more preferable to have. The viscosity at 25 ° C. is measured by the method described in Examples described later.
The number average molecular weight of the polyisocyanate precursor is preferably 500 or more and 2000 or less, and more preferably 500 or more and 1000 or less. The number average molecular weight is measured by the method described in Examples described later.

The average number of isocyanate functional groups of the polyisocyanate precursor (statistical average number of isocyanate groups contained in one molecule of the polyisocyanate precursor) is preferably 2.5 or more from the viewpoint of increasing the crosslinkability, and the polyisocyanate composition. From the viewpoint of improving the solubility in a solvent or the like, 20 or less is preferable, 2.5 or more and 10 or less is more preferable, and 2.5 or more and 7 or less is further preferable. The average number of isocyanate functional groups is measured by the method described in Examples described later.

The isocyanate group concentration of the polyisocyanate precursor is preferably 5% by mass or more and 25% by mass or less, more preferably 10% by mass or more and 24% by mass or less, and 15% by mass or more and 24% by mass or less. Is even more preferable. The isocyanate group concentration is measured by the method described in Examples described later.

≪Polycarbonate diol≫
The polycarbonate diol used in the present embodiment is obtained by copolymerizing at least one diol selected from the group consisting of diols having 2 to 20 carbon atoms with a carbonate compound.

The number average molecular weight of the polycarbonate diol is preferably 300 or more and 4000 or less, more preferably 400 or more and 2500 or less, and further preferably 500 or more and 2000 or less. When the number average molecular weight is within the above range, flexibility and workability tend to be more excellent. The number average molecular weight is measured by the method described in Examples described later.

Polycarbonate diols repeatedly have structural units in which two alcohol groups and one carbonate group are dehydrated and condensed. Further, the polycarbonate diol includes a first diol having 2 or more and 20 or less carbon atoms, a second diol having 2 or more and 20 or less carbon atoms (hereinafter, also simply referred to as “two kinds of diols”), a carbonate compound, and the like. Is preferably obtained by copolymerizing. As a result, workability tends to be better.

Examples of the method for producing the polycarbonate diol include a method of dealcoholizing and / or dephenolizing two kinds of diols and a carbonate compound, and a method of transesterifying a high molecular weight polycarbonate polyol with two kinds of diols. Can be mentioned. The method for reacting the two types of diols with the carbonate compound is not particularly limited, and known methods can be mentioned. Any of the various methods described on pages 9-20 of Schnell's "Polymer Reviews Vol. 9" (published by Interscience Publishing, Inc., USA, 1964) may be used.

Specific examples of the two diols include at least one diol selected from the group consisting of aliphatic diols and aromatic diols. Among these, an alkylene glycol having two hydroxyl groups and having 2 or more and 20 or less carbon atoms is preferable. By using the alkylene glycol, the weather resistance and chemical resistance when the polyisocyanate composition is used as a coating film tend to be more excellent. Here, the term "alkylene" refers to one that may have a branch and may contain an alicyclic structure. These diols may be used alone or in combination of two or more.

More specifically, as two kinds of diols, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 2-ethyl-1,6-hexanediol, 2-methyl- 1,3 propanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2,2'-bis (4-hydroxycyclohexyl) -propane, p-Xylylenediol, p-tetrachloroxylylenediol, 1,4-dimethylolcyclohexane, bishydroxymethyltetrahexane, di (2-hydroxyethyl) dimethylhydantoin, diethylene glycol, dipropylene glycol, polypropylene glycol, polytetramethylene glycol , 2,6'-Dihydroxyethylhexyl ether, 2,4'-dihydroxyethylbutyl ether, 2,5'-dihydroxyethylpentyl ether, 2,3'-dihydroxy-2', 2'-dimethylethylpropyl ether, thioglycol Can be mentioned.
Among these, a diol having 2 or more and 11 or less carbon atoms is preferable, and a diol having 3 or more and 6 or less carbon atoms is more preferable.

The combination of the two diols includes a combination of a diol having 5 carbon atoms and a diol having 6 carbon atoms, a combination of two or more isomers of a diol having 4 carbon atoms, and a diol having 4 carbon atoms and 6 carbon atoms. The combination with diol is preferable. By using these two types of diols, the extensibility, heat resistance, and water resistance (hydrolysis resistance) when the polyisocyanate composition is used as a coating film tend to be more excellent. As a combination of such two kinds of diols, specifically, a group consisting of 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 2-methyl-1,3 propanediol. At least one combination selected from the above is preferable, with a combination of 1,6-hexanediol and 1,5-pentanediol, a combination of 1,6-hexanediol and 1,4-butanediol, and 1,4-butanediol. A combination of 2-methyl-1,3-propanediol is more preferred.

Specific examples of the carbonate compound include alkylene carbonate, dialkyl carbonate, diaryl carbonate, and phosgene, and more specific examples thereof include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and diphenyl carbonate. .. Among these, diethyl carbonate is preferable from the viewpoint of ease of production.

{Use}
The polyisocyanate composition obtained by the production method according to the present embodiment is, for example, a curable composition such as a coating composition, a pressure-sensitive adhesive composition, an adhesive composition, a casting composition, and various kinds of fiber treatment agents. Surface treatment agent composition; various elastomer compositions; cross-linking agent such as foam composition; modifier; additive.

The coating composition is preferably used as a primer, an intermediate coating, and a top coating on various materials by, for example, roll coating, curtain flow coating, spray coating, electrostatic coating, and bell coating. In addition, this coating composition further imparts cosmetic properties, weather resistance, acid resistance, rust resistance, chipping resistance, adhesion, etc. to pre-coated metals including rust-preventive steel sheets, automobile coatings, and plastic coatings. , Suitable for use.

Examples of the pressure-sensitive adhesive composition and the pressure-sensitive adhesive composition include automobiles, building materials, home appliances, woodworking, and laminates for solar cells. Among these, optical members for liquid crystal displays of home appliances such as televisions, personal computers, digital cameras, and mobile phones need to be laminated with films and plates of various adherends in order to exhibit various functions. Therefore, since sufficient adhesiveness or adhesiveness is required between the films and plates of various adherends, it is preferable as an example of using the pressure-sensitive adhesive composition and the adhesive composition of the present embodiment.

As the adherend to which the curable composition can be used, for example, glass; various metals such as aluminum, iron, zinc steel plate, copper and stainless steel; porous members such as wood, paper, mortar and stone; fluorine coating , Urethane coating, acrylic urethane coating, etc .; Sealant cured product such as silicone-based cured product, modified silicone-based cured product, urethane-based cured product; Rubbers such as vinyl chloride, natural rubber, synthetic rubber; Natural leather , Artificial leather and other leathers; Plant-based fibers, animal-based fibers, carbon fibers, glass fibers and other fibers; Non-woven fabrics, polyesters, acrylics, polycarbonates, triacetyl celluloses, polyolefins and other resins films and plates; UV curing Examples thereof include a mold acrylic resin layer, printing ink, and inks such as UV ink.

Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples as long as the gist of the present embodiment is not exceeded. .. Various physical properties and evaluations in Examples and Comparative Examples were measured and evaluated as follows.

(Physical characteristics 1) Yield Using the polyisocyanate precursor as a sample, the yield of the polyisocyanate precursor was determined by measuring the refractive index of the reaction solution.

(Physical Properties 2) Viscosity Using the polyisocyanate precursor as a sample, the viscosity of the polyisocyanate precursor at 25 ° C. was determined using an E-type viscometer RE-80U (manufactured by Toki Sangyo Co., Ltd.). A standard rotor (1 ° 34'x R24) was used for the measurement. The rotation speed was set as follows.
100r. p. m. (If less than 128 mPa.s)
50r. p. m. (When 128 mPa.s or more and less than 256 mPa.s)
20r. p. m. (When 256 mPa.s or more and less than 640 mPa.s)
10r. p. m. (When 640 mPa.s or more and less than 1280 mPa.s)
5r. p. m. (When 1280 mPa.s or more and less than 2560 mPa.s)
2.5r. p. m. (When it is 2560 mPa.s or more and less than 5120 mPa.s)
1.0r. p. m. (When 5120 mPa.s or more and less than 10240 mPa.s)
0.5r. p. m. (When 10240 mPa.s or more and less than 20480 mPa.s)

(Physical characteristics 3) Isocyanate group concentration 1-3 g of polyisocyanate precursor is precisely weighed (Wg) in an Erlenmeyer flask, and then 20 ml of toluene is added to dissolve the polyisocyanate. Then, 10 ml of a toluene solution of 2N-butylamine is added, and after mixing, the mixture is left at room temperature for 15 minutes. Add 70 ml of isopropyl alcohol and mix. This solution is titrated into an indicator with a 1N hydrochloric acid solution (Factor F). The titration value was set to (V2 ml), the same operation was performed without polyisocyanate, and the titration value was set to (V1 ml), and the isocyanate group content of the polyisocyanate was calculated from the following formula (1).
Isocyanate group content (mass%) = (V1-V2) x F x 42 / (W x 1000) x 100 ... (1)

(Physical characteristics 4) Number average molecular weight of polyisocyanate precursor Using polyisocyanate precursor as a sample, the number average molecular weight of polyisocyanate precursor is measured by gel permeation chromatograph using the following device, and the number average molecular weight is based on polystyrene. Asked as.
Equipment: HLC-802A (manufactured by Tosoh)
Column: G1000HXL x 1 (manufactured by Tosoh)
G2000HXL x 1 (manufactured by Tosoh)
G3000HXL x 1 (manufactured by Tosoh)
Carrier: Tetrahydrofuran Flow velocity: 0.6 mL / min Sample concentration: 1.0 mass%
Injection volume: 20 μL
Temperature: 40 ° C
Detection method: Differential refractometer

(Physical characteristics 5) Average number of isocyanate functional groups Using a polyisocyanate precursor or a polyisocyanate composition as a sample, the average number of isocyanate functional groups was determined by the following formula (2).
Average number of isocyanate groups = average number of polyisocyanates Molecular weight (Mn) x isocyanate group content (mass%) x 0.01) / 42 ... (2)

(Physical Properties 6) Ratio of Number of Functional Groups of Alofanate Group / Urethane Group Using a polyisocyanate composition as a sample, using FT-NMR AVANCE 600 manufactured by Bruker, deuterated chloroform CDCl ₃ as a solvent, concentration 5% by mass, 600 MHz, number of integrations The proton nuclear magnetic resonance spectrum was measured 256 times to confirm the ratio of the number of functional groups of the isocyanate group and the urethane group. Based on all the β- and γ-position protons derived from HDI, the allophanate group is the signal area ratio of the hydrogen atom bonded to the allophanate-bonded nitrogen around 8.60 ppm, and the urethane group is the urethane-bonded nitrogen around 4.70 ppm. The area ratio of the signal of the hydrogen atom bonded to was measured, and the ratio was determined.

(Physical Properties 7) Number Average Molecular Weight of Polycarbonate Diol Using the polycarbonate diol as a sample, the number average molecular weight of the polycarbonate diol was calculated by the following formula (3). The hydroxyl value of the polycarbonate diol was determined by the following ((Physical characteristics 8).
Number average molecular weight = 2 / (hydroxyl value of polycarbonate diol x 10-3 / 56.11) ... (3)

(Physical Properties 8) Hydroxyl Value of Polycarbonate Diol Using the polycarbonate diol as a sample, the hydroxyl value of the polycarbonate diol was determined according to JIS K 0070: 1992. Specifically, 12.5 g of acetic anhydride was added to 50 mL of pyridine to prepare an acetylation reagent. Next, 2.5 to 5.0 g of the polycarbonate diol produced in the synthetic example was precisely weighed in a 100 mL eggplant flask. After adding 5 mL of the acetylation reagent and 10 mL of toluene to the eggplant flask with a whole pipette, a cooling tube was attached, and the mixture was stirred and heated at 100 ° C. for 1 hr. 2.5 mL of distilled water was added with a whole pipette, and the mixture was further heated and stirred for 10 minutes. After cooling for 2 to 3 minutes, 12.5 mL of ethanol was added, and 2 to 3 drops of phenolphthalein was added as an indicator, and then titrated with 0.5 mol / L ethanolic potassium hydroxide.
On the other hand, as a blank test, 5 mL of the acetylation reagent, 10 mL of toluene, and 2.5 mL of distilled water were placed in a 100 mL eggplant flask, heated and stirred for 10 minutes, and then titrated in the same manner. Based on this result, the hydroxyl value was calculated by the following formula (4).
OH value (mg-KOH / g) = {(ba) x 28.05 x f} / e ... (4)
In formula (4), a represents the titration amount (mL) of the sample, b represents the titration amount (mL) of the blank test, e represents the sample mass (g), and f represents the titration solution. Represents a factor.

(Physical Properties 9) Copolymerization Composition of Polycarbonate Diol Using the polycarbonate diol as a sample, the copolymerization composition of the polycarbonate diol was measured as follows. 1 g of a sample was taken in a 100 mL eggplant flask, 30 g of ethanol and 4 g of potassium hydroxide were added, and the reaction was carried out at 100 ° C. for 1 hr. After cooling to room temperature, 2-3 drops of phenolphthalein was added to the indicator and neutralized with hydrochloric acid. After cooling in a refrigerator for 1 hr, the precipitated salt was removed by filtration and analyzed by gas chromatography. The analysis was performed using gas chromatography GC-14B (manufactured by Shimadzu Corporation) equipped with DB-WAX (manufactured by J & W) as a column, using diethylene glycol diethyl ester as an internal standard, and using a detector as a FID. The temperature rise profile of the column was maintained at 60 ° C. for 5 minutes and then heated to 250 ° C. at 10 ° C./min.

[Synthesis Example 1] Polyisocyanate precursor a
The inside of a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube, and a dropping funnel was made into a nitrogen atmosphere, HDI: 1000 g was charged, and the temperature inside the reactor was maintained at 70 ° C. under stirring. Tetramethylammonium capriate was added thereto, and when the yield reached 25%, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporator to obtain a polyisocyanate precursor a. The obtained polyisocyanate precursor a is substantially free of allophanate groups, has a viscosity at 25 ° C. of 1300 mPa · s, an isocyanate group concentration of 23.1%, a number average molecular weight of 590, and an average number of isocyanate functional groups of 3.0. Met.

[Synthesis Example 2] Polyisocyanate precursor b
In the same apparatus as in Synthesis Example 1, 1000 g of HDI and 1.5 g of isobutanol were charged, and the temperature inside the reactor was maintained at 70 ° C. under stirring. Tetramethylammonium capriate was added thereto, and when the yield reached 20%, phosphoric acid was added to stop the reaction, and then the reaction solution was heated at 160 ° C. for 1 hour. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporator to obtain a polyisocyanate precursor b. The obtained polyisocyanate precursor b is substantially free of allophanate groups, has a viscosity at 25 ° C. of 500 mPa · s, an isocyanate group concentration of 23.2%, a number average molecular weight of 540, and an average number of isocyanate functional groups of 3.0. Met.

[Synthesis Example 3] Polycarbonate Diol A
382 g of 1,5-pentanediol, 433 g of 1,6-hexanediol, and 650 g of ethylene carbonate were placed in a 2 L separable flask equipped with a stirrer, a thermometer, and an older show with a vacuum jacket having a reflux head on the crown, and stirred at 70 ° C. After dissolution, 0.015 g of lead acetate trihydrate was added as a catalyst. The mixture was heated in an oil bath set at 175 ° C., and reacted for 12 hours at an internal temperature of 140 ° C. in a flask and a vacuum degree of 1.0 to 1.5 kPa while removing a part of the distillate from the reflux head at a reflux ratio of 4. After that, the older show was replaced with a simple distillation apparatus, heated in an oil bath set at 180 ° C., the internal temperature of the flask was 140 to 150 ° C., the degree of vacuum was lowered to 0.5 kPa, and the diol remaining in the separable flask was used. Ethylene carbonate was removed. Then, the setting of the oil bath was raised to 185 ° C., and the reaction was carried out at an internal temperature of 160 to 165 ° C. of the flask for another 4 hours while removing the diol produced. By this reaction, a liquid polycarbonate diol A which is viscous at room temperature was obtained. The obtained polycarbonate diol A had a hydroxyl value of 56.1 (molecular weight 2000) and a copolymer composition of 1,5-pentanediol / 1,6-hexanediol = 50/50 (molar ratio).

[Synthesis Example 4] Polycarbonate Diol B
In Synthesis Example 3, after replacing the polycarbonate with a simple distillation apparatus, the setting of the oil bath was raised to 185 ° C., the internal temperature of the flask was set to 160 to 165 ° C., and the time for removing the produced diol was set to 2.3 hours. Polycarbonate diol B was synthesized in the same manner as in Synthesis Example 3 except for the above. The obtained polycarbonate diol B had a hydroxyl value of 113.2 (molecular weight 1000) and a copolymer composition of 1,5-pentanediol / 1,6-hexanediol = 50/50 (molar ratio).

[Synthesis Example 5] Polycarbonate Diol C
In Synthesis Example 3, after replacing the polycarbonate with a simple distillation apparatus, the setting of the oil bath was raised to 185 ° C., the internal temperature of the flask was set to 160 to 165 ° C., and the time for removing the produced diol was set to 1.5 hours. Polycarbonate diol C was synthesized in the same manner as in Synthesis Example 3 except for the above. The obtained polycarbonate diol C had a hydroxyl value of 224.4 (molecular weight 500) and a copolymer composition of 1,5-pentanediol / 1,6-hexanediol = 50/50 (molar ratio).

[Example 1] Polyisocyanate composition [First step]
In the same reactor as in Synthesis Example 1, 100.0 g of the polyisocyanate precursor a obtained in Synthesis Example 1 and 54.3 g of the polycarbonate diol B obtained in Synthesis Example 4 were placed, and the urethanization reaction was carried out at 90 ° C. for 2 hours. went.
[Second step]
Next, 0.05 g of an allophanation catalyst zirconium 2-ethylhexanoate (20% 2-ethylhexanol solution) was charged and kept at 130 ° C. for 3 hours under a nitrogen atmosphere to carry out an allophanation reaction. Then, 66.4 g of n-butyl acetate was added to obtain the polyisocyanate composition of Example 1. The obtained polyisocyanate composition had a molar ratio of allophanate group to urethane group of 20:80 and an average number of isocyanate groups of 4.5.

[Comparative Example 1] Polyisocyanate Composition In the same reactor as in Synthesis Example 1, 100.0 g of the polyisocyanate precursor a obtained in Synthesis Example 1 and 54.3 g of the polycarbonate diol B obtained in Synthesis Example 4 were charged, and nitrogen was charged. It was kept at 100 ° C. for 3 hours in an atmosphere. Then, 66.3 g of n-butyl acetate was added to obtain the polyisocyanate composition of Comparative Example 1. The molar ratio of allophanate group to urethane group of the obtained polyisocyanate composition was 0: 100, and the average number of isocyanate groups was 3.5.

[Examples 2 to 4] Polyisocyanate composition The same method as in Example 1 except that the types of the polyisocyanate precursor and the polycarbonate diol shown in Table 1 and the amount of n-butyl acetate were changed as shown in Table 1. The first step and the second step were performed. The molar ratio of allophanate group to urethane group and the average number of isocyanate groups in the obtained polyisocyanate composition are as shown in Table 1.

[Comparative Examples 2 to 3] Polyisocyanate Composition The polyisocyanate precursor shown in Table 1 was reacted in the same manner as in Comparative Example 1 except that the types and amounts of polycarbonate diol, hydrophilic group and n-butyl acetate were used. It was. The molar ratio of allophanate group to urethane group and the average number of isocyanate groups in the obtained polyisocyanate composition are as shown in Table 1.

<Evaluation method>
(Evaluation 1) Evaluation method of dryness For each of the polyisocyanate compositions of Examples 1 to 4 and Comparative Examples 1 to 3, SETALUX 1767 (Acrylic polyol, manufactured by Nuplex resin, hydroxyl group concentration 4.5% (resin standard)). , Resin solid content 65%) was blended so that the functional group ratio (NCO / OH) = 1.0, and diluted with n-butyl acetate to a solid content of 50% by mass. The obtained coating composition was coated on a glass plate with an applicator so that the resin film thickness was 40 μm. A cotton ball was placed on the coating film every hour at 23 ° C., and a 100 g weight was placed on the coating film for 60 seconds. After that, the weight and the cotton ball were removed, the cotton traces remaining on the coating film were observed, and the time until the cotton residue disappeared was measured. The results are shown in Table 1.

(Evaluation 2) Evaluation method of hardness The polyisocyanate compositions of Examples 1 to 4 and Comparative Examples 1 to 3 similar to the above evaluation method of dryness are coated on a glass plate with an applicator so that the resin film thickness is 60 μm. Then, it was heated at 80 ° C. for 2 hours and then left at 23 ° C. for 24 hours to obtain a polyurethane coating film. The obtained coating film was measured using a König hardness tester (manufactured by BYK Garder, trade name "Pendulum hardness tester"). The results are shown in Table 1.

(Evaluation 3) Evaluation method of yield point stress A coating film similar to the polyurethane coating film obtained by the above hardness evaluation method was prepared except that the coating base material was changed to a polypropylene (PP) plate, and then the PP plate was prepared. A polyurethane resin film was obtained by peeling from the film.

The obtained polyurethane resin film was evaluated using the following apparatus.
Equipment: TENSILON RTE-1210 (manufactured by A & D)
Tensile speed: 20 mm / min
Sample dimensions: length 20 mm x width 10 mm
Temperature: 23 ° C
The evaluation criteria were as follows. The results are shown in Table 1.
⊚: Yield point stress is 20 MPa or more (yield point stress is extremely high).
◯: Yield point stress is 5 MPa or more and less than 20 MPa (yield point stress is high).
X: Yield point stress is less than 5 MPa, or there is no yield point.

As shown in the above results, in all of Examples 1 to 4 to which the present invention was applied, the drying time of the coating film was 2 hours, and the coating film was dried in a short time. Further, Examples 1 to 4 to which the present invention was applied had sufficient hardness in the future, and the evaluation of the yield point stress was also good. That is, in all of Examples 1 to 4 to which the present invention was applied, the drying property, hardness, and yield point stress when formed into a coating film were good.
On the other hand, Comparative Examples 1 to 3 to which the present invention was not applied were inferior in at least one of the evaluation of drying time, hardness, and yield point stress to Examples 1 to 4 to which the present invention was applied.
In Comparative Example 2 and Comparative Example 3, the presence of a trace amount of allophanate group was confirmed, which is considered to be an allophanate group originally contained in the polyisocyanate precursor used as a raw material.

Claims (2)

At least one selected from the group consisting of a polyisocyanate precursor having an isocyanurate group and a diol having 2 to 20 carbon atoms, which is obtained from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate. The first step of urethanizing the polycarbonate diol obtained by polymerizing the diol and the carbonate compound of
The second step of allophanizing the urethane groups in the obtained reaction product, and
It is a method for producing a polyisocyanate composition having
The molar ratio of allophanate group to urethane group of the polyisocyanate composition is 10:90 or more and 90:10 or less.
A production method in which the average number of isocyanate functional groups of the polyisocyanate composition is 4.0 or more and 9.0 or less . The method for producing a polyisocyanate composition according to claim 1, wherein the diisocyanate contains hexamethylene diisocyanate.