JP2008063568A - Reactive hot-melt adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactive hot-melt adhesive that has reduced environmental temperature dependence and has excellent initial cohesive power (initial adhesive strength) and thermal stability. <P>SOLUTION: The reactive hot-melt adhesive comprises a urethane prepolymer formed from (a) polyisocyanate and (b) a polyol comprising (b1) an aromatic ring-containing polyether polyol and/or (b2) an aromatic ring-containing polyester polyol and (b3) an aliphatic polyester polyol. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reactive hot melt adhesive. More specifically, the present invention relates to a reactive hot melt adhesive that exhibits excellent initial cohesion without depending on environmental temperature.

Conventionally, a reactive hot melt adhesive comprising a polyester-based or polyether-based urethane prepolymer and a low molecular weight xylene resin is known (for example, see Patent Document 1).
Japanese Patent No. 2651640

However, although the above-mentioned reactive hot melt adhesive is excellent in the length of time that can be bonded after application and the elasticity after curing, it is highly environmental temperature dependent and its cohesion is reduced at high temperatures in summer, and hard at low temperatures in winter. In order to cause poor adhesion immediately after coating, it was necessary to adjust the composition for summer and winter use respectively. Moreover, since it was poor in thermal stability when left in a state of being heated for a long time during coating, there was a problem of thickening (gelation) in the coating machine.
An object of the present invention is to provide a reactive hot melt adhesive that is excellent in thermal stability and exhibits excellent initial cohesive strength (initial adhesive strength) without depending on environmental temperature.

  The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems. That is, the present invention is formed from a polyisocyanate (a) and a polyol (b) comprising an aromatic ring-containing polyether polyol (b1) and / or an aromatic ring-containing polyester polyol (b2) and an aliphatic polyester polyol (b3). It is a reactive hot melt adhesive comprising a urethane prepolymer.

The reactive hot melt adhesive of the present invention has the following effects.
(1) Excellent thermal stability.
(2) Excellent initial adhesive strength without depending on the environmental temperature.
(3) A cured product obtained by curing the adhesive is excellent in heat-resistant creep resistance.
The initial adhesive strength is an adhesive strength measured 10 minutes after coating and represents an adhesive strength before complete curing.

  In the present invention, the polyisocyanate (a) is a bifunctional to trifunctional or higher polyisocyanate having a carbon number (hereinafter abbreviated as C) (excluding carbon in the NCO group, the same shall apply hereinafter) of 6 to 20 aroma. Polyisocyanates, C2-18 aliphatic polyisocyanates, C4-15 alicyclic polyisocyanates, C8-15 araliphatic polyisocyanates, modified products of these polyisocyanates, and mixtures of two or more of these It is.

Aromatic polyisocyanates include diisocyanates (hereinafter sometimes abbreviated as DI) [1,3- and / or 1,4-phenylene DI, 2,4- and / or 2,6-tolylene diisocyanate (TDI). 2,4′- and / or 4,4′-diphenylmethane diisocyanate (MDI), 4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanatobiphenyl, 3,3 '-Dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, m- and p-isocyanatophenylsulfonyl isocyanate, etc.], trifunctional or higher polyisocyanate [4,4', 4 "- Triphenylmethane triisocyanate, crude TDI, crude MDI, etc.].

Aliphatic polyisocyanates include diisocyanates [ethylene DI, tetramethylene DI, hexamethylene diisocyanate (HDI), dodecamethylene DI, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcapro. Acid, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, etc.], triisocyanate [2-isocyanatoethyl-2,6-diisocyanatohexanoate, 1,6,11 -Undecane triisocyanate etc.] etc. are mentioned.
Examples of alicyclic polyisocyanates include diisocyanates [isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4′-diisocyanate (hydrogenated MDI), cyclohexylene DI, methylcyclohexylene diisocyanate (hydrogenated TDI), bis (2-isocyanate). Natoethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5- and / or 2,6-norbornane diisocyanate and the like], triisocyanate [bicycloheptane triisocyanate and the like] and the like.

Examples of the araliphatic polyisocyanate include diisocyanate [m- and / or p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), etc.].
In addition, modified polyisocyanates include modified polyisocyanates such as modified (urethane modified, carbodiimide modified, trihydrocarbyl phosphate modified) MDI, urethane modified TDI, biuret modified HDI, isocyanurate modified HDI, isocyanurate modified IPDI and the like. And a mixture of two or more of these [for example, combined use of modified MDI and urethane-modified TDI (isocyanate group-containing prepolymer)].
Of these, HDI, IPDI, TDI, MDI, XDI, TMXDI, hydrogenated MDI, and hydrogenated TDI are preferred from the viewpoint of the cohesive strength of the adhesive described below (hereinafter abbreviated as cohesive strength), and HDI and MDI are particularly preferred. It is.

The polyol (b) consists of the following (b1) and / or (b2) and (b3), and (b4) can be used if necessary.
(B1): Aromatic ring-containing polyether polyol (b2): Aromatic ring-containing polyester polyol (b3): Aliphatic polyester polyol (b4): Other polyols

The aromatic ring-containing polyether polyol (b1) includes a phenol and / or aromatic dicarboxylic acid added with a C2-4 alkylene oxide (hereinafter abbreviated as AO).
Phenols include dihydric phenols [monocyclic [C6-18, such as catechol, resorcinol, hydroquinone, dihydroxymethylbenzene], polycyclic [C10-30, such as bisphenol A, -F and -S, dihydroxydiphenyl ether, dihydroxydiphenylthioether. , Binaphthol] and their alkyl (C1-10) or halogen-substituted products]; trivalent phenol [monocyclic [C6-24, such as pyrogallol], polycyclic [C10-30, such as anthocyanin] and their alkyl (C1 To 10) or halogen-substituted products.
Of these, dihydric phenol is preferred from the viewpoint of cohesive strength, and polycyclic, particularly bisphenol A and -F are more preferred.

  Aromatic dicarboxylic acids include monocyclic [C8-24, such as terephthalic acid, isophthalic acid, phthalic acid, phenylmalonic acid, homophthalic acid, phenylsuccinic acid, β-phenylglutaric acid, α- and β-phenyladipic acid] And polycyclic [C14-30, such as biphenyl-2,2 'and -4,4'-dicarboxylic acid, naphthalenedicarboxylic acid and the like]. Of these, monocyclic aromatic dicarboxylic acids are preferable from the viewpoint of cohesive strength, and terephthalic acid and isophthalic acid are more preferable.

Examples of AO include ethylene oxide, propylene oxide (hereinafter abbreviated as EO and PO, respectively), 1,2-, 1,3-, 2,3- and 1,4-butylene oxide and combinations of two or more of these [additions] The format may be either block addition (chip type, balance type, active secondary type, etc.) and / or random addition. ]. Of these, EO and / or PO are preferred from an industrial viewpoint.
The number of moles of AO added to phenol or aromatic dicarboxylic acid is preferably 1 to 100 moles, more preferably 2 to 50 moles from the viewpoint of cohesive strength.
The addition reaction of AO can be carried out by a known method, in the absence of a catalyst or in the presence of a catalyst (an alkali catalyst, an amine catalyst, an acidic catalyst, etc.) (especially in the latter stage of the addition reaction), at atmospheric pressure or It is carried out in one or more stages under pressure.

Number average molecular weight of (b1) [hereinafter abbreviated as Mn. The measurement is based on, for example, a gel permeation chromatography (GPC) method under the following conditions. same as below. ] Is preferably from 300 to 20,000, more preferably from 500 to 10,000, from the viewpoints of cohesive strength and melt viscosity.
(Mn measurement conditions by GPC method)
Solvent: Tetrahydrofuran reference material: Polyethylene glycol (hereinafter abbreviated as PEG)
Sample concentration: 0.25 wt / vol%
Column temperature: 23 ° C
Column type: Cross-linked styrene fine particle gel [trade name “Super HL”, “Super
H4000 "," Super H3000 "and" Super
H2000 ", manufactured by Tosoh Corporation]

  The aromatic ring content in (b1) is preferably 10 to 90%, more preferably 20 to 80%, and particularly preferably 30 to 70% from the viewpoints of cohesive strength and melt viscosity based on the weight of (b1).

As the aromatic ring-containing polyester polyol (b2), one formed from a polyol and a dicarboxylic acid in which any of the constituent components (polyol and / or dicarboxylic acid) contains an aromatic ring can be used. The aromatic ring in (b2) may be derived from either a polyol or a dicarboxylic acid.
The aromatic ring content in (b2) is preferably 10 to 90%, more preferably 20% to 80%, most preferably 30% to 70% from the viewpoint of cohesive strength and melt viscosity based on the weight of (b2). is there.

Polyols include alcohols and polyether polyols.
Alcohols are divalent {C2-20, such as aliphatic [ethylene glycol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,2-, 1,3- and 1,4-butanediol, neopentyl. Glycol, 1,3-, 1,4-, 1,6- and 2,5-hexanediol (hereinafter abbreviated as EG, DEG, PG, DPG, BD, NPG, HD), 1,2- and 1, 8-octanediol, 1,10-
Decanediol, 1,18-octadecanediol, 1,20-eicosanediol, etc.], alkyl (C1-3) dialkanolamine, having a ring [alicyclic ring-containing [1-hydroxymethyl-1-cyclobutanol, 1 , 2-, 1,3-, 1,4- and 1-methyl-3,4-cyclohexanediol, 2- and 4-hydroxymethylcyclohexanol, 1,4-cyclohexanedimethanol, 1,4-bis (hydroxy Methyl) cyclohexane etc.], aromatic ring-containing [m- and p-xylylene glycol, 1,4-bis (2-hydroxyethoxy) benzene, 1,4-bis (α-hydroxyisopropyl) benzene, 2,2-bis (4-hydroxyethoxyphenyl) propane, 2-phenyl-1,3-propanediol, 2-phenyl 1,4-butanediol, 2-benzyl-1,3-propanediol, triphenylethylene glycol, tetraphenylethylene glycol, benzopinacol, etc.] etc.], trivalent [C3-20, such as glycerin, trimethylolpropane, etc. (Hereinafter abbreviated as GR and TMP), hexanetriol and the like], tetravalent or higher polyhydric alcohols [C5-20, such as pentaerythritol (hereinafter abbreviated as PE), sorbitan, sorbitol, sucrose, etc.), etc. Can be mentioned. Of these, divalent and trivalent alcohols are preferable from the viewpoint of adhesiveness.

Examples of polyether polyols include AO adducts of the above alcohols or phenols. Examples of AO include those described above, and EO and PO are preferable from an industrial viewpoint.
The number of moles of AO added is preferably 1 to 100 moles, more preferably 2 to 50 moles from the viewpoint of cohesive strength.
The OH equivalent (molecular weight per OH group) of the polyether polyol is preferably 100 to 3,000, more preferably 150 to 1,000 from the viewpoints of flexibility and melt viscosity.

  Of the above polyols, aliphatic alcohols and aromatic ring-containing polyether polyols are preferable from the viewpoint of adhesiveness, and AO adducts of 1,4-BD, 1,6-HD, and bisphenol A are more preferable. is there.

Examples of the dicarboxylic acid include the aromatic dicarboxylic acids, aliphatic (saturated or unsaturated) dicarboxylic acids, and alicyclic dicarboxylic acids.
Of the aliphatic dicarboxylic acids, saturated aliphatic dicarboxylic acids include C2-24, such as oxalic acid, malonic acid, succinic acid, glutaric acid, methyl succinic acid, dimethyl malonic acid, β-methyl glutaric acid, ethyl succinic acid, isopropyl malon. Acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, tridecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, octadecanedicarboxylic acid and eicosandicarboxylic acid , And unsaturated aliphatic dicarboxylic acids include C4-24, such as maleic acid, fumaric acid, citraconic acid and mesaconic acid.
Examples of the alicyclic dicarboxylic acid include C6-30, such as 1,3- and 1,2-cyclopentanedicarboxylic acid, 1,2-, 1,3- and 1,4-cyclohexanedicarboxylic acid, 1,2 -, 1,3- and 1,4-cyclohexanediacetic acid, dicyclohexyl-4,4-dicarboxylic acid.
Of these, aliphatic dicarboxylic acids are preferable from the viewpoint of adhesiveness, and C2-10 saturated aliphatic dicarboxylic acids are more preferable.

  Mn in (b2) is preferably 300 to 20,000, more preferably 500 to 10,000 from the viewpoints of cohesive strength and melt viscosity.

The aliphatic polyester polyol (b3) includes (b31) those formed by condensation of aliphatic dihydric alcohols and aliphatic dicarboxylic acids, (b32) those obtained by polymerizing lactones, and (b33) hydroxycarboxylic acids. And at least one selected from the group consisting of those obtained by polymerizing.

Examples of the aliphatic dihydric alcohol constituting (b31) include divalent alcohols among the alcohols. Among these, EG, 1,4-BD, NPG, and 1,6-HD are preferable from the viewpoint of adhesiveness.
Examples of the aliphatic dicarboxylic acid include saturated and unsaturated aliphatic dicarboxylic acids among the dicarboxylic acids. Of these, saturated aliphatic dicarboxylic acids are preferable from the viewpoint of adhesiveness, and adipic acid and sebacic acid are more preferable.

Examples of the lactone constituting (b32) include C4-20, such as γ-butyrolactone, γ- and δ-valerolactone, ε-caprolactone, γ-pimerolactone, γ-caprolactone, γ-decanolactone, enanthlactone, and laurolactone. , Undecanolactone and eicosanolactone, which may be used alone or in combination of two or more.
Among these, γ-butyrolactone, ε-caprolactone, δ-valerolactone, enanthlactone and laurolactone are preferable from the viewpoint of the temperature dependency of the adhesive described later, and ε-caprolactone is more preferable.
In the production of (b32), a polyol (divalent or higher) is used as an initiator for ring-opening polymerization. Examples of the polyol include C2-18 diols such as EG, BD, NPG, and HD.

  Examples of the hydroxycarboxylic acid constituting (b33) include C2-20, such as hydroxyacetic acid, lactic acid, ω-hydroxycaproic acid, ω-hydroxyenanthic acid, ω-hydroxycaprylic acid, ω-hydroxypergonic acid, ω-hydroxy. Examples include capric acid, 11-hydroxyundecanoic acid, 12-hydroxydodecanoic acid and 20-hydroxyeicosanoic acid, and these may be used alone or in combination of two or more. Among these, lactic acid, ω-hydroxycaproic acid and 12-hydroxydodecanoic acid are preferable from the viewpoint of temperature dependency.

  In the case where the aromatic ring-containing polyester polyol (b2) and the aliphatic polyester polyol (b3) are (b31), the equivalent ratio of the esterification reaction between the component polyol and the dicarboxylic acid is the viewpoint of melt viscosity and adhesiveness. To preferably 100.5 / 100 to 200/100, more preferably 101/100 to 150/100.

The esterification reaction may be a catalyst-free or esterification catalyst. Examples of esterification catalysts include protonic acids (phosphoric acid, etc.), metals (alkali metals, alkaline earth metals, transition metals, 2B, 4A, 4B and 5B metals, etc.), carboxylic acid (C2-4) salts, carbonates , Sulfate, phosphate, oxide, chloride, hydroxide, alkoxide and the like.
Of these, from the viewpoint of reactivity, the trioxide is more preferable from the viewpoint of low colorability of carboxylic acid (C2-4) salts, oxides, alkoxides and products of 2B, 4A, 4B and 5B metals. Antimony, monobutyltin oxide, tetrabutyl titanate, tetrabutoxy titanate, tetrabutyl zirconate, zirconyl acetate, and zinc acetate. The amount of the esterification catalyst used is not particularly limited as long as a desired molecular weight is obtained, but is preferably 0.005 to 0.005 in terms of reactivity and low colorability based on the total weight of the polyol and the dicarboxylic acid. 3%, more preferably 0.01 to 1%.

The esterification reaction is carried out in the presence of an inert gas such as nitrogen under normal pressure or reduced pressure (for example, 133 Pa or less). In order to accelerate the reaction, an organic solvent can be added and refluxed. After completion of the reaction, the organic solvent is removed. The organic solvent is not particularly limited as long as it does not have active hydrogen such as a hydroxyl group. For example, hydrocarbon (toluene, xylene, etc.), ketone (methyl ethyl ketone, methyl isobutyl ketone, etc.), ester (ethyl acetate, Butyl acetate).
The reaction temperature is usually 120 to 250 ° C, preferably 150 to 230 ° C. The reaction time is usually 1 to 40 hours, preferably 3 to 24 hours.
The end point of the reaction can be judged by measuring the acid value (AV). The acid value at the end of the reaction is preferably 3 or less, more preferably 2 or less, from the viewpoint of reaction stability.

The OH value of (b3) is preferably 0.5 to 450, more preferably 1 to 280 from the viewpoint of melt viscosity and adhesiveness; Mn is preferably 500 to 200,000, more preferably 1,000 to 100. , 000.
Further, the OH value of (b31) is preferably from 5 to 450, more preferably from 10 to 280, particularly preferably from 25 to 140; from the viewpoint of melt viscosity and adhesiveness, the OH values of (b32) and (b33) are From the viewpoint of melt viscosity and cohesive strength, it is preferably 0.5 to 50, more preferably 0.8 to 30, and particularly preferably 1 to 20.
Among (b3), from the viewpoint of the initial adhesive strength, (b31) and the combined use of (b32) and / or (b33), (b31), and more preferably (b31) and (b32 ) And / or (b33).
Among the cases where (b31) and (b32) and / or (b33) are used in combination, the ratio is preferably based on the total weight of (b3) in the (b31) / (b32) / (b33) combined system. (10-99) / (45-0.5) / (45-0.5), more preferably (30-95) / (35-2.5) / (35-2.5), particularly preferably (50-90) / (25-5) / (25-5); (b31) / (b32) or (b31) / (b33) in the combined system based on the total weight of (b3), Preferably it is (10-99) / (90-1), More preferably, it is (30-95) / (70-5), Most preferably, it is (50-90) / (50-10).

  As the other polyol (b4), polyols other than (b1), (b2) and (b3), for example, polyoxyalkylene, polymer polyol (hereinafter abbreviated as P / P), polyolefin polyol, polyalkadiene polyol, castor oil And polyols, acrylic polyols, rosin polyols, and mixtures of two or more thereof.

As polyoxyalkylene, water and alcohol (same as above) added with AO [polyoxyethylene [namely, polyethylene glycol (PEG), polyoxypropylene [namely, polypropylene glycol (hereinafter abbreviated as PPG)], etc.], And those obtained by ring-opening polymerization of tetrahydrofuran.
P / P includes an ethylenically unsaturated monomer in the polyether polyol and / or polyester polyol (both OH-terminated), or a mixture thereof with the polyvalent (divalent to tetravalent or higher) alcohol. What is obtained by polymerizing is mentioned.
Ethylenically unsaturated monomers include C3-30 acrylic monomers such as (meth) acrylonitrile and alkyl (C1-20 or higher) (meth) acrylate (methyl methacrylate, etc.); hydrocarbon (hereinafter abbreviated as HC) monomers, For example, aromatic unsaturated HC (C8-20, such as styrene) and aliphatic unsaturated HC [C2-20 or higher alkenes, alkadienes, such as α-olefins (hexene, octene, etc.) and butadiene]; and these Two or more combined use [for example, combined use of acrylonitrile / styrene (weight ratio: 100/0 to 80/20)] is included. P / P has, for example, a polymer content of 5 to 80% by weight or more, preferably 30 to 70% by weight.

Examples of the polyolefin polyol include polyisobutene polyol.
Examples of the polyalkadiene polyol include polyisoprene polyol, polybutadiene polyol, hydrogenated polyisoprene polyol, and hydrogenated polybutadiene polyol.
Castor oil-based polyols include castor oil and modified castor oil (such as castor oil modified with a polyhydric alcohol such as TMP and PE).
Examples of the acrylic polyol include a copolymer of (meth) acrylic acid [alkyl (C1-30)] ester [methyl (meth) acrylate and the like] and a hydroxyl group-containing acrylic monomer [hydroxyethyl (meth) acrylate and the like]. .
Examples of the rosin-based polyol include a polyol having a rosin structure skeleton.

  Of these, polyoxyalkylene, polyolefin polyol, and polybutadiene glycol are preferable from the viewpoint of flexibility, and PEG, PPG, and polybutadiene glycol are more preferable.

  Mn of (b4) is preferably 500 to 100,000, more preferably 800 to 20,000, and particularly preferably 1,000 to 10,000 from the viewpoint of adhesiveness and melt viscosity.

The proportions of (b1), (b2), (b3) and (b4) in (b) are based on the total weight of (b); (b1) is usually 0-90%, agglomeration of adhesive Preferably from 0 to 70% from the viewpoint of strength and melt viscosity, more preferably 0 to 50%; (b2) is usually 0 to 90%, preferably from 0 to 80% from the viewpoint of adhesive cohesive force and melt viscosity, More preferably, it is 0 to 70% [however, (b1) and (b2) are not 0%. (B3) is usually 10 to 90%, preferably from 30 to 80%, more preferably 40 to 70% from the viewpoint of flexibility and cohesive strength; and (b4) is usually 30% or less, addition effect and adhesive From the viewpoint of adhesiveness, it is preferably 1 to 20%.
(B1) and (b2), which are polyols containing an aromatic ring, are used alone or in combination. From the viewpoint of initial adhesive strength, the combination or single use of (b2) is preferred. When used in combination, based on the total weight of (b1) and (b2), the ratio of (b1) / (b2) is preferably (10 to 90) / (90 to 10) from the viewpoint of initial adhesive strength. More preferably, it is (20-80) / (80-20).

  The reactive hot melt adhesive of the present invention comprises an NCO-terminated urethane prepolymer obtained by reacting an excess of the above polyisocyanate (a) with a polyol (b). The equivalent ratio [OH / NCO ratio] of the OH group in (b) to the NCO group in (a) in the reaction is preferably 1 / 1.01 to 1/5 from the viewpoint of melt viscosity and adhesiveness, Preferably it is 1 / 1.2-1/4, Most preferably, it is 1 / 1.5-1-1/3.

The urethanization reaction between (a) and (b) is not particularly limited, and the following two methods can be exemplified.
(I): (a) and (b1) and / or (b2), (a) and (b3), respectively
And then kneading and manufacturing.
(Ii): produced by reacting a mixture of (b1) and / or (b2) with (b3) and (a)
How to build.
Among the above methods, the method (ii) is preferable from the viewpoint of the simplicity of the manufacturing process and the thermal stability of the resulting adhesive.

In the urethanization reaction, a urethanization catalyst may be used, and various urethanization catalysts can be used. For example, a metal catalyst [tin catalyst [trimethyltin laurate, trimethyltin hydroxide, dimethyltin dilaurate, dibutyl Tin diacetate, dibutyltin dilaurate, stannous octoate, dibutyltin maleate, etc.], lead catalysts [lead oleate, lead 2-ethylhexanoate, lead naphthenate, lead octenoate, etc.], other metal catalysts [naphthenic acid Metal salt (such as cobalt naphthenate), phenylmercury propionate, etc.]]; amine catalyst {triethylenediamine, tetramethylethylenediamine, diazabicycloalkene [1,8-diazabicyclo [5,4,0] undecene-7 [ DBU (manufactured by San Apro Co., Ltd., registered trademark)] etc.] Dialkyl (C1-3) aminoalkyl (C2-4) amine [dimethylaminoethylamine, dimethylaminopropylamine, diethylaminopropylamine, dipropylaminopropylamine, etc.], heterocyclic aminoalkyl (C2-6) amine [2- (1-aziridinyl) ethylamine, 4- (1-piperidinyl) -2-hexylamine and the like], and carbonates and organic acids (C1-3, such as formic acid) salts thereof; N-methyl and -ethylmorpholine, triethylamine , Dimethyl- and diethylethanolamine, etc.}; and combinations of two or more of these.

The use amount of the urethanization catalyst is usually 0.5% or less based on the total weight of (a) and (b), preferably 0.0001 to 0.1% from the viewpoint of reactivity and thermal stability of the adhesive More preferably, it is 0.0005 to 0.05%, and particularly preferably 0.001 to 0.01%.
As a reaction method, for example, (a), (b) and a urethanization catalyst are charged into a reaction vessel having a temperature control function, the temperature is usually 30 to 160 (preferably 50 to 140) ° C., and the time is usually 30 to 1. , 1,000 (preferably 60 to 300) minutes of reaction, (a), (b) and the urethanization catalyst after homogeneous mixing, the mixture is poured into, for example, a twin screw extruder, and usually 80 to 250 (preferably 100-220) The method of making it react continuously at ° C etc. are mentioned.
The content (% by weight) of NCO groups in the obtained urethane prepolymer is preferably 0.2 to 10%, more preferably 0.5 to 0.5% from the viewpoints of heat resistance after curing and thermal stability during heat melting. 7%.

The reactive hot melt adhesive of the present invention can contain a tackifying resin (c) that does not contain a hydroxyl group for the purpose of improving the initial adhesive force during the production process or at any stage after production.
As (c), known tackifying resins {adhesion techniques, those described in Vol 20, (2), 13 (2000), etc.} can be used. For example, rosin, rosin derivatives (polymerized rosin, rosin ester, etc.); Mn 200 to 1,000), terpene resin [(co) polymer such as α-pinene, β-pinene and / or limonene, etc .; Mn 300 to 1,200], coumarone-indene resin, petroleum resin [C5 fraction, C9 Fractions, C5 / C9 fractions and / or (co) polymers such as dicyclopentadiene; Mn 300 to 1,200], styrene resins [(co) heavy such as styrene, α-methylstyrene and / or vinyltoluene Coalescence, etc .; Mn 200-3,000], acrylic resin [alkyl or alkenyl (meth) acrylate and / or (meth) acrylic acid ( ) Polymer, etc .; Mn 200-3,000], styrene-acrylic copolymer resin (Mn 200-5,000), xylene resin (xylene formaldehyde resin, etc .; Mn 300-3,000), and hydrogenated products of these resins Is mentioned. The copolymers include random, block and / or graft copolymers.
Of these, rosin derivatives, xylene resins and / or acrylic resins are preferable from the viewpoint of adhesiveness.

The ring and ball softening point (measurement method: based on JAI-7-1991) of (c) is preferably 30 to 160 ° C., more preferably 60 to 140 ° C. from the viewpoint of adhesiveness and melt viscosity.
If a liquid at room temperature is used alone, the cohesive force may be too low, but it can be used in combination with a solid at room temperature.
The amount of (c) used is usually 50% or less based on the total weight of the adhesive of the present invention, preferably 5 to 40%, more preferably 10 to 30% from the viewpoint of adhesiveness and adhesive strength after curing. It is.

Furthermore, the reactive hot melt adhesive of the present invention can be added to other resin additives (d) within a range that does not impair the effects of the present invention, depending on various purposes and uses, at any stage during or after the production process. ) Can be optionally contained.
As the additive (d), an antioxidant {hindered phenol compound [pentaerystyl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- ( 3,5-di-t-butyl-4-hydroxyphenyl) propionate etc.], phosphorus compounds [tris (2,4-di-t-butylphenyl) phosphite etc.], sulfur compounds [pentaerythryl-tetrakis (3 -Lauryl thiopropionate), dilauryl-3,3'-thiodipropionate, etc.]; UV absorber {benzotriazole compound [2- (3,5-di-t-amyl-2-hydroxyphenyl)] Benzotriazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, etc.]}; light stabilizer {hindered amine compound Product [(bis-2,2,6,6-tetramethyl-4-piperidyl) sebacate etc.] etc.]; adsorbent (alumina, silica gel, molecular sieve etc.); pigment (titanium oxide, carbon black etc.); dye ( Azo, anthraquinone, indigoid, alizarin, acridine, nitroso and aniline dyes); fillers (talc, mica, calcium carbonate, etc.); nucleating agents (sorbitol, phosphate metal salts, benzoate metal salts, phosphate metal salts, etc.) Lubricant (calcium stearate, butyl stearate, oleic acid amide, etc.); mold release agent (carboxyl-modified silicone oil, hydroxyl-modified silicone oil, etc.); flame retardant (halogen-containing flame retardant, phosphorus-containing flame retardant, antimony-containing flame retardant, Metal hydroxide-containing flame retardant, etc.); and fragrances.
The total amount used of (d) is usually 40% or less based on the total weight of the adhesive, preferably 0.002 to 30%, more preferably 0.1 to 10% from the viewpoint of the addition effect and adhesiveness. .

  The ring and ball softening point of the reactive hot melt adhesive of the present invention is preferably 20 to 120 ° C., more preferably 30 to 110 ° C. from the viewpoint of initial cohesive force and melt viscosity; From the viewpoint of cohesive strength and coatability, it is preferably 500 to 200,000 mPa · s, and more preferably 1,000 to 100,000 mPa · s.

Moreover, as a production facility for the reactive hot melt adhesive, it is only necessary that the components of the adhesive can be heated, melted and kneaded, and a normal hot melt production facility can be used.
Examples include a mixer having a highly compressible screw or ribbon stirrer, a reaction mixing tank, a single or twin screw extruder, a sigma blade mixer, a ribbon blender, a butterfly mixer, and a kneader.
The mixing temperature is preferably 60 to 250 ° C. from the viewpoints of mixing properties and thermal deterioration, and is preferably performed in an inert gas atmosphere such as nitrogen gas in order to prevent crosslinking of the reactive hot melt adhesive.

The reactive hot melt adhesive of the present invention is formed into a desired shape such as a block, a sheet or a film, if necessary. An extruder or the like is used for molding.
The method for using the reactive hot melt adhesive of the present invention is not particularly limited. For example, when the adhesive is in a block shape, the adhesive is melted and then adhered to the adherend to be bonded. Used by applying.

The applicator includes an ordinary applicator for hot melt adhesive, [roll coater (heater capable of heating, gravure roll, reverse roll, etc.), curtain coater, bead, spiral, spray, slot, etc.] and extruder [ Single screw and twin screw extruders, kneader ruder, etc.].
In the case of an applicator, an adhesive can be applied to one or both of the adherends and bonded together before cooling and solidification, or after cooling and solidification, the adherends can be combined, heated and bonded again. When bonding, it is better to pressurize and release the pressure after cooling and solidification.
In the case of an extruder, extrusion is performed on one or both of the adherends, and after cooling and solidification, the adherends are combined, heated again, and bonded. When bonding, it is better to pressurize and release the pressure after cooling and solidification. Moreover, it can coextrude between adherends and can perform bonding simultaneously.
When applied to the adherend, the melting temperature of the adhesive is usually 80 to 160 ° C., preferably 100 to 140 ° C. from the viewpoint of adhesion and thermal stability, and the melt viscosity at the coating temperature is usually 1 to 100 Pa · From the viewpoint of s and adhesiveness, it is preferably 2 to 50 Pa · s.

When the adhesive is a sheet or a film, the adhesive is sandwiched between adherends to be bonded together, heated and melted and bonded, or placed on one or both adherends and heated. It is melted and bonded before cooling and solidification, or after cooling and solidification, the adherends are combined, heated again and bonded together. The heating temperature at the time of heating and melting is not particularly limited, but is preferably 10 to 20 ° C. higher than the melting point (or softening point) from the viewpoint of adhesiveness. Moreover, it is better to pressurize when bonding, and the pressure is released after cooling and solidification. The pressure to be applied is not particularly limited as long as a desired adhesive force can be obtained, and is preferably 10 kPa to 5 MPa from the viewpoint of adhesiveness and moldability.
Although there is no restriction | limiting in particular in the thickness of a sheet | seat or a film, Preferably it is 10-500 micrometers from a viewpoint of adhesiveness and a moldability, More preferably, it is 30-300 micrometers.

  The curing reaction of the reactive hot melt adhesive of the present invention is triggered by the reaction between the NCO group contained and moisture in the air. The curing temperature is usually 5 ° C. or higher, and preferably 10 to 100 ° C. from the viewpoint of reactivity and side reaction suppression. The humidity condition is preferably 20% RH or more, more preferably 30 RH or more, from the viewpoint of reactivity. The curing time is usually several minutes to 200 hours, preferably 1 to 72 hours from the viewpoint of reactivity and workability. The cured product thus obtained has good cured properties and excellent durability such as heat resistance and solvent resistance.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In the examples, “parts” represents parts by weight, and “%” represents% by weight.

Production Example 1
In a separable flask equipped with a temperature controller and a stirrer, an aromatic ring-containing polyether polyol [trade name “New Paul BPE-20T”, manufactured by Sanyo Chemical Industries, Ltd., EO adduct of bisphenol A, OH value 351, Mn318] . same as below. ] (B1-1) 158 parts and 59 parts of adipic acid were added and reacted at 230 ° C. and normal pressure for 5 hours under a nitrogen atmosphere. Then, 0.004 part of tetrabutoxy titanate was added as a catalyst and reacted for 2 hours under reduced pressure. An aromatic ring-containing polyester polyol (b2-1) (OH value 49.5, Mn 2,300) was obtained.

Examples 1-15 and Comparative Examples 1-3
In a separable flask equipped with a temperature controller and a stirrer, (b1-1) 30 parts, aliphatic polyester polyol [trade name “San Ester KH45625”, manufactured by Sanyo Chemical Industries, Ltd., 1,4-BD and NPG Polyadipate of terminal OH composed of adipic acid, OH value 44.5, Mn 2,500] (b3-1) 60 parts, polycaprolactone [trade name “CAPA 6800”, manufactured by Nippon Solvay Co., Ltd., OH value 1, Mn 80 , 000] (b3-2) 10 parts, uniformly dissolved at 120 ° C., and then dehydrated under reduced pressure (120 ° C., 133 Pa, 1 hour). After adding 59 parts of MDI (a1-1) at 60 ° C. in a nitrogen atmosphere, reacting and aging at 80 ° C. for 3 hours, a reactive hot melt adhesive (NCO content: 6.2%, 120 ° C. melt viscosity: 10 Pa · s) (HM-1) was obtained.
Hereinafter, the reactive hot melt adhesives (HM-2 to HM-15) of the present invention are reacted by reacting the polyol (b) having the composition shown in Table 1 and the polyisocyanate (a) by the same procedure.
And comparative hot melt adhesives (ratio HM-1 to HM-3).

(Explanation of symbols in Table 1)
(B4-1): PPG [trade name “Sannicks GP-3000”, Sanyo Chemical Industries, Ltd.
Manufactured, OH value 56, Mn 3,000]
(C1-1): Tackifying resin [rosin ester, trade name “Pine Crystal KE-31
1 ”, manufactured by Arakawa Chemical Industries, Ltd., OH value 0, acid value 5, softening point 95 ° C.]

  About the obtained reactive hot-melt-adhesive, 120 degreeC melt viscosity, heat stability, initial stage adhesive strength, and heat-resistant creep property were evaluated with the following test methods. The results are shown in Table 2.

(1) 120 degreeC melt viscosity Based on JISK7117-1987 (SB type viscometer, SB4 spindle rotation speed 12rpm conditions), the melt viscosity at 120 degreeC was measured.
(2) Thermal stability The reactive hot melt adhesive is sealed in a cylindrical screw stopper type glass container having an inner diameter of 25 mm and a height of 5 cm, and left at 120 ° C. for 24 hours (heat treatment). Measure in the same manner as in (1), and calculate the thickening rate (%) compared to the melt viscosity before heat treatment.

Thickening rate = [melt viscosity (after heat treatment) −melt viscosity (before heat treatment)] × 100 / melt viscosity (before heat treatment)

(3) Initial bond strength Reactive hot melt adhesive was melted at a temperature of 120 ° C. and hot air pressure of 1.5 kg / cm using an ambient temperature of 5, 23 and 40 ° C. using a curtain spray coating machine. ^{2. On} a polyolefin decorative sheet (length 10 cm, width 2.5 cm, thickness 150 μm) at a hot air temperature of 140 ° C., a gun head temperature of 130 ° C., a distance of 5 cm between the gun head and the adherend, and an application amount of 60 g / m ^2. After coating, after 1 minute, MDF (medium density fiberboard, length 15 cm, width 3 cm, thickness 2 cm) 15 cm × 3 cm surface was matched to the coated surface, and a rubber roller with a load of 2 kg was used from above to 300 mm. A test piece was prepared by reciprocating at a speed of / min.
Further, after 10 minutes, under the same environmental temperature as at the time of coating, using an autograph [AGS-500B; manufactured by Shimadzu Corporation] according to JIS K6854-1999, peeling at 180 ° under the condition of a tensile speed of 200 mm / min. The strength was measured, and this maximum value was defined as the adhesive strength (unit: N / 25 mm).

(4) Heat-resistant creep resistance A test piece prepared by reacting a reactive hot melt adhesive in the same manner as the initial adhesive strength of (3) above was cured for 72 hours in an atmosphere of 23 ° C. and 50% RH for evaluation of heat-resistant creep resistance. A test piece was obtained.
The test piece was horizontally bridged on two struts having a distance of about 13 cm between the struts (each about 20 cm in height and 3 cm in width) with the polyolefin decorative sheet bonded side down.
Next, about 2 cm was peeled off from one end of the olefin-made decorative sheet, a marked line was drawn on the sheet at that position, a 500 g weight was attached to the peeled sheet end, and the sheet was suspended in the vertical direction.
This was left still in a 60 degreeC thermostat for 1 hour, and 90 degree heat resistant creep (deviation distance from a marked line, unit: mm / h) was measured.

  From the results shown in Table 2, the reactive hot melt adhesive of the present invention has a small viscosity increase rate (excellent thermal stability) compared to the comparative one, and is not dependent on the environmental temperature (5 to 40 ° C.). It can be seen that the adhesive strength is good, and the cured product obtained by curing the adhesive is excellent in heat-resistant creep resistance.

The reactive hot melt adhesive of the present invention is excellent in thermal stability, exhibits excellent initial adhesive strength without depending on environmental temperature, and a cured product obtained by curing the adhesive is excellent in heat-resistant creep resistance. It is widely used for the following applications.
(1) Building material applications: Adhesives for woody materials (plywood, particle board, hardboard, laminated wood, etc.) and other building materials (concrete, mortar, wallpaper, floor materials, tiles, etc.).
(2) Fiber material use: Adhesive for fiber material (nonwoven fabric, woven fabric, carpet, etc.).
(3) Other materials: Plastic (hard and soft vinyl chloride, foamed plastic, etc.), rubber (natural rubber, synthetic rubber, etc.), leather, ceramics (multi-layer glass, optical lens, polishing material, etc.), Adhesives for household goods (such as paper), cardboard, bookbinding, and electrical appliances.

Claims (6)

From a urethane prepolymer formed from a polyisocyanate (a) and a polyol (b) comprising an aromatic ring-containing polyether polyol (b1) and / or an aromatic ring-containing polyester polyol (b2) and an aliphatic polyester polyol (b3) Reactive hot melt adhesive. The adhesive according to claim 1, wherein the content based on the weight of (b) is (b1) 0 to 90%, (b2) 0 to 90%, and (b3) 10 to 90%. The adhesive according to claim 1 or 2, further comprising a tackifying resin. Furthermore, at least one additive selected from the group consisting of antioxidants, ultraviolet absorbers, light stabilizers, adsorbents, pigments, dyes, fillers, nucleating agents, lubricants, mold release agents, flame retardants, and fragrances. The adhesive according to any one of claims 1 to 3, which is contained. Hardened | cured material formed by hardening | curing the adhesive agent in any one of Claims 1-4. The adhesive body which adhere | attaches a to-be-adhered body with the adhesive agent in any one of Claims 1-4.