KR20230107548A - Solvent-free reactive adhesives, cured products and laminates thereof - Google Patents

Abstract

To provide a solvent-free reactive adhesive that can maintain excellent film strength and flexibility even after a heat resistance test and an oil resistance test, and has little effect on the elongation at break even when the mixing ratio of the main agent and the curing agent is changed. The above object includes a polyisocyanate containing a trimethylolpropane adduct of at least one of tolylene diisocyanate and diphenylmethane diisocyanate, and an aromatic polyisocyanate excluding the trimethylolpropane adduct, and a polyol, Based on the total mass of the polyisocyanate, the trimethylolpropane adduct of the tolylene diisocyanate and the trimethylolpropane adduct of the diphenylmethane diisocyanate are included in the range of 40 to 80% by mass in total It is solved by a solvent-free reactive adhesive.

Description

Solvent-free reactive adhesives, cured products and laminates thereof

The present invention relates to a solvent-free reactive adhesive having high film strength and flexibility and excellent in heat resistance, oil resistance, adhesion, and workability, and a cured product and laminate thereof.

In the fields of automobiles, building materials, ships, and aircraft, various structural adhesives are used to adhere and fix metals such as iron, aluminum, and stainless steel, resins, glass, and ceramics. In recent years, in the field of automobiles and aircraft, weight reduction has been progressing to improve fuel efficiency, increasing the use rate of materials made of plastic or fiber-reinforced plastic (hereinafter abbreviated as FRP), or replacing steel with lighter aluminum. Movement is becoming active, and adhesives capable of bonding them firmly are required. Further, from the viewpoints of workability and environmental impact reduction, adhesives containing no volatile organic compounds are required.

However, when bonding materials having different coefficients of linear expansion, such as aluminum and other materials, such as FRP, high stress is applied to the adhesive layer due to differences in expansion coefficients between materials caused by temperature changes in the manufacturing process or operating temperature environment. , there is a problem that destruction or deterioration of the adhesive layer is accelerated.

At this time, Patent Documents 1 to 3 disclose a method of adding long-chain polyamine or nano-dispersed rubber-like particles to an epoxy compound having high adhesion to metal or FRP for the purpose of stress relaxation. However, in these methods, although a certain flexibility can be imparted, the resulting adhesive layer is still hard and tends to break, so the effect may not be sufficient.

Further, Patent Literature 4 discloses a non-solvent type urethane-based adhesive composition having excellent elongation at break, comprising a main agent containing a urethane prepolymer and a cured product containing a curing agent containing a compound having an active hydrogen group. However, when the adhesive described in Patent Literature 4 is applied with a two-component mixing and dispensing device, there is a problem that the elongation at break can be significantly reduced due to fluctuations in the mixing ratio or uneven mixing in the mixing nozzle.

Regarding such a problem, in Patent Document 5, by using a base material containing a urethane polymer and a curing agent containing an amorphous polyol compound and a polyamine compound, even if the mixing ratio of the base material and the curing agent fluctuates, the decrease in elongation at break is suppressed A urethane-based adhesive composition is disclosed. However, since the adhesive described in Patent Document 5 uses a large amount of an amine compound, it is sometimes difficult to adjust the curing speed, and nozzle clogging at the time of application or bonding unevenness may occur in large area or manual adhesion. There is a task. In addition, although the curing rate can be slowed down by reducing the amount of the amine compound used, flexibility and strength of the coating film tend to decrease. Further, in these methods, since a trace amount of amino groups remain in the cured film, there is a problem that chemical resistance such as heat resistance and oil resistance may decrease.

Japanese Patent Publication No. 2018-506635 International Publication No. 2007/025007 Japanese Unexamined Patent Publication No. 2015-182248 Japanese Unexamined Patent Publication No. 2017-218539 Japanese Unexamined Patent Publication No. 2020-055923

An object of the present invention is to be able to maintain excellent coating film strength and flexibility even after a heat resistance test and an oil resistance test, and also affect the elongation at break even when the mixing ratio of the main agent (corresponding to polyol) and the curing agent (corresponding to polyisocyanate) fluctuates. This enemy lies in providing a non-solvent type reactive adhesive.

As a result of intensive studies, the inventors of the present invention have found that an adhesive using a polyisocyanate containing an aromatic polyisocyanate and a specific amount of a trimethylolpropane adduct of at least one of tolylene diisocyanate and diphenylmethane diisocyanate, together with a polyol. It was found that the above problems could be solved.

That is, the present invention relates to a polyisocyanate comprising a trimethylolpropane adduct of at least one isocyanate of tolylene diisocyanate and diphenylmethane diisocyanate, and an aromatic polyisocyanate excluding the trimethylolpropane adduct, and a polyol A non-solvent type reactive adhesive comprising a, based on the total mass of the polyisocyanate, the trimethylolpropane adduct of the tolylene diisocyanate and the trimethylolpropane adduct of the diphenylmethane diisocyanate, in total It relates to a non-solvent type reactive adhesive containing in the range of 40 to 80% by mass.

Furthermore, in the present invention, the solvent-free type wherein the aromatic polyisocyanate contains at least one selected from the group consisting of diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and carbodiimide-modified diphenylmethane diisocyanate. It is about reactive adhesives.

Further, the present invention relates to the non-solvent type reactive adhesive containing the aromatic polyisocyanate in a range of 20 to 60% by mass in total based on the total mass of the polyisocyanate.

In addition, the present invention, based on the total mass of the polyisocyanate, the trimethylolpropane adduct of the tolylene diisocyanate and the trimethylolpropane adduct of the diphenylmethane diisocyanate are 45 to 75 mass in total It relates to the solvent-free reactive adhesive, including in the range of %.

Further, the present invention relates to the solvent-free reactive adhesive, wherein the polyol includes a polycarbonate polyol having no urethane bond.

Further, the present invention relates to the solvent-free reactive adhesive, wherein the polyol includes a polyol having a urethane bond.

Further, the present invention relates to the non-solvent type reactive adhesive containing the polyol having a urethane bond in a range of 30 to 70% by mass in total based on the total mass of the polyol.

Further, the present invention relates to a cured product of the non-solvent type reactive adhesive.

Further, the present invention relates to a laminate having an adhesive layer made of the above cured material on a substrate.

According to the present invention, it is possible to provide a solvent-free reactive adhesive that can maintain excellent film strength and flexibility even after a heat resistance test and an oil resistance test, and has little effect on the elongation at break even when the mixing ratio of the main agent and the curing agent is changed. there is.

<Solvent-free reactive adhesive>

The non-solvent type reactive adhesive of the present invention is characterized by containing a specific polyisocyanate and a polyol. The said polyisocyanate is at least (i) the trimethylolpropane adduct of at least one isocyanate of tolylene diisocyanate and diphenylmethane diisocyanate (it can henceforth be called adduct body (i)); and (ii) aromatic polyisocyanates (except for the adduct (i)).

Further, the adduct (i) may be only the trimethylolpropane adduct of tolylene diisocyanate or only the trimethylolpropane adduct of diphenylmethane diisocyanate. That is, the adduct (i) may be a trimethylolpropane adduct of tolylene diisocyanate or diphenylmethane diisocyanate. Further, the adduct (i) may be both a trimethylolpropane adduct of tolylene diisocyanate and a trimethylolpropane adduct of diphenylmethane diisocyanate. In this way, the adduct body (i) may be used singly or in combination of several types.

In addition, based on the total mass of the polyisocyanate, the adduct (i) (trimethylolpropane adduct of tolylene diisocyanate and trimethylolpropane adduct of diphenylmethane diisocyanate), in total It contains in the range of 40-80 mass %.

In this way, by using a specific polyisocyanate containing an aromatic polyisocyanate and an adduct (i) in a predetermined range together with a polyol, even when the mixing ratio of the main agent (polyol) and the curing agent (polyisocyanate) fluctuates, A cured film with little change in elastic modulus can be obtained, and excellent flexibility can be stably exhibited. In addition, the solvent-free reactive adhesive of the present invention can exhibit high film strength and flexibility, excellent heat resistance, oil resistance, adhesive strength, and appropriate tact time.

Therefore, the solvent-free reactive adhesive of the present invention is suitably used in fields such as automobiles, building materials, ships, and aircraft.

<Polyisocyanate>

The polyisocyanate in the present invention is 40 to 80% by mass of the adduct body (i) in total based on the total mass of the polyisocyanate together with the aromatic polyisocyanate excluding the adduct body (i). to be included in the scope. Since the adduct body (i) is usually a viscous solid at room temperature (eg, 25° C.), it is difficult to handle and has not been used as a solvent-free adhesive until now. However, a specific crosslinked form can be formed by containing the adduct body (i) at a high compounding ratio of 40 to 80% by mass in total in all polyisocyanates. As a result, even when the mixing ratio of the main agent and the curing agent fluctuates, the change in elastic modulus of the cured film is suppressed, and the resulting cured film exhibits high flexibility, excellent coating strength, heat resistance, and oil resistance.

The total content of the adduct (i) is preferably in the range of 45 to 75% by mass, more preferably in the range of 50 to 75% by mass, based on the total mass of the polyisocyanate. When the content of the adduct body (i) is 45% by mass or more, it is preferable because the breaking stress and breaking elongation are more excellent. In addition, when the content of the adduct body (i) is 75% by mass or less, the shear stress and elongation at break are more excellent, so it is preferable.

The trimethylolpropane adduct of tolylene diisocyanate can be used without particular limitation as long as it is a reaction product between 2,4-tolylene diisocyanate and/or 2,6-tolylene diisocyanate and trimethylolpropane. Examples of the trimethylolpropane adduct of tolylene diisocyanate include "Takenate D103H", a trade name manufactured by Mitsui Chemicals, and "Desmodule L", a trade name manufactured by Sumika Bayer Urethane Co., Ltd.

The trimethylolpropane adduct of diphenylmethane diisocyanate is not particularly limited as long as it is a reaction product of 4,4'-diphenylmethane diisocyanate and/or 2,4'-diphenylmethane diisocyanate and trimethylolpropane. can be used

The polyisocyanate contains polyisocyanates other than the adduct body (i) (hereinafter sometimes referred to as other polyisocyanates) in the range of 20 to 60% by mass. Other polyisocyanates include at least aromatic polyisocyanates (however, modified products of aromatic polyisocyanates are also included). The other polyisocyanates are not particularly limited to those other than aromatic polyisocyanates, and examples thereof include aromatic aliphatic polyisocyanates, aliphatic polyisocyanates and alicyclic polyisocyanates, and modified products thereof.

Examples of the aromatic polyisocyanates include aromatic diisocyanates such as diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, phenylene diisocyanate, tolylene diisocyanate, and naphthalene diisocyanate; and aromatic polyisocyanates such as polymethylene polyphenyl polyisocyanate.

As described above, the aromatic polyisocyanate contained in the non-solvent type reactive adhesive of the present invention includes monomer isocyanates such as diphenylmethane diisocyanate and polymer isocyanates such as polymethylene polyphenyl polyisocyanate. Thus, the "polyisocyanate" in this specification may be a compound having two or more isocyanate groups in the molecule, and the arrangement of the isocyanate groups is not particularly limited.

Examples of the aromatic aliphatic polyisocyanate include 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω,ω'-diisocyanate-1,4-diethylbenzene, and 1,3- or 1 and aromatic aliphatic diisocyanates such as ,4-bis(1-isocyanate-1-methylethyl)benzene or mixtures thereof.

As said aliphatic polyisocyanate, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1, aliphatic diisocyanates such as 3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl caproate, lysine diisocyanate, and dimer acid diisocyanate; there is.

Examples of the alicyclic polyisocyanates include 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), and methyl 2,4. -Cyclohexane diisocyanate, methyl 2,6-cyclohexane diisocyanate, 1,4-bis (isocyanate methyl) cyclohexane, 1,3-bis (isocyanate methyl) cyclohexane, norbornene diisocyanate and other alicyclic diisocyanates can be heard

Examples of modified polyisocyanates include allophanate-type modified products, isocyanurate-type modified products, biuret-type modified products, and adduct-type modified products, as well as conditions where the polyisocyanate component and the polyol have excess isocyanate groups. and a reaction product having an isocyanate group and a urethane bond reacted under. The polyol forming the modified polyisocyanate is not particularly limited and can be selected from known polyols, such as polyester polyol, polyesterurethane polyol, polycarbonate polyol, polycaprolactone polyol, and polyether polyol. , polyetherurethane polyols, polyolefin polyols, acrylic polyols, silicone polyols, castor oil-based polyols, and fluorine-based polyols.

These other polyisocyanates may be used individually by 1 type, and may be used in combination of 2 or more type.

The non-solvent type reactive adhesive of the present invention includes aromatic polyisocyanates as other polyisocyanates, but diphenylmethane diisocyanates, polymethylene polyphenyl polyisocyanates, and carbodiimide-modified diphenylmethane diisocyanates are used as the aromatic polyisocyanates. It is preferable to include at least 1 sort(s) selected from the group which consists of.

When the polyisocyanate contains an aromatic polyisocyanate, the content of the aromatic polyisocyanate is preferably 20 to 60% by mass, more preferably 20 to 50% by mass, in total based on the total mass of the polyisocyanate. and more preferably 25 to 45% by mass. If it is within the above range, it is preferable because the flexibility, coating strength, and heat resistance of the obtained cured film are more excellent.

<Polyol>

The polyol in the present invention plays a role of forming a strong cross-linked structure through reaction with polyisocyanate, imparting appropriate flexibility and cohesion to the obtained cured film, and imparting excellent coating film strength, flexibility and heat resistance. The polyol may be a compound having two or more hydroxyl groups in the molecule, and when the compound is a resin, the hydroxyl group may be present at the terminal, side chain, or side group of the resin.

Examples of such polyols include polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, vegetable oil polyols, acrylic polyols, other polyols, and complexes thereof. In addition, for the purpose of adjusting the concentration of urethane bonds in the cured film or introducing various functional groups, a low molecular weight polyol described later may be used.

The polyol contained in the non-solvent type reactive adhesive of the present invention may be an acid-modified product in which a part of the hydroxyl groups in the polyol is acid-modified, or a product in which a carboxyl group is introduced by reacting an acid anhydride or a urethane bond is introduced by reacting a diisocyanate. do.

These polyols may be used individually by 1 type, and may be used in combination of 2 or more type.

(polyether polyol)

The polyether polyol may be a compound each having two or more hydroxyl groups and ether bonds in a molecule. Examples of the polyether polyol include polymers or copolymers such as polyethylene glycol, polypropylene glycol, poly(ethylene/propylene) glycol, and polytetramethylene glycol, such as methylene oxide, ethylene oxide, propylene oxide, and tetrahydrofuran; polyether polyols by condensation of hexanediol, methylhexanediol, heptanediol, octanediol or mixtures thereof; A compound having at least two or more active hydrogen groups such as low molecular weight polyols, aliphatic amine compounds, aromatic amine compounds, alkanolamines, or bisphenols is used as a starting material, and methylene oxide, ethylene oxide, propylene oxide, and butylene oxide are added thereto , tetrahydrofuran, or a polyol obtained by adding an alkylene oxide such as polyoxytetramethylene oxide.

Examples of the low molecular weight polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, neopentylglycol, and pentanediol. , hexanediol, octanediol, nonanediol, dipropylene glycol, diethylene glycol, triethylene glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2- Ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, polyoxyethylene glycol (additional mole number 10 or less), polyoxypropylene glycol (additional mole number 10 or less), cyclohexanediol, cyclohexanedimethanol , tricyclodecane dimethanol, cyclopentadiene dimethanol, dimer diol, bisphenol B,N,N-bis(2-hydroxypropyl)aniline, dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutanoic acid, 2,2-dimethylol bifunctional low-molecular-weight polyols such as lactic acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, dihydroxypropionic acid, and dihydroxybenzoic acid;

Trimethylolethane, trimethylolpropane, 1,1,1-trimethylolbutane, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,6-butanetriol, trimethylol Butene, trimethylolpentene, trimethylolhexene, trimethylolheptene, trimethyloloctene, trimethylolnonene, trimethyloldecene, trimethylolundecene, trimethyloldodecene, trimethyloltridecene, trimethylolpentadecene, trimethylolhexadecene , trimethylolheptadecene, trimethyloloctadecene, 1,1,1-trimethylol-2-methyl-hexane, 1,1,1-trimethylol-3-methyl-hexane, 1,1,1-trimethylol- 2-ethyl-hexane, 1,1,1-trimethylol-3-ethyl-hexane, trimethylolhexene, 1,2,3-octanetriol, 1,3,7-octanetriol, 3,7-dimethyl -1,2,3-octanetriol, 1,1,1-trimethyloldecane, 1,2,10-decanetriol, 1,1,1-trimethylolisoheptadecane, 1,1,1-trimethyl ol-seA-butane, 1,1,1-trimethylol-tert-pentane, 1,1,1-trimethylol-tert-nonane, 1,1,1-trimethylol-tert-tridecane, 1,1, 1-trimethylol-tert-heptadecane, 1,1,1-trimethylol-2-methyl-hexane, 1,1,1-trimethylol-3-methyl-hexane, 1,1,1-trimethylol-2 -Ethyl-hexane, 1,1,1-trimethylol-3-ethyl-hexane, 1,1,1-trimethylolisoheptadecane, 1,2,3,4-butanetetraol, pentaerythritol, dipentaerythritol , tripentaerythritol, glycerin, diglycerin, triglycerin, polyglycerin, ditrimethylolethane, ditrimethylolpropane, tris(2-hydroxyethyl)isocyanurate, benzene-1,3,5-triol, trifunctional or higher molecular weight polyols such as benzene-1,2,3-triol, stilbene-3,4',5-triol, sucrose, inositol, sorbitan, sorbitol, mannitol, saccharose, cellulose, and xylitol can be heard

Examples of the aliphatic amine compounds include ethylenediamine, triethylenetetramine, diethylenetriamine, and triaminopropane. Examples of the aromatic amine compounds include toluene diamine and diphenylmethane-4,4-diamine. Examples of the alkanolamines include ethanolamine and diethanolamine. Examples of the bisphenols include bisphenol B, bisphenol BP, bisphenol C, bisphenol A, bisphenol E, and bisphenol F.

(polyester polyol)

As a polyester polyol, the polyester polyol which the above-mentioned low molecular weight polyol and dibasic acid component were condensation-reacted, and the lactone system polyester polyol obtained by ring-opening polymerization of cyclic ester compounds, such as lactones, are mentioned, for example.

Examples of the dibasic acid component include terephthalic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, hydrogenated dimer acid, phthalic anhydride, isophthalic acid, trimellitic acid, glutaric acid, pimelic acid, and suberic acid. aliphatic or aromatic dibasic acids such as the like, and anhydrides thereof.

Examples of the lactones include ε-caprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone.

(Polycarbonate Polyol)

As a polycarbonate polyol, the reaction product of the above-mentioned low molecular weight polyol and carbonate compounds, such as a dialkyl carbonate, an alkylene carbonate, and a diaryl carbonate, is mentioned, for example.

As said dialkyl carbonate, dimethyl carbonate, diethyl carbonate, etc. are mentioned. Ethylene carbonate etc. are mentioned as said alkylene carbonate. As said diaryl carbonate, diphenyl carbonate etc. are mentioned.

(Polyolefin Polyol)

Examples of the polyolefin polyol include hydroxyl group-containing polybutadiene, hydrogenated hydroxyl group-containing polybutadiene, hydroxyl group-containing polyisoprene, hydrogenated hydroxyl group-containing polyisoprene, hydroxyl group-containing chlorinated polypropylene, and hydroxyl group-containing chlorinated polyethylene. .

(vegetable oil polyol)

Examples of vegetable oil-based polyols include plant-derived sunflower oil, dimer acid, and polyols made from soybean oil as a raw material.

As described above, these polyols may be acid-modified products in which some of the hydroxyl groups in the polyol are acid-modified, or may be products in which carboxyl groups are introduced by reacting acid anhydrides or urethane bonds are introduced by reacting diisocyanate.

Examples of the acid anhydride include pyromellitic anhydride, meritic acid anhydride, trimellitic anhydride, and trimellitic acid ester anhydride. As a trimellitic acid ester anhydride, the ester compound formed by carrying out the esterification reaction of C2-C30 alkylene glycol or alkanetriol with trimellitic anhydride is mentioned, for example. As a trimellitic acid ester anhydride, ethylene glycol bisanhydro trimellitate, a propylene glycol bisanhydro trimellitate, etc. are mentioned more specifically.

Examples of the diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and 1,5-naphthalene diisocyanate. , hexamethylene diisocyanate, and hydrogenated diphenylmethane diisocyanate.

Further, it is preferable that the non-solvent type reactive adhesive of the present invention contains a polyol having a urethane bond. Examples of the polyol having such a urethane bond include a polyol in which a urethane bond is introduced by reacting the diisocyanate described above, and a block polymer in which different polymer species are linked may be used.

It is preferable that the hydroxyl group is localized in the terminal region of resin in the polyol which has the said urethane bond. When the hydroxyl group is localized in the terminal region of the resin, the cured film is excellent in flexibility, so it is preferable.

The polyol having a urethane bond having a hydroxyl group at the terminal of such a resin can be obtained, for example, by reacting the above-mentioned polyisocyanate and polyol so that the molar equivalent ratio of the isocyanate group and the hydroxyl group (NCO moles/OH moles) is less than 1. there is.

Among these, the polyol preferably contains at least one selected from the group consisting of polyether polyols and polycarbonate polyols, more preferably contains polycarbonate polyols, and still more preferably polycarbonates. It includes a polyol (but not having a urethane bond) and a polyol having a urethane bond.

When the polyol contains a polycarbonate polyol, the content of the polycarbonate polyol is preferably 30% by mass or more, more preferably 50% by mass or more, and preferably 100% by mass, based on the total mass of the polyol. % or less, more preferably 90% by mass or less, still more preferably 70% by mass or less.

When the polyol contains a polyol having a urethane bond, the total content of the polyol having a urethane bond is preferably 30 to 70% by mass based on the total mass of the polyol. When the content rate of the polyol having a urethane bond is 30% by mass or more, the resulting cured film has better foamability. When the content of the polyol having a urethane bond is 70% by mass or less, the pot life described later is more excellent.

The number average molecular weight of the polycarbonate polyol having no urethane bond is preferably 500 or more and less than 5,000, more preferably 700 or more and less than 3,500.

The weight average molecular weight of the polyol having the urethane bond is preferably 3,000 to 200,000. When the weight average molecular weight is 3,000 or more, the flexibility of the obtained cured film is more excellent, and when it is 200,000 or less, adjustment of the viscosity is easier.

The hydroxyl value of the polyol having a urethane bond is preferably 50 to 500 mgKOH/g, and more preferably 100 to 300 mgKOH/g. If it is 50-500 mgKOH/g, since the adhesive force of the cured film obtained, flexibility, and heat resistance are more excellent, it is preferable.

<Adjustment of solvent-free reactive adhesive>

The solvent-free reactive adhesive of the present invention is a two-component curing type urethane-based solventless adhesive obtained by blending the above-mentioned polyisocyanate and polyol, and the blending ratio of the polyol and polyisocyanate is the total isocyanate group contained in the isocyanate and the polyol. The molar equivalent ratio of all hydroxyl groups [NCO/OH] is preferably in the range of 0.8 to 2.5, more preferably in the range of 1.0 to 2.0.

In the case of mass ratio, the ratio of polyisocyanate to the total mass of polyol is preferably 20 to 100% by mass.

The content of the polyisocyanate in the non-solvent type reactive adhesive of the present invention is preferably in the range of 20 to 100% by mass in total based on the total mass of the polyol. If it is within the above range, it is preferable because the coating film strength, flexibility, and heat resistance of the cured film obtained are more excellent.

The viscosity of the non-solvent type reactive adhesive of the present invention is preferably 10 to 1,000 Pa·s, more preferably 50 to 750 Pa·s at room temperature of 25°C.

If the viscosity is 10 Pa·s or more, the initial cohesive force of the adhesive is excellent, so it is preferable. A viscosity of 1,000 Pa·s or less is preferable because coatability is excellent.

[Other Ingredients]

The solvent-free reactive adhesive of the present invention also contains a reaction accelerator, a silane coupling agent, phosphoric acid or a phosphoric acid derivative, a leveling agent or antifoaming agent, a filler, a propellant, a plasticizer, a superplasticizer, a wetting agent, a flame retardant, a viscosity modifier, a preservative, a stabilizer and a colorant Such known additives may be included. These additives may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the reaction promoter include metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dimaleate; 1,8-diaza-bicyclo(5,4,0)undecene-7,1,5-diazabicyclo(4,3,0)nonene-5,6-dibutylamino-1,8-dia tertiary amines such as zabicyclo (5,4,0) undecene-7; and reactive tertiary amines such as triethanolamine.

The compounding amount of the reaction accelerator is preferably 0.005 to 5% by mass based on the total mass of the polyisocyanate.

Examples of the silane coupling agent include trialkoxysilane having a vinyl group such as vinyltrimethoxysilane and vinyltriethoxysilane, 3-aminopropyltriethoxysilane, and N-(2-aminoethyl)3-aminopropyl. trialkoxysilanes having amino groups such as trimethoxysilane; trialkoxysilanes having glycidyl groups such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane; trialkoxysilanes having an isocyanato group such as 3-isocyanate propyltriethoxysilane; Trialkoxysilane which has a mercapto group, such as 3-mercaptopropyl methyl dimethoxysilane and 3-mercapto propyl trimethoxysilane, is mentioned.

The compounding amount of the silane coupling agent is preferably 0.05 to 10% by mass based on the total mass of polyisocyanates.

Among phosphoric acid or phosphoric acid derivatives, the phosphoric acid may be one having at least one free oxygen acid, and examples thereof include phosphoric acids such as hypophosphorous acid, phosphorous acid, orthophosphoric acid, and hypophosphorous acid; and condensed phosphoric acids such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, and ultraphosphoric acid. Moreover, as a phosphoric acid derivative, what the above-mentioned phosphoric acid was partially esterified with alcohol in the state which left at least one free oxygen acid, etc. are mentioned. Examples of these alcohols include aliphatic alcohols such as methanol, ethanol, ethylene glycol, and glycerin; and aromatic alcohols such as phenol, xylenol, hydroquinone, catechol, and phloroglycinol.

The compounding amount of phosphoric acid and its derivatives is preferably 0.005 to 5% by mass in total based on the total mass of polyisocyanates.

Examples of the leveling agent include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, polyester-modified hydroxyl group-containing polydimethylsiloxane, polyether ester-modified hydroxyl group-containing polydimethylsiloxane, and acrylic type. copolymers, methacrylic copolymers, polyether-modified polymethylalkylsiloxanes, acrylic acid alkyl ester copolymers, methacrylic acid alkyl ester copolymers, and lecithin.

Examples of the antifoaming agent include known ones such as silicone resins, silicone solutions, and copolymers of alkyl vinyl ethers, alkyl acrylate esters, and alkyl methacrylates.

<Laminate, cured product>

The cured product of the present invention is obtained by curing the non-solvent type reactive adhesive of the present invention, and can be obtained by mixing the polyisocyanate, polyol, and other components as necessary by a known method and conducting a urethane crosslinking reaction.

Further, the laminate of the present invention has an adhesive layer made of the above cured material on a substrate. The method for producing the laminate is not particularly limited. For example, a non-solvent type reactive adhesive is applied to one side of a substrate, then another substrate is overlaid on the uncured adhesive side, and heat treatment is performed at about 20 to 150° C. , A laminate can be obtained by curing the non-solvent type reactive adhesive. The thickness of the adhesive layer after curing is preferably 0.1 μm to 300 mm.

The solvent-free reactive adhesive of the present invention can be used for bonding between multiple substrates. Suitable substrates include, for example, metals such as aluminum, thermoplastic polymers such as polyethylene, polypropylene, polyurethane, polyacrylates and polycarbonates and copolymers thereof, thermosetting polymers such as vulcanized rubber, urea-formaldehyde foam, and melamine. resin, wood, carbon fiber reinforced plastics, glass fiber reinforced plastics and other fiber reinforced plastics, and the substrates to be bonded through the adhesive layer may be the same or different.

The non-solvent type reactive adhesive of the present invention has excellent coating film strength, flexibility, heat resistance, oil resistance, adhesive strength and appropriate tact time, and a laminate using the adhesive can be used for transportation equipment such as automobiles, building materials, ships, and aircraft. It is useful as a structural member (panel parts, skeleton parts, suspension parts, etc.).

embodiment

Hereinafter, the present invention will be described in more detail by examples, but the following examples do not limit the scope of the present invention at all. In addition, unless otherwise indicated, "parts" in Examples represent "parts by mass".

[Weight Average Molecular Weight (Mw)]

The weight average molecular weight (Mw) of the resin was determined as a value converted to standard polystyrene by gel permeation chromatography (GPC). The measurement was performed by connecting three GPC-8020 (trade name, manufactured by Tosoh Corporation) as a GPC device, tetrahydrofuran as an eluent, and TSKgelSuperHM-M (trade name, manufactured by Tosoh Corporation) as a column in series, and a flow rate of 0.6 ml/min and an injection amount. It was carried out under conditions of 10 μl and a column temperature of 40°C.

The abbreviated name of the compound in this specification is shown below.

<Polyisocyanate>

TDI-TMP adduct: trimethylolpropane adduct of tolylene diisocyanate, trade name "Takenate D103H", ethyl acetate solution (solid content concentration: 75% by mass), manufactured by Mitsui Chemicals Co., Ltd., obtained by removing ethyl acetate under reduced pressure

HDI: hexamethylene diisocyanate

MDI: mixture of 2,4'- and 4,4'-diphenylmethane diisocyanate, trade name "Lupranate MI", manufactured by BASF INOAC Polyurethanes

・Carbodiimide-modified MDI: Trade name “Lupranate MM103”, manufactured by BASF INOAC Polyurethane Co., Ltd.

・Polymeric MDI: Polymethylene polyphenyl polyisocyanate, trade name “Lupranate M5S”, manufactured by BASF INOAC Polyurethane Co., Ltd.

<Polyol>

T5651: bifunctional polycarbonate polyol, number average molecular weight 1,000, hydroxyl value 110 mgKOH/g, trade name "Duranol T5651", manufactured by Asahi Kasei Co., Ltd.

T5650E: bifunctional polycarbonate polyol, number average molecular weight 500, hydroxyl value 220 mgKOH/g, trade name "Duranol T5650E", manufactured by Asahi Kasei Co., Ltd.

P-1000: bifunctional polypropylene glycol, number average molecular weight 1,000, hydroxyl value 56.1 mgKOH/g, manufactured by Adeka

P-400: bifunctional polypropylene glycol, number average molecular weight 400, hydroxyl value 280 mgKOH/g, manufactured by Adeka

PTMG-1000SN: bifunctional polytetramethylene ether glycol, number average molecular weight 1,000, hydroxyl value 112mgKOH/g, manufactured by Hodogaya Chemical Co., Ltd.

GI-1000: hydrogenated polybutadiene diol, number average molecular weight 1,400, hydroxyl value 75 mgKOH/g, manufactured by Nippon Soda Co., Ltd.

・URIC HF2009: bifunctional sunflower oil polyol, number average molecular weight 2,640, hydroxyl value 41.5 mgKOH/g, manufactured by Itoseiyu Co., Ltd.

NS-2400: bifunctional polyester polyol, number average molecular weight 2000, hydroxyl value 56 mgKOH/g, trade name "Adeca New Ace NS-2400", manufactured by Adeka

<Low Molecular Polyol>

1,3-propanediol (molecular weight: 76.1)

<Production example of polyisocyanate>

[Preparation of trimethylolpropane adduct of diphenylmethane diisocyanate (MDI-TMP adduct)]

100.0 parts of MDI, 10.0 parts of trimethylolpropane, and 30.0 parts of ethyl acetate were added to a reaction vessel equipped with a nitrogen gas inlet pipe, a stirrer, a thermometer, and a reflux device, and after uniform stirring, the mixture was stirred at 3°C under a nitrogen atmosphere. The trimethylolpropane adduct (MDI-TMP adduct) of diphenylmethane diisocyanate was obtained by reacting for a period of time, then removing all ethyl acetate under reduced pressure, and removing unreacted MDI using a known thin film distillation method. Got it. The weight average molecular weight of the obtained MDI-TMP adduct was 900.

[Preparation of Polyisocyanate A]

100 parts of PTMG-1000SN and 150 parts of MDI were added to a reaction vessel equipped with a nitrogen gas inlet pipe, a stirrer, a thermometer, and a reflux machine, and the mixture was reacted under a nitrogen atmosphere at 80° C. for 4 hours to obtain aromatic polyisocyanate A.

<Production example of polyol B having a urethane bond>

[Preparation of Polyol B1]

100.0 parts of T5651, 19.9 parts of isophorone diisocyanate, and 0.02 part of dibutyltin dilaurate as a catalyst were added to a reaction vessel equipped with a nitrogen gas inlet pipe, a stirrer, a thermometer, and a reflux device, and uniform stirring was performed. It was made to react at 100 degreeC for 5 hours in an atmosphere, and the polyol B1 which has a urethane bond was obtained. The weight average molecular weight of the obtained polyol B1 was 15,000.

[Preparation of polyol B2]

100.0 parts of T5651 and 21.3 parts of MDI were placed in a reaction vessel equipped with a nitrogen gas inlet pipe, a stirrer, a thermometer, and a reflux device, and after stirring uniformly, the reaction was performed at 100° C. for 5 hours under a nitrogen atmosphere to obtain a polyol having a urethane bond. Got B2. The weight average molecular weight of the obtained polyol B2 was 11,000.

[Preparation of Polyol B3]

To a reaction vessel equipped with a nitrogen gas inlet pipe, a stirrer, a thermometer, and a reflux machine, 50.0 parts of P-1000, 50.0 parts of PTMG-1000SN, 19.9 parts of isophorone diisocyanate, and 0.02 part of dibutyltin dilaurate as a catalyst. After throwing in and stirring uniformly, it was made to react at 100 degreeC for 5 hours in nitrogen atmosphere, and polyol B3 which has a urethane bond was obtained. The weight average molecular weight of the obtained polyol B3 was 15,000.

[Preparation of polyol B4]

Into a reaction vessel equipped with a nitrogen gas inlet tube, a stirrer, a thermometer and a reflux machine, 50.0 parts of GI-1000, 50.0 parts of PTMG-1000SN, 16.2 parts of isophorone diisocyanate, and 0.02 part of dibutyltin dilaurate as a catalyst were added. After throwing in and stirring uniformly, it was made to react at 100 degreeC for 5 hours in nitrogen atmosphere, and polyol B4 which has a urethane bond was obtained. The weight average molecular weight of the obtained polyol B4 was 15,000.

[Preparation of polyol B5]

50.0 parts of URIC HF2009, 50.0 parts of PTMG-1000SN, 12.5 parts of isophorone diisocyanate, and 0.02 part of dibutyltin dilaurate as a catalyst were added to a reaction vessel equipped with a nitrogen gas inlet pipe, a stirrer, a thermometer, and a reflux machine. After uniform stirring, the mixture was reacted at 100°C for 5 hours under a nitrogen atmosphere to obtain polyol B5 having a urethane bond. The weight average molecular weight of obtained polyol B5 was 15,000.

[Preparation of polyol B6]

To a reaction vessel equipped with a nitrogen gas inlet pipe, a stirrer, a thermometer, and a reflux machine, 50.0 parts of P-1000, 50.0 parts of NS-2400, 14.2 parts of isophorone diisocyanate, and 0.02 part of dibutyltin dilaurate as a catalyst. After throwing in and stirring uniformly, it was made to react at 100 degreeC for 5 hours in nitrogen atmosphere, and polyol B6 which has a urethane bond was obtained. The weight average molecular weight of the obtained polyol B6 was 15,000.

<Preparation of adhesive>

[Example 1]

40.0 parts of TDI-TMP adduct and 60.0 parts of MDI were stirred and degassed and mixed at 100°C to obtain polyisocyanate. Separately, 194.4 parts of T5651 was added to 83.3 parts of polyol B1 having a urethane bond, and stirring and defoaming mixing were carried out at 100°C to obtain a polyol. Subsequently, the obtained polyisocyanate and polyol were mixed at room temperature (25°C) to prepare a solvent-free adhesive.

[Examples 2 to 48, Reference Examples 1 to 2, and Comparative Examples 1 to 12]

Except having changed to the compounding composition shown in Tables 1-4, the same operation as Example 1 was performed, and the adhesives of Examples 2-48, Reference Examples 1-2, and Comparative Examples 1-12 were prepared.

<Evaluation of adhesive>

The adhesives prepared in Examples and Comparative Examples were evaluated as follows. The judgment result was described in Tables 1-4. In Comparative Examples 3, 4, 11, and 12, polyisocyanate has a high viscosity, and mixing with polyol is difficult, and since it cannot be used as a solvent-free adhesive, subsequent evaluation was not performed.

[Shear adhesion]

Each adhesive is applied on a stainless substrate (length 100 mm, width 25 mm, thickness 2 mm) to a width of 25 mm, length 10 mm, and thickness 0.1 mm, and it is attached to a carbon fiber reinforced plastic substrate (length 100 mm, width 25 mm, thickness 2 mm). Together, it was cured at 80°C for 1 day in a state where it was crimped so as to maintain a thickness of 0.1 mm, and a test piece was obtained. The shear adhesive strength of the obtained test piece was measured using a tensile tester at a tensile speed of 1 mm/min under conditions of a temperature of 25°C and a relative humidity of 50%, and the following evaluation criteria were used.

(Evaluation standard)

A: Shear adhesion, 7 MPa or more (good)

B: Shear adhesion, 5 MPa or more, less than 7 MPa (available)

C: shear adhesion, less than 5 MPa (cannot be used)

[Breaking stress/breaking elongation]

Each adhesive was filled in a sheet-shaped mold with a thickness of 2 mm, the surface was prepared, and after curing at 80 ° C. for 1 day, it was punched out in a No. 3 dumbbell shape to produce a dumbbell-shaped test piece for evaluation. Using this dumbbell piece, a tensile test was performed at a tensile speed of 50 mm/min, the breaking stress (MPa) and the breaking elongation (%) were measured, and determined according to the following criteria.

(Evaluation criteria for breaking stress)

A: Breaking stress is 25 MPa or more (good)

B: Breaking stress of 20 MPa or more and less than 25 MPa (can be used)

C: Breaking stress is less than 20 MPa (cannot be used)

(Evaluation criteria for elongation at break)

A: Elongation at break is 250% or more (good)

B: Elongation at break, 200% or more, less than 250% (available)

C: elongation at break, less than 200% (cannot be used)

[100℃ heat resistance]

Dumbbell-shaped test pieces were produced in the same manner as the above [breaking stress/breaking elongation]. After heat treatment of this dumbbell piece in an environment of 100 ° C. for 500 hours, a tensile test was performed in the same manner as in the above [breaking stress and elongation at break], and the breaking stress (MPa) and breaking elongation (%) were measured. The rate of change was calculated for the test piece before and after the test, and determined according to the following criteria.

(Evaluation Criteria for Change Rate of Breaking Stress)

A: Change rate is less than 30% (good)

B: The change rate is greater than or equal to 30% and less than 50% (available)

C: Change rate is 50% or more (unusable)

(Evaluation criteria for rate of change in elongation at break)

A: Change rate is less than 30% (good)

B: The change rate is greater than or equal to 30% and less than 50% (available)

C: Change rate is 50% or more (unusable)

[100℃ oil resistance]

Dumbbell-shaped test pieces were produced in the same manner as the above [breaking stress/breaking elongation]. After immersing this dumbbell piece in Automa oil at 100 ° C. for 100 hours, a tensile test was performed in the same manner as in the above [breaking stress and elongation at break], and the breaking stress (MPa) and breaking elongation (%) were measured. The rate of change was calculated for the test piece before and after the test, and judged according to the following criteria.

(Evaluation Criteria for Change Rate of Breaking Stress)

A: Change rate is less than 30% (good)

B: The change rate is greater than or equal to 30% and less than 50% (available)

C: Change rate is 50% or more (unusable)

(Evaluation criteria for rate of change in elongation at break)

A: Change rate is less than 30% (good)

B: The change rate is greater than or equal to 30% and less than 50% (available)

C: Change rate is 50% or more (unusable)

[Effervescence]

Dumbbell-shaped test pieces were prepared in the same manner as the above [breaking stress/breaking elongation], and the presence or absence of foaming on the surface and inside of the test piece was visually observed, and judged according to the following criteria.

A: Foaming is not observed (good)

B: 1 or 2 bubbles are observed (usable)

C: 3 or more bubbles are observed (unusable)

[household time]

After mixing the polyisocyanate and the polyol, the time until the fluidity was remarkably lost was observed and judged according to the following criteria.

A: Pot life is 15 minutes or more (good)

B: Pot life is more than 10 minutes and less than 15 minutes (can be used)

C: pot life, less than 10 minutes (unusable)

[Evaluation Criteria for Decreasing Elongation at Break]

For Examples (for example, Example 1 and Example 2) differing only in the compounding ratio of polyisocyanate and polyol, the evaluation results of elongation at break were compared and determined according to the following criteria.

A: The evaluation results of the elongation at break are the same (good)

C: The evaluation results of the elongation at break are different (cannot be used)

[Table 1]

[Table 2]

[Table 3]

[Table 4]

The solvent-free reactive adhesive of the present invention has good adhesive strength, exhibits excellent coating strength (breaking stress) and flexibility (breaking elongation), and maintains excellent breaking stress and breaking elongation even after a heat resistance test and an oil resistance test. Further, the adhesive of the present invention was stable with no change in elongation at break even when the mixing ratio of the main agent and the curing agent was varied. Further, the adhesive of the present invention suppressed foaming, exhibited an appropriate tact time, and exhibited good pot life.

On the other hand, in the case of the adhesive of Comparative Example, when the mixing ratio of the base material and the curing agent fluctuated, the elongation at break changed and was unstable. In addition, the adhesives of the comparative examples were unable to achieve both breaking stress and flexibility, and were poor in heat resistance and oil resistance.

This application relates to Japanese Patent Application No. 2020-193766 filed on November 20, 2020, Japanese Patent Application No. 2021-105556 filed on June 25, 2021, and Japanese Patent Application No. 2021-105556 filed on November 9, 2021. Priority is claimed on the basis of Patent Application No. 2021-182699, the entire disclosure of which is incorporated herein.

Claims (9)

A polyisocyanate containing a trimethylolpropane adduct of at least one isocyanate of tolylene diisocyanate and diphenylmethane diisocyanate, an aromatic polyisocyanate excluding the trimethylolpropane adduct, and a solvent-free type containing a polyol It is a reactive adhesive,
Based on the total mass of the polyisocyanate, the trimethylolpropane adduct of the tolylene diisocyanate and the trimethylolpropane adduct of the diphenylmethane diisocyanate are included in the range of 40 to 80% by mass in total , solvent-free reactive adhesive.
According to claim 1,
The solvent-free reactive adhesive, wherein the aromatic polyisocyanate contains at least one selected from the group consisting of diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and carbodiimide-modified diphenylmethane diisocyanate.
According to claim 1 or 2,
A non-solvent type reactive adhesive comprising the aromatic polyisocyanate in a range of 20 to 60% by mass in total based on the total mass of the polyisocyanate.
According to any one of claims 1 to 3,
Based on the total mass of the polyisocyanate, the trimethylolpropane adduct of the tolylene diisocyanate and the trimethylolpropane adduct of the diphenylmethane diisocyanate are included in the range of 45 to 75% by mass in total , solvent-free reactive adhesive.
According to any one of claims 1 to 4,
A non-solvent type reactive adhesive in which the polyol comprises a polycarbonate polyol having no urethane bond.
According to any one of claims 1 to 5,
A non-solvent type reactive adhesive wherein the polyol contains a polyol having a urethane bond.
According to claim 6,
A non-solvent type reactive adhesive containing the polyol having the urethane bond in a range of 30 to 70% by mass in total based on the total mass of the polyol.
A cured product of the non-solvent type reactive adhesive according to any one of claims 1 to 7.
A laminate having, on a substrate, an adhesive layer comprising the cured product according to claim 8.