JP7688966B2 - resin composition - Google Patents

Description

The present invention relates to a polyisocyanate composition and a resin composition.

In recent years, there has been an increasing market need for higher quality and performance curing agents to achieve coating properties that cannot be achieved with conventional curing agents for cured polyurethanes. In particular, further development is required for coatings, pressure sensitive adhesives, glues, sealants, etc., whose final properties are achieved through curing, because the performance derived from the curing agent contributes greatly. In particular, there is a market trend toward a demand for high flexibility of the cured composition.

Patent Documents 1 and 2 disclose polyisocyanate compositions modified with polyester polyol or polyether polyol. They disclose that coating films formed by incorporating the compositions have excellent extensibility and flex resistance.

Japanese Unexamined Patent Publication No. 61-28518 Japanese Unexamined Patent Publication No. 2-1718

There is a demand for a polyisocyanate composition that can provide a coating film with better flexibility under harsh environments, specifically at low temperatures of about -10°C, than the polyisocyanate compositions described in Patent Documents 1 and 2.

The present invention has been made in consideration of the above circumstances, and provides a polyisocyanate composition that has good compatibility with the base agent in a low-temperature environment of about -10°C, and has excellent flexibility when formed into a coating film at a low temperature of about -10°C and at room temperature of about 23°C. The present invention also provides a resin composition using the polyisocyanate composition.

That is, the present invention includes the following aspects.
(1) A resin composition comprising a polyisocyanate and an acrylic polyol,
the polyisocyanate is derived from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, a polycaprolactone polyol (A), and a polyether polyol (B);
Contains 20 parts by mass or more of polypropylene glycol relative to 100 parts by mass of the polyether polyol (B),
the polycaprolactone polyol (A) has an average hydroxyl functional group number of 3, and a number average molecular weight of the polycaprolactone polyol (A) is 500 or more and 1500 or less,
The number average molecular weight of the polyether polyol (B) is 1,000 or more and 7,000 or less,
a molar ratio of an isocyanate group of the diisocyanate to a hydroxyl group of the polycaprolactone polyol (A) and the polyether polyol (B) is 2 or more and 10 or less, and
The resin composition is a pressure-sensitive adhesive composition.
(2) The resin composition according to (1), wherein in the polyether polyol (B), a mass ratio of polytetramethylene ether glycol to the polypropylene glycol is 0/100 or more and 60/40 or less.
(3) The resin composition according to (1) or (2), wherein a mass ratio of the polycaprolactone polyol (A) to the polyether polyol (B) is 10/90 or more and 90/10 or less.

The polyisocyanate composition of the above embodiment has good compatibility with the base agent in a low-temperature environment of about -10°C, and can provide a polyisocyanate composition that has excellent flexibility at low temperatures of about -10°C and at room temperatures of about 23°C when formed into a coating film. The resin composition of the above embodiment contains the polyisocyanate composition, and has excellent flexibility at low temperatures of about -10°C and at room temperatures of about 23°C when formed into a coating film.

The following describes in detail the form for carrying out the present invention (hereinafter, "the present embodiment"). The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be modified in various ways without departing from the gist of the invention.

In this specification, the term "polyol" refers to a compound having two or more hydroxyl groups (-OH) in one molecule.
In this specification, the term "polyisocyanate" refers to a reaction product in which a plurality of monomer compounds having two or more isocyanate groups (--NCO) are bonded together.
In this specification, unless otherwise specified, "(meth)acrylic" includes both methacrylic and acrylic, and "(meth)acrylate" includes both methacrylate and acrylate.

<Polyisocyanate composition>
The polyisocyanate composition of the present embodiment is derived from a diisocyanate, a polycaprolactone polyol (A), and a polyether polyol (B). That is, the polyisocyanate composition of the present embodiment is a reaction product of a diisocyanate, a polycaprolactone polyol (A), and a polyether polyol (B), and contains a polyisocyanate modified with the polycaprolactone polyol (A) and the polyether polyol (B). The diisocyanate is at least one selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate.
The polyisocyanate composition of the present embodiment contains 20 parts by mass or more of polypropylene glycol per 100 parts by mass of the polyether polyol (B).

As described above, the polyisocyanate composition of this embodiment uses two different types of polyols and contains polypropylene glycol as the polyether polyol (B), which results in a coating film that is more flexible than conventional compositions; specifically, it has good compatibility with the base resin in low-temperature environments of about -10°C, and has excellent flexibility at low temperatures of about -10°C and at room temperature of about 23°C.

Next, each component of the polyisocyanate composition of this embodiment will be described in detail below.

<Polyisocyanate>
The polyisocyanate composition of the present embodiment may be a polyisocyanate having, in one molecule, all of the constituent units derived from a diisocyanate, a polycaprolactone polyol (A), and a polyether polyol (B), or may be a mixture of polyisocyanates having, in one molecule, a constituent unit derived from at least one selected from the group consisting of a diisocyanate, a polycaprolactone polyol (A), and a polyether polyol (B).

The polyisocyanate may have at least one structure selected from the group consisting of an allophanate structure, a uretdione structure, an iminooxadiazinedione structure, an isocyanurate structure, a urea structure, a urethane structure, and a biuret structure. Of these, it is preferable that the polyisocyanate has at least one structure selected from the group consisting of a urethane structure, an allophanate structure, a biuret structure, a urea structure, and an isocyanurate group.

[Diisocyanate]
The diisocyanate is at least one selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

Examples of aliphatic diisocyanates include, but are not limited to, 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, ethyl (2,6-diisocyanato)hexanoate, 1,6-diisocyanatohexane (hereinafter sometimes abbreviated as "HDI"), 1,9-diisocyanatononane, 1,12-diisocyanatododecane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, etc. These aliphatic diisocyanates may be used alone or in combination of two or more.

Examples of alicyclic diisocyanates include, but are not limited to, 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane (hereinafter sometimes abbreviated as "hydrogenated XDI"), 1,3- or 1,4-diisocyanatocyclohexane, 3,5,5-trimethyl-1-isocyanato-3-(isocyanatomethyl)cyclohexane (hereinafter sometimes abbreviated as "IPDI"), 4-4'-diisocyanato-dicyclohexylmethane (hereinafter sometimes abbreviated as "hydrogenated MDI"), 2,5- or 2,6-diisocyanatomethylnorbornane, etc. These alicyclic diisocyanates may be used alone or in combination of two or more.

These aliphatic diisocyanates and alicyclic diisocyanates may be used alone, or two or more of the aliphatic diisocyanates and alicyclic diisocyanates may be used in combination.

Among them, the diisocyanate is preferably HDI, IPDI, hydrogenated XDI, or hydrogenated MDI, more preferably HDI or IPDI, and even more preferably HDI.

In the production of polyisocyanates, in addition to the diisocyanates described above, isocyanate monomers such as those shown below may be further used.
(1) Aromatic diisocyanates such as diphenylmethane-4,4'-diisocyanate (MDI), 1,5-naphthalene diisocyanate, tolylene diisocyanate (TDI), xylylene diisocyanate, and m-tetramethylxylylene diisocyanate (TMXDI).
(2) Triisocyanates such as 4-isocyanatomethyl-1,8-octamethylene diisocyanate (hereinafter sometimes referred to as "NTI"), 1,3,6-hexamethylene triisocyanate (hereinafter sometimes referred to as "HTI"), bis(2-isocyanatoethyl) 2-isocyanatoglutarate (hereinafter sometimes referred to as "GTI"), and lysine triisocyanate (hereinafter sometimes referred to as "LTI").

<Polycaprolactone polyol (A)>
Polycaprolactone polyol is not particularly limited, but specifically, it can be obtained by ring-opening polymerization of ε-caprolactone in the presence of a catalyst using a dihydric or higher alcohol, preferably a trihydric alcohol, as an initiator. Although not particularly limited, specific examples of such initiators include dihydric alcohols such as ethylene glycol, propylene glycol, 1,3-butylene glycol, and neopentyl glycol; and trihydric alcohols such as trimethylolpropane and glycerin. From the viewpoint of obtaining a polyisocyanate with a low viscosity, a branched polycaprolactone polyol is preferred. Such polycaprolactone polyol can be obtained by using a trihydric or higher alcohol as an initiator.

The catalyst is not particularly limited, but examples thereof include organic titanium compounds such as tetrabutyl titanate, tetrapropyl titanate, and tetraethyl titanate; and tin compounds such as tin octoate, dibutyltin oxide, dibutyltin laurate, stannous chloride, and stannous bromide.

The ring-opening polymerization of ε-caprolactone is not particularly limited, but specifically, it can be carried out in a nitrogen gas atmosphere by setting the molar ratio of ε-caprolactone to the above initiator so as to obtain the desired molecular weight, adding 0.1 ppm to 100 ppm by mass of a catalyst to ε-caprolactone, and reacting at a temperature of 150°C to 200°C for 4 hours to 10 hours.

Polyisocyanate is formed by the reaction of the hydroxyl groups of polycaprolactone polyol (A) with the isocyanate groups of diisocyanate to form urethane groups.

The average number of hydroxyl functional groups of the polycaprolactone polyol (A) is preferably 2.0 or more and 8.0 or less, more preferably 2 or more and 6 or less, even more preferably 2 or more and 5 or less, and particularly preferably 3. The average number of hydroxyl functional groups of the polycaprolactone polyol (A) referred to here is the number of hydroxyl groups present in one molecule of the polycaprolactone polyol (A).

The number average molecular weight of the polycaprolactone polyol (A) is preferably 500 or more and 1,500 or less, more preferably 600 or more and 1,400 or less, even more preferably 700 or more and 1,300 or less, and particularly preferably 850 or more and 1,250 or less.
When the number average molecular weight of the polycaprolactone polyol (A) is within the above range, the flexibility of the resulting coating film at low temperature and room temperature is excellent. The number average molecular weight Mn of the polycaprolactone polyol (A) is, for example, the number average molecular weight based on polystyrene standards measured by gel permeation chromatography (GPC).

Commercially available polycaprolactone polyols include, for example, trade names "Placcel 305" (number average molecular weight 550), "Placcel 308" (number average molecular weight 850), "Placcel 309" (number average molecular weight 900), "Placcel 312" (number average molecular weight 1250), "Placcel 205" (number average molecular weight 530), and "Placcel 210" (number average molecular weight 1000) manufactured by Daicel Corporation; and trade names "Polylite OD-X-2735" (number average molecular weight 500), "Polylite OD-X-2586" (number average molecular weight 850), and "Polylite OD-X-2588" (number average molecular weight 1250) manufactured by DIC Corporation.

<Polyether polyol (B)>
The polyether polyol (B) includes polypropylene glycol (PPG, also known as polyoxypropylene polyol).
The content of PPG relative to 100 parts by mass of the polyether polyol (B) in the polyisocyanate composition of the present embodiment is 20 parts by mass or more, preferably 40 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 55 parts by mass or more, particularly preferably 60 parts by mass, and most preferably 100 parts by mass. By having the content of PPG be equal to or more than the above lower limit, the compatibility with the base agent in a low-temperature environment can be improved.

The polypropylene glycol is not particularly limited, but specific examples include polyoxypropylene diol or triol; so-called Pluronic (registered trademark) type polyoxypropylene diol or triol in which ethylene oxide is addition polymerized to the terminal of polyoxypropylene diol or triol; polyoxypropylene polyoxyethylene polymer diol or triol, etc. Among these, the Pluronic (registered trademark) type polyoxypropylene diol or triol is preferred because of its excellent reactivity with diisocyanate.

A method for producing polypropylene glycol includes a method in which propylene oxide, and if necessary, ethylene oxide, etc. are added alone or in mixture to an initiator and a catalyst. The initiator is not particularly limited, but specific examples include polyhydric alcohols, polyhydric phenols, polyamines, alkanolamines, or mixtures thereof. More specific examples include dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, and bisphenol A; trihydric alcohols such as glycerin and trimethylolpropane; diamines such as ethylenediamine; and mixtures thereof. The catalyst is not particularly limited, but specific examples include hydroxides of lithium, sodium, potassium, etc.; strong basic catalysts such as alcoholates and alkylamines; metal porphyrins, composite metal cyanide compound complexes, complexes of metals and chelating agents with tridentate or higher coordination, and composite metal complexes such as zinc hexacyanocobaltate complexes. Other examples include a method in which polyhydric alcohols are dehydrated and condensed to obtain polypropylene glycol.

Commercially available polypropylene glycols include those manufactured by Asahi Glass Co., Ltd. under the trade names "Exenol 510" (polyoxypropylene diol with EO added to the end, number average molecular weight 4000), "Exenol 840" (polyoxypropylene triol with EO added to the end, number average molecular weight 6500), "Exenol 1020" (polyoxypropylene diol with EO added to the end, number average molecular weight 1000), and "Exenol 2020" (polyoxypropylene diol with EO added to the end, number average molecular weight 2000).

The polyether polyol (B) may contain other polyether polyols in addition to polypropylene glycol.
Other polyether polyols are not particularly limited, but examples include polyether polyols obtained by adding an alkylene oxide or a mixture of an alkylene oxide to a polyhydric alcohol or a mixture of an alkylene oxide using an alkali metal hydroxide or a strong basic catalyst, polyether polyols obtained by reacting an alkylene oxide with a polyamine compound, and so-called polymer polyols obtained by polymerizing acrylamide or the like using the above-mentioned polyether as a medium.
Examples of the alkali metal include lithium, sodium, and potassium.
Examples of the strong basic catalyst include alcoholates and alkylamines.
The polyhydric alcohol is not particularly limited, but examples thereof include at least one polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin.
Examples of the alkylene oxide include ethylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide.
Examples of the polyamine compound include ethylenediamines.

Among these, polytetramethylene ether glycol (PTMG, also known as polyoxytetramethylene polyol) is preferred as another polyether polyol.

Polytetramethylene ether glycol is produced by cationic polymerization of tetrahydrofuran using a catalyst. The catalyst used is not particularly limited, but specifically, acetic anhydride-perchloric acid, fluorosulfonic acid, fuming sulfuric acid, etc. are used. For example, the production of polyoxytetramethylene glycol is not particularly limited, but specifically, it can be carried out under conditions where fluorosulfonic acid is usually added to the raw material tetrahydrofuran at a rate of approximately 1% by mass to 30% by mass, and the reaction is carried out at a temperature of 5°C to 65°C for several minutes to several tens of hours. Also, as in the above-mentioned production method of polypropylene glycol, it can be obtained by adding butylene oxide using a polyhydric alcohol or the like as an initiator and a strong basic catalyst. Furthermore, the molecular weight of the polytetramethylene ether glycol produced can be adjusted by changing the polymerization temperature, polymerization time, amount of catalyst used, etc.

Commercially available polytetramethylene ether glycols include, for example, Mitsubishi Chemical Corporation's product names "PTMG1000" (number average molecular weight 1000), "PTMG2000" (number average molecular weight 2000), "PTMG3000" (number average molecular weight 2900), and "PTMG4000" (number average molecular weight 4000).

In the polyether polyol (B), the mass ratio of polytetramethylene ether glycol to polypropylene glycol (PTMG/PPG mass ratio) is preferably 0/100 or more and 80/20 or less, more preferably 0/100 or more and 60/40 or less, even more preferably 0/100 or more and 50/50 or less, and particularly preferably 0/100 or more and 45/55 or less.
By setting the mass ratio of PTMG/PPG within the above range, compatibility with the base resin in a low-temperature environment can be improved.

The number average molecular weight of the polyether polyol (B) is preferably 1,000 or more and 7,000 or less, more preferably 2,000 or more and 7,000 or less, even more preferably 3,000 or more and 6,700 or less, and particularly preferably 4,000 or more and 6,500 or less.
The number average molecular weight of the polyether polyol (B) is within the above range, and the flexibility of the resulting coating film at low temperature and room temperature is excellent. The number average molecular weight Mn of the polyether polyol (B) is, for example, a number average molecular weight based on polystyrene standards measured by GPC. When two or more kinds of polyether polyols (B) are mixed and used, the number average molecular weight of the mixture is calculated.

In the polyisocyanate composition of the present embodiment, the mass ratio of the polycaprolactone polyol (A) to the polyether polyol (B) (the mass ratio of (A)/(B)) is preferably 10/90 or more and 90/10 or less, more preferably 15/85 or more and 85/15 or less, and even more preferably 18/82 or more and 83/17 or less.
When the mass ratio of (A)/(B) is equal to or greater than the lower limit, the compatibility with the base agent in a low-temperature environment can be improved, whereas when the mass ratio is equal to or less than the upper limit, a coating film having superior flexibility at low and normal temperatures can be obtained.
The mass ratio of (A)/(B) can be calculated, for example, from the blending amount of each polyol.

<Method for producing polyisocyanate composition>
The polyisocyanate is obtained by reacting the above diisocyanate with a polycaprolactone polyol (A) and a polyether polyol (B). Hereinafter, the polycaprolactone polyol (A) and the polyether polyol (B) may be collectively referred to as a polyol.

The polycaprolactone polyol (A) and the polyether polyol (B) can be used alone or as a mixture. When used as a mixture, they may be mixed before reacting with a diisocyanate, or each polyol may be reacted with a diisocyanate alone to form a polyisocyanate and then mixed.
That is, examples of methods for producing a polyisocyanate composition include a method of simultaneously reacting a diisocyanate, a polycaprolactone polyol (A), and a polyether polyol (B) to obtain a polyisocyanate composition; a method of mixing a reaction product of a diisocyanate and a polycaprolactone polyol (A) with a reaction product of a diisocyanate and a polyether polyol (B) to obtain a polyisocyanate composition; and a method of reacting a diisocyanate with a polycaprolactone polyol (A) or a polyether polyol (B) and then further reacting the remaining polyol to obtain a polyisocyanate composition.

The amounts of polycaprolactone polyol (A) and polyether polyol (B) are preferably mixed so that the mass ratio of polycaprolactone polyol (A) to polyether polyol (B) is within the above range.

The reaction between polyol and diisocyanate is carried out as follows. The reaction temperature is usually from room temperature (about 23°C) to 200°C, and preferably from 80°C to 120°C. If the reaction temperature is above the lower limit, the reaction time is shorter. On the other hand, if the reaction temperature is below the upper limit, an increase in the viscosity of the polyisocyanate due to undesirable side reactions can be more effectively avoided, and discoloration of the resulting polyisocyanate can also be more effectively avoided.

The reaction may be carried out without a solvent or in any solvent that is inert to isocyanate groups. If necessary, a known catalyst may be used to promote the reaction between the isocyanate groups and the hydroxyl groups.

During the reaction, the molar ratio of the isocyanate groups of the diisocyanate to the hydroxyl groups of the polycaprolactone polyol (A) and the polyether polyol (B) (molar ratio of hydroxyl groups/isocyanate groups) is preferably 2 to 10, more preferably 3 to 9, and even more preferably 4 to 8. By having the molar ratio of hydroxyl groups/isocyanate groups be equal to or greater than the lower limit, it is possible to more effectively avoid an increase in the viscosity of the polyisocyanate due to the successive addition reaction between the diisocyanate and the polyol. On the other hand, by having the molar ratio be equal to or less than the upper limit, productivity is improved.

At the end of the reaction, unreacted diisocyanate in the reaction mixture is recovered by known methods such as a thin-film distillation apparatus or solvent extraction. If the amount of unreacted diisocyanate remaining is small, odor, toxicity, irritation, etc. caused by diisocyanate during thermal curing can be more easily avoided.

<Physical Properties of Polyisocyanate Composition>
The isocyanate group content (NCO group content) of the polyisocyanate composition of the present embodiment, in a state substantially free of solvent or diisocyanate, is preferably 3 mass% or more and 8 mass% or less, more preferably 3.1 mass% or more and 7.5 mass% or less, and even more preferably 3.3 mass% or more and 7.3 mass% or less, relative to the total mass of the polyisocyanate composition.
The NCO group content can be determined, for example, by reacting the isocyanate groups of the polyisocyanate composition with an excess of an amine (such as dibutylamine) and then back-titrating the remaining amine with an acid such as hydrochloric acid.

≪Resin composition≫
The resin composition of the present embodiment contains the above-mentioned polyisocyanate composition as a curing agent component and a polyol as a main component.

The resin composition of this embodiment contains the polyisocyanate composition as a curing agent component, and thus produces a coating film that has excellent flexibility at low temperatures of about -10°C and at room temperature of about 23°C.

The resin composition of the present embodiment can be used, for example, in architectural paints, automotive paints, automotive repair paints, plastic paints, pressure sensitive adhesives, adhesives, building materials, household water-based paints, other coating agents, sealants, inks, casting materials, elastomers, foams, plastic raw materials, fiber treatment agents, and the like.
Among these, the resin composition of the present embodiment is preferably used as a pressure-sensitive adhesive composition, since it has good flexibility at low and normal temperatures, particularly when formed into a coating film.

Next, each component contained in the resin composition of this embodiment will be described in detail below.

<Polyol>
Specific examples of the polyol include aliphatic hydrocarbon polyols, polyether polyols, polyester polyols, epoxy resins, fluorine-containing polyols, and acrylic polyols.
Among them, the polyol is preferably an acrylic polyol.

[Aliphatic Hydrocarbon Polyol]
Examples of the aliphatic hydrocarbon polyol include hydroxyl-terminated polybutadiene and hydrogenated products thereof.

[Polyether polyol]
The polyether polyol may be, for example, one obtained by any one of the following methods (1) to (3).
(1) Polyether polyols or polytetramethylene ether glycols obtained by adding alkylene oxides, either alone or in a mixture, to a polyhydric alcohol, either alone or in a mixture.
(2) Polyether polyols obtained by reacting alkylene oxides with polyfunctional compounds.
(3) Polymer polyols obtained by polymerizing acrylamide or the like using the polyether polyol obtained in (1) or (2) as a medium.
Examples of the polyhydric alcohol include glycerin and propylene glycol.
Examples of the alkylene oxide include ethylene oxide and propylene oxide.
Examples of the polyfunctional compound include ethylenediamine and ethanolamine.

[Polyester polyol]
The polyester polyol may be, for example, any one of the following polyester polyols (1) and (2).
(1) Polyester polyol resins obtained by a condensation reaction between a dibasic acid alone or a mixture of two or more kinds and a polyhydric alcohol alone or a mixture of two or more kinds.
(2) Polycaprolactone polyol obtained by ring-opening polymerization of ε-caprolactone with a polyhydric alcohol.
Examples of the dibasic acid include carboxylic acids such as succinic acid, adipic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and 1,4-cyclohexanedicarboxylic acid.
Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, trimethylolpropane, glycerin, pentaerythritol, 2-methylolpropanediol, and ethoxylated trimethylolpropane.

[Epoxy resin]
Examples of the epoxy resin include novolac type epoxy resins, β-methylepicrotype epoxy resins, cyclic oxirane type epoxy resins, glycidyl ether type epoxy resins, glycol ether type epoxy resins, epoxy type aliphatic unsaturated compounds, epoxidized fatty acid esters, ester type polycarboxylic acids, aminoglycidyl type epoxy resins, halogenated type epoxy resins, and resorcin type epoxy resins, as well as resins obtained by modifying these epoxy resins with amino compounds, polyamide compounds, or the like.

[Fluorine-containing polyol]
Examples of the fluorine-containing polyol include copolymers of fluoroolefins, cyclohexyl vinyl ethers, hydroxyalkyl vinyl ethers, and monocarboxylic acid vinyl esters, which are disclosed in Reference Document 1 (JP-A-57-34107) and Reference Document 2 (JP-A-61-275311), etc.

[Acrylic polyol]
The acrylic polyol can be obtained, for example, by polymerizing a polymerizable monomer having one or more active hydrogens in one molecule, or by copolymerizing a polymerizable monomer having one or more active hydrogens in one molecule with another monomer copolymerizable with the polymerizable monomer, as necessary.

Examples of the polymerizable monomer having one or more active hydrogens in one molecule include the following (i) to (iii). These may be used alone or in combination of two or more.
(i) Acrylic acid esters having active hydrogen, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate.
(ii) Methacrylic acid esters having active hydrogen, such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 2-hydroxybutyl methacrylate.
(iii) (meth)acrylic acid esters having polyvalent active hydrogen, such as acrylic acid monoesters or methacrylic acid monoesters of glycerin, and acrylic acid monoesters or methacrylic acid monoesters of trimethylolpropane.

Examples of other monomers copolymerizable with the polymerizable monomer include the following (i) to (v). These may be used alone or in combination of two or more.
(i) Acrylic acid esters such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate.
(ii) Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, and glycidyl methacrylate.
(iii) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid.
(iv) Unsaturated amides such as acrylamide, N-methylol acrylamide, and diacetone acrylamide.
(v) Styrene, vinyl toluene, vinyl acetate, acrylonitrile, etc.

Other examples include acrylic polyols obtained by copolymerizing polymerizable ultraviolet-stable monomers, as disclosed in Reference 3 (JP Patent Publication 1-261409 A) and Reference 4 (JP Patent Publication 3-006273 A).

Specific examples of the polymerizable ultraviolet-stable monomer include 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, and 2-hydroxy-4-(3-methacryloxy-2-hydroxypropoxy)benzophenone.

For example, the above monomer components can be solution polymerized in the presence of a known radical polymerization initiator such as a peroxide or an azo compound, and then diluted with an organic solvent, etc., as necessary, to obtain an acrylic polyol.

Water-based acrylic polyols can be produced by known methods such as a method of solution polymerization of an olefinic unsaturated compound and converting it into a water layer, or emulsion polymerization. In this case, water solubility or water dispersibility can be imparted by neutralizing the acidic moieties of carboxylic acid-containing monomers such as acrylic acid and methacrylic acid, and sulfonic acid-containing monomers, with amines or ammonia.

[Isocyanate group/hydroxyl group]
The molar ratio of the isocyanate groups of the polyisocyanate composition to the hydroxyl groups of the polyol contained in the resin composition of this embodiment (the molar ratio of isocyanate groups/hydroxyl groups) is determined based on the required physical properties of the resin film, but is usually 0.01 or more and 22.5 or less.

<Other ingredients>
The resin composition of the present embodiment may further contain other additives.
Examples of other additives include curing agents other than the polyisocyanate composition that can react with polyols, curing catalysts, solvents, pigments (extender pigments, colored pigments, metallic pigments, etc.), photopolymerization initiators, ultraviolet absorbers, light stabilizers, radical stabilizers, yellowing inhibitors that suppress coloring during the baking process, coating surface adjusters, flow adjusters, pigment dispersants, defoamers, thickeners, film-forming assistants, and the like.

Examples of the curing agent include melamine resins, urea resins, epoxy group-containing compounds or resins, carboxy group-containing compounds or resins, acid anhydrides, alkoxysilane group-containing compounds or resins, and hydrazide compounds.

The curing catalyst may be a basic compound or a Lewis acid compound.
Examples of the basic compound include metal hydroxides, metal alkoxides, metal carboxylates, metal acetylacetinates, hydroxides of onium salts, onium carboxylates, halides of onium salts, metal salts of active methylene compounds, onium salts of active methylene compounds, aminosilanes, amines, phosphines, etc. As the onium salts, ammonium salts, phosphonium salts, or sulfonium salts are preferable.
Examples of the Lewis acid compound include an organotin compound, an organozinc compound, an organotitanium compound, and an organozirconium compound.

Examples of the solvent include 1-methylpyrrolidone, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, 3-methoxy-3-methyl-1-butanol, ethylene glycol diethyl ether, diethylene glycol diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether (DPDM), propylene glycol dimethyl ether, methyl ethyl ketone, acetone, Examples of the solvent include methyl isobutyl ketone, propylene glycol monomethyl ether acetate, ethanol, methanol, iso-propanol, 1-propanol, iso-butanol, 1-butanol, tert-butanol, 2-ethylhexanol, cyclohexanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, ethyl acetate, isopropyl acetate, butyl acetate, toluene, xylene, pentane, iso-pentane, hexane, iso-hexane, cyclohexane, solvent naphtha, and mineral spirits. These solvents may be used alone or in combination of two or more.

In addition, known pigments (extender pigments, color pigments, metallic pigments, etc.), ultraviolet absorbers, light stabilizers, radical stabilizers, yellowing inhibitors that suppress coloring during the baking process, coating surface conditioners, flow conditioners, pigment dispersants, defoamers, thickeners, and film-forming aids can be appropriately selected and used.

<Method of producing resin composition>
The resin composition of the present embodiment can be produced by a conventionally known method.
When the resin composition of the present embodiment is a pressure-sensitive adhesive composition, for example, a melt-kneading method using a general mixer such as a Banbury mixer, a single-screw extruder, a twin-screw extruder, a co-kneader, or a multi-screw extruder, or a method in which each component is dissolved or dispersed and mixed, then coated onto a substrate film using a coater or the like, and the solvent is then removed by heating, can be used.

The resin composition of this embodiment may be foamed to achieve the effects of weight reduction, flexibility, and improved adhesion. Foaming methods include chemical methods, physical methods, and the use of thermally expandable microballoons. Bubbles can be distributed inside the material by adding a chemical foaming agent such as an inorganic foaming agent or an organic foaming agent, or a physical foaming agent, or by adding thermally expandable microballoons.

In addition, hollow fillers (pre-expanded balloons) can be added to reduce weight, increase flexibility, and improve adhesion.

When the resin composition of this embodiment is an adhesive composition, a tackifier resin may be added to adjust the adhesive strength and cohesive strength. Examples of tackifier resins include rosin-based tackifier resins, terpene-based tackifier resins, petroleum-based tackifier resins, and styrene-based tackifier resins. These tackifier resins may be used alone or in combination of two or more. In addition, the softening point of the tackifier resin is preferably 90°C or higher and 160°C or lower.

The present embodiment will be described in more detail below based on examples and comparative examples, but the present embodiment is not limited to the following examples. In the following, Example 8 is a reference example.

<Test items>
The polyisocyanate compositions produced in the Examples and Comparative Examples were subjected to measurement and evaluation of various physical properties according to the methods described below.

[Physical Properties 1]
(Isocyanate group (NCO) content)
First, 2 g or more and 3 g or less of the measurement sample was precisely weighed out (Wg) in a flask. Then, 20 mL of toluene was added to dissolve the measurement sample. Then, 20 mL of a 2N toluene solution of di-n-butylamine was added, mixed, and left at room temperature for 15 minutes. Then, 70 mL of isopropyl alcohol was added and mixed. Then, this liquid was titrated with a 1N hydrochloric acid solution (Factor F) as an indicator. The titration value obtained was V2 mL. Then, the titration value obtained without the polyisocyanate sample was V1 ml. Then, the isocyanate group (NCO) content (NCO%) (mass%) of the polyisocyanate was calculated from the following formula.

Isocyanate group (NCO) content (mass%) = (V1-V2) x F x 42/(W x 1000) x 100

[Physical Properties 2]
(number average molecular weight)
The number average molecular weight is a number average molecular weight measured by gel permeation chromatography (GPC) using the following apparatus, with a polystyrene standard.

(Measurement conditions)
Apparatus: Tosoh Corporation, HLC-802A
Column: Tosoh Corporation, G1000HXL x 1
G2000HXL x 1
G3000HXL x 1 Carrier: Tetrahydrofuran Detection method: Differential refractometer

[Preparation of resin composition]
Each polyisocyanate composition and an acrylic polyol (manufactured by Allnex, product name "Setalux 1152") were mixed so that the molar ratio of isocyanate groups to hydroxyl groups was 1.0, and the mixture was further diluted with butyl acetate so that the solid content was 50 mass%. Next, a tin catalyst (manufactured by Nitto Kasei Co., Ltd., product name "Neostan U-100") was further mixed into the diluted solution in an amount of 300 mass ppm relative to the solid content to obtain each resin composition.

[Evaluation 1]
(Compatibility with base agent)
Immediately after preparation, each resin composition was kept for 5 days in an environment at −10° C. The state of the coating liquid was visually observed and evaluated according to the following evaluation criteria.

(Evaluation Criteria)
◎: Uniformly transparent △: Cloudy in some areas ×: Cloudy throughout

[Preparation of coating film]
Each resin composition was applied onto a polypropylene plate to a film thickness of 30 μm, and then dried by heating at 120° C. for 30 minutes, followed by drying for 1 day in an environment of 23° C. and 50% humidity to prepare each coating film.

[Evaluation 2]
(Low temperature elongation at break)
The coating film thus produced was cut into a rectangular shape to produce a test piece. The test piece was then attached to a tensile tester (Tensilon universal testing machine) so as to have a length of 20 mm and a width of 10 mm, and the test was carried out at a test temperature of -10°C and a tensile speed of 20 mm/min to measure the elongation at break (%). The elongation at break was evaluated according to the following criteria.

(Evaluation Criteria)
◎: Breaking elongation of 150% or more ○: Breaking elongation of 100% or more but less than 150% ×: Breaking elongation of less than 100%

[Evaluation 3]
(Low temperature and low stress properties (stress at 20% elongation))
The coating film thus produced was cut into a rectangular shape to produce a test piece. The test piece was then attached to a tensile tester (Tensilon universal testing machine) with a length of 20 mm and a width of 10 mm, and the test was carried out at a test temperature of -10°C and a tensile speed of 20 mm/min. The stress value at an elongation of 20% was used to evaluate the test piece according to the following evaluation criteria.

(Evaluation Criteria)
◎: Less than 10 MPa ○: 10 MPa or more but less than 30 MPa ×: 30 MPa or more

[Evaluation 4]
(Low stress at room temperature (stress at 75% elongation))
The prepared coating film was cut into a rectangular shape to prepare a test piece. Then, the test piece was attached to a tensile tester (Tensilon universal testing machine) so as to have a length of 20 mm and a width of 10 mm, and the test was carried out at a test temperature of 23° C. and a tensile speed of 20 mm/min. The stress value at an elongation of 75% was used to evaluate the test piece according to the following evaluation criteria.

(Evaluation Criteria)
◎: Less than 2 MPa ○: 2 MPa or more but less than 5 MPa ×: 5 MPa or more

<Production of polyisocyanate composition>
[Example 1]
(Production of polyisocyanate composition PA-a1)
A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube, and a dropping funnel was filled with nitrogen, 1000 g of HDI and 496.0 g of trifunctional polycaprolactone polyol (manufactured by DIC Corporation, trade name "OD-X2588", number average molecular weight 1250) were charged, and the temperature inside the reactor was kept at 100°C while stirring to allow the urethane reaction to proceed. After filtering the reaction liquid, unreacted HDI was removed using a thin-film evaporator to obtain a polyisocyanate precursor. 100.0 g of the polyisocyanate precursor was charged in a flask, and 57.0 g of polyoxypropylene diol (manufactured by AGC Corporation, trade name "EXCENOL 510", number average molecular weight 4000) was charged, and the temperature inside the reactor was kept at 100°C while stirring to allow the urethane reaction to proceed, to obtain a polyisocyanate composition PA-a1.

[Examples 2 to 6]
(Production of polyisocyanate compositions PA-a2 to PA-a6)
Each polyisocyanate composition was obtained in the same manner as in Example 1, except that the compositions shown in Table 1 were used.

[Example 7]
(Production of polyisocyanate composition PA-a7)
A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube, and a dropping funnel was conditioned with a nitrogen atmosphere, and 1000 g of HDI, 150.0 g of trifunctional polycaprolactone polyol (manufactured by DIC Corporation, trade name "OD-X2735", number average molecular weight 500), 200.0 g of polytetramethylene ether glycol (manufactured by Mitsubishi Chemical Corporation, trade name "PTMG1000", number average molecular weight 1000), and 300.0 g of polyoxypropylene diol (manufactured by AGC Inc., trade name "EXCENOL 510", number average molecular weight 4000) were charged, and the temperature inside the reactor was maintained at 100° C. with stirring to allow the urethane reaction to proceed. The reaction liquid was filtered, and then unreacted HDI was removed using a thin-film evaporator to obtain a polyisocyanate composition PA-a6.

[Example 8 and Comparative Examples 1 to 3]
(Production of polyisocyanate compositions PA-a8 and PA-b1 to PA-b3)
Each polyisocyanate composition was obtained in the same manner as in Example 7, except that the compositions shown in Table 2 were used.

The physical properties of each polyisocyanate composition obtained and the evaluation results using the methods described above are shown in Tables 1 and 2.

In addition, the abbreviations in Tables 1 and 2 represent the following compounds.

(Polycaprolactone polyol (A))
A: Polycaprolactone polyol OD-X-2735: manufactured by DIC Corporation, trifunctional polycaprolactone polyol, number average molecular weight 500
OD-X-2586: DIC Corporation, trifunctional polycaprolactone polyol, number average molecular weight 850
OD-X-2588: DIC Corporation, trifunctional polycaprolactone polyol, number average molecular weight 1250

(Polyether polyol (B))
B1: Polypropylene glycol Excenol 510: AGC Corporation, polyoxypropylene diol, number average molecular weight 4000
Excenol 840: AGC Corporation, polyoxypropylene triol, number average molecular weight 6500
Excenol 1020: AGC Corporation, polyoxypropylene diol, number average molecular weight 1000

B2: Other polyether polyols PTMG1000: Polytetramethylene ether glycol, manufactured by Mitsubishi Chemical Corporation, number average molecular weight 1000

Polyisocyanate compositions PA-a1 to PA-a8 (Examples 1 to 8) derived from a diisocyanate, a polycaprolactone polyol (A), and a polyether polyol (B) and containing 20 parts by mass or more of polypropylene glycol per 100 parts by mass of the polyether polyol (B) had good compatibility with the base agent in a low-temperature environment of about -10°C, and when formed into a coating, had excellent breaking elongation at a low temperature of about -10°C, as well as low stress at a low temperature of about -10°C and at room temperature of about 23°C.

In the polyisocyanate composition PA-b1 (Comparative Example 1) derived from a diisocyanate and a polycaprolactone polyol (A), the compatibility with the base agent in a low-temperature environment of about -10°C was good, but when formed into a coating film, the breaking elongation at a low temperature of about -10°C and the low stress properties at a low temperature of about -10°C and at normal temperature of about 23°C were poor.
In addition, in the polyisocyanate composition PA-b2 (Comparative Example 2) derived from a diisocyanate, a polycaprolactone polyol (A), and a polyether polyol (B) containing no polypropylene glycol, the breaking elongation at a low temperature of about -10°C and the low stress properties at a low temperature of about -10°C and at normal temperature of about 23°C when formed into a coating film were within the allowable ranges, but the compatibility with the base agent in a low temperature environment of about -10°C was poor.
In addition, in the polyisocyanate composition PA-b3 (Comparative Example 3) derived from a diisocyanate, a polycaprolactone polyol (A), and a polyether polyol (B) and containing less than 20 parts by mass (10 parts by mass) of polypropylene glycol per 100 parts by mass of the polyether polyol (B), the breaking elongation at a low temperature of about -10°C and the low stress properties at a low temperature of about -10°C and at normal temperature of about 23°C when formed into a coating film were within the allowable range, but the compatibility with the base agent in a low temperature environment of about -10°C was poor.

The polyisocyanate composition of this embodiment has good compatibility with the base agent in low-temperature environments of about -10°C, and can provide a polyisocyanate composition that, when formed into a coating film, has excellent flexibility at low temperatures of about -10°C and at room temperature of about 23°C.

Claims (3)

A resin composition comprising:
Polyisocyanate and acrylic polyol,
the polyisocyanate is derived from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, a polycaprolactone polyol (A), and a polyether polyol (B);
Polypropylene glycol is 20 parts by mass or more relative to 100 parts by mass of the polyether polyol (B),
the polycaprolactone polyol (A) has an average hydroxyl functionality of 3;
The number average molecular weight of the polycaprolactone polyol (A) is 500 or more and 1500 or less,
The number average molecular weight of the polyether polyol (B) is 1,000 or more and 7,000 or less,
a molar ratio of an isocyanate group of the diisocyanate to a hydroxyl group of the polycaprolactone polyol (A) and the polyether polyol (B) is 2 or more and 10 or less, and
The resin composition is a pressure-sensitive adhesive composition. The resin composition according to claim 1, wherein in the polyether polyol (B), the mass ratio of polytetramethylene ether glycol to polypropylene glycol is 0/100 or more and 60/40 or less. The resin composition according to claim 1 or 2, wherein the mass ratio of the polycaprolactone polyol (A) to the polyether polyol (B) is 10/90 or more and 90/10 or less.