JP2015000911A - Release agent for reactive hot melt resin, release method and substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a release agent for reactive hot-melt resins, which has excellent releasability, a release method using the release agent, and a base material.SOLUTION: The release agent for reactive hot-melt resins contains benzyl alcohol. The release method comprises a step of releasing the base material and a reactive hot-melt adhesive layer from a laminate, which is obtained by sticking the reactive hot-melt adhesive layer to the base material, by using the release agent for reactive hot-melt resins. The base material is obtained by the release method. The release agent for reactive hot-melt resins can impart excellent releasability to the reactive hot-melt adhesive layer obtained by using a reactive hot-melt resin. Since the base material stuck to the reactive hot-melt adhesive layer is separated, the release agent for reactive hot-melt resins is excellent also in reworkability of the base material.

Description

  The present invention relates to a release agent for a reactive hot melt resin excellent in peelability, a peeling method using the same, and a substrate.

  Adhesives obtained using reactive hot-melt resins are solvent-free, and as a result, they have been used as environmentally-friendly adhesives, and have been extensively studied in the industry, focusing on fiber bonding and building material lamination. Has been.

  In recent years, in the pasting of optical components, in response to the growing needs for weight reduction and thinning of optical components, consideration has been given to substituting hot melt adhesives for acrylic pressure-sensitive adhesives that have been the mainstream until now. ing.

  Examples of the adhesive include (a) 100 parts by weight of a polyurethane resin having a flow start temperature of 55 ° C. or higher and 110 ° C. or lower, and (b) a saturated polyester resin having a Tg of 0 ° C. or higher and 110 ° C. or lower and a molecular weight of 10,000 to 25,000. 5 to 150 parts by weight, (c) 10 to 150 parts by weight of an epoxy resin having a softening point of 60 ° C. or more and 140 ° C. or less and a molecular weight of 700 to 3000, and (d) 10 to 200 parts by weight of an inorganic filler surface-treated with a coupling agent. An adhesive using a heat-and-moisture resistant hot-melt adhesive composition characterized in that is formulated is disclosed (for example, see Patent Document 1).

  Since the laminate obtained by using the adhesive has a strong adhesive strength, it has an advantageous effect in terms of adhesiveness. However, on the other hand, since it cannot peel, there was a problem that it was inferior in reworkability. Particularly in recent years when reactive hot melt resins are often used for bonding optical parts, display parts such as liquid crystal panels and expensive adherends (base materials) such as housings are used. Therefore, there is a strong demand for improving the reworkability of the substrate by peeling off the adhesive.

JP 2003-27030 A

  The problem to be solved by the present invention is to provide a release agent for a reactive hot melt resin excellent in peelability, a peeling method using the same, and a substrate.

  The inventors of the present invention, while pursuing research to solve the above-mentioned problems, paid attention to the use of a release agent, proceeded with earnest research, and completed the present invention.

  That is, the present invention provides a release agent for a reactive hot melt resin characterized by containing benzyl alcohol.

  In the present invention, the substrate and the reactive hot melt adhesive layer are peeled from the laminate in which the substrate and the reactive hot melt adhesive layer are bonded by the reactive hot melt resin release agent. The peeling method characterized by the above is provided.

  Moreover, this invention relates to the base material characterized by the said peeling method.

  The release agent for a reactive hot melt resin of the present invention can impart good release properties to an adhesive layer obtained using the reactive hot melt resin. Moreover, since the base material adhere | attached by the said adhesive bond layer can be isolate | separated by this, it is excellent also in the rework property of a base material.

  The release agent for reactive hot melt resin of the present invention can impart excellent peelability to the reactive hot melt resin by containing benzyl alcohol. As a mechanism for exhibiting releasability, the reactive hot melt resin swells by injecting the release agent around the interface between the base material and the reactive hot melt resin, and adhesion at the time of peeling. It is estimated that the strength decreases. When another release agent is used as the release agent, the reactive hot melt resin does not swell and the desired release property cannot be obtained.

  The reactive hot melt resin release agent preferably contains benzyl alcohol in an amount of 50% by mass or more, more preferably 60% by mass or more from the viewpoint of further reducing the adhesive strength at the time of peeling and further improving the peelability. It is more preferable to contain.

  Examples of components other than the benzyl alcohol that can be contained in the reactive hot melt resin release agent include toluene, xylene, solvent naphtha, normal hexane, isohexane, cyclohexane, methylcyclohexane, normal heptane, isooctane, and normal decane. Hydrocarbon compounds such as methanol, ethanol, butanol, isopropyl alcohol, normal propyl alcohol, butanol, isobutanol, t-butanol, butanediol, ethylhexanol, benzyl alcohol, etc .; ethylene glycol, diethylene glycol, triethylene glycol, Glycol compounds such as propylene glycol; acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl keto Ketone compounds such as cyclohexanone and diacetone alcohol; ester compounds such as ethyl acetate, methyl acetate, butyl acetate, methoxybutyl acetate, cellosolve acetate, amyl acetate, normal propyl acetate, isopropyl acetate, methyl lactate, ethyl lactate, butyl lactate; Ether compounds such as isopropyl ether, methyl cellosolve, cellosolve, butyl cellosolve, dioxane, methyl tertiary butyl ether, butyl carbitol, 1-butoxyethoxy-2-propanol; diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, dipropylene-n-butyl ether , Glycols such as polypropylene glycol monomethyl ether, 3-methoxy-3-methyl-1-butanol, hexyl diglycol Ether compounds; glycol ester compounds such as ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate; N-methylpyrrolidone, tetrahydrofuran, dimethylformamide, dibasic acid ester, 3-ethoxypropion Ethyl acid, sulfolane, dimethyl carbonate, diethyl carbonate, water and the like can be used. These compounds may be used alone or in combination of two or more.

  As the reactive hot melt resin, for example, a polyester resin, a modified olefin resin, a moisture curable hot melt resin containing a urethane prepolymer having an isocyanate group can be used. According to the release agent of the present invention, good release properties can be imparted to these reactive hot melt resins.

  As the urethane prepolymer having an isocyanate group, for example, one obtained by reacting a polyol and a polyisocyanate can be used. Further, these compounds may be further reacted with a compound having a (meth) acryloyl group to impart active energy ray curability.

  As the polyol, polyether polyol, crystalline polyester polyol, amorphous polyester polyol, acrylic polyol, polycarbonate polyol, polybutadiene polyol, dimer diol and the like can be used. These polyols may be used alone or in combination of two or more. As the polyol, when a reactive hot melt resin is used for bonding optical parts, it has excellent waterproofness, quick curing properties, flexibility, adhesiveness, coating workability, and shape retention after coating. It is preferable to contain a polyether polyol, a crystalline polyester polyol, an amorphous polyester polyol, and an acrylic polyol from the viewpoint that can be imparted to the adhesive phase.

  The polyether polyol is used to provide excellent workability, adhesion, waterproofness, flexibility, drop impact resistance, etc. by adjusting the appropriate melt viscosity and open time (bonding time) after coating. Preferably, for example, polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol, ethylene oxide-modified polypropylene glycol and the like can be used.

  The number average molecular weight of the polyether polyol is preferably in the range of 500 to 5,000 from the viewpoint that excellent adhesiveness (initial adhesive strength, final adhesive strength) and appropriate open time after coating can be imparted. A range of 5,000 is more preferred. In addition, the number average molecular weight of the said polyether polyol was measured on condition of the following by the gel permeation chromatography (GPC) method.

Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4 mass%)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation

  The crystalline polyester polyol is preferable for imparting excellent waterproofness and adhesiveness (initial adhesive strength), open time, drop impact resistance, and the like. For example, a reaction product of a compound having a hydroxyl group and a polybasic acid is used. Can be used. In the present invention, the crystallinity means that the peak of crystallization heat or heat of fusion can be confirmed in DSC (Differential Scanning Calorimetry) measurement based on JIS K 7121, and the non-crystalline property means the peak. Indicates an item that cannot be confirmed.

  Examples of the compound having a hydroxyl group include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, trimethylolpropane, trimethylolethane, and glycerin. Can do. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use butanediol, hexanediol, octanediol, and decanediol from the viewpoint that crystallinity can be improved and waterproofness and adhesiveness can be improved.

  Examples of the polybasic acid include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, 1,12-dodecanedicarboxylic acid, and the like.

  The number average molecular weight of the crystalline polyester polyol is preferably in the range of 500 to 5,000, more preferably in the range of 1,000 to 4,000, from the viewpoint of waterproofness and adhesiveness. The number average molecular weight of the crystalline polyester polyol is a value obtained by measurement in the same manner as the number average molecular weight of the polyether polyol.

  Moreover, as a glass transition temperature (Tg) of the said crystalline polyester polyol, the range of 40-130 degreeC is preferable. The glass transition temperature of the crystalline polyester polyol is a value measured by DSC according to JIS K 7121-1987. Specifically, the crystalline polyester polyol is placed in a differential scanning calorimeter. , (Tg + 50 ° C.), the temperature was raised at a rate of temperature increase of 10 ° C./min, held for 3 minutes, then rapidly cooled, and the intermediate glass transition temperature (Tmg) read from the obtained differential heat curve is shown.

  As the usage-amount of the said crystalline polyester polyol, the range of 20-120 mass parts is preferable with respect to 100 mass parts of said ether polyol from the point which can improve a softness | flexibility, adhesiveness, an open time, etc., and 30- The range of 100 parts by mass is more preferable.

  As the crystalline polyester polyol, polycaprolactone polyol can also be used. As the polycaprolactone polyol, for example, a reaction product of the compound having a hydroxyl group and ε-caprolactone can be used.

  Further, when polycaprolactone polyol is used as the crystalline polyester polyol, the number average molecular weight is preferably in the range of 20,000 to 200,000.

  The amorphous polyester polyol adjusts the appropriate melt viscosity and open time (bonding time) after coating to give excellent workability, adhesion, waterproofness, flexibility, drop impact resistance, etc. Preferably, for example, a reaction product of a compound having a hydroxyl group and a polybasic acid can be used.

  Examples of the compound having a hydroxyl group include ethylene glycol, propylene glycol, 1,4-butanediol, pentanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, Hexanediol, neopentyl glycol, hexamethylene glycol, glycerin, trimethylolpropane, bisphenol A and bisphenol F, and alkylene oxide adducts thereof can be used. Among these, it is preferable to use an alkylene oxide adduct of bisphenol A from the viewpoint of improving water resistance, adhesion, flexibility, drop impact resistance, and the like. Moreover, as addition mole number of the said alkylene oxide, 2-10 mol is preferable and 4-8 mol is still more preferable.

  As the polybasic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, dimer acid, sebacic acid, undecanedicarboxylic acid, hexahydroterephthalic acid, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, etc. should be used. Can do.

  The number average molecular weight of the amorphous polyester polyol is preferably in the range of 500 to 5,000, more preferably in the range of 1,000 to 4,000, from the viewpoint of further improving waterproofness, adhesiveness, flexibility and the like. More preferred is a range of 1,000 to 3,000.

  The glass transition temperature of the amorphous polyester polyol is preferably in the range of −70 to −10 ° C. from the viewpoint of further improving waterproofness, adhesiveness, flexibility and the like. The glass transition temperature of the amorphous polyester polyol is the same as the method for measuring the glass transition temperature (Tg) of the crystalline polyester polyol.

  As a usage-amount of the said amorphous polyester polyol, the range of 20-130 mass parts is preferable with respect to 100 mass parts of said ether polyol from a viewpoint which can improve waterproofness, adhesiveness, a softness | flexibility, etc., and 25-120. The range of parts by mass is more preferable.

  The acrylic polyol is preferable for adjusting an appropriate open time (applicable time for bonding) after application and imparting excellent workability, waterproofness, adhesiveness, drop impact resistance, etc., and a (meth) acrylic compound is used. It is obtained by polymerization. In the present invention, “(meth) acrylic compound” refers to one or both of a methacrylic compound and an acrylic compound.

  Examples of the (meth) acrylic compound include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and tert-butyl (meth) acrylate. , Neopentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cetyl (meth) acrylate, lauryl (meth) acrylate, isobonyl ( (Meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 2- (P Fluorooctyl) ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, cyclohexyl (meth) acrylate, sidiclopentanyl (meth) acrylate, dicyclopentenyl Oxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, methoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, benzyl (meth) Acrylate, 2-ethyl-2-methyl- [1,3] -dioxolan-4-yl-methyl (meth) acrylate, dimethylaminoethyl (meth) Acrylate, can be used isobornyl (meth) acrylate. These (meth) acrylic compounds may be used alone or in combination of two or more. Among these, from the point which can improve waterproofness, adhesiveness, open time, drop impact resistance, etc. further, (meth) acrylate which has a C1-C10 alkyl group and (meth) acrylate which has a hydroxyl group. It is preferable to use a combination, and it is particularly preferable to use methyl (meth) acrylate, n-butyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate.

  When the combination of (meth) acrylate having an alkyl group having 1 to 10 carbon atoms and (meth) acrylate having a hydroxyl group is used in combination, the mass ratio between them ([(having an alkyl group having 1 to 10 carbon atoms (meth) [Acrylate] / [(meth) acrylate having a hydroxyl group]) is preferably in the range of 90/10 to 99/1 from the viewpoint of waterproofness, adhesiveness, open time, drop impact resistance, and the like.

  The number average molecular weight of the acrylic polyol is preferably from 5,000 to 50,000, particularly preferably from 10,000 to 30,000, from the viewpoint of improving waterproofness, adhesiveness, open time, and the like. The number average molecular weight of the acrylic polyol is the same as the method for measuring the number average molecular weight of the polyether polyol.

  The glass transition temperature of the acrylic polyol is preferably in the range of 5 to 150 ° C., from the viewpoint of improving waterproofness and adhesiveness (particularly, initial adhesive strength due to improved cohesive strength), open time, and the like. The range is more preferable, and the range of 50 to 80 ° C. is further preferable. In addition, the glass transition temperature of the said acrylic polyol is the same as that of the measuring method of the glass transition temperature (Tg) of the said crystalline polyester polyol.

  As a usage-amount of the said acrylic polyol, the range of 20-200 mass parts is preferable with respect to 100 mass parts of said ether polyols from a viewpoint which can improve waterproofness, adhesiveness, and open time, The range of 30-150 mass parts Is more preferable.

  As the polyisocyanate, for example, polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate isocyanate, phenylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate and other aromatic polyisocyanates, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, Aliphatic or alicyclic polyisocyanates such as isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate can be used. Among these, it is particularly preferable to use diphenylmethane diisocyanate from the viewpoints of reactivity and adhesiveness.

  Moreover, as a usage-amount of the said polyisocyanate, the range of 5-50 mass parts is preferable with respect to 100 mass parts of reactive hot-melt resin from points, such as a viscosity, The range of 8-30 mass parts is more preferable.

  The urethane prepolymer is obtained by reacting the polyol and the polyisocyanate, and reacts with moisture present in the casing or adherend to which the urethane prepolymer is applied in the air or a cross-linked structure. Having an isocyanate group capable of forming a polymer at the terminal or in the molecule.

  As a method for producing the urethane prepolymer, for example, the reaction mixture containing the polyisocyanate is heated after dropping the mixture of the polyol, and the isocyanate group of the polyisocyanate is compared with the hydroxyl group of the polyol. The method of manufacturing by making it react on the conditions which become excess can be used.

  When the urethane prepolymer is produced, the equivalent ratio of the isocyanate group of the polyisocyanate to the hydroxyl group of the polyol ([isocyanate group / hydroxyl group]) is waterproof, adhesive, flexible, and drop impact resistant. In view of the above, the range of 1.1 to 5.0 is preferable, and the range of 1.5 to 3.0 is more preferable.

  The urethane prepolymer can be usually produced in the absence of a solvent, but may be produced by reacting the polyol and polyisocyanate in an organic solvent. When reacting in an organic solvent, an organic solvent such as ethyl acetate, n-butyl acetate, methyl ethyl ketone, and toluene that does not hinder the reaction can be used, but by a method such as heating under reduced pressure during or after the reaction. It is necessary to remove the organic solvent.

  When manufacturing the said urethane prepolymer, a urethanation catalyst can be used as needed. The urethanization catalyst can be appropriately added at any stage of the reaction.

  Examples of the urethanization catalyst include nitrogen-containing compounds such as triethylamine, triethylenediamine and N-methylmorpholine; metal salts such as potassium acetate, zinc stearate and tin octylate; and organometallic compounds such as dibutyltin dilaurate. Can do.

  As the isocyanate group content (hereinafter abbreviated as “NCO%”) of the urethane prepolymer obtained by the above method, the waterproofness, adhesiveness, and flexibility can be further improved. The range of ˜8.0% is preferable, the range of 1.7 to 5.0 is more preferable, and the range of 1.8 to 3.0 is particularly preferable. In addition, NCO% of the said urethane prepolymer shows the value measured by the potentiometric titration method based on JISK1603-1.

  As the viscosity of the urethane prepolymer, the melt viscosity at 125 ° C. is preferably in the range of 1,000 to 50,000 mPa · s, and more preferably in the range of 2,000 to 10,000 mPa · s. The melt viscosity at 125 ° C. is a value measured with an ICI cone plate viscometer.

  The softening point of the urethane prepolymer is preferably in the range of 30 to 120 ° C. from the viewpoint of waterproofness, adhesiveness, workability, drop impact resistance, and the like. The softening point refers to the temperature at which the fluid starts to flow and loses cohesion when the temperature of the ureta prepolymer is raised stepwise. Further, the softening point of the urethane prepolymer indicates a value obtained by a ring and ball method in accordance with JIS K 5902.

  Moreover, as a compound which has the said (meth) acryloyl group which can be made to react when providing active energy ray curability to the said urethane prepolymer, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl ( (Meth) acrylic acid alkyl esters having a hydroxyl group such as (meth) acrylate, 3-hydroxypropyl acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl acrylate, hydroxyethylacrylamide; Polyfunctional (meth) acrylates having hydroxyl groups such as trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate; poly Tylene glycol monoacrylate, polypropylene glycol monoacrylate; 2- (meth) acryloyloxyethyl isocyanate, 2- (2- (meth) acryloyloxyethyloxy) ethyl isocyanate, 1,1-bis ((meth) acryloyloxymethyl) ethyl A (meth) acrylic compound having an isocyanate group such as isocyanate can be used.

  The moisture-curable hot melt resin containing the urethane prepolymer having an isocyanate group may be composed of only the urethane prepolymer, but may contain other additives as necessary.

  Examples of the other additives include curing catalysts, antioxidants, tackifiers, plasticizers, stabilizers, fillers, dyes, pigments, fluorescent brighteners, silane coupling agents, and waxes. it can.

  The hot melt resin obtained by using the preferred polyol described above has excellent waterproofness, flexibility, quick curing, drop impact resistance, adhesion to various substrates, coating workability, and shape retention after coating. Since the open time can be imparted to the adhesive, it can be suitably used not only for fiber bonding and building material lamination, but also for bonding optical components.

  As an aspect used for bonding of the optical component, for example, a sealing agent such as a mobile phone, a personal computer, a game machine, a television, a car navigation system, a camera speaker, and an electric reel for fishing gear can be given.

  When the bonding is performed, for example, the reactive hot melt resin is heated and melted in a temperature range of 50 to 130 ° C., the composition is applied onto one substrate, and then the resin layer is applied. There is a method in which the other base material is bonded to obtain a laminate.

  Examples of the substrate include glass plates, metal plates such as stainless steel (SUS), magnesium, and aluminum, cycloolefin resins such as norbornene, acrylic resins, urethane resins, silicone resins, epoxy resins, fluororesins, and polystyrene resins. , Polyester resin, polysulfone resin, polyarylate resin, polyvinyl chloride resin, polyvinylidene chloride, polyolefin resin, polyimide resin, alicyclic polyimide resin, polyamide resin, cellulose resin, polycarbonate (PC), polybutylene terephthalate (PBT) , Polyphenylene ether (modified PPE), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), lactic acid polymer, acrylonitrile-butadiene-styrene copolymer (ABS), acrylo Tolyl - it can be used those derived from styrene copolymer (AS) and the like. Further, the substrate may be subjected to corona treatment, plasma treatment, primer treatment or the like, if necessary.

  As a method of applying the reactive hot melt resin group to the substrate, for example, a roll coater, a spray coater, a T-tie coater, a knife coater, a comma coater or the like can be used. Moreover, since the reactive hot melt resin has low viscosity and shape retention after application, it can also be applied by a method such as dispenser, ink jet printing, screen printing, and offset printing. These application methods are preferable because the reactive hot melt resin can be applied to the part on the member where it is desired to be applied, so that a loss such as punching does not occur. Further, according to these coating methods, the reactive hot melt resin is continuously or intermittently formed on the substrate in various shapes such as dotted, linear, triangular, square, round, and curved. Can be formed.

  The thickness of the adhesive layer using the reactive hot melt resin can be set according to the application to be used, but can be preferably set within a range of 10 μm to 5 mm, for example.

  The aging conditions after the bonding can be appropriately determined, for example, at a temperature of 20 to 80 ° C., a relative humidity of 50 to 90% RH, and 0.5 to 5 days.

  By the above method, a laminate having at least two layers of the base material firmly bonded and the reactive hot melt adhesive layer is obtained. As a method of peeling the reactive hot melt adhesive layer from the laminate and recovering the substrate, for example, a syringe or the like is provided at the interface between the substrate layer and the reactive hot melt adhesive layer of the laminate. The release agent of the present invention is injected and the reactive hot melt adhesive is swollen and peeled, or the release agent of the present invention is used for the reactive hot melt adhesive layer of the laminate using a syringe or the like. A method of injecting and swelling the reactive hot melt adhesive to peel off, a method of spraying or applying the release agent of the present invention to the reactive hot melt adhesive layer, and the like. It is preferable to use the first two methods from the viewpoint of further reducing the thickness and further improving the peelability.

  When peeling the base material and the reactive hot melt adhesive layer, it is preferable to heat in the range of 40 to 150 ° C in order to further improve the peelability, and in the range of 35 to 80 ° C. Heating is more preferable, and heating in the range of 40 to 60 ° C. is particularly preferable. It is preferable to set the temperature at the time of heating to a condition in which components other than benzyl alcohol contained in the release agent of the present invention do not volatilize. In addition, although the said heating is not an essential condition and favorable peelability can be acquired even at normal temperature, the curing time longer than the time at the time of heating is needed generally.

  Hereinafter, the present invention will be described in more detail with reference to examples.

[Synthesis Example 1]
<Synthesis of urethane prepolymer (1)>
In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 15 parts by mass of polypropylene glycol (number average molecular weight; 1,000, hereinafter abbreviated as “PPG1000”), polypropylene glycol ( Number average molecular weight: 2,000, hereinafter abbreviated as “PPG2000”) 15 parts by mass, crystalline polyester polyol-1 (reaction of 1,6-hexanediol and adipic acid, number average molecular weight; 2,000 ) 10 parts by mass, crystalline polyester polyol-2 (reacted 1,6-hexanediol and 1,12-dodecanedicarboxylic acid, number average molecular weight; 3,500) 10 parts by mass, amorphous polyester polyol -1 (reacted propylene oxide 6 mol adduct of bisphenol A, sebacic acid and isophthalic acid , Number average molecular weight: 2,000) 15 parts by mass, acrylic polyol-1 (butyl acrylate / methyl methacrylate / ethyl acrylate / 2-hydroxyethyl methacrylate = 69.65 / 25/5 / 0.35) (Mass ratio), number average molecular weight; 13,000, glass transition temperature; −30.3 ° C.) was charged in 2.5 parts by mass, and the moisture content was 0.05% by mass under reduced pressure. Dehydrated until:
Next, after cooling to 70 ° C. in the container, 16.5 parts by mass of 4,4′-diphenylmethane diisocyanate (hereinafter abbreviated as “MDI”) is added, the temperature is raised to 100 ° C., and the isocyanate group content is increased. It was made to react for about 3 hours until it became constant, and the urethane prepolymer (1) which has an isocyanate group was obtained.

[Production of laminate]
The urethane prepolymer (1) was melted by heating to 110 ° C., and a dispenser needle (dispenser “VAVE MASTER ME-5000VT” manufactured by Musashi Engineering Co., Ltd.) having an inner diameter of 0.4 mm heated to 110 ° C. was used. , Discharge pressure: 0.3 MPa, processing speed 60 / mm second, on an ABS plate (7 cm × 7 cm) with a 1 cm diameter hole in the center, a square with a side of 4 cm and a thickness of 0.2 mm After being applied in a bead shape, an acrylic plate (5 cm × 5 cm) is pasted thereon, and then left in a constant temperature and humidity chamber at a temperature of 23 ° C. and a relative humidity of 65% for 3 days. Obtained.

[Example 1]
A release agent of 100% by mass of benzyl alcohol is injected with a syringe into the ABS plate / adhesive layer interface and the adhesive phase / acrylic plate interface of the obtained laminate, and 30 at 50 ° C. atmosphere. It was left for a minute, and it was tested whether push strength and peeling by hand were possible.
In addition, those that could be peeled by hand were evaluated as “T”, and those that could not be peeled by hand were evaluated as “F”.

[Examples 2 to 8, Comparative Examples 1 to 6]
A peel test of the laminate was performed in the same manner as in Example 1 except that the release agent used and the heating conditions were changed as shown in Tables 1-2.

[Measurement method of push strength]
The push strength (MPa) before injecting the release agent and after injecting and curing the release agent was measured using a Tensilon (Tensilon Universal Testing Machine “RTC-1210A” manufactured by Orientec Co., Ltd.), and the crosshead speed: 10 mm / The measurement was performed under the condition of minutes.

  It was found that the reactive hot melt resin release agent of the present invention can easily release the reactive hot melt adhesive layer and the substrate by hand.

  On the other hand, Comparative Examples 1 to 5 are embodiments using a release agent other than those specified in the present invention, but none of them could be peeled by hand.

  In addition, although the comparative example 6 is the aspect which performed only the heating without using a peeling agent, the change of push intensity | strength was not seen.

Claims (5)

A release agent for a reactive hot-melt resin, characterized by containing benzyl alcohol. The release agent for a reactive hot melt resin according to claim 1, wherein the content of the benzyl alcohol is 50% by mass or more based on the total amount of the release agent. The release agent for a reactive hot melt resin according to claim 1, wherein the reactive hot melt resin contains a urethane prepolymer having an isocyanate group. The base material and the reactive hot melt adhesive are peeled off from the laminate in which the base material and the reactive hot melt adhesive layer are bonded to each other by the reactive hot melt resin release agent according to any one of claims 1 to 3. A peeling method characterized by peeling a layer. A substrate obtained by the peeling method according to claim 4.