JP2007045977A - Reactive hot-melt adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactive hot-melt adhesive composition excellent in a balance among initial bond strength, final bond strength, and heat stability and to provide a method for producing such reactive hot-melt adhesive composition. <P>SOLUTION: It has been found out that a reactive hot-melt adhesive composition comprising (A) a urethane polymer terminated with an isocyanate group and having not more than two isocyanate groups on the average per molecule, (B) a tackifying resin containing chemical structures derived from indene and/or coumarone, and (C) a polyfunctional polyisocyanate having more than two isocyanate groups on the average per molecule is excellent in a balance among initial bond strength, final bond strength, and heat stability. It is desirable that the prepolymer (A) is one obtained by reacting a difunctional polyol with a difunctional polyisocyanate. It is also desirable that the urethane polymer (A) is one further containing chemical structures derived from a silane coupling agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reactive hot melt adhesive composition that is widely used in the field of building interior materials, and particularly in the field of flooring, where the required performance for adhesives is severe, the application of decorative sheets to substrates, and profile wrapping. The present invention relates to a reactive hot melt adhesive composition that can be used.

  In the field of building interior materials (or building materials), reactive hot melt adhesives are widely used. In this specification, the “reactive hot melt adhesive” refers to an adhesive mainly composed of a polyurethane resin containing a reactive isocyanate group.

  “Reactive hot melt adhesives” generally adhere to adherends in a heated and melted state, and after cooling and solidification, the isocyanate group crosslinks in the presence of moisture, so that the thermoplastic resin of the main component has a higher molecular weight. Thus, the adhesive strength, heat resistance and the like are improved (see, for example, Patent Document 1). As is apparent from Examples 1 to 3 in Table 1, the reactive hot melt adhesive described in Patent Document 1 is excellent in heat resistance, solvent resistance, and thermal stability.

  However, reactive hot melt adhesives are also required to have higher performance in terms of adhesion. As the adhesive strength, two types of adhesive strength are mainly important: initial adhesive strength and final adhesive strength. "Initial bond strength" refers to the adhesive strength that occurs when an adhesive is applied to an adherend at a high temperature and the adhesive changes from a liquid to a solid, and "final bond strength" The adhesive strength in a state where the isocyanate group contained in the adhesive and moisture in the atmosphere react and the reaction is completed.

  In the field of building materials, the demand for initial adhesive strength is higher than other fields in special fields such as flooring. Therefore, various means have been studied so far in order to particularly increase the initial adhesive strength of the reactive hot melt adhesive.

  In the prior art, there is known a method of adding an olefin resin and a tackifying resin to a urethane prepolymer obtained by reacting a polyisocyanate compound with a polyol mainly composed of polyethylene butylene polyol (Patent Document 2). reference). A method of synthesizing a urethane prepolymer having two or more isocyanate groups and adding a coumarone indene resin as a tackifier resin is also known (see Patent Document 3). All of these methods improve the initial bond strength of the reactive hot melt adhesive, but the final bond strength is not always sufficient. It is well known that the final bond strength is reduced when coumarone indene resin is added to a reactive hot melt adhesive.

  In Patent Document 3, in order not to lower the final adhesive strength, a urethane prepolymer is synthesized using a trifunctional polyisocyanate and blended therewith. However, the use of trifunctional polyisocyanates for the synthesis of urethane prepolymers can result in a decrease in the thermal stability of the resulting reactive hot melt adhesive.

JP-A-2005-75877 Japanese Patent Laid-Open No. 11-323301 Japanese Patent No. 2674846

  The present invention has been made to solve such a problem, and the problem is a reactive hot melt adhesive composition having an excellent balance of initial adhesive strength, final adhesive strength, and thermal stability, and such reactive hot melt. It is providing the manufacturing method of an adhesive composition.

As a result of intensive studies, the present inventors have surprisingly found that a reactive hot melt adhesive composition comprising a specific urethane prepolymer, a specific tackifying resin, and a specific functional polyisocyanate, The present inventors have found that the balance between the initial adhesive strength, the final adhesive strength and the thermal stability is excellent, and have completed the present invention.
In the present specification, the “reactive hot melt adhesive composition” means a composition constituting the reactive hot melt adhesive.

That is, the present invention
(A) a urethane prepolymer having an isocyanate group at the end and an average number of isocyanate groups contained per molecule of 2 or less (hereinafter also referred to as “(A) prepolymer”),
(B) a tackifying resin containing a chemical structure derived from indene and / or coumarone (hereinafter also referred to as “(B) tackifying resin”), and (C) the number of isocyanate groups contained per molecule is 2 on average More polyfunctional polyisocyanates (hereinafter also referred to as “(C) polyfunctional polyisocyanates”)
A reactive hot melt adhesive composition is provided.

  In one aspect of the present invention, (A) the urethane prepolymer provides the reactive hot melt adhesive composition described above further having a chemical structure based on a silane coupling agent.

  In another aspect of the invention, (B) the tackifying resin provides the reactive hot melt adhesive composition described above, which is a coumarone indene resin.

  In a preferred embodiment of the present invention, it includes (A) 50 to 95 parts by weight of a urethane prepolymer, (B) 5 to 50 parts by weight of a tackifier resin, and (C) 0.5 to 5 parts by weight of a polyfunctional polyisocyanate. A reactive hot melt adhesive composition as described above is provided.

In another aspect of the invention,
(A) a urethane prepolymer having an isocyanate group at the terminal and having an average number of isocyanate groups of 2 or less per molecule;
(B) a step of mixing a tackifying resin containing a chemical structure derived from indene and / or coumarone, and (C) a polyfunctional polyisocyanate having an average of more than two isocyanate groups per molecule. A process for producing a reactive hot melt adhesive composition is provided.

  In one aspect of the present invention, (A) the urethane prepolymer provides the above-described production method including a step obtained by reacting a difunctional polyol and a difunctional polyisocyanate.

  In another embodiment of the present invention, (A) the urethane prepolymer provides the above-described production method including a step obtained by reacting a polyol and a polyisocyanate and further reacting with a silane coupling agent.

The reactive hot melt adhesive composition of the present invention comprises:
(A) a urethane prepolymer having an isocyanate group at the terminal and having an average number of isocyanate groups of 2 or less per molecule;
(B) because it comprises a tackifying resin containing a chemical structure derived from indene and / or coumarone, and (C) a polyfunctional polyisocyanate having an average of more than two isocyanate groups per molecule Excellent balance between initial adhesive strength, final adhesive strength and thermal stability.

  Furthermore, when the (A) urethane prepolymer further has a chemical structure based on a silane coupling agent, the final adhesive strength is superior due to the three-dimensional cross-linking structure of the silane coupling agent.

  When the (B) tackifying resin is a coumarone indene resin, the reactive hot melt adhesive composition of the present invention is more excellent in initial adhesive strength and compatibility.

  The reaction of the present invention comprises (A) 50 to 95 parts by weight of urethane prepolymer, (B) 5 to 50 parts by weight of tackifying resin, and (C) 0.5 to 5 parts by weight of polyfunctional polyisocyanate. The hot-melt adhesive composition is superior due to the balance of initial adhesive strength, final adhesive strength, and thermal stability.

The method for producing the reactive hot melt adhesive composition of the present invention comprises:
(A) a urethane prepolymer having an isocyanate group at the terminal and having an average number of isocyanate groups of 2 or less per molecule;
(B) a step of mixing a tackifying resin containing a chemical structure derived from indene and / or coumarone, and (C) a polyfunctional polyisocyanate having an average of more than two isocyanate groups per molecule. Therefore, a reactive hot melt adhesive composition having an excellent balance of initial adhesive strength, final adhesive strength, and thermal stability can be produced.

  (A) When the urethane prepolymer includes a step obtained by reacting a bifunctional polyol and a difunctional polyisocyanate, the production method of the present invention controls the thermal stability of the resulting composition and the production step. From the point of view, it is better.

  (A) When the urethane prepolymer includes a step obtained by reacting a polyol with a polyisocyanate and further reacting with a silane coupling agent, the production method of the present invention reacts with a three-dimensional cross-linked structure with the silane coupling agent. The cured product of the reactive hot melt adhesive composition has a reactive hot melt adhesive composition that is more excellent in final adhesive strength.

Since the present invention has the above-described configuration, it exhibits the above-described excellent effects. The reason is considered to be as follows.
In the reactive hot melt adhesive composition according to the present invention, (B) a specific tackifying resin is used in order to improve the initial adhesive strength. However, when (B) a specific tackifying resin is used, the final adhesive strength is lowered. Therefore, in order to improve the final adhesive strength, the urethane prepolymer is cured by reaction with moisture to form a three-dimensional network structure. It is considered necessary to In order to form this three-dimensional network structure, when the number of isocyanate groups contained per molecule of the prepolymer is more than 2 on average (for example, in the case of the reactive hot melt adhesive described in Reference 3) ), The final adhesive strength can be increased. However, since the prepolymers react with each other and the viscosity increase due to the reaction is large, the thermal stability of the resulting reactive hot melt adhesive composition can be insufficient, and as a result, the initial adhesive strength, the final adhesive strength, It was found that a product with an excellent balance of stability could not be obtained. This is thought to be related to the relatively high molecular weight of the prepolymer.

  Therefore, in order to reduce the reaction between the prepolymers, the inventors set the average number of isocyanate groups per molecule of the prepolymer to 2 or less, but in order to form a three-dimensional network structure. Surprisingly, when a polyfunctional isocyanate having an average of more than 2 isocyanate groups per molecule is used in combination with this prepolymer, a surprisingly reactive hot melt adhesive composition It was found that it is possible to improve the stability while improving the final adhesive strength. This is because the polyfunctional isocyanate also reacts with itself, but the resulting molecular weight is smaller than that obtained by reacting the prepolymers, resulting in a reactive hot melt adhesive. This is considered to be because the influence on the stability of the composition, more specifically, on the viscosity is small.

  For the reasons described above, the reactive hot melt adhesive composition according to the present invention is considered to have excellent properties as described above, but these reasons do not limit the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, “(A) urethane prepolymer” is generally a polyurethane prepolymer having an isocyanate group at the terminal, and the average number of isocyanate groups contained in one molecule is 2 or less. As long as the reactive hot melt adhesive composition can be obtained, there is no particular limitation.
Such (A) urethane prepolymer can be obtained by reacting a polyol and a polyisocyanate compound according to a conventionally known method.
(A) The urethane prepolymer has an average number of isocyanate groups of 2 or less per molecule, but is preferably 1.0 to 2 on average and 1.3 to 2 on average. Is more preferable, and an average of 1.5 to 2 is particularly preferable.

  The “polyol” is not particularly limited as long as the target (A) urethane prepolymer can be obtained, and conventionally known polyols used for ordinary polyurethane production can be used. As the polyol, those having 2 or less functional groups are preferred, and bifunctional polyols, so-called diols, are particularly preferred. Polyols can be used alone or in combination.

  As such polyols, for example, polyols classified into ether-based, ester-based, polycarbonate-based, polydiene-based, and the like can be used. Examples of ether-based polyols include polyoxytetramethylene polyol (PTMG) and polyoxypropylene polyol (PPG). Examples of ester-based polyols include polyethylene adipate (PEA), polybutylene adipate (PBA), and polycaprolactone polyol (PCL). It can be illustrated. These copolymers, for example, a block copolymer of PTMG and caprolactone, a copolymer of polyester polyol and polyether polyol, and the like can also be used. These copolymers can be synthesized by, for example, ring-opening copolymerization of ε-caprolactone with PTMG, or ring-opening copolymerization of tetrahydrofuran, ethylene oxide, or propylene oxide with polyester polyol. Examples thereof also include substituted or unsubstituted polyalkylene ether glycols, polyhydroxy diethers such as polyhydroxy polyalkylene ethers, polyhydroxy polyesters, ethylene oxide adducts of polyols, and mono-substituted esters of glycols.

  The number average molecular weight of the polyol is preferably 10,000 or less. When the number average molecular weight exceeds 10,000, when the polyurethane prepolymer is produced, the molecular weight of the prepolymer may be too high and the viscosity may be high, and the obtained adhesive may not obtain the desired performance.

  The number average molecular weight of the polyol is measured by gel permeation chromatography (GPC). “Number average molecular weight” refers to the number average molecular weight measured using GPC and converted to monodispersed molecular weight polystyrene. More specifically, it refers to a value measured using the following GPC apparatus and measurement method.

  As the GPC apparatus, 600E manufactured by Waters was used, and RI (Waters 410) and UV (Waters 486, 220 nm) were used as detectors. As the GPC column, a total of two ultrastyrogels 100 Å (for molecular weight 50 to 1500) manufactured by Waters and one ultrastyrogel 500 Å (for molecular weight 1000 to 10,000) manufactured by Waters were used. The sample was dissolved in tetrahydrofuran, the flow rate was 0.5 ml / min, the column temperature was 40 ° C., and a calibration curve using monodisperse molecular weight polystyrene (molecular weight 1300, 3000 and 10,000) as a standard substance was used. The molecular weight was converted to obtain Mn.

  The “polyisocyanate compound” is not particularly limited as long as the target (A) urethane prepolymer can be obtained, and a conventionally known polyisocyanate compound used for ordinary polyurethane production is used. be able to. As the polyisocyanate compound, those having an average number of isocyanate groups of 2 or less per molecule are preferred, and bifunctional polyisocyanate compounds, so-called diisocyanate compounds, are particularly preferred. Polyisocyanate compounds can be used alone or in combination.

  Examples of the polyisocyanate compound include ethylene diisocyanate, ethylidene-diisocyanate, propylene diisocyanate, butylene-diisocyanate, hexamethylene-diisocyanate, toluene-diisocyanate, cyclopentylene-1,3-diisocyanate, cyclohexylene-1,4-diisocyanate, Cyclohexylene-1,2-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, xylylene diisocyanate, 1,4- Naphthylene diisocyanate, 1,5-naphthylene diisocyanate, diphenyl-4,4'-diisocyanate, azobenzene 4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, dichloro-hexamethylene diisocyanate, furfurylidene den diisocyanate, can be exemplified 1-chlorobenzene-2,4-diisocyanate, used solely or in combination.

  When (A) urethane prepolymer is synthesized, monool and monoisocyanate can be used as long as the desired urethane prepolymer (A) can be obtained, and trifunctional polyol and trifunctional polyisocyanate can also be used. However, it is preferable to use a bifunctional polyol (diol) and a difunctional polyisocyanate (diisocyanate). (A) It is more preferable that the urethane prepolymer is obtained by reacting a bifunctional polyol and a difunctional polyisocyanate from the viewpoint of thermal stability of the resulting composition and control of the production process. In addition, it is preferable to use 2 moles of difunctional isocyanate with respect to 1 mole of bifunctional polyol, because the target (A) urethane prepolymer can be produced relatively easily.

The (A) urethane prepolymer of the present invention may further have a chemical structure based on (or derived from) a silane coupling agent. In this case, the number of isocyanate groups contained in one molecule of (A) urethane prepolymer is an average of 2 or less per molecule of (A) urethane prepolymer having a chemical structure based on a silane coupling agent.
The (A) urethane prepolymer having a chemical structure based on a silane coupling agent can be generally obtained by reacting a urethane prepolymer obtained from a polyol and a polyisocyanate with a silane coupling agent. The number of isocyanate groups contained in one molecule of the urethane prepolymer before reacting with the silane coupling agent does not need to be two or less on average, and may be more than two on average. After the reaction between the polymer and the silane coupling agent, it is necessary to have an average of 2 or less. The number of isocyanate groups contained in one molecule of the urethane prepolymer before reacting with the silane coupling agent is preferably 2 or less on average. The urethane prepolymer before reacting with the silane coupling agent can be obtained by reacting a bifunctional polyol and a difunctional polyisocyanate from the viewpoint of thermal stability of the resulting composition and control of the production process. preferable.

In the present invention, the “silane coupling agent” is an organoalkoxysilane, and is not particularly limited as long as the intended reactive hot melt adhesive composition can be obtained.
Examples of such organoalkoxysilanes include compounds represented by the following general formulas (1) and (2).
Formula (1): R—Si (X) ₃
Formula (2): R—Si (R ′) (X) ₂
[However, in the above formulas (1) and (2),
R is an organic group having a vinyl group, an epoxy group, a mercapto group, an amino group or an isocyanate group,
R ′ is an alkyl group having 1 to 3 carbon atoms,
X means a methoxy group or an ethoxy group. ]

  Specific examples of “organoalkoxysilanes” include vinylalkoxysilanes such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, and vinyldimethylmethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ -Examples include glycidoxypropylmethyldimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, epoxyalkoxysilane such as 3,4-epoxycyclohexylethyldimethoxysilane, and mercaptoalkoxysilane such as γ-mercaptopropyltrimethoxysilane. it can. These organoalkoxysilanes can be used alone or in combination.

  The silane coupling agent preferably contains an active hydrogen group, and preferably contains at least one selected from a mercapto group, an amino group, a hydroxyl group and an imidazole group. Furthermore, it is more preferable to use mercaptoalkoxysilane as the silane coupling agent.

(A) As a "chemical structure based on a silane coupling agent" which a urethane prepolymer may have, the chemical structure represented by the following general formula (3) and (4) can be illustrated, for example.
Formula (3): -Si (X) ₃
Formula (4): —Si (R ′) (X) ₂
[However, in the above formulas (3) and (4),
R ′ is an alkyl group having 1 to 3 carbon atoms,
X means a methoxy group or an ethoxy group. ]
In addition, it is preferable that this chemical structure exists in the terminal part of a prepolymer.

  In the present invention, “(B) tackifying resin” means “tackifying resin containing a chemical structure derived from indene and / or coumarone”, and indene and / or coumarone (inden and coumarone are homologues thereof). And a chemical structure derived from (including derivatives), and is not particularly limited as long as the intended reactive hot melt adhesive composition can be obtained.

Examples of the “chemical structure derived from indene and / or coumarone” include, for example, a structure (I) in which an olefinic double bond of indene is changed to a single bond and a structure (II) in which an olefinic double bond of coumarone is changed to a single bond (II ) Can be illustrated. These chemical structures may be incorporated in the resin in any form, but generally, for example, as shown in (I) and (II), indene and coumarone olefinic double bonds are single bonds. Bonded with other units at the carbon atom changed to. In addition, these chemical structures may be substituted at any position with any substituent.

  In the present specification, “tackifying resin containing a chemical structure derived from indene and / or coumarone” more specifically means, for example, “indene and / or coumarone (inden and coumarone include homologues and derivatives thereof). A tackifying resin comprising a polymer obtained by polymerizing a monomer comprising Examples of such tackifying resins include, for example, coumarone homopolymer, indene homopolymer, copolymer obtained by copolymerizing coumarone and indene (ie, so-called coumarone indene resin), coumarone and / or inden (coumarone and Inden includes homologues and derivatives thereof (for example, coumarone and indene having a substituent) and copolymers obtained by copolymerizing with other monomers, and combinations of these polymers with other resins. It can be illustrated.

Other monomers include styrene, substituted styrene, vinyl toluene, substituted vinyl toluene, vinyl acetate, ethylene, vinyl esters (vinyl acetate, vinyl propionate, etc.), vinyl ether, fumarate, acrylonitrile, acrylic acid and methacrylic acid. Examples include esters of acids and C1-C12 alcohols, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-propyl acrylate, isopropyl acrylate, and the like.
Examples of other resins include homopolymers and copolymers of other monomers described above.

(B) As tackifying resin, coumarone homopolymer, indene homopolymer, copolymer obtained by copolymerizing coumarone and indene (ie, so-called coumarone indene resin), coumarone and / or inden (coumarone and inden Is preferably a copolymer obtained by copolymerizing a homologue thereof, a derivative thereof (for example, coumarone and indene having a substituent) and other monomers, a coumarone homopolymer, an indene homopolymer, coumarone and the like. A copolymer obtained by copolymerizing with indene (that is, so-called coumarone indene resin) is more preferred, and coumarone indene resin is particularly preferred.
(B) A commercially available thing can be used as tackifying resin.

(B) The tackifying resin preferably has a softening point of 150 ° C. or lower. The softening point is more preferably 50 to 130 ° C. The reactive hot melt adhesive composition is usually dissolved by heating, and can be applied to an adherend in a molten state at 120 ° C., for example. (B) When the softening point of the tackifying resin exceeds 130 ° C., it is necessary to apply the reactive hot melt adhesive composition at a higher temperature, and (B) the tackifying resin is miscible with the prepolymer. Can also be reduced.
In the present specification, “softening point” refers to a value measured according to the method defined in Japan Adhesive Industry Association Standard JAI-7-1991.

  In the present invention, “(C) polyfunctional polyisocyanate” is a polyisocyanate having an average of more than two isocyanate groups per molecule, and is intended to be a reactive hot melt adhesive composition. As long as it can be obtained, there is no particular limitation.

  (C) The number of isocyanate groups contained in one molecule of polyfunctional polyisocyanate is more than 2 on average, but it is preferably more than 2 and less than 8 on average, and more than 2 on average More preferably, it is 4 or less.

(C) The polyfunctional polyisocyanate preferably has a number average molecular weight of 50 to 1,000, more preferably 100 to 750, and particularly preferably 100 to 500.
(C) If the number average molecular weight of the polyfunctional polyisocyanate is less than 50, the adhesion and heat resistance may not be improved sufficiently. If the number average molecular weight exceeds 2000, There is a possibility that the thermal stability of is insufficient.

  (C) The “number average molecular weight (Mn)” of the polyfunctional polyisocyanate was measured using a gel permeation chromatography (GPC) apparatus as follows, and determined using an internal standard solution method. Number average molecular weight. More specifically, it refers to a value measured using the following GPC apparatus and measurement method. As the GPC apparatus, a 6LC-10GPC SYSTEM manufactured by Shimadzu Corporation was used, and a UV detector (wavelength 245 nm) was used as a detector. As the GPC column, SHODEX KF-801, SHODEX KF-802, and SHODEX KF-803 manufactured by Showa Denko Co., Ltd. were used. A sample methanolized in advance was dissolved in tetrahydrofuran, and the flow rate was 0.7 ml / min and the column temperature was 40 ° C. The internal standard solution method was used to determine the number average molecular weight. Using acetophenone as the internal standard solution and identifying the polyisocyanate peak contained in the polyfunctional polyisocyanate, the number average molecular weight of the sample was determined from the peak area ratio.

As such (C) polyfunctional polyisocyanate, for example,
Polymeric MDI;
4,4 ′, 4 ″ -triisocyanato-triphenylmethane, 1,3,5-triisocyanatobenzene, 2,4,5-triisocyanatotoluene and 4,4′-dimethyldiphenylmethane-2,2 ′ At least one selected from -5,5'-tetraisocyanate; and a trimer of tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate or isophorone diisocyanate, biuret type, adduct type or isocyanurate type polyisocyanate At least one selected from can be exemplified.
Regarding polymeric MDI, edited by Keiji Iwata, “Polyurethane Resin Handbook”, Nikkan Kogyo Shimbun, September 25, 1987, p. 33-35, JP-A-9-255663, and JP-A-2002-206081 can be referred to, and the contents of these cited references are incorporated in this specification by this citation.
(C) A commercially available polyfunctional polyisocyanate can be used.

  The reactive hot melt adhesive composition according to the present invention comprises (A) 50 to 95 parts by weight of urethane prepolymer, (B) 5 to 50 parts by weight of tackifying resin, and (C) polyfunctional polyisocyanate. It is preferable to comprise 5 to 5 parts by weight, (A) 50 to 85 parts by weight of urethane prepolymer, (B) 5 to 30 parts by weight of tackifying resin, and (C) polyfunctional polyisocyanate 0.5. More preferably, it comprises ~ 3 parts by weight, (A) 60 to 85 parts by weight of urethane prepolymer, (B) 5 to 20 parts by weight of tackifying resin, and (C) polyfunctional polyisocyanate 0.5. It is particularly preferred that it comprises ˜2 parts by weight.

  The reactive hot melt adhesive composition of the present invention may contain other additives as required. Examples of such additives include plasticizers, antioxidants, pigments, light stabilizers, and flame retardants. And a catalyst etc. can be illustrated.

Examples of the plasticizer include dioctyl phthalate, dibutyl phthalate, dioctyl adipate, mineral spirit, and the like.
Examples of antioxidants include phenolic antioxidants, phosphite antioxidants, thioether antioxidants, amine antioxidants, and the like.
Examples of the pigment include titanium oxide and carbon black.
Examples of the light stabilizer include benzotriazole, hindered amine, benzoate, and benzotriazole.
Examples of the flame retardant include halogen flame retardant, phosphorus flame retardant, antimony flame retardant, metal hydroxide flame retardant and the like.
Catalysts include metal catalysts such as tin catalysts (trimethyltin laurate, trimethyltin hydroxide, dibutyltin dilaurate, dibutyltin maleate, etc.), lead-based catalysts (lead oleate, lead naphthenate, lead octenoate, etc.), etc. Metal catalysts (such as naphthenic acid metal salts such as cobalt naphthenate) and amine catalysts such as triethylenediamine, tetramethylethylenediamine, tetramethylhexylenediamine, diazabicycloalkenes, dialkylaminoalkylamines, etc. .
These additives can be used alone or in combination.

The reactive hot melt adhesive according to the present invention described above is
(A) a urethane prepolymer having an isocyanate group at the terminal and having an average number of isocyanate groups of 2 or less per molecule;
(B) by mixing a tackifying resin containing a chemical structure derived from indene and / or coumarone, and (C) a polyfunctional polyisocyanate having an average number of isocyanate groups greater than 2 per molecule. Can be manufactured.
Therefore, this invention provides the manufacturing method of the reactive hot-melt-adhesive composition including the process of mixing (A) urethane prepolymer, (B) tackifying resin, and (C) polyfunctional polyisocyanate.

The mixing of (A) urethane prepolymer, (B) tackifying resin, and (C) polyfunctional polyisocyanate uses a conventionally known method as long as the desired reactive hot melt adhesive composition can be obtained. For example, a method of adding (B) and (C) with stirring to (A) dissolved by heating can be exemplified. When mixing, it is preferably performed in an atmosphere that does not contain moisture, such as a nitrogen atmosphere.
The mixing order of (A) urethane prepolymer, (B) tackifying resin, and (C) polyfunctional polyisocyanate is particularly limited as long as the desired reactive hot melt adhesive composition can be obtained. Instead, it can be selected as appropriate. Therefore, for example, they may be mixed in the order of (A), (B), (C), or may be mixed in the order of (B), (C), (A). (A), (B) and (C) may all be mixed simultaneously.

(A) As described above, the urethane prepolymer is obtained by reacting a polyol and a polyisocyanate compound according to a conventionally known method, and the resulting urethane prepolymer has an isocyanate group at the terminal and is contained per molecule. It can be obtained by making the number of groups an average of 2 or less.
It is preferable that the manufacturing method of this invention is a manufacturing method including the process of making a bifunctional polyol and bifunctional polyisocyanate react and obtaining (A) urethane prepolymer.

Furthermore, as described above, in the production method of the present invention, after reacting the polyol and the polyisocyanate, it is further reacted with a silane coupling agent to have an isocyanate group at the terminal and the number of isocyanate groups contained per molecule. It is preferable that it is a manufacturing method including the process of obtaining (A) urethane prepolymer by making it become 2 or less on average.
Moreover, the manufacturing method of this invention is a manufacturing method including the process obtained by making (A) urethane prepolymer react with a silane coupling agent after reacting a bifunctional polyol and a bifunctional polyisocyanate. Is more preferable.

  The reactive hot melt adhesive composition thus obtained is generally solid at room temperature and can be used using conventional methods. In general, a reactive hot melt adhesive is heated and melted and applied to a substrate, an adherend or the like.

  The reactive hot melt adhesive composition according to the present invention can be used in a field where a reactive hot melt adhesive composition has been conventionally used, but the flooring field and the base material are more demanding of initial adhesive strength. It can also be used in fields such as sticking a decorative sheet to a sheet and profile wrapping. The reactive hot melt adhesive composition of the present invention is suitable for attaching a building interior member such as a decorative sheet to a floor, but is not limited to being attached to a floor, and is suitable for other substrates. You can also apply a decorative sheet. Therefore, the reactive hot melt adhesive composition of the present invention can also be used for woodworking, paper processing, fiber processing, general use and the like.

The reactive hot melt adhesive of the present invention can be used by using the same method as that of the conventional reactive hot melt adhesive, and is not particularly limited as long as the desired member can be obtained. For example, when a decorative sheet is attached to a wood material, the reactive hot melt adhesive composition may be applied to the base material side or the decorative sheet side.
As the “decorative sheet”, those commonly used can be used, and are not particularly limited, but examples thereof include the following.
Plastic material sheets such as rigid or semi-rigid vinyl chloride resin, polyolefin resin, polyester resin;
A veneer processed from wood into a sheet; and decorative paper with various decorative prints.

As the “substrate”, those usually used can be used, and are not particularly limited, but examples thereof include the following.
Wood based materials such as plywood such as lauan plywood, medium fiber board (MDF), particle board, solid wood, wood fiber board; and inorganic materials such as cement board, gypsum board, lightweight cellular concrete (ALC).
Furthermore, the reactive hot melt adhesive composition according to the present invention can be used for profile wrapping in which a decorative sheet is bonded to a substrate having an irregular cross section.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely and in detail, these Examples are only one aspect | mode of this invention, and this invention is not limited at all by these examples.

Example 1
Polyoxypropylene diol having a number average molecular weight of 2000 (Accor Diol-2000 (trade name) manufactured by Mitsui Takeda Chemical Co., Ltd., hydroxyl value = 56) 45.11 g, polyester diol having a number average molecular weight of 3500 (Toyoku Oil Co., Ltd.) 165.41 g of HS2H-351A (trade name), hydroxyl value = 29.6) made in the reactor was put in a reactor, and dried under reduced pressure (10 mmHg or less) at 120 ° C. for 3 hours. Next, return the reactor to normal pressure with nitrogen, add 24.82 g of diphenylmethane diisocyanate (MDI) at about 100 ° C., and react at 100 ° C. for 3 hours to have an isocyanate group at the end and are contained per molecule. A urethane prepolymer (A-1) having an average number of isocyanate groups of 2 or less was obtained (the number of isocyanate groups contained per molecule was 2 on average). Next, a sufficiently dried tackifying resin (B-1) containing a chemical structure derived from indene and / or coumarone (Escron V-120 (trade name), a coumarone indene resin manufactured by Nippon Steel Chemical Co., Ltd.) , Softening point = 120 ° C), and polymer MDI (C-1) (manufactured by Sumika Bayer Urethane Co., Ltd.) having an average number of isocyanate groups of 2.55 per molecule. 4.51 g of Sumidur 44V10 (trade name), number average molecular weight = 410) was added and dried under reduced pressure at 130 ° C. for 1 hour to obtain the reactive hot melt adhesive composition of Example 1.

Example 2
In the same manner as in Example 1, the above urethane prepolymer (A-1) was obtained. Next, sufficiently dried tackifying resin (B-2) containing a chemical structure derived from indene and / or coumarone (Escron G-90 (trade name), a coumarone indene resin manufactured by Nippon Steel Chemical Co., Ltd.) HDI biuret body (C-2) (Sumika Bayer Urethane Co., Ltd .: Desmodur N3200) having an average number of isocyanate groups of 3 per molecule, 60.15 g, softening point = 90 ° C. (Product Name) 4.51 g was added and dried under reduced pressure at 100 ° C. for 1 hour to obtain a reactive hot melt adhesive composition of Example 2.

Example 3
In the same manner as in Example 1, the above urethane prepolymer (A-1) was obtained. Next, 1.5 g of a silane coupling agent (manufactured by Nippon Unicar Co., Ltd .: A189, γ-mercaptopropyltrimethoxysilane) is added to the urethane prepolymer (A-1), and the mixture is reacted at 100 ° C. for 2 hours with stirring. A urethane prepolymer (A-2) having an average number of isocyanate groups per molecule of 1.76 was obtained. Further, 60.15 g of the above-mentioned tackifying resin (B-1) and 4.51 g of the above-mentioned polymeric MDI (C-1) were added and dried under reduced pressure at 130 ° C. for 1 hour. The reactivity of Example 3 A hot melt adhesive composition was obtained.

Comparative Example 1
The urethane prepolymer (A-1) was obtained in the same manner as in the example. Next, 60.15 g of the above-mentioned tackifying resin (B-1) sufficiently dried was further added and dried under reduced pressure at 130 ° C. for 30 minutes to obtain a reactive hot melt adhesive composition of Comparative Example 1.

Comparative Example 2
Comparative Example 2 gives a reactive hot melt adhesive composition corresponding to the adhesive disclosed in Reference 2 (i.e., Patent No. 2,674,846).
Polyoxypropylene diol having a number average molecular weight of 2000 (Mitsui Takeda Chemical Co., Ltd .: Actol Diol-2000 (trade name), hydroxyl value = 56) 45.11 g, polyester diol having a number average molecular weight of 3500 (Toyoku Oil Co., Ltd.) Product: HS2H-351A (trade name), hydroxyl value = 29.6) 165.41 g was placed in a reactor, dried at 120 ° C. for 3 hours under reduced pressure (10 mmHg or less). Next, the reactor was returned to normal pressure with nitrogen, and polymer MDI (Suika Bayer) having an average number of isocyanate groups of 2.55 per molecule and diphenylmethane diisocyanate (MDI) 24.82 g at about 100 ° C. Urethane Co., Ltd. product: Sumidur 44V10 (trade name), number average molecular weight = 410) 4.51 g was added and reacted at 100 ° C. for 3 hours, and the average number of isocyanate groups contained in one molecule was 2. 96 urethane prepolymers (A′-3: not corresponding to (A) according to the present invention) were obtained. Next, 60.15 g of the above-mentioned tackifying resin (B-1) sufficiently dried was further added and dried under reduced pressure at 130 ° C. for 1 hour to obtain a reactive hot melt adhesive composition of Comparative Example 2.

Comparative Example 3
In the same manner as in Example 1, the above urethane pore polymer (A-1) was obtained. Next, sufficiently dried tackifying resin (B'-3: not applicable to (B) according to the present invention) (rosin ester, Arakawa Chemical Co., Ltd .: Superester A-115 (trade name), softening point = 115 ° C ) 60.15 g and 4.51 g of the above-described polymeric MDI (C-1) were further added. It dried under reduced pressure at 120 degreeC for 1 hour, and the reactive hot-melt-adhesive composition of the comparative example 3 was obtained.

Comparative Example 4
In the same manner as in Example 1, the above urethane pore polymer (A-1) was obtained. Next, sufficiently dried tackifying resin (B'-4: not corresponding to (B) according to the present invention) (alicyclic saturated hydrocarbon resin, Arakawa Chemical Co., Ltd .: Alcon M-100 (trade name), softening (Point = 100 ° C.) 60.15 g and 4.51 g of the above-described polymeric MDI (C-1) were further added. Drying under reduced pressure at 120 ° C. for 1 hour gave a reactive hot melt adhesive composition of Comparative Example 4. When this was placed in an oven at 120 ° C. for 1 day, phase separation occurred and it was impossible to make another evaluation.

<Evaluation method>
The obtained reactive hot melt adhesive composition was evaluated as follows. The results are shown in Table 1.
(Compatibility)
The reactive hot melt adhesive composition was heated to 120 ° C. and stored for 1 day, and then visually observed. The case where no phase separation occurred was marked with ◯, and the case where phase separation occurred was marked with ×.
(viscosity)
The reactive hot melt adhesive composition was heated to 120 ° C. and melted, and 30 minutes later, the viscosity was measured using a Brookfield viscometer (spindle No. 27). The viscosity measurement conditions were 120 ° C. and the rotation speed was 10 rpm or 20 rpm.
(Thermal stability)
In the present specification, “thermal stability” is determined by measuring the viscosity.
The reactive hot melt adhesive composition after measuring the above “viscosity” was left as it was at 120 ° C. for 1 hour in a Brookfield viscometer (spindle No. 27), and then the viscosity was measured at the same temperature. The increase rate of the viscosity measured after 1 hour with respect to the previously measured viscosity was determined. When the rate of increase in viscosity was 10% or less, the stability was good, and ◯, and when the rate of increase in viscosity exceeded 10%, the viscosity stability was poor, and x.
(Initial bond strength)
On a glass plate (430 × 300 mm) heated to 120 ° C., the reactive hot melt adhesive composition is applied with a width of 16 mm and a thickness of 0.1 mm, and bonded to a paper with a width of 25 mm and a length of 500 mm. After a predetermined temperature, the front and back surfaces of the glass plate were reversed, and a 64 g weight was attached to the end of the paper. While measuring the glass plate temperature, record the length of the paper peeled at 20 second intervals. After measurement, the relationship between temperature and peel rate is calculated. If the peel rate at 34 ° C. is 0 mm / min, the initial strength is good, ◯, if the peel rate at 34 ° C. is less than 5 mm / min, Δ, and if the peel rate at 34 ° C. is 5 mm / min or more, If so, the initial strength was low, and it was marked as x.

The “final adhesive strength” in this specification was comprehensively evaluated by the following three tests.
(Final strength)
Using a reaction hot melt adhesive composition in a molten state at 120 ° C., a 4 mm thick plywood and a decorative sheet (EB sheet (trade name) manufactured by Dai Nippon Printing Co., Ltd.) are bonded together for one week at room temperature. Take care. Next, the laminate surface layer portion of the test specimen was cut into a width of 25 mm, and the final strength was measured at room temperature. If the decorative sheet material was broken, it was rated as ◯, and if it was cohesive failure, it was marked as x.
(Heat resistance 1)
Using a reactive hot melt adhesive composition in a molten state at 120 ° C., a 4 mm thick plywood and a decorative sheet (EB sheet (trade name) manufactured by Dai Nippon Printing Co., Ltd.) are bonded together for one week at room temperature. Take care. Next, the laminate surface layer portion of the test specimen was cut into a width of 25 mm, and a static load of 500 g / 25 mm was applied in the 90 ° direction at 60 ° C., and then the peel length after 1 hour was measured. A peeling length of 5 mm or less was evaluated as ◯, and a peeling length exceeding 5 mm was evaluated as x.
(Heat resistance 2)
A reactive hot melt adhesive composition is used to make a 1 mm thick film, and after curing at room temperature for 10 days, the dynamic viscoelasticity of the film is measured using Rheogel-E4000 (trade name) manufactured by UBM Co., Ltd. It was measured. Measurement was performed at a temperature of 100 to 250 ° C. and a frequency of 10 Hz. The temperature corresponding to Tan δ = 1 is called the heat resistant temperature. When the heat resistant temperature exceeded 150 ° C., it was rated as “◯”, and when it was 150 ° C. or less, it was marked as “X”.

As shown in Table 1, the reactive hot melt adhesive compositions of Examples 1 to 3 have initial adhesive strength (initial strength), final adhesive strength (final strength, heat resistance 1, heat resistance 2), and thermal stability. Excellent (viscosity stability). Since the reactive hot melt adhesive composition of Comparative Example 1 does not contain (C) the polyfunctional polyisocyanate, it is inferior in final adhesive strength and inferior in thermal stability. The reactive hot melt adhesive composition of Comparative Example 2 has an average number of isocyanate groups per molecule of urethane prepolymer (A′-3) exceeding 2, so that the thermal stability (viscosity Inferior in stability. The reactive hot melt adhesive compositions of Comparative Examples 3 and 4 do not use a resin containing a chemical structure derived from indene and / or coumarone as a tackifier resin (B′-3 and B′-4). In Comparative Example 3, the initial adhesive strength (initial strength) is inferior, and in Comparative Example 4, the three components are essentially not mixed and cannot be a reactive hot melt adhesive composition.

Claims (7)

(A) a urethane prepolymer having an isocyanate group at the terminal and having an average number of isocyanate groups of 2 or less per molecule;
(B) a reaction comprising a tackifying resin comprising a chemical structure derived from indene and / or coumarone; and (C) a polyfunctional polyisocyanate having an average of more than two isocyanate groups per molecule. Hot melt adhesive composition.   The reactive hot melt adhesive composition according to claim 1, wherein the (A) urethane prepolymer further has a chemical structure based on a silane coupling agent.   The reactive hot melt adhesive composition according to claim 1 or 2, wherein (B) the tackifying resin is a coumarone indene resin.   4. A composition according to claim 1, comprising (A) 50 to 95 parts by weight of a urethane prepolymer, (B) 5 to 50 parts by weight of a tackifying resin, and (C) 0.5 to 5 parts by weight of a polyfunctional polyisocyanate. The reactive hot-melt-adhesive composition in any one. (A) a urethane prepolymer having an isocyanate group at the terminal and having an average number of isocyanate groups of 2 or less per molecule;
(B) a step of mixing a tackifying resin containing a chemical structure derived from indene and / or coumarone, and (C) a polyfunctional polyisocyanate having an average of more than two isocyanate groups per molecule. A method for producing a reactive hot melt adhesive composition.   (A) A urethane prepolymer is a manufacturing method of Claim 5 including the process obtained by making bifunctional polyol and bifunctional polyisocyanate react. (A) A urethane prepolymer is a manufacturing method of Claim 5 or 6 including the process obtained by making it react with a silane coupling agent after reacting a polyol and polyisocyanate.