JP6868508B2 - Polyurethane-based curable composition - Google Patents

Description

The present invention relates to polyurethane-based curable compositions.

For the adhesion of window glass for automobiles, for example, a polyurethane-based curable composition containing a urethane prepolymer containing an isocyanate group at the molecular end, which is a reaction product of a polyol and an excess polyisocyanate compound, is used (Patented). Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2001-192635 International Publication No. 2014/196303 Pamphlet

However, the polyurethane-based curable compositions proposed in Patent Documents 1 and 2 do not satisfy all of heat-resistant adhesiveness, storage stability and low-temperature curability at the same time, and the carboxylic acid eluted from the curable composition. May have an adverse effect on peripheral parts and painting.

As a result of diligent studies to solve the above problems, the present inventors have made a curable composition by using a specific carboxylic acid in an amount according to a specific formula in a curable composition containing an isocyanate group-terminated urethane prepolymer. It has been found that a polyurethane-based curable composition having excellent heat-resistant adhesiveness, storage stability and low-temperature curability can be obtained while suppressing elution from the material.
That is, the present invention includes the following preferred embodiments.
[1] A polyurethane-based curable composition containing an isocyanate group-terminated urethane prepolymer and a carboxylic acid having 8 to 14 carbon atoms, and the content of the carboxylic acid in the polyurethane-based curable composition is A polyurethane-based curable composition that satisfies the following formula.
y ≦ 0.009 × 10 ^n-8
[In the formula, y represents the content [mass%] of the carboxylic acid in the polyurethane-based curable composition, and n represents the number of carbon atoms of the carboxylic acid, and y is 0.0001 or more and 3 or less].
[2] The polyurethane-based curable composition according to [1], wherein the carboxylic acid having 8 to 14 carbon atoms has a solubility parameter (SP value) of 9.7 [cal / cc / 25 ° C.] or less. Stuff.
[3] The polyurethane according to [1] or [2], wherein the carboxylic acid is at least one selected from the group consisting of octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid and isomers thereof. System curable composition.
[4] The polyurethane-based curable composition according to any one of [1] to [3], wherein the carboxylic acid is 2-ethylhexanoic acid and / or neodecanoic acid.
[5] The polyurethane-based curable composition according to any one of [1] to [4], which further contains a curing catalyst.
[6] The polyurethane-based curable composition according to [5], wherein the curing catalyst is a bismuth carboxylate and / or a morpholine compound.
[7] The polyurethane-based curable composition according to [6], wherein the bismuth carboxylate is bismuth 2-ethylhexanoate and / or bismuth neodecanoate.
[8] The morpholine compound is selected from the group consisting of morpholine, 2,2'-dimorpholinodiethyl ether, di (2,6-dimethylmorpholinoethyl) ether and 4- [1- (dimethylamino) ethyl] morpholine. The polyurethane-based curable composition according to [6], which is at least one kind.
[9] The polyurethane-based curable composition according to [8], which contains 0.01 to 0.03% by mass of 2,2'-dimorpholinodiethyl ether or di (2,6-dimethylmorpholinoethyl) ether.

The curable composition of the present invention is excellent in heat-resistant adhesiveness, storage stability and low-temperature curability, and since the components in the curable composition are difficult to elute, glass is used as an adhesive for automobile parts, especially automobile windows. It can be suitably used for adhesion to an adherend (including a transparent resin such as acrylic or polycarbonate), and has no adverse effect on acrylic automobile parts and the like deployed around the application site.

The polyurethane-based curable composition of the present invention contains an isocyanate group-terminated urethane prepolymer and a carboxylic acid having 8 to 14 carbon atoms.

As the isocyanate group-terminated urethane prepolymer, a reaction product of a polyol and a polyisocyanate can be used.

Examples of the polyol include polyether polyols such as polyoxyalkylene polyols, modified polyether polyols, and sorbitol-based polyols; polyester polyols such as condensed polyester polyols, lactone-based polyester polyols, and polycarbonate diols; acrylic polyols, polybutadiene-based polyols, and polyolefins. Polyols such as polypolyols and saponified ethylene-vinyl acetate copolymers in which the main chain is composed of CC bonds; other flame-retardant polyols, phosphorus-containing polyols, halogen-containing polyols and the like can be mentioned. These may be used alone or in combination of two or more. Of these, polyether polyols are preferable, and polyoxyalkylene polyols are more preferable. Examples of the polyoxyalkylene polyol include polypropylene glycol, ethylene oxide / propylene oxide copolymer, polytetramethylene ether glycol, polytetraethylene glycol, polyoxypropylene triol, polyethylene diol, polyethylene / propylene copolymer diol and triol, and the like. Be done.

The weight average molecular weight (Mw) of the polyol is preferably 100 to 20000, more preferably 2000 to 15000. When the weight average molecular weight (Mw) is in this range, the physical properties such as hardness, breaking strength, and breaking elongation of the isocyanate group-terminated urethane prepolymer tend to be good, and an appropriate viscosity tends to be easily obtained.

Examples of the polyisocyanate include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), hydrogenated XDI, 1,4-phenylenediocyanate, polymethylene polyphenylene polyisocyanate, and tetramethyl. Aromatic polyisocyanates such as xylylene diisocyanate (TMXDI), trizine diisocyanate (TODI), 1,5-naphthalenediisocyanate (NDI), triphenylmethane triisocyanate, hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), aliphatic polyisocyanates such as lysine diisocyanate, trans-cyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), isopropylidene bis (4-cyclohexyl isocyanate), bis (isocyanatomethyl) cyclohexane _(H 6 XDI), dicyclohexylmethane diisocyanate ( H _{12 MDI)} alicyclic polyisocyanates such as these carbodiimide modified products, isocyanurate modified product, an adduct modified product, and biuret modified products and the like. These may be used alone or in combination of two or more. Of these, 4,4'-diphenylmethane diisocyanate is preferable.

The isocyanate group-terminated urethane prepolymer has a polyol and a polyisocyanate in an excess of polyisocyanate, preferably an equivalent ratio of the OH group of the polyol to the isocyanate group of the polyisocyanate NCO / OH of 1.5 / 1-4. It is obtained by reacting at 0/1 using a known method.

The curable composition contains an isocyanate group-terminated urethane prepolymer, preferably 20 to 60% by mass, more preferably 25 to 50% by mass, and further preferably 30 to 40% by mass, based on the curable composition.

The curable composition contains a carboxylic acid having 8 to 14 carbon atoms. The content of carboxylic acid in the curable composition is as follows:
y = 0.009 × 10 ^n-8
[In the formula, y represents the content [mass%] of the carboxylic acid in the curable composition, and n represents the number of carbon atoms of the carboxylic acid, and y is 0.0001 or more and 3 or less]. When the curable composition contains a carboxylic acid having 8 to 14 carbon atoms in an amount according to the above formula, excellent heat-resistant adhesiveness, storage stability and curability are obtained, and the components in the curable composition are obtained. Tends to be difficult to elute. If the content of the carboxylic acid in the curable composition is less than the lower limit of 0.0001, it is difficult to exhibit storage stability, and if it exceeds the upper limit of 3, the effect on various physical properties of the cured product and the curability. Tends to spoil.

In a preferred embodiment, the content of the carboxylic acid in the curable composition is as follows:
y = 0.0085 × 10 ^n-8
[In the formula, y represents the content [mass%] of the carboxylic acid in the curable composition, and n represents the number of carbon atoms of the carboxylic acid, and y is 0.0001 or more and 3 or less].
Meet.

In a further preferred embodiment, the content of the carboxylic acid in the curable composition is as follows:
y = 0.008 × 10 ^n-8
[In the formula, y represents the content [mass%] of the carboxylic acid in the curable composition, and n represents the number of carbon atoms of the carboxylic acid, and y is 0.0001 or more and 3 or less].
Meet.

The content y of the carboxylic acid in the curable composition is preferably 0.0005% by mass or more and 2% by mass or less, and more preferably 0.001% by mass or more and 1% by mass or less.

Since the carboxylic acid having 8 to 14 carbon atoms has good compatibility with the curable composition, the solubility parameter (SP value) described later is 9.7 [cal / cc / 25 ° C.]. The following carboxylic acids are preferable, and carboxylic acids having a solubility parameter of 9.2 to 9.7 [cal / cc / 25 ° C.] are more preferable.

〔式中、δは溶解性パラメーター［ｃａｌ／ｃｃ／２５℃］、Δｅ_１は各単位官能基当たりの凝集エネルギー［ｃａｌ／ｍｏｌ］、Δν_１は分子容［ｃｃ／モル／２５℃］を示す〕
に基づいて計算することができる（大藪則雄、「ポリウレタン樹脂原料の溶解性パラメーターの推算」、コーティング時報、第１９３号、１９９２年、第９−１９頁、およびＲ．Ｆ．Ｆｅｄｏｒｓ，Ｐｏｌｙｍｅｒ Ｅｎｇｉｎｅｅｒｉｎｇ ａｎｄ Ｓｃｉｅｎｃｅ，１４，（２），１４７（１９７４））。各単位官能基についての２５℃における凝集エネルギー（Δｅ_１）および分子容（Δν_１）は当業者に既に知られている値である。例えば２−エチルヘキサン酸の場合、２個の−ＣＨ_３、４個の−ＣＨ_２−、１個の＞ＣＨ−、１個の−ＣＯＯＨから構成され、−ＣＨ_３のΔｅ_１およびΔν_１はそれぞれ１．１２５および３３．５、−ＣＨ_２−のΔｅ_１およびΔν_１はそれぞれ１．１８０および１６．１、＞ＣＨ−のΔｅ_１およびΔν_１はそれぞれ８２０および−１．０、−ＣＯＯＨのΔｅ_１およびΔν_１はそれぞれ６６００および２８．５であることから（上述の「ポリウレタン樹脂原料の溶解性パラメーターの推算」、第１１頁参照）、２−エチルヘキサン酸の溶解性パラメーターは約９．５２と算出される。 The solubility parameter is expressed by the following formula:

[In the formula, δ indicates the solubility parameter [cal / cc / 25 ° C], Δe ₁ indicates the aggregation energy [cal / mol] per unit functional group, and Δν ₁ indicates the molecular volume [cc / mol / 25 ° C]. ]
It can be calculated based on (Norio Oyabu, "Estimation of Solubility Parameter of Polyurethane Resin Raw Material", Coating Time Signal, No. 193, 1992, pp. 9-19, and RF Fedors, Polymer Engineering and. Science, 14, (2), 147 (1974)). _{The aggregation energy (Δe 1} ) and molecular volume (Δν ₁ ) at 25 ° C. for each unit functional group are values already known to those skilled in the art. For example, in the case of 2-ethylhexanoic acid, it is composed of two -CH ₃ , four -CH _2- , one> CH-, and one -COOH, and Δe ₁ and Δν ₁ of _{-CH 3 are} 1.125 and 33.5, respectively, Δe ₁ and Δν _{1 of −CH 2} − are 1.180 and 16.1, respectively, and> Δe ₁ and Δν ₁ of CH − are 820 and −1.0, and −COOH, respectively. Since Δe ₁ and Δν ₁ are 6600 and 28.5, respectively (see “Estimation of solubility parameter of polyurethane resin raw material” above, page 11), the solubility parameter of 2-ethylhexanoic acid is about 9. It is calculated as 52.

Specific examples of carboxylic acids having 8 to 14 carbon atoms include saturated fatty acids such as octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, and isomers thereof, such as 2-ethylhexane. Examples include aromatic carboxylic acids such as acids, neodecanoic acid and isononylic acid, such as silicic acid, o-, m- and p-toluic acid, unsaturated fatty acids, carboxylic diic acid and alicyclic carboxylic acids. Of these, 2-ethylhexanoic acid and neodecanoic acid are more preferable because they are liquid, have good compatibility with the curable composition, and are colorless and odorless.

When a carboxylic acid having 7 or less carbon atoms, such as enanthic acid, is used, the components in the adhesive are eluted by rain or car wash water under the market environment, which adversely affects adjacent automobile parts such as acrylics. May affect. That is, low molecular weight and highly polar carboxylic acids can be extracted into water and should be avoided from being added more than necessary. On the other hand, a carboxylic acid having 15 or more carbon atoms has a high molecular weight and a low polarity, so that the compatibility with the components in the adhesive is poor and the adhesiveness tends to be poor. This tendency tends to be particularly strong in a two-component material that is agitated before use.

The curable composition may include a curing catalyst. Examples of the curing catalyst include bismuth carboxylate, morpholin compound, DBU compound, monoamine, diamine, triamine, etheramine, organic carboxylate metal salt, imidazole compound and the like. Bismuth carboxylate and morpholine compounds are preferred as the curing catalyst.

Examples of the bismuth carboxylate include bismuth 2-ethylhexanoate, bismuth octylate, and bismuth neodecanoate. The structural unit derived from bismuth carboxylic acid is preferably the same as the structural unit derived from the above-mentioned carboxylic acid. Preferred bismuth carboxylates are bismuth 2-ethylhexanoate, bismuth neodecanoate and combinations thereof.

Bismuth carboxylate can be used alone or as a mixture of bismuth carboxylate and carboxylic acid. The carboxylic acid in the mixture is a mixture of the types of carboxylic acids exemplified for the above-mentioned carboxylic acids in an amount such that the content of the total carboxylic acid in the curable composition does not exceed the content described for the above-mentioned carboxylic acid. It is preferably contained therein. Of these, a carboxylic acid having a structural unit derived from the carboxylic acid of bismuth carboxylic acid is preferable, and 2-ethylhexanoic acid and neodecanoic acid are more preferable.

Examples of the morpholine compound include 2,2'-dimorpholinodiethyl ether, di (2,6-dimethylmorpholinoethyl) ether, 4- [1- (dimethylamino) ethyl] morpholine and the like.

Examples of the DBU compound include DBU [1,8-diazabicyclo (5.4.0) undecene-7], DBU phenol salt, DBU octylate, DBU formate and the like.

Examples of monoamines include triethylamine and the like.

Examples of the diamine include N, N, N', N'-tetramethylethylenediamine and the like.

Examples of the triamine include tetramethylguanidine and the like.

Examples of the cyclic amine include triethylenediamine and the like.

Examples of the alcohol amine include dimethylaminomethanol and the like.

Examples of the ether amine include bis (2-dimethylaminoethyl) ether and the like.

Examples of the organic carboxylic acid metal salt include Sn-based (dibutyltin dilaurate, tin octylate, etc.), Pb-based (lead octylate, etc.), and Zn-based (zinc octylate, etc.).

Examples of the imidazole compound include 2-methylimidazole and 1,2-dimethylimidazole.

When the curable composition contains a morpholine compound as a curing catalyst, the content of the morpholine compound in the curable composition is preferably 2.0% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass. % Or less, particularly preferably 0.1% by mass or less, and more particularly preferably 0.05% by mass or less. When the curable composition contains a morpholine compound as a curing catalyst, the content of the morpholine compound in the curable composition is preferably 0.001% by mass or more, more preferably 0.002% by mass or more.

When the curable composition contains bismuth carboxylate as a curing catalyst, the content of bismuth carboxylate in the curable composition is preferably 2.0% by mass or less, more preferably 1% by mass or less, still more preferably 0. It is 5% by mass or less, particularly preferably 0.1% by mass or less, and more particularly preferably 0.05% by mass or less. When the curable composition contains bismuth carboxylate as a curing catalyst, the content of bismuth carboxylate in the curable composition is preferably 0.001% by mass or more, more preferably 0.002% by mass or more. ..

The curable composition can further contain a plasticizer, a filler, a solvent and the like.

Examples of the plasticizer include diisononyl phthalate, dioctyl phthalate (DOP), dibutyl phthalate, dilauryl phthalate, butyl benzyl phthalate, dioctyl adipate, diisodecyl adipate, trioctyl phosphate, tris (chloroethyl) phosphate, tris (dichloropropyl) phosphate, and adipine. Protewic acid glycol polyester, butylene glycol polyester adipate, alkyl epoxide stearate, alkylbenzene, epoxidized soybean oil, diisononyl adipate, isodecyl succinate, diethylene glycol benzoate, pentaerythritol ester, butyl oleate, methyl acetyllicinolate, tricresyl phosphate, Examples thereof include trioctyl phosphate and the like. These may be used alone or in combination of two or more. The plasticizer may be present in an amount of 10 to 100% by weight based on the entire curable composition.

As fillers, for example, calcium carbonate, heavy calcium carbonate, precipitated calcium carbonate (light calcium carbonate), colloidal calcium carbonate, magnesium carbonate, zinc carbonate; silica, for example, fumed silica, calcined silica, precipitated silica, ground silica, etc. Fused silica, etc .; carbon black; clay such as wax stone clay, kaolin clay, calcined clay; talc, titanium oxide, iron oxide, zinc oxide, barium oxide, magnesium oxide, quicklime, zeolite, diatomaceous earth; these fatty acid treated products, resins Examples thereof include acid-treated products, urethane compound-treated products, and fatty acid ester-treated products. These may be used alone or in combination of two or more. The filler may be present in an amount of 10 to 200% by weight based on the entire curable composition.

Examples of the solvent include xylene and toluene. The solvent may be present in an amount of 0 to 20% by weight based on the entire curable composition.

The curable composition contains, if necessary, an adhesive-imparting agent (silane-based coupling agent, titanate-based coupling agent, etc.), an antioxidant, an antioxidant, an ultraviolet absorber, a pigment, and the like in an appropriate amount range. be able to.

The curable composition type is a one-component moisture-curing type containing an isocyanate group-terminated urethane prepolymer, a two-component type consisting of a main agent and a curing agent, and a two-component main agent that satisfies the function as a one-component moisture curing and a two-component main agent only when necessary. It may be a half-two-component type containing a curing agent for accelerating curing by mixing as.

The curable composition can be produced by sequentially adding and mixing a curing catalyst, a plasticizer, a filler, a solvent and other additives to an isocyanate group-terminated urethane prepolymer.

The curable composition can be applied to the peripheral edge of the window glass, attached to the vehicle body flange, and pressed to adhere the window glass to the vehicle body.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

[Stain evaluation]
10 g of a cured product of a polyurethane-based curable composition coated in a bead shape of 2 mmφ and 2 g of distilled water are placed in a polyethylene bag, and the bag is continuously rubbed so that the water and the cured product come into contact with each other for 3 minutes. 50 μliters of the contacted water was dropped onto the acrylic resin part, and the mixture was allowed to stand in an atmosphere of 40 degrees for 1 hour. Then, the parts were washed with water and the surface of the parts was visually observed.
Evaluation criteria: The case where cracks or remarkable stains occurred was evaluated as x, the case where slight stains could be observed was evaluated as Δ, and the case where no cracks or stains occurred was evaluated as ◯.

[Adhesiveness]
A primer (# 435-41 manufactured by Sunstar Engineering Inc.) is applied to the glass plate and dried. Next, the polyurethane-based curable composition is applied in a bead shape of about 9 mmφ, crimped to a thickness of 3 mm, and then left at 20 ° C. and 65% RH for 72 hours. The adhesiveness was evaluated according to the peeling adhesiveness test of JASOM338-89.

[Curing rate]
Evaluation was performed according to JIS K6850. First, a primer (# 435-41 manufactured by Sunstar Engineering Inc.) is applied to a glass plate, and a primer (# 435-97B manufactured by Sunstar Engineering Inc.) is applied on a PPGF (polypropylene / glass fiber) sheet. It was dry. Next, a polyurethane-based curable composition was applied onto each primer, and the adhesive wrap allowance was adjusted to 10 mm and the thickness was adjusted to 3 mm to prepare an adhesive test piece. Then, it was heated at 40 ° C. and 50% RH for 8 minutes, and the tensile shear adhesive strength was measured at a tensile speed of 200 mm / min with an Instron type tensile tester.
Evaluation criteria: ○ for 0.3 MPa or more, Δ for those that were left to stand at room temperature of 20 ° C and 65% humidity for 72 hours, and × for those that were not cured after being left at room temperature of 20 ° C and 65% humidity for 72 hours. did.

[Preparation of isocyanate group-terminated urethane prepolymer]
To 3000 g of polyoxypropylene triol having a hydroxyl value of 25.0, 350 g of 4,4'-diphenylmethane diisocyanate (MDI) was added and reacted at 80 ° C. for 3 hours in a nitrogen atmosphere to obtain a free NCO group content of 1.90%. An isocyanate group-terminated urethane prepolymer having a viscosity of 50,000 mPas (20 ° C.) was prepared.

[Examples 1 to 10 and Comparative Examples 1 to 6]
Each component by mass shown in Table 1 was stirred and mixed under defoaming under reduced pressure to prepare a polyurethane-based curable composition. The obtained polyurethane-based curable composition was evaluated for stains and curing speed. The results are shown in Table 2.

[Urethane prepolymer 1]
MDI-based prepolymer, reaction product of polyoxypropylene glycol and MDI, NCO / OH equivalent ratio = 2.05
[Carboxylic acid 1]
2-Ethylhexanoic acid (number of carbon atoms: 8, SP: 9.52)
[Carboxylic acid 2]
Neodecanoic acid (number of carbon atoms: 10, SP: 9.23)
[Carboxylic acid 3]
Phthalic acid (number of carbon atoms: 8, SP: 13.8)
[Carboxylic acid 4]
Stearic acid (number of carbon atoms: 18, SP: 9.12)
[Curing catalyst 1]
2,2'-Dimorpholino diethyl ether [curing catalyst 2]
Di (2,6-dimethylmorpholinoethyl) ether [curing catalyst 3]
4- [1- (dimethylamino) ethyl] morpholine [curing catalyst 4]
Bismuth 2-ethylhexanoate [curing catalyst 5]
Bismuth neodecanoate [Plasticizer 1]
DINP
[Plasticizer 2]
Xylene [filler 1]
Mixture of carbon black (Niteron # 200, manufactured by Shin Nikka Carbon Co., Ltd.) and carbon black 2 (Niteron # 300, manufactured by Shin Nikka Carbon Co., Ltd.) (mass ratio = 75/25)
[Filler 2]
CaCO ₃ (Viscolite SV, manufactured by Shiroishi Technical High School)

Claims (9)

A polyurethane-based curable composition containing an isocyanate group-terminated urethane prepolymer and a carboxylic acid having 8 to 14 carbon atoms, and the content of the carboxylic acid in the polyurethane-based curable composition is as follows. A polyurethane-based curable composition that meets the requirements.
y ≦ 0.009 × 10 ^n-8
[In the formula, y represents the content [mass%] of the carboxylic acid in the polyurethane-based curable composition, and n represents the number of carbon atoms of the carboxylic acid, and y is 0.0001 or more and 3 or less]. The polyurethane-based curable composition according to claim 1, wherein the carboxylic acid having 8 to 14 carbon atoms has a solubility parameter (SP value) of 9.7 [cal / cc / 25 ° C.] or less. The polyurethane-based curable composition according to claim 1 or 2, wherein the carboxylic acid is at least one selected from the group consisting of octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid and isomers thereof. .. The polyurethane-based curable composition according to any one of claims 1 to 3, wherein the carboxylic acid is 2-ethylhexanoic acid and / or neodecanoic acid. The polyurethane-based curable composition according to any one of claims 1 to 4, further containing a curing catalyst. The polyurethane-based curable composition according to claim 5, wherein the curing catalyst is a bismuth carboxylate and / or a morpholine compound. The polyurethane-based curable composition according to claim 6, wherein the bismuth carboxylate is bismuth 2-ethylhexanoate and / or bismuth neodecanoate. The morpholine compound is at least one selected from the group consisting of 2,2'-dimorpholinodiethyl ether, di (2,6-dimethylmorpholinoethyl) ether and 4- [1- (dimethylamino) ethyl] morpholine. , The polyurethane-based curable composition according to claim 6. The polyurethane-based curable composition according to claim 8, which contains 0.01 to 0.03% by mass of 2,2'-dimorpholinodiethyl ether or di (2,6-dimethylmorpholinoethyl) ether.