JP7298070B2 - Moisture-curable hot-melt adhesive, book using said adhesive, and method for manufacturing book - Google Patents

Description

TECHNICAL FIELD The present invention relates to a moisture-curable hot-melt adhesive, a book using the same, and a method for manufacturing a book.

Hot-melt adhesives, which can repeat reversible changes of melting and solidification due to heat, are used to bond the inner sheets of books such as textbooks, comics, and magazines to the back side of the cover, and have excellent initial adhesive strength immediately after solidification. For this reason, EVA (ethylene-vinyl acetate copolymer) hot-melt adhesives are mainly used as resins.

However, EVA-based hot-melt adhesives hitherto known need to have a thick coating film in order to exhibit satisfactory adhesive strength. It was difficult to take.

The adhesive developed there is a reactive hot-melt adhesive. This reactive hot-melt adhesive is an adhesive that combines the advantages of hot-melt adhesives, which are excellent in initial adhesive strength immediately after solidification, with the advantages of liquid reactive adhesives, which are excellent in strong adhesion and high durability.
Most liquid reactive adhesives contain a main agent and a curing agent that utilize a thermal curing reaction, and may or may not contain an organic solvent. When it contains an organic solvent, it is applied to one of the objects to be adhered, and after the organic solvent is volatilized, the curing reaction proceeds while another object is superimposed. In the case where the organic solvent is not contained, the adhesive which has been heated to have a low viscosity is applied to one of the objects to be adhered, and the curing reaction is allowed to proceed while another object is superimposed. Although the liquid reactive adhesive is excellent in strong adhesion and high durability, the initial adhesive strength is low immediately after the objects to be adhered are superimposed because the curing reaction has not progressed sufficiently.
On the other hand, reactive hot-melt adhesives achieve initial adhesive strength by solidification, and strong adhesion and high durability by curing.
Among reactive hot melt adhesives, there are several methods for imparting reactivity. It is a moisture-curable urethane-based reactive hot-melt adhesive (hereinafter referred to as a moisture-curable hot-melt adhesive) that uses the reaction with moisture in the material for curing.

Here, a bookbinding process using a moisture-curable hot-melt adhesive will be described.
Bookbinding with a bookbinding machine involves making cuts and holes in several places on the edges of the stack of papers aligned by the collating machine (the spine to be pasted together), and then applying a moisture-curing hot-melt adhesive with a roll coater. Then, the bundle of paper is wrapped with the cover, and the spine of the bundle of paper is pressed against the inside (back surface) of the spine of the cover, and the bundle of paper and the cover are integrated, or the bundle of paper is aligned by a collating machine. Prepare a bundle of paper for pasting by making several cuts or holes in the edge of the cover (the spine to be pasted together), and separately apply a moisture-curing hot-melt adhesive to the inside of the spine of the cover. The spine of the bundle of paper is pressed against the inside of the spine of the cover so that the bundle of paper and the cover are integrated, and then quickly cut by a cutting machine to produce a book.

Moisture-curable hot-melt adhesives for bookbinding are required to have basic bookbinding performance such as spreadability and adhesive strength (also called bookbinding strength), and bookbinding performance such as coating suitability and cutting suitability.
For example, Patent Document 1 describes moisture-curable polyurethane hot-melt adhesives for bookbinding that are excellent in high-speed application suitability, cutting suitability, spreadability, initial strength, and bookbinding strength. A moisture-curable polyurethane hot-melt adhesive containing a urethane prepolymer having isocyanate groups, which is a reaction product of polyisocyanate with polyols containing other polyether polyols, acrylic polyols and polycaprolactone polyols, is disclosed. The use of polypropylene glycol is disclosed as another polyether polyol.

JP 2017-222758 A

By the way, in the case of books with relatively thin covers such as magazines, they are cut by a paper cutting machine, and after the books are manufactured, they are bound in units of several dozen with polypropylene (PP) bands, which are convenient and economical for transportation. be done. At the time of bundling, a strong pressure is applied to the portion of the cover fastened by the PP band of the moisture-curable hot-melt adhesive, that is, between the surface portion and the spine portion (corner portion) of the cover.
Although the adhesive described in Patent Document 1 has a long open time (a time during which bonding can be performed), it takes time for the adhesive to harden, so the adhesive itself before curing does not have sufficient resistance to deformation. Therefore, when a plurality of books are bound with a PP band within a short period of time after bookbinding, there is a problem that the space between the surface portion and the spine portion (corner portion) of each book cover is deformed. In particular, the deformation of the two outermost corners was a big problem. In addition, since strong pressure is applied to the flatly stacked lower books, there is also the problem that the adhesive portion (spine portion) of the lower books is deformed.

The problem to be solved by the present invention is to provide a moisture-curable hot-melt adhesive that is excellent in deformation resistance in addition to coatability, cutting suitability, spreadability, and bookbinding strength.

The inventors of the present invention have completed the present invention as a result of earnest studies in order to solve the above problems.
That is, an embodiment of the present invention is a moisture-curable hot-melt adhesive containing a urethane polymer having an isocyanate group obtained by reacting a polyol compound (A) and a polyisocyanate (B), wherein the polyol compound (A) contains a crystalline polyester polyol (a1), a polypropylene glycol (a2), and a polyethylene glycol (a3) obtained by condensation polymerization of a linear polycarboxylic acid having 8 to 16 carbon atoms and a linear polyol. Moisture curing hot melt adhesive.

Further, an embodiment of the present invention contains 60 to 100% by mass of the crystalline polyester polyol (a1), polypropylene glycol (a2), and polyethylene glycol (a3) in total in 100% by mass of the polyol compound (A). It is the moisture-curable hot-melt adhesive described above.

Further, in an embodiment of the present invention, the crystalline polyester polyol (a1): 20 to 50% by mass, polypropylene glycol (a2): 30 to 50% by mass, and polyethylene glycol in 100% by mass of the polyol compound (A) (a3): The moisture-curable hot-melt adhesive containing 5 to 30% by mass.

Further, an embodiment of the present invention is the moisture-curable hot-melt adhesive having a viscosity of 1000 to 25000 mPa·s at 120°C.

An embodiment of the present invention is the moisture-curable hot-melt adhesive, wherein the polyethylene glycol (a3) has a number average molecular weight of 2,000 to 10,000.

Also, an embodiment of the present invention is the moisture-curable hot-melt adhesive described above containing a tackifying resin.

Further, an embodiment of the present invention is the moisture-curable hot-melt adhesive containing 2 to 50 parts by mass of a tackifying resin with respect to 100 parts by mass of the urethane polymer.

An embodiment of the present invention is the moisture-curable hot-melt adhesive, wherein the tackifying resin has a softening point of 80° C. or higher.

Further, an embodiment of the present invention is the moisture-curable hot-melt adhesive described above, wherein the tackifying resin is a petroleum resin.

Further, an embodiment of the present invention is the moisture-curable hot-melt adhesive, wherein the petroleum resin is aromatic.

Further, an embodiment of the present invention is the moisture-curable hot-melt adhesive for bookbinding.

Further, an embodiment of the present invention is a book having a paper bundle formed by stacking a plurality of paper sheets and a cover for covering three sides of the paper bundle, wherein the end portion of the paper bundle and the cover cover A part is a book formed by bonding with a cured product of the moisture-curable hot-melt adhesive.

Further, an embodiment of the present invention is a method for manufacturing a book having a stack of sheets of paper and a cover for covering three sides of the stack of sheets,
Attaching the moisture-curable hot-melt adhesive in a molten state to the spine of the paper bundle,
After the moisture-curable hot-melt adhesive is solidified while the back side of the spine of the cover sheet is in contact with the moisture-curable hot-melt adhesive applied to the spine of the bundle of papers, the moisture-curable hot-melt adhesive is solidified.
Moisture in the environment causes the isocyanate groups in the moisture-curable hot-melt adhesive to react,
Adhering the paper bundle and the cover with a cured product of a moisture-curing hot-melt adhesive,
It is a method of manufacturing a book.

The moisture-curable hot-melt adhesive of the present invention is superior in deformation resistance to conventional moisture-curable hot-melt adhesives. INDUSTRIAL APPLICABILITY The present invention can provide a moisture-curable hot-melt adhesive that does not deform even when a strong pressure is applied. In addition, the moisture-curable hot-melt adhesive of the present invention is excellent in coatability, cutting suitability, spreadability, bookbinding strength, and deformation resistance, and is therefore suitable as a bookbinding adhesive for adhering a bundle of paper and a cover. ing. Furthermore, the moisture-curable hot-melt adhesive of the present invention has a relatively low viscosity and moderate permeability to substrates, so that it can be suitably used for apparel applications and bonding of non-woven fabrics, cloth and leather.

The moisture-curable hot-melt adhesive of the present invention will be described. In this specification, "parts" and "%" represent "mass parts" and "mass%", respectively, unless otherwise specified. Also, "molecular weight" shall mean number average molecular weight (Mn) unless otherwise specified. In addition, "Mn" is the number average molecular weight of polystyrene conversion calculated|required by the gel permeation chromatography (GPC) measurement.

<Urethane polymer having an isocyanate group>
A urethane polymer having an isocyanate group is a reaction product obtained by subjecting one or more polyol compounds (A) and one or more polyisocyanates (B) to a urethanization reaction.
During the reaction, the isocyanate groups (isocyanato groups) of the polyisocyanate are used at a molar ratio (NCO/OH ratio) that is greater than the hydroxyl groups of the polyol compound. As a result, a urethane polymer having an isocyanate group at the molecular end is obtained. This isocyanate group can react with moisture present in the air or in the object to be adhered to form a crosslinked structure.
A urethane polymer having an isocyanate group can be used alone or in combination of two or more.

The weight average molecular weight (Mw) of the urethane polymer having an isocyanate group is preferably 10,000 to 50,000, more preferably 10,000 to 30,000. By adjusting Mw to the above range, coatability and initial adhesive strength can be improved.

<Polyol compound (A)>
Polyol compound (A) is a polyol having two or more hydroxyl groups in one molecule.
The polyol compound (A) is a crystalline polyester polyol (a1) obtained by condensation polymerization of a linear polycarboxylic acid having 8 to 16 carbon atoms and a linear polyol, polypropylene glycol (a2), and polyethylene glycol (a3). includes.

<Crystalline polyester polyol (a1)>
The crystalline polyester polyol (a1) contains a reaction product of at least one or two or more specific linear polycarboxylic acids and at least one or two or more linear polyols. In the present invention, crystallinity can be confirmed by using a differential scanning calorimeter (DSC) device to confirm an exothermic peak associated with a change in state from liquid to solid when the temperature is lowered.

Aliphatic polycarboxylic acids among polycarboxylic acids used for polyester formation include, for example, oxalic acid, malonic acid, succinic acid, glutamic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9 -nonanedicarboxylic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, and the like. Among these, in the present invention, by using a linear polycarboxylic acid having 8 to 16 carbon atoms, the crystallization temperature can be raised and the cutting suitability can be further improved. That is, in the present invention, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, dodecanedioic acid, tetradecanedioic acid and hexadecanedioic acid are used, preferably sebacic acid, dodecanedioic acid, tetradecanedioic acid and hexadecane. It uses a diacid.

Aliphatic polyols among polyols used for forming polyesters include, for example, ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7- heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, trimethylolpropane, trimethylolethane, glycerin, etc. can give. Among these, in the present invention, by using a linear polyol, the crystallization temperature can be raised and the cutting suitability can be further improved. That is, in the present invention, ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1, 9-nonanediol and 1,10-decanediol are preferably used, and 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol and 1,10-decane More preferably, diols are used.

When the number average molecular weight of the crystalline polyester polyol (a1) is 500 or more, cohesive force is imparted to the moisture-curable hot-melt adhesive, and bookbinding strength can be improved. On the other hand, when the number average molecular weight of the crystalline polyester polyol (a1) is 10000 or less, the melt viscosity can be lowered and the coatability can be improved. The crystalline polyester polyol preferably has a number average molecular weight of 500 to 10,000, more preferably 1,000 to 5,000.

When the crystallization temperature of the crystalline polyester polyol (a1) is 30° C. or higher, the cutting suitability and deformation resistance of the moisture-curable hot-melt adhesive can be improved. On the other hand, when the crystallization temperature of the crystalline polyester polyol (a1) is set to 100° C. or lower, it is possible to design an appropriate open time and improve coatability. The crystallization temperature of the crystalline polyester polyol (a1) is preferably 30 to 100°C, more preferably 40 to 70°C.
The crystalline polyester polyol (a1) can be used alone or in combination of two or more.

The crystalline polyester polyol (a1) is mainly used for speeding up the hardening of moisture-curable hot-melt adhesives, although its effects are not limited. By making the crystalline polyester polyol (a1) 20% by mass or more in 100% by mass of the polyol compound (A), the solidification can be accelerated and the cutting suitability can be improved, and the crystalline polyester polyol (a1) is 50% by mass or less. Spread property becomes more favorable. The content of the crystalline polyester polyol (a1) in 100% by mass of the polyol compound (A) is preferably 25 to 50% by mass, more preferably 35 to 50% by mass.

<Polypropylene glycol (a2)>
Polypropylene glycol (a2) is a compound having repeating units of oxypropylene and hydroxyl groups at both ends. Propylene oxide is used as a starting material, and it is not particularly limited as long as it is generally used as a raw material for urethane resins and the like.

When the number average molecular weight of the polypropylene glycol (a2) is 200 or more, the flexibility of the moisture-curable hot-melt adhesive can be improved, and the spreadability and open time can be improved. On the other hand, when the number average molecular weight of the polypropylene glycol is 10,000 or less, the solidification speed can be designed to be appropriate, and the cutting suitability is improved. The number average molecular weight of the polypropylene glycol is preferably 200-10,000, more preferably 500-5,000. Polypropylene glycol (a2) can be used alone or in combination of two or more.

Polypropylene glycol (a2) is used mainly for imparting flexibility to moisture-curable hot-melt adhesives, although its effects are not limited. When the polypropylene glycol (a2) is 30% by mass or more in 100% by mass of the polyol compound (A), the spreadability can be improved, and when the polypropylene glycol (a2) is 50% by mass or less, the deformation resistance is good. becomes. The content of polypropylene glycol (a2) is preferably 35 to 45% by mass, more preferably 40 to 45% by mass, based on 100% by mass of the polyol compound (A).

<Polyethylene glycol (a3)>
Polyethylene glycol (a3) is a compound having oxyethylene as a repeating unit and hydroxyl groups at both ends. It is not particularly limited as long as it uses ethylene oxide as a starting material and is commonly used as a raw material for urethane resins and the like.

When the polyethylene glycol (a3) has a number average molecular weight of 1000 or more, the hardness of the moisture-curable hot-melt adhesive increases when it is solidified, and cutting suitability and deformation resistance can be improved. On the other hand, when the polyethylene glycol has a number average molecular weight of 20,000 or less, the melt viscosity can be lowered and the coatability can be improved. The number average molecular weight of polypropylene glycol (a3) is preferably 1,000 to 20,000, more preferably 2,000 to 10,000. Polypropylene glycol (a3) can be used alone or in combination of two or more.

Polyethylene glycol (a3) is used mainly for imparting resistance to deformation to moisture-curable hot-melt adhesives, although its effects are not limited. In addition, it also plays a role of lowering the melt viscosity, so that the coatability can be further improved. When the polyethylene glycol (a3) is 5% by mass or more in 100% by mass of the polyol compound (A), the deformation resistance is excellent, and when the polyethylene glycol (a3) is 30% by mass or less, the spread property is good. Become. The content of polyethylene glycol (a3) is preferably 10 to 30% by mass, more preferably 10 to 25% by mass, based on 100% by mass of the polyol compound (A).

The polyol compound (A) contains the crystalline polyester polyol (a1), polypropylene glycol (a2), and polyethylene glycol (a3), and may contain other polyols as necessary.

Examples of other polyols that can be used include polyoxyethylene polyoxypropylene glycol, polybutylene glycol, polytetramethylene glycol, polybutadiene diol, glycerin, trimethylolpropane, and trimethylolethane.
Other polyols can be used alone or in combination of two or more.

The moisture-curable hot-melt adhesive of the present invention contains 60 to 100% by mass, preferably 70 to 100% by mass, of (a1) to (a3) in 100% by mass of the polyol compound (A). preferable. When the amount of polyol compounds other than (a1) to (a3) is reduced and the total of (a1) to (a3) is 60% by mass or more, coatability, cutting suitability, spreadability, bookbinding strength, and deformation resistance are improved. Better.

<Polyisocyanate (B)>
Polyisocyanate (B) is a polyisocyanate having two or more isocyanate groups in one molecule. Polyisocyanate (B) is preferably a bifunctional isocyanate (also referred to as diisocyanate) having two isocyanate groups in one molecule.
Polyisocyanate (B) is, for example, 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2 ,4′-MDI), p-phenylene diisocyanate, toluene diisocyanate (TDI), 1,5-naphthalene diisocyanate (NDI), xylylene diisocyanate (XDI), 1,5-octylene diisocyanate, hexamethylene diisocyanate (HDI), Examples include isophorone diisocyanate (IPDI), hydrogenated MDI (hydrogenated MDI), hydrogenated XDI (hydrogenated XDI), polymeric MDI, and the like. Among these, it is preferable to use aromatic polyisocyanate from the viewpoint of reactivity. MDI, p-phenylene diisocyanate, TDI, NDI, XDI and polymeric MDI are preferred, MDI and polymeric MDI are more preferred, and 4,4'-MDI is preferred as MDI. Polyisocyanate (B) can be used alone or in combination of two or more.

A method for producing a urethane prepolymer will be described. However, the present invention is not limited to the manufacturing method described below. For example, (a1) to (a3) are placed in a reaction vessel. At this time, if necessary, other additives may be added. (a1) to (a3) are heated and melted, and the mixture is stirred while being heated to 100 to 140° C. with a heater capable of controlling a uniform temperature distribution, and dehydration is sufficiently performed under reduced pressure. Next, a predetermined amount of polyisocyanate (B) is added, dry nitrogen is blown into the reaction vessel, and the reaction is carried out at 90 to 140° C. while preventing moisture from entering. Although this reaction does not require a solvent, a solvent may be used. In this case, the reaction temperature should be below the boiling point of the solvent.

When producing the urethane prepolymer, the equivalent ratio (isocyanate group/hydroxyl group) between the isocyanate group of the polyisocyanate (B) and the hydroxyl group of the polyol compound (A) is determined from the viewpoint of coatability and safety. , preferably 1.1 to 2.0, more preferably 1.2 to 1.6.

The isocyanate group content of the obtained urethane prepolymer (hereinafter abbreviated as "NCO %") is preferably 0.5 to 3.5 from the viewpoint of suppressing viscosity increase during heat storage or coating. , more preferably 1.0 to 2.0. The NCO % of the urethane prepolymer is measured by potentiometric titration in accordance with JISK1603-1, and calculated according to the following formula.
NCO% = 4.202 x (V1 - V2) x c/m
V1: Amount of hydrochloric acid used for blank test (mL)
V2: Measured amount of hydrochloric acid used for sample titration (mL)
c: concentration of hydrochloric acid (mol/L)
m: Mass of sample (g)
4.202: Equivalent weight of NCO groups (42.02 mg/meq).

The urethane prepolymer itself can be used as the moisture-curable hot-melt adhesive of the present invention, or a tackifying resin can be added to the urethane prepolymer to provide the moisture-curable hot-melt adhesive of the present invention. .
When the moisture-curable hot-melt adhesive contains a tackifying resin, the NCO% of the moisture-curable hot-melt adhesive is the total amount of the urethane prepolymer and the tackifying resin in the above formula, "m: mass of sample (g )”. The NCO% of the moisture-curable hot-melt adhesive is preferably 0.5 to 3.5, more preferably 1.0 to 2.0, from the viewpoint of suppressing the viscosity increase during heat storage or coating. be.

<Tackifying resin>
Tackifying resins include, for example, phenolic resins, modified phenolic resins, terpene phenolic resins, xylene phenolic resins, xylene resins, cyclopentadiene-phenolic resins, aliphatic, alicyclic and aromatic petroleum resins, hydrogenated aliphatic, alicyclic and aromatic petroleum resins, phenol-modified petroleum resins, rosin ester resins, modified rosin ester resins, low molecular weight polystyrene resins, terpene resins, hydrogenated terpene resins, etc. are mentioned. These can be used alone or in combination of two or more. Among these, terpene phenol resins, rosin ester resins, maleic acid-modified rosin ester resins and aromatic petroleum resins are preferably used, and rosin ester resins and aromatic petroleum resins are more preferably used. The rosin ester resin is not particularly limited as long as it is commonly used, and examples thereof include the Super Ester series of Arakawa Chemical Co., Ltd. and the Haritac series of Harima Chemicals. The aromatic petroleum resin is not particularly limited as long as it is commonly used, and examples thereof include the Crystalex series of Eastman Chemical Company and the FTR series of Mitsui Chemicals.

If the softening point of the tackifying resin is 80° C. or higher, the deformation resistance and heat resistance of the moisture-curable hot-melt adhesive can be improved. On the other hand, when the softening point of the tackifier resin is 130° C. or lower, it has good compatibility with the urethane prepolymer and can be used preferably. In the present invention, the softening point is determined by the ring and ball method and indicates a value measured according to JIS K5601-2-2.

The effect of the tackifying resin is not limited, but when used in combination with the urethane prepolymer, the bookbinding strength and deformation resistance can be further improved. By adding 2 to 50 parts by mass or more of the tackifying resin to 100 parts by mass of the urethane prepolymer, bookbinding strength and deformation resistance can be further improved without significantly deteriorating coatability and spreadability. The content of the tackifying resin is preferably 5 to 40 parts by mass, more preferably 10 to 30 parts by mass, based on 100 parts by mass of the urethane prepolymer.

The moisture-curable polyurethane hot-melt adhesive of the present invention contains the urethane prepolymer, and may further contain other additives as necessary.

Examples of other additives include chain extenders, curing catalysts, moisture removers, antioxidants, plasticizers, stabilizers, fillers, dyes, pigments, fluorescent brighteners, silane coupling agents, waxes, A thermoplastic resin or the like can be used. These additives may be used alone or in combination of two or more.

The melt viscosity at 120° C. of the moisture-curable hot-melt adhesive of the present invention is preferably 1,000 to 25,000 mPa·s, more preferably 3,000 to 10,000 mPa·s from the viewpoint of coatability. The method for measuring the melt viscosity will be described in detail in Examples described later.

The moisture-curable hot-melt adhesive of the present invention can be used as a bookbinding adhesive for adhering a stack of paper sheets and a cover covering three sides of the stack.

Examples of the paper used for the bundle of paper include book paper, high-quality paper, recycled high-quality paper, waste paper, and the like, and may be printed as appropriate. Printing may be performed by any conventionally known printing method such as letterpress printing, gravure printing, and offset printing.

As a method for manufacturing a book, for example, the moisture-curable hot-melt adhesive of the present invention is melted at a temperature of 100 to 140°C, preferably 110 to 130°C, on the inside of the spine of a bundle of paper or the spine of a cover. is applied, and the moisture-curable hot-melt adhesive is allowed to harden while the stack of paper is in contact with the cover. are reacted, and the bundle of paper and the cover are adhered with a cured moisture-curable hot-melt adhesive.

After the moisture-curable hot-melt adhesive is solidified in a state in which the paper stack and the cover are in contact with each other, it is preferable to cure them at 25° C. and 50% RH for one day or more.

Methods for applying the moisture-curable hot-melt adhesive to the inside of the spine of the bundle of paper or the spine of the cover include a roll coater method, a slot die method, a nozzle method, a spray method, and the like.

A more specific description will be given below with reference to Production Examples and Examples. However, the invention is not limited to the following examples.

[Measurement of molecular weight]
Weight average molecular weight (Mw) and number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) method. The measurement conditions are as follows. Both Mw and Mn are polystyrene equivalent values.

Measurement device: Shoko Science GPC device “SHODEX GPC-101”
Column: KF-G 4A/KF-805/KF-803/KF-802
Temperature: 40°C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL/min Detector: RI (differential refractometer)

Production example 1
(Synthesis of crystalline polyester polyol a1-1)
280 g (1.0 mol) of hexadecanedioic acid and 130 g (1.1 mol) of 1,6-hexanediol were reacted to obtain a hydroxyl value of 38.7, a number average molecular weight of 2900, a melting point of 82.1°C and a crystallization temperature of 64.0°C. A 5° C. crystalline polyester polyol a1-1 was obtained.

(Evaluation method for hydroxyl value and number average molecular weight)
The hydroxyl value of the obtained polyester polyol was measured according to JIS K 1557-1. Moreover, the number average molecular weight indicates the value measured by the GPC method described above.

(Evaluation method for melting point and crystallization temperature)
The melting point and crystallization temperature of the obtained polyester polyol were obtained from the maximum endothermic and exothermic peak temperatures using a differential scanning calorimeter (DSC220C) manufactured by SII Nanotechnology. DSC measurements were performed at a heating rate of 10°C/min and a cooling rate of -10°C/min.

(Production Examples 2 to 6)
The compositions shown in Table 1 were reacted in the same manner as in Production Example 1 to obtain crystalline polyester polyols a1-2 to 5 and a'1. Table 1 shows the results of hydroxyl value, number average molecular weight, melting point and crystallization temperature.

(Example 1)
(moisture curing hot melt adhesive)
A reaction vessel equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a pressure reducing device was charged with 35 parts of the a1-1 as the crystalline polyester polyol (a1) and Sannix PP-1000 (Sanyo Kasei Co., Ltd.) as the polypropylene glycol (a2). , number average molecular weight 1000) and 25 parts of PEG 4000 (Sanyo Chemical Co., Ltd., number average molecular weight 3400) as polyethylene glycol (a3) were heated and melted, and heated under reduced pressure at 120°C for 2 hours. After cooling the inside of the reaction vessel to 110°C, 21 parts of 4,4'-diphenylmethane diisocyanate (hereinafter referred to as 4,4'-MDI) heated and melted at 70°C was added under a nitrogen atmosphere, and the mixture was reacted at 110°C for 4 hours. to obtain a urethane polymer having an isocyanate group, and the urethane polymer was used as a moisture-curable hot-melt adhesive.
The resulting moisture-curable hot-melt adhesive was used as a bookbinding adhesive, and the viscosity at 120° C. was used to determine the coating properties, the solidification properties were used to determine the cutting suitability, and the deformation resistance after solidification and before curing was determined. The breaking elongation after curing was used to evaluate the spreadability, and the breaking strength after curing was used to evaluate the strength as a book (bookbinding strength).

(Examples 2-5)
Moisture-curable hot melt adhesives were produced in the same manner as in Example 1, except that a1-2 to a1-5 obtained in Production Examples 2 to 5 were used as the crystalline polyester polyol instead of a1-1. , was similarly evaluated.

(Examples 6-7)
PEG2000 with a number average molecular weight of 2000 and a number average molecular weight of 1000 from Sanyo Kasei Co., Ltd., instead of the a1-3 as the crystalline polyester polyol, Sannix PP-1000 as the polypropylene glycol (a2), and PEG4000 as the polyethylene glycol (a3). Moisture-curable hot-melt adhesives were prepared in the same manner as in Example 1 except that PEG 1000 was used, respectively, and evaluated in the same manner.

(Examples 8-18)
Example 3 except that the amounts of a1-3, which is a crystalline polyester polyol, Sannix PP-1000, which is polypropylene glycol (a2), and PEG4000, which is polyethylene glycol (a3), were changed as shown in Table 2. A moisture-curable hot-melt adhesive was prepared in the same manner and evaluated in the same manner.

(Examples 19-21)
As shown in Table 3, crystalline polyester polyol a1-3, polypropylene glycol (a2) Sannix PP-1000, polyethylene glycol (a3) PEG4000, and other polyols manufactured by Mitsubishi Chemical Corporation Polytetramethylene glycol "PTMG2000" having a number average molecular weight of 2000 was reacted with 4,4'-MDI in the same manner as in Example 3 to obtain a moisture-curable hot melt adhesive containing a urethane polymer having an isocyanate group. , and so on.

(Examples 22-29)
To 125 parts of the urethane polymer obtained in Example 8, a tackifier resin shown in Table 3 was added at 110° C. and melted to prepare a moisture-curable hot-melt adhesive, which was evaluated in the same manner.

(Comparative example 1)
Instead of the crystalline polyester polyol a1-3 obtained in Production Example 3 using a linear polycarboxylic acid having 12 carbon atoms as a raw material, the crystal obtained in Production Example 6 using a linear polycarboxylic acid having 6 carbon atoms as a raw material A moisture-curable hot-melt adhesive was prepared in the same manner as in Example 3, except that a urethane polymer having an isocyanate group was obtained using the polyether polyol a′, and the same evaluation was made below.

(Comparative example 2)
A moisture-curable hot-melt adhesive was prepared in the same manner as in each example, except that another polyol component was used in place of polyethylene glycol (a3) as shown in Table 3 to obtain a urethane polymer having an isocyanate group. and evaluated in the same manner.

(Comparative Example 3)
As shown in Table 3, crystalline polyester polyol a1-3 and polyethylene glycol (a3) were used instead of polypropylene glycol (a2) to obtain a urethane polymer having an isocyanate group. Then, a moisture-curable hot-melt adhesive was prepared and evaluated in the same manner.

Abbreviations in Tables 2 and 3 are as follows.
polypropylene glycol (a2)
・Sannics PP-1000 (Sanyo Kasei Co., Ltd., number average molecular weight 1000)

polyethylene glycol (a3)
・PEG4000 (Sanyo Kasei Co., Ltd., number average molecular weight 3400)
・PEG2000 (Sanyo Kasei Co., Ltd., number average molecular weight 2000)
・ PEG1000 (Sanyo Kasei Co., Ltd., number average molecular weight 1000)

Polyisocyanate (B)
・4,4′-diphenylmethane diisocyanate (“4,4′-MDI”)

Tackifier resin Crystalex F-100 (Eastman Chemical Co., aromatic petroleum resin, softening point 100°C)
· Super ester A-100 (Arakawa Chemical Co., rosin ester, acid value 3.1 mgKOH / g, softening point: 100 ° C.)
・ Ester gum H (Arakawa Chemical Co., Ltd., hydrogenated rosin ester, softening point 68 ° C.)

Other polyol components Newpol 80-4000 (Sanyo Kasei Co., Ltd., polyoxyethylene polyoxypropylene glycol, number average molecular weight 4000)
・PTMG2000 (Mitsubishi Chemical Co., polytetramethylene glycol, number average molecular weight 2000)
-Acrylic polyol AcPOH (polymerized methyl methacrylate, n-butyl methacrylate, and 2-hydroxyethyl methacrylate, number average molecular weight 20000)
・Capa6400 (Perstorp Co., caprolactone polyol, number average molecular weight 37000)

(Viscosity at 120°C: coatability)
The melt viscosity at 120° C. of the obtained moisture-curable hot-melt adhesive was measured with a Brookfield viscometer (rotor #3, number of revolutions 12 or 3 rpm), and the coatability was evaluated as follows.
○ (excellent): 1000 mPa·s or more and 10000 mPa·s or less.
◯△ (good): 10000 mPa·s or more and 25000 mPa·s or less.
(triangle|delta) (possible): 25000 mPa*s or more and 50000 mPa*s or less.
x (impossible): less than 1000 mPa·s or more than 50000 mPa·s.

(Solidity: cutting suitability)
10 g of the resulting moisture-curable hot-melt adhesive was weighed into a plurality of shallow metal containers, melted in an oven at 120° C., and all the containers were taken out of the oven into a temperature-controlled room at 25° C. and 50% RH. Every 1 minute after removal, a weight of 1 kg was put on the surface of the melted adhesive in turn, and a pressure of 0.6 MPa was applied for 5 seconds. The solidification speed was defined as the elapsed time after removal until no residue remained. If the solidification speed is fast, the cutting process can be quickly started after coating, which is excellent from the viewpoint of productivity.
○ (excellent): less than 8 minutes.
◯△ (good): 8 minutes or more and less than 10 minutes.
(triangle|delta) (possible): 10 minutes or more and less than 12 minutes.
x (impossible): 12 minutes or more.

(Deformation resistance after solidification and before curing)
10 g of the resulting moisture-curable hot-melt adhesive was weighed into a shallow metal container and melted in an oven at 120°C. The JISA hardness of the mold hot melt adhesive surface was measured according to JISK7312.
In addition, when the evaluation of "hardening property: cutting suitability" was "Δ" or "×", the "deformation resistance after hardening and before hardening" could not be evaluated.
○ (excellent): 40° or more.
◯△ (Good): 35° or more and less than 40°.
(triangle|delta) (possible): 25 degrees or more and less than 35 degrees.
× (impossible): less than 25°.

(Breaking elongation after curing: spreadability)
A moisture-curable hot-melt adhesive was melted by heating at 120° C. and applied to a release-treated polyethylene terephthalate film (hereinafter referred to as a release PET film) using an applicator to a thickness of 250 μm. After allowing to stand at 25° C. and 50% RH for 24 hours, disappearance of isocyanate groups was confirmed by IR, and the moisture-curable hot melt adhesive was cured.
A cured film with a thickness of 250 μm is isolated from the release PET film, a measurement sample of a predetermined shape is cut out, and a measurement sample width: 10 mm, distance between chucks (measurement sample length): 24 mm, 100 mm in accordance with JISK7311. /min to determine the elongation at break.
When the book is opened and left standing still, the ability to maintain the open state is required, and it is not desirable for the book to close immediately. If the elongation is high, the book can be kept in an open state, which is suitable for bookbinding.
Note that the case where a sample with a length of 24 mm is stretched to 48 mm is defined as 100%. Moreover, the measurement limit of the used apparatus is 900%.
○ (excellent): 500% or more.
◯△ (good): 300 _% or more and less than 500%.
Δ (acceptable): 150 _% or more and less than 300%.
x (impossible): less than 150%.

(Breaking strength after curing: bookbinding strength)
The breaking strength was obtained together with the breaking elongation after curing. The cross-sectional area of the cured coating was measured at 2.5 mm ² , and the tensile strength was a value converted per unit area.
○ (excellent): 4.0 MPa or more.
◯△ (good): 3.0 _MPa or more and less than 4.0 MPa.
Δ (acceptable): 1.5 _MPa or more and less than 3.0 MPa.
x (impossible): less than 1.5 MPa.

The moisture-curable hot-melt adhesives of the present invention shown in Examples 1 to 29 in Tables 2 and 3 were excellent in coatability, cutting suitability, spreadability, bookbinding strength, and deformation resistance.

On the other hand, the moisture-curable hot-melt adhesive shown in Comparative Example 1 in Table 3 did not contain the crystalline polyester polyol (a1), and was unsuitable for cutting.

In addition, the moisture-curable hot-melt adhesive shown in Comparative Example 2 in Table 3 did not contain the polyethylene glycol (a3), and had poor deformation resistance.

In addition, the moisture-curable hot-melt adhesive shown in Comparative Example 3 in Table 3 did not contain the polypropylene glycol (a2), and had poor spreadability.

The moisture-curable hot-melt adhesive of the present invention has a relatively low viscosity and moderate permeability to substrates, so it is suitable for use in apparel applications and lamination of non-woven fabrics, cloth, and leather, in addition to bookbinding. can.

Claims (12)

A moisture-curable hot-melt adhesive containing a urethane polymer having an isocyanate group obtained by reacting a polyol compound (A) with a polyisocyanate (B),
The polyol compound (A) is a crystalline polyester polyol (a1) obtained by condensation polymerization of a linear polycarboxylic acid having 8 to 16 carbon atoms and a linear polyol, a polypropylene glycol (a2), and a polyethylene glycol (a3). ), including
Moisture-curing hot-melt adhesive for bookbinding . In 100% by mass of the polyol compound (A), the crystalline polyester polyol (a1), polypropylene glycol (a2), and polyethylene glycol (a3) are contained in a total of 60 to 100% by mass,
The moisture-curable hot-melt adhesive according to claim 1. In 100% by mass of the polyol compound (A), the crystalline polyester polyol (a1): 20 to 50% by mass, polypropylene glycol (a2): 30 to 50% by mass, and polyethylene glycol (a3): 5 to 30% by mass. include,
The moisture-curable hot-melt adhesive according to claim 2. The moisture-curable hot melt adhesive according to any one of claims 1 to 3, which has a viscosity of 1000 to 25000 mPa·s at 120°C. The moisture-curable hot melt adhesive according to any one of claims 1 to 4, wherein the polyethylene glycol (a3) has a number average molecular weight of 1,000 to 20,000. The moisture-curable hot-melt adhesive according to any one of claims 1 to 5, further comprising a tackifying resin. The moisture-curable hot-melt adhesive according to claim 6, which contains 2 to 50 parts by mass of a tackifying resin per 100 parts by mass of the urethane polymer. The moisture-curable hot-melt adhesive according to claim 6 or 7, wherein the tackifying resin has a softening point of 80°C or higher. The moisture-curable hot melt adhesive according to any one of claims 6 to 8, wherein the tackifying resin is a petroleum resin. 10. The moisture-curable hot-melt adhesive according to claim 9, wherein the petroleum resin is aromatic. A book having a stack of sheets of paper and a cover for covering three sides of the stack of sheets,
11. A book, wherein an end portion of said bundle of paper and a portion of said cover are adhered with a cured product of the moisture-curable hot-melt adhesive according to any one of claims 1 to 10 . A method for manufacturing a book having a stack of paper sheets and a cover for covering three sides of the stack of paper,
The moisture-curable hot-melt adhesive according to any one of claims 1 to 10 is applied in a molten state to the spine of the paper bundle,
After the moisture-curable hot-melt adhesive is solidified while the back side of the spine of the cover sheet is in contact with the moisture-curable hot-melt adhesive applied to the spine of the bundle of papers, the moisture-curable hot-melt adhesive is solidified.
Moisture in the environment causes the isocyanate groups in the moisture-curable hot-melt adhesive to react,
Adhering the paper bundle and the cover with a cured product of a moisture-curing hot-melt adhesive,
How to make a book.