WO2022118684A1

WO2022118684A1 - Two-component polyurethane adhesive, and adherend

Info

Publication number: WO2022118684A1
Application number: PCT/JP2021/042657
Authority: WO
Inventors: 哲也島田; 恭輔森本
Original assignee: 三洋化成工業株式会社
Priority date: 2020-12-01
Filing date: 2021-11-19
Publication date: 2022-06-09
Also published as: JPWO2022118684A1; JP7295341B2

Abstract

A purpose of the present invention is to provide a two-component polyurethane adhesive having exceptional safety and excellent resin strength, heat resistance, durability, and coating properties. The present invention relates to, inter alia, a two-component polyurethane adhesive formed from: a main agent (X) containing a polyol component (A) having, as an essential component, a polyether polyol (a) in which ethylene oxide and/or propylene oxide is added to a 6- to 14-functional polyol; and a curing agent (Y) containing an isocyanate component (B), wherein the NCO content of entire the isocyanate component (B) is 18-30 wt%, and the glass transition temperature of the two-component polyurethane adhesive after curing is 100-150°C.

Description

Two-component polyurethane adhesive and adherend

The present invention relates to a two-component polyurethane adhesive and an adherend.

Conventionally, as a two-component urethane adhesive composed of a main agent of a polyol composition and a curing agent of an isocyanate composition, a two-component curing type composed of a main agent containing a polyurethane polyol as a main component and a curing agent containing a polyurethane polyisocyanate as a main component. Polyurethane adhesives are known. (See, for example, Patent Document 1).
Further, it is a two-component curing type urethane adhesive having a main agent containing a urethane prepolymer and a curing agent containing a compound having two or more active hydrogen groups in one molecule, and the curing agent is terpene. Two-component curable urethane adhesives containing compounds are known. (See, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 5-31146 JP-A-2015-131940

However, since the adhesive described in Patent Document 1 contains a solvent, there is a problem in safety. Therefore, it has been difficult to use it in applications where solvent content is a problem. Further, the adhesive described in Patent Document 2 is excellent in safety because it does not use a solvent, but has problems in adhesive properties such as adhesive strength (resin strength), heat resistance and durability.

Epoxy adhesives are known as two-component adhesives with excellent adhesive strength and heat resistance, but they have low flexibility and may cause problems when used in areas subject to vibration or impact. In addition, the epoxy adhesive has a relatively slow curing speed and easily drips, so that there is a problem in coatability at the time of adhesion.

An object of the present invention is to provide a two-component polyurethane adhesive having excellent safety and good resin strength, heat resistance, durability and coatability.

As a result of diligent studies in view of the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved, and have reached the present invention. That is, in the present invention, the main agent (X) and the isocyanate component (B) containing the polyol component (A) containing the polyether polyol (a) obtained by adding ethylene oxide and / or propylene oxide to the 6 to 14 functional polyol as an essential component are contained. ) Is a two-component polyurethane adhesive composed of the curing agent (Y), the NCO content of the entire isocyanate component (B) is 18% by weight to 30% by weight, and the two-component polyurethane adhesive is adhered. It is a two-component polyurethane adhesive having a glass transition temperature of 100 ° C. to 150 ° C. after curing of the agent, and an adherend bonded with the two-component polyurethane adhesive.

The cured product obtained by curing the two-component polyurethane adhesive of the present invention has the following effects as compared with the conventional adhesive.
(1) Excellent resin strength such as breaking strength and hardness, and excellent durability.
(2) It has excellent cold resistance and heat resistance, and has excellent adhesive strength.
(3) It is low in odor (no peculiar odor), has little elution, and is low in contamination (non-eluting), so it is excellent in safety.
(4) Excellent flexibility and toughness.
(5) Since the adhesive does not easily drip after coating, it has excellent coatability.

<Main agent (X)>
The main agent (X) in the present invention contains a polyol component (A) containing a polyether polyol (a) in which ethylene oxide and / or propylene oxide is added to a 6 to 14 functional polyol as an essential component.

Examples of the 6 to 14 functional polyols include 6 to 14 valent alcohols having 6 to 20 carbon atoms [aliphatic polyols (sorbitol, mannitol, dipentaerythritol, etc.) and polysaccharides (sucrose, lactose, maltose, trehalose, turanose, etc.). Cellobiose, Raffinose, Melezitose, Malttriose, Acarbose, Stachyose, etc.)]. Of these, sorbitol and sucrose are preferable from the viewpoint of processability (viscosity of the adhesive). When the viscosity of the adhesive is improved, the coatability of the adhesive is improved.

The polyether polyol (a) is obtained by adding ethylene oxide (hereinafter, may be referred to as EO) and / or propylene oxide (hereinafter, may be referred to as PO) to the 6 to 14 functional polyol. Obtained. The method for adding EO and / or PO is not particularly limited, but a known method can be used.
The total number of ethylene oxide and propylene oxide additions of the polyether polyol (a) is preferably 1.0 to 2.0 per hydroxyl group, more preferably 1.0 to 2.0, from the viewpoint of processability, heat resistance and low elution. It is 1.1 to 1.8, particularly preferably 1.2 to 1.6, and most preferably 1.3 to 1.5.

The hydroxyl value of the polyol component (A) is preferably 300 to 900 mgKOH / g, more preferably 300 to 600 mgKOH / g, and particularly preferably 350 to 500 mgKOH, from the viewpoint of processability, heat resistance and coatability. / G. In the present invention, the hydroxyl value is measured according to JIS K 1557-1.

The main agent (X) of the present invention can contain other polyol component (a1) in addition to the polyether polyol (a) as the polyol component (A).
Examples of the other polyol component (a1) include a low molecular weight polyol (a11) having a number average molecular weight (hereinafter abbreviated as Mn) of less than 300, a high molecular weight polyol (a12) having an Mn of 300 or more, and these and later described below. Examples thereof include a prepolymer (a13) having a hydroxyl group at the terminal obtained by reacting with an isocyanate (b1), (b2), (b3), (b4) and / or an isocyanate-modified product (b5). It is preferable that the prepolymer (a13) having a hydroxyl group at the terminal does not have an isocyanate group. As the other polyol component (a1), one type may be used alone, or two or more types may be used in combination.

The number average molecular weight in the present invention is measured by gel permeation chromatography using tetrahydrofuran as a solvent and polyoxypropylene glycol as a standard substance. The sample concentration may be 0.25% by weight, the column stationary phase may be one each of TSKgel SuperH2000, TSKgel SuperH3000, and TSKgel SuperH4000 (all manufactured by Tosoh Corporation) connected, and the column temperature may be 40 ° C.

The low molecular weight polyol (a11) having a Mn of less than 300 also includes a polyol having a chemical formula of less than 300, specifically, a dihydric alcohol having 2 to 20 carbon atoms and a trivalent to 5 carbon atoms having 3 to 20 carbon atoms. Examples thereof include valent polyhydric alcohols and polyols having 5 to 20 carbon atoms having functional groups other than hydroxyl groups.

Examples of the dihydric alcohol having 2 to 20 carbon atoms include aliphatic dihydric alcohols having 2 to 12 carbon atoms (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,2-, 2,3- , 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 3-methylpentanediol, dodecanediol and other mono- or polyalkylene glycols); containing an alicyclic having 6 to 10 carbon atoms. Dihydric alcohols (1,4-cyclohexanediol, cyclohexanedimethanol, etc.); aromatic aliphatic dihydric alcohols having 8 to 20 carbon atoms [xylylene glycol, bis (hydroxyethyl) benzene, etc.] and the like can be mentioned.

Examples of trihydric to pentahydric polyhydric alcohols having 3 to 20 carbon atoms include (cyclo) alkane polyols and their intramolecular or intermolecular dehydrations [glycerin, trimethylolpropane, pentaerythritol, 1, 2, 6-. Hexatriol, erythritol, cyclohexanetriol, xylitol, sorbitan, diglycerin, etc.], and alkylene oxides of alkylenediamines such as N, N, N', N'-tetrakis (2-hydroxypropyl) ethylenediamine (hereinafter referred to as AO). (May be) Additives, etc. may be mentioned.

Examples of the polyol having a functional group other than a hydroxyl group having 5 to 20 carbon atoms include a polyol having a carboxyl group; a polyol having an amino group such as dimethylolpropionic acid and dimethylolbutanoic acid; and a polyol having 2 to 18 carbon atoms of a hydroxyalkyl group. Examples thereof include dialkanol monoamine and diethanolamine.

Examples of the polymer polyol (a12) having Mn of 300 or more include a polyether polyol (a121), a polyester polyol (a122), and other polyols (a123).

Examples of the polyether polyol (a121) include poly (oxyalkylene) glycol [poly (oxyethylene) glycol, poly (oxypropylene) glycol, poly (oxytetramethylene) glycol, and poly (oxy-3-methyltetramethylene) glycol. Etc.], copolymerized poly (oxyalkylene) diol [EO / PO copolymerized diol, THF / EO copolymerized diol, THF / 3-methyltetrahydrofuran copolymerized diol, etc. (weight ratio is, for example, 1/9 to 9/1)]. And AO adducts of bisphenol compounds; trifunctional or higher functional polyether polyols, eg, AO adducts of trihydric or higher polyhydric alcohols [AO adducts of glycerin, AO adducts of trimethylolpropane, etc.]; and 1 of these. Examples include those obtained by coupling seeds or more with methylene dichloride. In addition, THF means tetrahydrofuran.

Examples of the bisphenol compound in the above include bisphenol A, bisphenol B, bisphenol E, bisphenol F and the like, and more specifically, those described in JP-A-2008-126108.
The number of moles of AO added in the above is preferably 2 to 100 mol, more preferably 2 to 50 mol, and particularly preferably 2 to 30 mol from the viewpoint of adhesive strength.
In the case of the AO adduct of the bisphenol compound, the number of moles of the AO adduct is preferably 2 to 10 mol, more preferably 2 to 6 mol, and particularly preferably 2 to 4 mol from the viewpoint of the cohesive force of the adhesive. When the cohesive force of the adhesive is improved, the resin strength is improved.

Examples of the polyester polyol (a122) include condensed polyester polyols, polylactone polyols, castor oil-based polyols, and polycarbonate polyols.

The condensed polyester polyol includes a low molecular weight polyol (a11) or a polyether polyol (a121) having a Mn of less than 300, and a polycarboxylic acid or an ester-forming derivative thereof (acid anhydride, an alkyl ester having 1 to 4 carbon atoms, etc.). Examples thereof include a polycondensate with.

Examples of the polycarboxylic acid include a dicarboxylic acid and a trivalent to tetravalent or higher polycarboxylic acid, and specifically, saturated or saturated with 2 to 30 or more carbon atoms (preferably 2 to 12 carbon atoms). Unsaturated aliphatic polycarboxylic acid [2 to 15 carbon number dicarboxylic acid (succinic acid, succinic acid, malonic acid, adipic acid, suberic acid, azelaic acid, sebatic acid, dodecandicarboxylic acid, maleic acid, fumaric acid and itaconic acid) Etc.) and tricarboxylic acids having 6 to 20 carbon atoms (tricarbaryl acid, hexanetricarboxylic acid, etc.)]; Aromatic polycarboxylic acids having 8 to 15 carbon atoms [dicarboxylic acids such as terephthalic acid, isophthalic acid and phthalic acid, and trimerits Tri or tetracarboxylic acid such as acid and pyromellitic acid]; alicyclic polycarboxylic acid having 6 to 40 carbon atoms (Dimer acid etc.); and sulfo group-containing polycarboxylic acid [Sulf group introduced into the above polycarboxylic acid Such as sulfosuccinic acid, sulfomalonic acid, sulfoglutaric acid, sulfoadipic acid and sulfoisophthalic acid and salts thereof (eg metal salts, ammonium salts, amine salts and quaternary ammonium salts)]; and carboxyl groups at the ends. Examples thereof include a polymer having the above.

Examples of the polymer having a carboxyl group at the terminal include polyether polycarboxylic acid [for example, carboxymethyl ether of a polyol such as a low molecular weight polyol (a11) having a Mn of less than 300 or a polyether polyol (a121) (monochloroacetic acid in the presence of an alkali). (Etc., etc. obtained by reacting with)]; polyamide and / or polyester polycarboxylic acid [for example, lactam having 4 to 15 carbon atoms (for example, caprolactam, enantractam, laurolactam, undecanolactam, etc.) using the above polycarboxylic acid as an initiator). Alternatively, polylactam polycarboxylic acid and polylactone polycarboxylic acid obtained by ring-opening polymerization of a lactone having 4 to 15 carbon atoms (γ-butyrolactone, γ-valerolactone, ε-caprolactone, etc.)] and the like can be mentioned.

As the polylactone polyol, ring-opening adduct of a lactone having 4 to 15 carbon atoms (γ-butyrolactone, γ-valerolactone, ε-caprolactone, etc.) starting with water or a low molecular weight polyol (a11) having Mn less than 300 is added. Things etc. can be mentioned.

Examples of the castor oil-based polyol include castor oil (lithinol acid triglyceride), partially dehydrated castor oil, partially acylated castor oil, hydrogenated castor oil and modified products thereof [polyether polyol (a121) or low molecular weight Mn of less than 300. Ester polyol obtained by ester exchange reaction between polyol (a11) and castor oil, partially dehydrated castor oil or hydrogenated castor oil, and polyether polyol (a121) or low molecular weight polyol (a11) having Mn less than 300 and castor oil. Esters obtained by esterification reaction with fatty acids or hydrogenated castor oil fatty acids] and the like.

Examples of the polycarbonate polyol include a ring-opened addition / polycondensate of an alkylene carbonate using a low molecular weight polyol (a11) having a Mn of less than 300 as an initiator, and a weight of a low molecular weight polyol (a11) having a Mn of less than 300 and diphenyl or a dialkyl carbonate. Condensation (ester exchange) products and the like can be mentioned.

Examples of other polyols (a123) include polymer polyols, polyolefin polyols, polyalkaziene polyols, acrylic polyols, amino group-containing polyols and the like.

The polymer polyol is obtained by dispersing and stabilizing polymer particles obtained by polymerizing a vinyl monomer having 3 to 24 carbon atoms (for example, styrene or acrylonitrile) in one or more polyols in the presence of a radical polymerization initiator. Examples thereof include polyols (polymer content is, for example, 5 to 30% by weight).
Examples of the polyolefin polyol include polyisobutene polyols.
Examples of the polyalkaziene polyol include polyisoprene polyols, polybutadiene polyols, hydrogenated polyisoprene polyols, hydrogenated polybutadiene polyols and the like.

Examples of the acrylic polyol include a copolymer of an alkyl (meth) acrylic acid (alkyl having 1 to 30 carbon atoms) ester [butyl (meth) acrylate, etc.] and a hydroxyl group-containing acrylic monomer [hydroxyethyl (meth) acrylate, etc.]. Can be mentioned.
Examples of the amino group-containing polyol include AO adducts of poly (n = 2 to 6) alkylene (carbon number 2 to 6) poly (n = 3 to 7) amine [N, N, N', N', N ". -Pentakis (2-hydroxypropyl) -diethylenetriamine, etc.].

The Mn of the polymer polyol (a12) having an Mn of 300 or more is preferably 400 to 3000, and more preferably 500 to 2000.

NCO groups in isocyanates (b1), (b2), (b3), (b4) and / or isocyanate modified products (b5), which will be described later, when producing a prepolymer (a13) having a hydroxyl group at the terminal, and a polyether. The equivalent ratio (NCO / active hydrogen molar ratio) with the active hydrogen in the polyol (a), the low molecular weight polyol (a11) having an Mn of less than 300 and / or the high molecular weight polyol (a12) having an Mn of 300 or more is preferable. 0.25 / 1 to 0.99 / 1, more preferably 0.5 / 1 to 0.95 / 1, particularly preferably 0.6 / 1 to 0.9 / 1, most preferably 0.7 / 1. It is about 0.85 / 1.

Among the other polyol components (a1), it is preferably a high molecular weight polyol (a12) having an Mn of 300 or more, more preferably a polyether polyol (a121), and particularly preferably a 2 to 4 functional polyether polyol. Most preferably, it is an AO adduct of glycerin and an AO adduct of trimethylolpropane. Examples of the AO adduct of glycerin include polyoxypropylene triol.
Further, among the other polyol components (a1), a polyester polyol (a122) is also preferable, a castor oil-based polyol is more preferable, and castor oil (refined castor oil) is most preferable.

The content of the polyether polyol (a) of the present invention is preferably 50% by weight or more, more preferably 55% by weight or more from the viewpoint of heat resistance, coatability and odor, based on the weight of the polyol component (A). From the viewpoint of heat resistance, odor and flexibility, it is particularly preferably 60% by weight to 90% by weight.

The content of the polyol component (a1) other than the polyether polyol (a) is preferably 50% by weight or less, more preferably 45% by weight, based on the weight of the polyol component (A) from the viewpoint of heat resistance. It is the following, and it is particularly preferably 10% by weight to 40% by weight from the viewpoint of heat resistance and flexibility.
The content of the small molecule polyol (a11) having a Mn of less than 300 is preferably 20% by weight or less from the viewpoint of heat resistance and low contamination (low elution) based on the weight of the polyol component (A).

<Curing agent (Y)>
The curing agent (Y) in the present invention contains an isocyanate component (B).
The isocyanate component (B) includes an aliphatic isocyanate (b1) having 2 to 18 carbon atoms (excluding carbon in the NCO group, the same applies hereinafter), an alicyclic isocyanate (b2) having 4 to 15 carbon atoms, and a carbon number of carbon atoms. 8 to 15 aromatic aliphatic isocyanates (b3), 6 to 20 carbon atoms aromatic isocyanates (b4), isocyanurate groups, uretoimine groups, allophanate groups, biuret groups, uretoimine groups of the isocyanates (b1) to (b4). , Isocyanate modified product (b5) having a carbodiimide group and / or uretdione group, and excess isocyanate (b1), (b2), (b3), (b4) and / or isocyanate modified product (b5) and Mn are less than 300. Examples thereof include a prepolymer (b6) having an isocyanate group at the terminal obtained from the low molecular weight polyol (a11) and / or the high molecular weight polyol (a12) having Mn of 300 or more. It is preferable that the prepolymer (b6) having an isocyanate group at the terminal does not have a hydroxyl group. The isocyanate component (B) may be used alone or in combination of two or more.

Examples of the aliphatic isocyanate (b1) having 2 to 18 carbon atoms include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4. -Or 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, 2,6-diisocyanatoethyl caproate, bis (2-isosyanatoethyl) fumarate and bis ( 2-Isocyanatoethyl) carbonate and the like can be mentioned.

Examples of the alicyclic isocyanate (b2) having 4 to 15 carbon atoms include isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, and bis (2-). Isocyanatoethyl) -4-cyclohexylene-1,2-dicarboxylate and 2,5- or 2,6-norbornan diisocyanate and the like can be mentioned.

Examples of the aromatic aliphatic isocyanate (b3) having 8 to 15 carbon atoms include m- or p-xylylene diisocyanate (XDI), diethylbenzene diisocyanate and α, α, α', α'-tetramethylxylylene diisocyanate (TMXDI). Can be mentioned.

As the aromatic isocyanate (b4) having 6 to 20 carbon atoms, 1,3- or 1,4-phenylenediocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), 4,4'-or 2 , 4'-diphenylmethane diisocyanate (MDI), m- or p-isocyanatophenylsulfonyl isocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3, Examples thereof include 3'-dimethyl-4,4'-diisocyanatodiphenylmethane and 1,5-naphthylene diisocyanate.

Examples of the isocyanate modified product (b5) having an isocyanurate group, a uretoimine group, an allophanate group, a biuret group, a uretoimine group, a carbodiimide group and / or a uretdione group include a modified product having a uretoimine group of MDI and a modification having a biuret group of HDI. Examples thereof include a modified product having an isocyanurate group of the body and HDI.

The prepolymer (b6) having an isocyanate group at the terminal includes a low molecular weight polyol (a11) having an Mn of less than 300 and / or a high molecular weight polyol (a12) having an Mn of 300 or more, and an excess of isocyanate (b1), (b2). , (B3), (b4) and / or the isocyanate-modified product (b5). In this case, the hydroxyl group equivalent of the polyol (molecular weight per hydroxyl group, the same applies hereinafter) is preferably 1,000 or less, more preferably 30 to 500, from the viewpoint of the cohesive force of the adhesive and the like.

Specific examples of the prepolymer (b6) having an isocyanate group at the terminal include a hydrogenated MDI (2 mol) adduct of glycerin mono (meth) acrylate (1 mol) and TDI (4 mol) of pentaerythritol (1 mol). ) Additives, HDI (3 mol) or TDI (3 mol) adducts of trimethylolpropane (1 mol), hydrogenated MDI (2 mol) adducts of AO2 mol adduct (1 mol) of bisphenol A and poly ( Examples thereof include an MDI (2 mol) adduct of oxypropylene) glycol (1 mol).

From the viewpoint of the cohesive force of the adhesive among the low molecular weight polyol (a11) having a Mn of less than 300 and / or the high molecular weight polyol (a12) having a Mn of 300 or more constituting the prepolymer (b6) having an isocyanate group at the terminal. , A divalent to trivalent polyol is preferable, and a trivalent polyol is more preferable.
Further, among the excess isocyanates (b1), (b2), (b3), (b4) and / or isocyanate modified products (b5) constituting the prepolymer (b6) having an isocyanate group at the terminal, the adhesive is aggregated. From the viewpoint of force, aromatic aliphatic isocyanates (b3) having 8 to 15 carbon atoms, aromatic isocyanates (b4) having 6 to 20 carbon atoms and their modified products are preferable, and 6 to 6 carbon atoms are more preferable. 20 aromatic isocyanates (b4).

As the isocyanate component (B), from the viewpoint of the cohesive force of the adhesive, the aromatic aliphatic isocyanate (b3) having 8 to 15 carbon atoms, the aromatic isocyanate (b4) having 6 to 20 carbon atoms, and the terminal are preferable. A prepolymer (b6) having an isocyanate group is more preferable, and a prepolymer (b6) having an isocyanate group at the terminal is more preferable.

The NCO content of the entire isocyanate component (B) is 18% by weight to 30% by weight, preferably 18% by weight to 28% by weight, and more preferably 18% by weight to 26% by weight.
If the NCO content of the entire isocyanate component (B) is less than 18% by weight, heat resistance and low odor are insufficient, and if it exceeds 30% by weight, the adhesive becomes brittle and easily cracked.
The NCO content of the entire isocyanate component (B) indicates the isocyanate group content (% by weight) measured according to JIS K 1603-1: 2007.

A method for adjusting the NCO content of the entire isocyanate component (B) will be described.
By adjusting the NCO content of each of the isocyanates (b1) to (b6) in the isocyanate component (B) and the respective contents of the isocyanates (b1) to (b6), the NCO content of the entire isocyanurate component (B) is adjusted. Can be adjusted.

The two-component polyurethane adhesive of the present invention can contain a catalyst used for polyurethane, if necessary, in order to promote the curing reaction. Specific examples of the catalyst include organic metal compounds [dibutyltin dilaurate, dioctyltinlaurate, bismuth carboxylate, bismuth alkoxide, chelate compounds of bismuth with compounds having a dicarbonyl group, etc.], and inorganic metal compounds [bismuth oxide, water. Bismuth oxide, bismuth halide, etc.]; Amine [triethylamine, triethylenediamine, diazabicycloundecene, etc.] and a combination of two or more thereof can be mentioned. The amount of the catalyst used is not particularly limited, but is preferably 0.0001 to 0.3% by weight, more preferably 0.001 to 0.2, based on the total weight of the main agent (X) and the curing agent (Y). By weight%, particularly preferably 0.01 to 0.1% by weight.
The catalyst may be added to either the main agent (X) and / or the curing agent (Y), but it is preferably added to the main agent (X) from the viewpoint of storage stability.

<Two-component polyurethane adhesive>
The two-component polyurethane adhesive of the present invention comprises the main agent (X) and the curing agent (Y).
The two-component polyurethane adhesive of the present invention further contains additives such as a tackifier, an antioxidant, an ultraviolet absorber, a plasticizer, a filler, a pigment and a solvent as long as the effect of the present invention is not impaired. be able to. The above-mentioned additive may be added to either the main agent (X) and / or the curing agent (Y), but it is preferable to add the additive that reacts with the isocyanate component to the main agent (X).

Examples of the tackifier include terpene resin, terpene phenol resin, phenol resin, aromatic hydrocarbon-modified terpene resin, rosin resin, modified rosin resin, synthetic petroleum resin (aliphatic, aromatic or alicyclic synthetic petroleum resin, etc.). ), Kumaron-inden resin, xylene resin, styrene resin, dicyclopentadiene resin, and hydrogenated substances having an unsaturated double bond that can be hydrogenated. The tackifier may be used alone or in combination of two or more.
Of these, those having an acid value and / or a hydroxyl value are preferable from the viewpoint of adhesive strength, and rosin resin, phenol resin, terpene phenol resin, xylene resin and their hydrogen additives are more preferable, and terpene phenol resin and its hydrogen are more preferable. Additives are particularly preferred.

The amount of the tackifier used is preferably 100% by weight or less, more preferably 1 to 50, based on the total weight of the main agent (X) and the curing agent (Y) from the viewpoint of the adhesive strength and heat resistance of the adhesive. By weight%, particularly preferably 3 to 40% by weight, particularly preferably 5 to 35% by weight, most preferably 10 to 30% by weight.

Antioxidants include hindered phenol compounds [triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,5). -Di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], etc.] and phosphite Ester compounds [Tris (2,4-di-t-butylphenyl) phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octylphosphite, bis (2,6-di-t-) Butylphenyl) pentaerythritol-di-phosphite, tetrakis (2,4-di-t-butylphenyl) 4,4'-biphenylene-di-phosphonite, etc.]. These antioxidants may be used alone or in combination of two or more. The amount of the antioxidant used is preferably 5% by weight or less, more preferably 0.05, based on the total weight of the main agent (X) and the curing agent (Y) from the viewpoint of the antioxidant effect and the adhesive strength of the adhesive. ~ 1% by weight.

Examples of the ultraviolet absorber include salicylic acid derivatives (phenyl salicylate, -P-octylphenyl salicylate, -P-tertiary butylphenyl salicylate, etc.), benzophenone compounds [2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2 , 2'-Dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfobenzophenone, 2-hydroxy-4 -Methoxy-2'-carboxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-octadesiloxybenzophenone, 2,2 ', 4,4'-Tetrahydroxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 2-hydroxy-4- (2-hydroxy-3-methacryloxy) propoxybenzophenone, bis (2-methoxy-4-hydroxy-5- Benzoylphenyl) methane, etc.], benzotriazole compound {2- (2'-hydroxy-5'-methyl-phenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-di-t-butyl-phenyl) ) Benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methyl-phenyl) -5-chlorobenzotriazol, 2- (2'-hydroxy-3', 5'- Di-t-butyl-phenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-4'-n-octoxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) ) Bentriazole, 2- (2'-hydroxy-3', 5'-di-t-amylphenyl) benzotriazole, 2- [2'-hydroxy-3'-(3 ", 4", 5 ", 6" "-Tetrahydrophthalimidemethyl) -5'-Methylphenyl] benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazole-2-yl) Phenol] etc.}, cyanoacrylate compounds (2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate, ethyl-2-cyano-3,3'-diphenyl acrylate, etc.) and the like. As the ultraviolet absorber, one type may be used alone or two or more types may be used in combination. The amount of the ultraviolet absorber used is preferably 5% by weight or less, more preferably 0.1% by weight, based on the total weight of the main agent (X) and the curing agent (Y), from the viewpoint of the ultraviolet absorbing effect and the adhesive strength of the adhesive. ~ 1% by weight.

Examples of the plasticizer include hydrocarbons [process oil, liquid polybutadiene, liquid polyisobutylene, liquid polyisoprene, liquid paraffin, chlorinated paraffin, paraffin wax, and copolymerization of ethylene and α-olefin (3 to 20 carbon atoms) (weight ratio). Copolymerization of 99.9 / 0.1 to 0.1 / 99.9) oligomer (weight average molecular weight Mw is 5,000 to 100,000) and α-olefin (4 to 20 carbon atoms) excluding propylene and ethylene Oligomer (weight ratio 99.9 / 0.1 to 0.1 / 99.9) oligomer (weight average molecular weight Mw is 5,000 to 100,000)]; chlorinated paraffin; ester [phthalate ester [diethylphthalate (diethylphthalate) DEP), dibutylphthalate (DBP), di-2-ethylhexylphthalate (DOP), didecylphthalate, dilaurylphthalate, distealylphthalate, diisononylphthalate, etc.], adiponic acid ester [di (2-ethylhexyl) adipate (DOA) , Dioctyl adipate, etc.] and sevatinic acid ester (dioctyl sevacate, etc.)]; Animal and vegetable fats and oils (linoleic acid, linolenic acid, etc.); Can be mentioned. The plasticizer may be used alone or in combination of two or more. The amount of the plasticizer used is preferably 100% by weight or less, more preferably 0.5 to 30 from the viewpoint of the adhesive strength and cohesive strength of the adhesive, based on the total weight of the main agent (X) and the curing agent (Y). It is% by weight.

As fillers, carbonates (magnesium carbonate, calcium carbonate, etc.), sulfates (aluminum sulfate, calcium sulfate, barium sulfate, etc.), sulfites (calcium sulfite, etc.), molybdenum disulfide, silicate (aluminum silicate, etc.) Calcium silicate etc.), diatomaceous soil, silicate powder, talc, silica, zeolite and the like. The filler is fine particles having a volume average particle size of preferably about 0.01 to 5 μm, and one type may be used alone or two or more types may be used in combination. The amount of the filler used is preferably 250% by weight or less, more preferably 0.5 to 100% by weight, based on the total weight of the main agent (X) and the curing agent (Y) from the viewpoint of the cohesive force of the adhesive. be.

Pigments include inorganic pigments (alumina white, graphite, titanium oxide, ultrafine titanium oxide, zinc flower, black iron oxide, mica-like iron oxide, lead white, white carbon, molybdenum white, carbon black, litharge, lithopone, barite, etc. Cadmium Red, Cadmium Mercury Red, Bengala, Molybdenum Red, Lithopone, Yellow Lead, Cadmium Yellow, Barium Yellow, Strontium Yellow, Titanium Yellow, Titanium Black, Chromium Oxide Green, Cobalt Cobalt, Cobalt Green, Cobalt Chrome Green, Ultramarine, Navy blue, cobalt blue, cerulean blue, manganese purple, cobalt purple, etc.), and organic pigments (sherack, insoluble azo pigment, soluble azo pigment, condensed azo pigment, phthalocyanine blue, dyed lake, etc.) can be mentioned. The pigment is fine particles having a volume average particle size of preferably about 0.01 to 5 μm, and one type may be used alone or two or more types may be used in combination. The amount of the pigment used is preferably 250% by weight or less, more preferably 0.1 to 50% by weight, based on the total weight of the main agent (X) and the curing agent (Y), from the viewpoint of the cohesive force of the adhesive.

Examples of the solvent include toluene, xylene, ethyl acetate, butyl acetate, dimethylformamide, acetone, methyl ethyl ketone, tetrahydrofuran and the like.

The adhesive obtained by curing the main agent (X) and the curing agent (Y) in the present invention has a difference in storage elastic modulus (E'-40) at −40 ° C. and storage elastic modulus ( _E'90 ) at ₉₀ ° C. Since it is small and has little temperature dependence, its physical properties do not change over a wide range of temperatures and stable adhesive strength can be maintained.
The cured product obtained by curing the two-component polyurethane adhesive of the present invention has a high storage elastic modulus at -40 ° C to 90 ° C, and has excellent cold resistance and heat resistance because it has little change and is excellent in temperature dependence. Has adhesive strength.
The storage elastic modulus (E'- ₄₀ ) at −40 ° C. after curing of the two-component polyurethane adhesive is preferably 2000 MPa to 10000 MPa, more preferably 2000 MPa to 5000 MPa, and particularly, from the viewpoint of flexibility and resin strength. It is preferably 2000 MPa to 3000 MPa. The storage elastic modulus (E'90) at ₉₀ ° C. is preferably 200 MPa to 3000 MPa, more preferably 500 MPa to 3000 MPa, and particularly preferably 1000 MPa to 2000 MPa from the viewpoint of flexibility and resin strength. The storage elastic modulus is adjusted by changing the content of the polyether polyol (a) based on the weight of the polyol component (A) and the number of ethylene oxide and propylene oxide added per hydroxyl group of the polyether polyol (a). can do.

Further, the ratio of the storage elastic modulus at -40 ° C to the storage elastic modulus at ₉₀ ° C (E'- ₄₀ / E'90) is preferably 0.9 to 10, more preferably 1.0 to 10 from the viewpoint of temperature dependence. It is 5.0, particularly preferably 1.0 to 3.0. By designing the storage elastic modulus ratio within the above range, the cured adhesive does not crack at low temperatures, the adhesive strength (resin strength) does not decrease at high temperatures, and the adhesive has excellent cold resistance and heat resistance. It becomes an agent.
The ratio of the storage modulus at -40 ° C to the storage modulus at ₉₀ ° C (E'- ₄₀ / E'90) can be determined, for example, by changing the covalent bond crosslink density of the cured product of the two-component polyurethane adhesive. Can be adjusted. The covalent bond cross-linking density is the number of moles at which the two-component polyurethane adhesive causes cross-linking based on the covalent bond contained in 1 g of the cured urethane resin.

The glass transition temperature after curing of the two-component polyurethane adhesive is the peak temperature of tan δ obtained by the following viscoelasticity measuring method using the following test piece.
The glass transition temperature of the two-component polyurethane adhesive after curing is 100 ° C. to 150 ° C., the lower limit is preferably 105 ° C., more preferably 110 ° C., and the upper limit is preferably 140 ° C., further preferably. Is 130 ° C. In one embodiment, the glass transition temperature of the two-component polyurethane adhesive after curing is preferably 105 ° C to 140 ° C, more preferably 110 ° C to 130 ° C. When the glass transition temperature is less than 100 ° C., the heat resistance is lowered, and when it exceeds 150 ° C., the processability (viscosity of the adhesive) is lowered.

<Preparation of sample for viscoelasticity measurement>
The main agent (X) containing the polyol component (A) and the curing agent (Y) containing the isocyanate component (B) are uniformly mixed at 50 ° C. at a ratio such that the equivalent ratio (OH / NCO ratio) is 1. After defoaming by centrifugation, molding into a sheet having a thickness of 1 mm, curing at 50 ° C. for 3 days, and cutting into a size of 30 mm in length × 5 mm in width, a test piece is obtained.
<Viscoelasticity measurement>
The storage elastic modulus E', loss elastic modulus E'' and tan δ after curing of the two-component polyurethane adhesive are determined by the following viscoelasticity measurements.
<Viscoelasticity measurement method>
Measuring device: Rheogel-E4000 [manufactured by UBM Co., Ltd.]
Measuring jig: Pull distance between clamps: 20 mm
Power meter: 1kg
Static load meter: 2 kg
Measurement temperature: -50 ° C to 200 ° C
Temperature rise rate: 5 ° C / min Measurement frequency: 10Hz

A method for adjusting the glass transition temperature after curing of the two-component polyurethane adhesive will be described.
As for the glass transition temperature after curing, for example, increasing the content of urethane groups and / or aromatic rings can increase the glass transition temperature, and decreasing the content of urethane groups and / or aromatic rings lowers the glass transition temperature. Can be done.
The content of the urethane group is the number of moles of the urethane group contained in 1 g of the urethane resin obtained by curing the two-component polyurethane adhesive.
The content of the aromatic ring is the weight% of the aromatic ring contained in 1 g of the urethane resin obtained by curing the two-component polyurethane adhesive.

The two-component polyurethane adhesive of the present invention is particularly useful for adhering adherends such as various plastic films, plastic molded products, rubber molded products, fibrous resins and fiber reinforced resins, as well as inorganic plates and metal plates. It can also be used to bond adherends such as wood and various fibers.

Examples of the plastic film include polypropylene film, polyethylene film, polyester film, polyacrylic film, polyvinyl chloride film, polystyrene film, nylon film, ethylene vinyl alcohol copolymer film, polyvinyl alcohol film, fluorine film, and ethylene vinyl acetate weight. Examples thereof include a combined film and a plastic film in which the surface of these films is vapor-deposited with aluminum or silica or coated with polyvinylidene chloride.
Examples of plastic molded products include injection molding, extrusion molding, blow molding, and pressing of plastic resins such as ABS resin, polystyrene resin, polyester resin, acrylic resin, urethane resin, polycarbonate resin, polyvinyl chloride resin, melamine resin, and polyolefin resin. Examples thereof include molded plates and molded parts obtained by molding and the like.
From the viewpoint of adhesiveness, it is preferable that the plastic film or the plastic molded product as the adherend is subjected to surface treatment such as corona treatment or plasma treatment.

Examples of the inorganic board include a slate board, a calcium silicate board, a gypsum board, a wood wool cement board and a foamed concrete board.
Examples of the metal plate include a stainless steel plate, a galvanized steel plate, a chemical conversion-treated steel plate, and an aluminum plate.

The equivalent ratio (OH / NCO ratio) of the two-component polyurethane adhesive composed of the main agent (X) and the curing agent (Y) for forming the two-component polyurethane adhesive of the present invention is preferable from the viewpoint of heat resistance. Is 0.5 / 1 to 2/1, more preferably 0.7 / 1 to 1.5 / 1, and particularly preferably 0.8 / 1 to 1.2 / 1.
The equivalent ratio (OH / NCO ratio) in the present invention can be obtained by the following formula 1.
(Hydroxy group value of (X) x weight of (X) / 56100) / (NCO content of (Y) x weight of (Y) / 4200) ... (Equation 1)

The content of the polyether polyol (a) contained in the two-component polyurethane adhesive of the present invention is preferably 20 to 60 based on the weight of the two-component polyurethane adhesive from the viewpoint of heat resistance, odor and flexibility. It is% by weight, more preferably 25 to 55% by weight, and particularly preferably 30 to 50% by weight.

The content of the polyol component (A) contained in the two-component polyurethane adhesive of the present invention is preferably 25 to 55 weight based on the weight of the two-component polyurethane adhesive from the viewpoint of heat resistance, odor and flexibility. %, More preferably 30 to 50% by weight.

The content of the isocyanate component (B) contained in the two-component polyurethane adhesive of the present invention is preferably 45 to 70% by weight based on the weight of the two-component polyurethane adhesive from the viewpoint of heat resistance and odor. Yes, more preferably 50-70% by weight.

When using a two-component polyurethane adhesive, each component for forming a polyurethane resin can be weighed in a predetermined amount and then mixed with a static mixer, a mechanical mixer, or the like to react to form the polyurethane resin. The gelation time is preferably 3 to 60 minutes, and complete curing takes 1 to 240 hours at room temperature. The point at which the hardness does not change is defined as complete curing (reaction end point). It is also possible to shorten the time until complete curing by raising the curing temperature (for example, 30 ° C to 60 ° C). The D hardness (ASTM D2240; maximum value) of the cured resin obtained by reacting each component for forming the polyurethane resin is preferably 50 to 90, more preferably 50 to 90, from the viewpoint of adhesiveness, resin strength, toughness and flexibility. It is 60 to 85, most preferably 70 to 83.

The viscosity (25 ° C.) of the mixture composed of the main agent (X) and the curing agent (Y) is preferably 100 to 50,000 mPa · s, more preferably 500 to 10,000 mPa · s, particularly from the viewpoint of coatability. It is preferably 1,000 to 8,000 mPa · s. The viscosity in the present invention is measured with a B-type rotational viscometer.

Further, the NCO content in the mixed solution immediately after mixing the main agent (X) and the curing agent (Y) calculated by the formula 2 shown below is the total of the main agent (X) and the curing agent (Y) from the viewpoint of curability. Based on the weight, it is preferably 2% by weight to 16% by weight, more preferably 5% by weight to 15% by weight, and most preferably 8% by weight to 14% by weight.
NCO content of (Y) × weight of (Y) / (weight of (X) + weight of (Y))
... (Equation 2)

The adherend of the present invention is an adherend bonded with a two-component polyurethane adhesive.
Examples of the adherend include a plastic film and a plastic molded product, and it is preferable to perform surface treatment such as corona treatment and plasma treatment from the viewpoint of adhesiveness.
As for the method for producing the adherend, a known production method is used.

As a method for producing a cured product of a two-component polyurethane adhesive, a known method for producing a cured product of a two-component polyurethane adhesive can be used. For example, a solvent (toluene, xylene, ethyl acetate, butyl acetate, dimethylformamide, acetone) can be used. , Methylethylketone, tetrahydrofuran, etc.) In the presence or absence, preferably in the absence, a method of reacting a main agent (X) containing a polyol component with a curing agent (Y) containing an isocyanate component can be mentioned.
A known reaction device (mixing tank equipped with a stirrer, static mixer, etc.) can be used for the reaction, and the reaction temperature is preferably 10 to 160 ° C., more preferably 25 to 160 ° C. from the viewpoint of reactivity and suppression of thermal deterioration. The temperature is 120 ° C., and it is preferable to replace the gas phase portion with nitrogen from the viewpoint of stability.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

<Manufacturing example 1>
A stainless steel autoclave equipped with a stirrer, a temperature control device, a heat exchanger as a condensation facility, a raw material supply line and an exhaust line is charged with 385 parts by weight of sorbitol (six-functional) and 3 parts by weight of potassium hydroxide, and then stirred. Was started, and the pressure inside the autoclave and the condensing facility was reduced to 0.005 MPa. Through the raw material supply line, 735 parts by weight of PO was charged while controlling the reaction temperature to be maintained at 90 to 100 ° C. However, the PO was continuously added over 6 hours. A refrigerant at -30 ° C was circulated to condense and recover PO in the condensing facility. Subsequently, it was aged at 100 ° C. for 3 hours. Next, 30 parts by weight of synthetic silicate [manufactured by Kyowa Chemical Industry Co., Ltd .; "Kyoward 600"] and 40 parts by weight of water were added and treated at 60 ° C. for 3 hours. After taking out from the autoclave, the mixture was filtered through a 1 micron filter and then dehydrated for 2 hours to obtain a liquid polyether polyol (a-1). The hydroxyl value of (a-1) was 634 mgKOH / g, and the number of moles of PO added per hydroxyl group was 1.0.

<Manufacturing example 2>
The synthesis was carried out in the same manner as in Production Example 1 except that the amount of PO added was changed from 735 parts by weight to 1100 parts by weight to obtain a polyether polyol (a-2). The hydroxyl value of (a-2) was 477 mgKOH / g, and the number of moles of PO added per hydroxyl group was 1.5.

<Manufacturing example 3>
The synthesis was carried out in the same manner as in Production Example 1 except that the amount of PO added was changed from 735 parts by weight to 1470 parts by weight to obtain a polyether polyol (a-3). The hydroxyl value of (a-3) was 383 mgKOH / g, and the number of moles of PO added per hydroxyl group was 2.0.

<Manufacturing example 4>
The synthesis was carried out in the same manner as in Production Example 1 except that the amount of PO added was changed from 735 parts by weight to 3675 parts by weight to obtain a polyether polyol (a-4). The hydroxyl value of (a-4) was 175 mgKOH / g, and the number of moles of PO added per hydroxyl group was 5.0.

<Manufacturing example 5>
Synthesized in the same manner as in Production Example 1 except that 385 parts by weight of sorbitol (6-functional) was changed to 723 parts by weight of sucrose (8-functional) and the amount of PO input was changed from 735 parts by weight to 1465 parts by weight. a-5) was obtained. The hydroxyl value of (a-5) was 432 mgKOH / g, and the number of moles of PO added per hydroxyl group was 1.5.

<Manufacturing example 6>
Synthesis was carried out in the same manner as in Production Example 1 except that 735 parts by weight of PO was changed to 838 parts by weight of EO to obtain a polyether polyol (a-6). The hydroxyl value of (a-6) was 582 mgKOH / g, and the number of moles of EO added per hydroxyl group was 1.5.

<Manufacturing example 7>
4,4'-MDI [manufactured by Toso Co., Ltd .; "Millionate MT"] 260 parts by weight and 4,4'-MDI and 2, in a four-necked flask equipped with a batch stirrer, a thermometer and a nitrogen introduction tube. With a mixture of 4'-MDI [BASF INOAC Polyurethane Co., Ltd .; "Luplanate MI"] 260 parts by weight and a carbodiimide-modified 4,4'-MDI [BASF INOAC Polyurethane Co., Ltd .; "Luplanate MM103"] 180 parts by weight. 240 parts by weight of refined castor oil [manufactured by Toyokuni Seiyu Co., Ltd .; "ELA-DR"] was charged and reacted at 70 to 80 ° C. under a nitrogen stream for 4 hours, and an isocyanate component (B-) composed of an NCO-terminated urethane prepolymer was prepared. 1) was obtained. The NCO content of (B-1) was 18% by weight.

<Manufacturing example 8>
260 parts by weight to 400 parts by weight of 4,4'-MDI "Millionate MT", 260 parts by weight to 280 parts by weight of the mixture of 4,4'-MDI and 2,4'-MDI "Luplanate MI", and carbonidiimide. The modified 4,4'-MDI "Lupranate MM103" was changed from 180 parts by weight to 200 parts by weight, and 240 parts by weight of refined castor oil "ELA-DR" was changed to polypropylene glycol [manufactured by Sanyo Kasei Kogyo Co., Ltd .; "Sannicks GP-". 250 ”] Synthesis was carried out in the same manner as in Production Example 7 except that the weight was changed to 120 parts by weight to obtain an isocyanate component (B-2) composed of an NCO group-terminated urethane prepolymer. The NCO content of (B-2) was 22.5% by weight.

<Manufacturing example 9>
260 parts by weight to 280 parts by weight of 4,4'-MDI "Millionate MT", 260 parts by weight to 120 parts by weight of the mixture "Lupranate MI" of 4,4'-MDI and 2,4'-MDI, and carbonidiimide. The modified 4,4'-MDI "Lupranate MM103" was changed from 180 parts by weight to 200 parts by weight, and 240 parts by weight of the refined castor oil "ELA-DR" was made into polypropylene glycol (bifunctional) [manufactured by Sanyo Kasei Kogyo Co., Ltd .; " Sannicks PP-1000 "] The isocyanate component (B-3) composed of an NCO group-terminated urethane prepolymer was obtained by synthesizing in the same manner as in Production Example 7 except that the amount was changed to 400 parts by weight. The NCO content of (B-3) was 16% by weight.

<Examples 1 to 11 and Comparative Examples 1 to 6>
As the polyol component (A), a main agent (X) containing a polyether polyol (a-1) to (a-6) and other polyols (a1-1) to (a1-3) described later, and an isocyanate component ( B-1) to (B-3) and a curing agent (Y) containing an isocyanate component (B-4) described later were mixed at the weight ratios shown in Tables 1 and 2, and Examples 1 to 11 were used. And the two-component polyurethane adhesives of Comparative Examples 1 to 6 were obtained.
For each adhesive, the storage elastic modulus, glass transition temperature, coatability, adhesive strength at 100 ° C, D hardness, resin strength, durability test at each temperature of the cured product molded and cured by the following methods. The results of the subsequent tests on the resin strength, odor, and elution amount are shown in Tables 1 and 2.

(A1-1) Polyoxypropylene triol (trifunctional) [manufactured by Sanyo Chemical Industries, Ltd .; "Sannicks GP-1000"], hydroxyl value 168 mgKOH / g
(A1-2) Refined castor oil (2.7 functional) [manufactured by Toyokuni Oil Co., Ltd .; "ELA-DR"], hydroxyl value 161 mgKOH / g
(A1-3) Polyoxypropylene triol (trifunctional) [manufactured by Sanyo Chemical Industries, Ltd .; "Sannicks GP-3000"], hydroxyl value 56 mgKOH / g
(B-4) Carbodiimide-modified 4,4'-MDI [manufactured by BASF INOAC Polyurethane Co., Ltd .; "Lupranate MM103"], NCO content 29.4% by weight

<Storage modulus>
A two-component polyurethane adhesive composed of a main agent (X) containing a polyol component (A) and a curing agent (Y) containing an isocyanate component (B) at 50 ° C. by weight ratio shown in Tables 1 and 2. The mixture was uniformly mixed, centrifugally defoamed, molded into a sheet having a thickness of 1 mm, cured at 50 ° C. for 3 days, and then cut into a size of 30 mm in length × 5 mm in width to obtain a test piece.
-Measuring method In the above-mentioned viscoelasticity measurement, the storage elastic modulus E'at -40 ° C, 25 ° C, 70 ° C and 90 ° C was recorded.

<Glass transition temperature>
A two-component polyurethane adhesive composed of a main agent (X) containing a polyol component (A) and a curing agent (Y) containing an isocyanate component (B) was prepared at 50 ° C. by weight ratios shown in Tables 1 and 2. The viscoelasticity was measured in the same manner as the above viscoelasticity measurement except that the mixture was uniformly mixed, defoamed under reduced pressure, molded into a sheet having a thickness of 1 mm, and cured at 50 ° C. for 3 days. The peak temperature of tan δ (loss elastic modulus / stored elastic modulus ratio) in the range of was determined. The peak temperature of tan δ was defined as the glass transition temperature.

<Coatability>
A two-component polyurethane adhesive composed of a main agent (X) containing a polyol component (A) and a curing agent (Y) containing an isocyanate component (B) at 50 ° C. in the weight ratios shown in Tables 1 and 2. The mixture was uniformly mixed and defoamed by centrifugation. Twenty minutes after the start of uniform mixing, 0.5 g of an adhesive was applied to one end of a 25 mm × 100 mm steel sheet, and the steel sheet was placed vertically so that the applied end was on the upper side and allowed to stand. The time from vertical installation until the adhesive drips from the bottom of the steel sheet was recorded, and the coatability was judged according to the following criteria.
⊚: 10 minutes or more, ○: 7 minutes or more, Δ: 3 minutes or more and less than 7 minutes, ×: less than 3 minutes

<D hardness (flexibility and toughness)>
A two-component polyurethane adhesive composed of a main agent (X) containing a polyol component (A) and a curing agent (Y) containing an isocyanate component (B) at 50 ° C. in the weight ratios shown in Tables 1 and 2. Uniformly mix, defoam under reduced pressure, weigh 30 g of the mixed solution in a polypropylene cup, cure at 50 ° C for 1 day, remove from the cup, adjust the temperature at 25 ° C for 2 hours, and then polymer meter Co., Ltd. The D hardness (Shore D: instantaneous value) was measured using a Shore D hardness meter manufactured by the same manufacturer. The measurement was performed at 5 points, and the average value was calculated. The instantaneous value is the value immediately after the needle of the hardness tester is pressed against the resin. When the D hardness is 50 to 90, it means that the flexibility and toughness are excellent.

<Adhesive strength at 100 ° C>
A two-component polyurethane adhesive composed of a main agent (X) containing a polyol component (A) and a curing agent (Y) containing an isocyanate component (B) at 50 ° C. in the weight ratios shown in Tables 1 and 2. Uniformly mix and centrifuge defoam, apply adhesive to the adhesive part (25 mm x 10 mm) of the 25 mm x 100 mm aluminum adherend, place a spacer with a thickness of 100 μm, and then place another 25 mm x 100 mm aluminum. The adhesive part of the adherend was bonded and fixed with a jig, and the test piece obtained by curing at 50 ° C for 3 days was subjected to shear adhesion strength at 100 ° C and a tensile speed of 100 mm / min using a tensile tester. (Unit: MPa) was measured, and the adhesive strength was judged according to the following criteria.
⊚: 3 MPa or more, ◯: 1.5 MPa or more and less than 3 MPa, Δ: 0.5 MPa or more and less than 1.5 MPa, ×: less than 0.5 MPa

<Strength of cured resin>
A two-component polyurethane adhesive composed of a main agent (X) containing a polyol component (A) and a curing agent (Y) containing an isocyanate component (B) at 50 ° C. at the weight ratios shown in Tables 1 and 2. After uniform mixing, centrifugation and defoaming, molding into a sheet having a thickness of about 0.3 mm and curing at 50 ° C. for 3 days, a dumbbell-shaped No. 3 test piece was prepared and used at 23 ° C. using a tensile tester. The breaking strength (unit: MPa) was measured under the condition of a tensile speed of 100 mm / min in an environment of 50% RH. The measurement was performed on 5 test pieces, and the average value was evaluated.

<Strength of cured resin after durability test (durability)>
A two-component polyurethane adhesive composed of a main agent (X) containing a polyol component (A) and a curing agent (Y) containing an isocyanate component (B) at 50 ° C. in the weight ratios shown in Tables 1 and 2. Uniformly mixed, centrifugally defoamed, molded into a sheet with a thickness of about 0.3 mm, cured at 50 ° C for 3 days, and then subjected to an environment of 121 ° C, 100% RH, and 2 atm using an advanced accelerated life test device. After exposure for 3 days, a dumbbell-shaped No. 3 test piece was prepared, and the breaking strength (unit: MPa) was measured under the condition of a tensile speed of 100 mm / min in an environment of 23 ° C. and 50% RH using a tensile tester. .. The measurement was performed on 5 test pieces, and the average value was evaluated.

<Odor of cured product (low odor)>
A two-component polyurethane adhesive composed of a main agent (X) containing a polyol component (A) and a curing agent (Y) containing an isocyanate component (B) at 50 ° C. in the weight ratios shown in Tables 1 and 2. The mixture is uniformly mixed, defoamed under reduced pressure, molded into a sheet having a thickness of 1 cm, cured at 25 ° C. for 48 hours, then 10 g of the obtained cured resin is cut out, sealed in a glass bottle with a lid, and sealed at 60 ° C. for 1 hour. After adjusting the temperature, the odor was judged according to the following criteria.
◯: No peculiar odor, Δ: Slightly peculiar odor, ×: No peculiar odor.
The low odor suggests that the content of the low boiling point component contained in the cured product is low.

<Elution test (low pollution)>
A two-component polyurethane adhesive composed of a main agent (X) containing a polyol component (A) and a curing agent (Y) containing an isocyanate component (B) at 50 ° C. in the weight ratios shown in Tables 1 and 2. The mixture was uniformly mixed, defoamed under reduced pressure, molded into a sheet having a thickness of 1 cm, and cured at 25 ° C. for 72 hours. About 10 g of a cured resin sample cut into 1 cm squares was placed in a polycup, 100 g of acetone was added, and the mixture was allowed to stand at 40 ° C. for 6 hours. The weight of the eluate obtained by drying and removing acetone from the filtrate after filtration was measured, and the elution rate was calculated from the following formula 3.
Elution rate (% by weight) = (weight of eluate / weight of cured resin sample) x 100 ... (Equation 3)
The low elution rate suggests that the content of low molecular weight substances contained in the cured product is low.

As shown in Tables 1 and 2, it can be seen that the two-component polyurethane adhesive of the present invention has a small change in elastic modulus from −40 ° C. to 90 ° C., good adhesive strength at 100 ° C., and excellent heat resistance. .. Further, since the durability is excellent and the D hardness is in an appropriate range of 50 to 90, it is found that the flexibility and toughness are excellent, and the adhesive strength and the strength of the cured resin can be compatible with each other. Further, the two-component polyurethane adhesive of the present invention is excellent in coatability. Furthermore, since the cured resin has a small odor and the amount of elution is small, it has little effect on the human body and is excellent in safety.

The two-component polyurethane adhesive of the present invention is excellent in safety and low stain resistance, has good resin strength, heat resistance and durability, has little odor, and has little elution of low molecular weight substances into the treatment liquid. Therefore, it is particularly useful for applications that come into contact with living organisms and applications related to foods and beverages (medical instruments, water purification applications). In addition, since the cured resin obtained from the adhesive has excellent electrical insulation, water resistance, and adhesiveness to various substrates, it is used for electrical insulation such as sealing of electronic circuit boards, and water stoppage such as sealing of optical fiber cable connections. For applications such as bonding of heat insulating aluminum sashes and bonding of aluminum honeycomb panels, bonding of parts that are exposed to heat around automobile engines and brakes, various films that require heat resistance, and bonding of parts. Can also be suitably used.

Claims

Curing containing a main agent (X) containing a polyol component (A) containing an essential component of a polyether polyol (a) obtained by adding ethylene oxide and / or propylene oxide to a 6 to 14 functional polyol, and an isocyanate component (B). A two-component polyurethane adhesive composed of the agent (Y), wherein the NCO content of the entire isocyanate component (B) is 18% by weight to 30% by weight, and the two-component polyurethane adhesive is cured. A two-component polyurethane adhesive having a glass transition temperature of 100 ° C to 150 ° C.
The two-component polyurethane adhesive according to claim 1, wherein the polyol component (A) has a hydroxyl value of 300 to 900 mgKOH / g.
The two-component polyurethane adhesive according to claim 1 or 2, wherein the total number of ethylene oxide and propylene oxide added to the polyether polyol (a) is 1.0 to 2.0 per hydroxyl group.
The two-component polyurethane adhesive according to any one of claims 1 to 3, wherein the content of the polyether polyol (a) is 50% by weight or more based on the weight of the polyol component (A).
The storage elastic modulus (E'- 40 ) at −40 ° C. after curing of the two-component polyurethane adhesive is 2000 MPa to 10000 MPa, the storage elastic modulus (E'90) at 90 ° C. is 200 MPa to 3000 MPa, and The two-component polyurethane adhesive according to any one of claims 1 to 4, wherein the ratio (E'- 40 / E'90) of the storage elastic modulus at -40 ° C to the storage elastic modulus at 90 ° C is 0.9 to 10. Agent.
An adherend bonded with the two-component polyurethane adhesive according to any one of claims 1 to 5.