WO2019124266A1

WO2019124266A1 - Reactive hot-melt adhesive composition and method for manufacturing same, bonding method, and image display device and method for manufacturing same

Info

Publication number: WO2019124266A1
Application number: PCT/JP2018/046156
Authority: WO
Inventors: 聡一郎小宮; 鈴村　浩二; 知佳倉持; 和幸馬籠
Original assignee: 日立化成株式会社
Priority date: 2017-12-20
Filing date: 2018-12-14
Publication date: 2019-06-27
Also published as: KR20200100052A; JPWO2019124266A1; PH12020550931A1; JP7415559B2; TW201930530A; CN111465671A

Abstract

This reactive hot-melt adhesive composition contains a urethane prepolymer having an isocyanate group, which is a reaction product of a polyol compound and a polyisocyanate compound, the polyol compound including at least 50% by mass of a crystalline polyester polyol in terms of the total mass of the polyol compound.

Description

Reactive Hot Melt Adhesive Composition, Method of Manufacturing the Same, Method of Bonding, Image Display Device, Method of Manufacturing the Same

The present invention relates to a reactive hot melt adhesive composition and a method for producing the same, a bonding method, an image display device and a method for producing the same.

The reactive hot melt adhesive is a non-solvent type adhesive, so the load on the environment and the human body is small, and it can be adhered for a short time, so it is an adhesive suitable for improving productivity. The reactive hot melt adhesive contains a reactive resin as a main component, can be made to have a high molecular weight by a chemical reaction, and can exhibit high adhesive strength and the like. As a reactive resin, a urethane prepolymer having an isocyanate group is used (see, for example, Patent Documents 1 and 2).

Japanese Patent Application Publication No. 2008-500406 International Publication No. 2016/157614

The reactive hot melt adhesive exhibits a certain degree of adhesive strength in a short time due to cooling and solidification of the adhesive itself after being applied to an adherend. Thereafter, the isocyanate group of the urethane prepolymer reacts with the moisture in the air or the surface of the adherend to form a high molecular weight, and by causing crosslinking, an adhesive layer is formed to exhibit excellent adhesive strength. However, adhesion with a reactive hot melt adhesive may become high in molecular weight immediately after application and may not have an initial bond strength to a substrate because crosslinking does not occur instantaneously. Therefore, the reactive hot melt adhesive is required to develop excellent initial adhesive strength in a short time, that is, to have a fast setting property.

The object of the present invention is to provide a reactive hot melt adhesive composition having rapid solidification and a method for producing the same, a bonding method using the reactive hot melt adhesive composition, an image display device and a method for producing the same. It is to do.

The present invention contains a urethane prepolymer having an isocyanate group which is a reaction product of a polyol compound and a polyisocyanate compound, and the polyol compound contains 50% by mass or more of a crystalline polyester polyol based on the total mass of the polyol compound. The present invention provides a hot melt adhesive composition. The reactive hot melt adhesive composition according to the present invention has a structural unit derived from a polyol compound and a structural unit derived from a polyisocyanate compound, and 50% by mass or more of structural units derived from a polyol compound are And a urethane prepolymer which is a structural unit derived from a crystalline polyester polyol.

The polyol compound may contain 50 to 90% by mass of a crystalline polyester polyol. The crystalline polyester polyol may have a structure based on a polycarboxylic acid having 6 to 12 carbon atoms and a polyhydric alcohol having 4 to 10 carbon atoms. The polyol compound may comprise a polyether polyol.

The reactive hot melt adhesive composition according to the present invention may further contain a pigment.

The present invention is also an image display device comprising a flat panel display and a backlight unit, wherein the flat panel display and the backlight unit are adhered by the reactive hot melt adhesive composition according to the present invention. , Provide an image display device.

The present invention is also a method for producing a reactive hot melt adhesive composition containing a urethane prepolymer having an isocyanate group, which comprises reacting a polyol compound and a polyisocyanate compound to produce an urethane prepolymer having an isocyanate group. Providing a step of obtaining, wherein the polyol compound contains 50% by mass or more of the crystalline polyester polyol based on the total mass of the polyol compound.

The present invention is also a bonding method for bonding a flat panel display and a backlight unit, which is formed by laminating the backlight unit on the upper surface of the flat panel display, and exposing the side surface of the backlight unit and the flat panel display. An adhesive method is provided, in which an adhesive layer is formed by using the reactive hot melt adhesive composition according to the present invention at the inner corner with the upper surface.

The present invention further provides a method of manufacturing an image display device, which manufactures an image display device using the bonding method.

According to the present invention, there is provided a reactive hot melt adhesive composition having rapid solidification, a method for producing the same, an adhesion method using the reactive hot melt adhesive composition, an image display device and a method for producing the same. can do.

It is a schematic cross section which shows one aspect of adhesion | attachment using the reactive hot melt adhesive composition which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited at all to the following embodiments.

<Definition>
In the present specification, a numerical range indicated by using “to” indicates a range including numerical values described before and after “to” as the minimum value and the maximum value, respectively. The upper limit or lower limit of the numerical range of one step may be replaced with the upper limit or lower limit of the numerical range of another step in the numerical range described stepwise in the present specification. In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. “A or B” may contain either A or B, and may contain both.

[Reactive Hot Melt Adhesive Composition]
The reactive hot melt adhesive composition of the present embodiment (hereinafter sometimes abbreviated as “adhesive composition”) is a urethane prepolymer having an isocyanate group which is a reaction product of a polyol compound and a polyisocyanate compound. And the polyol compound contains 50% by mass or more of the crystalline polyester polyol based on the total mass of the polyol compound.

In general, the reactive hot melt adhesive composition can be made to have a high molecular weight by reacting with moisture in the air or on the surface of the adherend, and can develop adhesive strength (final adhesive strength). The adhesive composition according to the present embodiment can exhibit excellent initial adhesive strength in a shorter time than conventional reactive hot melt adhesive compositions, and has excellent rapid solidification.

The fast setting property of the adhesive composition according to the present embodiment can be evaluated, for example, by the following method. The adhesive composition is applied to a substrate with a width of 1 mm at room temperature (23 ° C., 50% RH) to form an adhesive layer, and then the time taken for the adhesive layer surface to lose tack, The settability of the composition can be evaluated. From the viewpoint of rapid solidification, the tack is preferably eliminated within 2 minutes, and more preferably within 1 minute. Here, "lack of tack" indicates that tackiness disappears when the adhesive layer is touched with a finger.

(Urethane Prepolymer Having Isocyanate Group)
The urethane prepolymer having an isocyanate group according to the present embodiment (hereinafter sometimes referred to as "reactive urethane prepolymer") reacts a polyol compound containing 50% by mass or more of a crystalline polyester polyol with a polyisocyanate compound. And has an isocyanate group at the end of the urethane prepolymer. Thus, the adhesive composition according to the present embodiment can exhibit excellent initial adhesive strength at an early stage.

From the viewpoint of rapid solidification and coating workability, the polyol compound preferably contains 50 to 90% by mass, more preferably 50 to 85% by mass, and still more preferably 50 to 80% by mass of the crystalline polyester polyol. preferable.

The reactive urethane prepolymer has a structural unit derived from a polyol compound and a structural unit derived from a polyisocyanate compound, and 50% by mass or more of the structural units derived from the polyol compound is derived from a crystalline polyester polyol Containing structural units. The content of structural units can be measured using known analytical techniques such as NMR, thermal decomposition GC / MS and the like. From the viewpoint of rapid solidification and coating workability, the structural unit derived from the polyol compound preferably contains 50 to 90% by mass, more preferably 50 to 85% by mass, of the structural units derived from the crystalline polyester polyol. More preferably, the content is 50 to 80% by mass.

The crystallinity and amorphousness of the polyester polyol are judged in the state at 25 ° C. The crystallinity can be determined by heating the polyester polyol to 25 ° C. or more to confirm that it becomes liquid, or by checking the melting temperature of the polyester polyol with a differential scanning calorimeter. In the present specification, among polyester polyols, a polyester polyol which is crystalline at 25 ° C. is taken as a crystalline polyester polyol, and a polyester polyol which is non-crystalline at 25 ° C. is taken as an amorphous polyester polyol. The polyol compound according to the present embodiment contains a crystalline polyester polyol as an essential component, but may optionally contain an amorphous polyester polyol.

The polyester polyol has, for example, a polyhydric alcohol having 2 to 15 carbon atoms and 2 or 3 hydroxyl groups, and 2 to 14 carbon atoms (including carbon atoms in the carboxyl group), It may be a polycondensate with a polycarboxylic acid having 6 carboxyl groups. The polyester polyol may be a linear polyester diol produced from a diol and a dicarboxylic acid, or may be a branched polyester triol produced from a triol and a dicarboxylic acid. Branched polyester triols can also be obtained by the reaction of diols and tricarboxylic acids.

Examples of polyhydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, isomers of butanediol, isomers of pentanediol, isomers of hexanediol, 2, 2- Dimethyl-1,3-propanediol, 2-methylpropanediol, 1,6-hexanediol, 2,4,4-trimethylhexane-1,6-diol, 2,2,4-trimethylhexane-1,6- Aliphatic or alicyclic diols such as diol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol; and aromas such as 4,4'-dihydroxydiphenylpropane, bisphenol A, bisphenol F, pyrocatechol, resorcinol, hydroquinone and the like Family diols.

Among these, from the viewpoint of easily obtaining a crystalline polyester polyol, as the polyhydric alcohol, an aliphatic diol is preferable, an aliphatic diol having 2 to 10 carbon atoms is more preferable, and 4 to 10 carbon atoms are more preferable. More preferred are aliphatic diols having the formula: aliphatic diols having 4 to 8 carbon atoms. From the viewpoint of easily obtaining a crystalline polyester polyol with higher crystallinity, the polyhydric alcohol is preferably a linear aliphatic diol. The number of carbon atoms of the linear aliphatic diol is preferably 3 to 10, more preferably 4 to 10, still more preferably 4 to 8, and further preferably 4 to 6 It is more preferable that the number is one, particularly preferably five or six. A polyhydric alcohol may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of polycarboxylic acids include aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid and 1,2,4-benzenetricarboxylic acid; maleic acid, fumaric acid, aconitic acid, 1,2,3-propane Tricarboxylic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, cyclohexane-1,2-dicarboxylic acid, 1,4-cyclohexadiene-1,2 And aliphatic or alicyclic polycarboxylic acids such as dicarboxylic acids.

Among these, from the viewpoint of easily obtaining a crystalline polyester polyol, as the polycarboxylic acid, aliphatic dicarboxylic acids are preferable, aliphatic dicarboxylic acids having 4 to 12 carbon atoms are more preferable, and 6 to 12 More preferred are aliphatic dicarboxylic acids having carbon atoms, and even more preferred are aliphatic dicarboxylic acids having 6 to 10 carbon atoms. From the viewpoint of easily obtaining a crystalline polyester polyol having higher crystallinity, a linear aliphatic dicarboxylic acid is preferable as the polycarboxylic acid. The number of carbon atoms in the linear aliphatic dicarboxylic acid is preferably 4 to 12, more preferably 6 to 12, and still more preferably 6 to 10. The polycarboxylic acids may be used alone or in combination of two or more.

From the viewpoint of facilitating obtaining an adhesive composition excellent in rapid solidification, the crystalline polyester polyol according to the present embodiment comprises a polycarboxylic acid having 6 to 12 carbon atoms, and 4 to 10 carbon atoms. It is particularly preferable to have a structure based on having a polyhydric alcohol.

Instead of the polycarboxylic acid, it is also possible to use a polycarboxylic acid derivative such as a carboxylic acid anhydride or a compound in which a part of the carboxyl group is esterified. Examples of polycarboxylic acid derivatives include dodecylmaleic acid and octadecenylmaleic acid.

The number average molecular weight (Mn) of the crystalline polyester polyol is preferably 500 to 10000, more preferably 1000 to 8000, still more preferably 1500 to 6000, from the viewpoint of easily obtaining waterproofness and high initial adhesive strength. Is even more preferred.

In the present specification, the number average molecular weight is a value measured by gel permeation chromatography (GPC) and converted to standard polystyrene. The measurement of GPC can be performed under the following conditions.
Columns: “Gelpack GLA130-S”, “Gelpack GLA150-S” and “Gelpack GLA160-S” (manufactured by Hitachi Chemical Co., Ltd., packed column for HPLC)
Eluent: tetrahydrofuran Flow rate: 1.0 mL / min Column temperature: 40 ° C
RI Detector: L-3350 (Hitachi High-Tech Science, Product Name)

The number average molecular weight of the amorphous polyester polyol is preferably 500 to 3,000, more preferably 1,000 to 3,000, and still more preferably 1,500 to 2,500, from the viewpoint of being able to improve the initial adhesive strength of the adhesive composition.

The polyol compound according to the present embodiment may further contain a polyether polyol. The polyether polyol adjusts the melt viscosity and open time (bonding time) after the application of the adhesive composition to make the adhesive composition excellent in workability, adhesive strength, waterproofness and flexibility. It can be granted. From the viewpoint of improving the coating workability of the adhesive composition, polyether diols are preferred. Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol and ethylene oxide modified polypropylene glycol . The polyether polyols may be used alone or in combination of two or more.

The content of the polyether polyol is 50% by mass or less based on the total mass of the polyol compound from the viewpoint of easily adjusting the adhesive composition to a low viscosity and improving the adhesion to the adherend. The content is preferably 10 to 50% by mass, and more preferably 15 to 50% by mass.

The number average molecular weight of the polyether polyol is preferably in the range of 500 to 6000, more preferably in the range of 800 to 5000, and still more preferably in the range of 1000 to 4500, from the viewpoint of facilitating obtaining adhesive strength and flexibility.

As polyisocyanate compounds, for example, aromatic diisocyanates such as diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, p-phenylene diisocyanate, etc .; alicyclic diisocyanates such as dicyclohexylmethane diisocyanate, isophorone diisocyanate; hexamethylene diisocyanate etc. Of aliphatic diisocyanates. The polyisocyanate compound preferably contains an aromatic diisocyanate, and more preferably diphenylmethane diisocyanate, from the viewpoint of improving the reactivity and the adhesive strength. The polyisocyanate compounds may be used alone or in combination of two or more.

When a reactive urethane prepolymer is synthesized, the mixing ratio of the polyisocyanate compound and the polyol compound is such that NCO / OH, which is the ratio of isocyanate group (NCO) equivalent of polyisocyanate compound / hydroxyl group (OH) equivalent of polyol, is 1. It is preferably 6 to 3.0, and more preferably 1.8 to 2.5. When the ratio of NCO / OH is 1.6 or more, the viscosity of the resulting reactive urethane prepolymer tends to be high, and the workability tends to be improved. When the NCO / OH ratio is 3.0 or less, foaming is less likely to occur during the moisture curing reaction of the adhesive composition, and the decrease in the final adhesive strength tends to be suppressed.

The method for producing the reactive urethane prepolymer is not particularly limited. When preparing the adhesive composition, the polyisocyanate compound and the polyol compound may be mixed to synthesize a reactive urethane prepolymer, and a reactive urethane prepolymer is previously synthesized from the polyisocyanate compound and the polyol compound. Once done, the adhesive composition may be prepared.

(Pigment)
The adhesive composition according to the present embodiment may further contain a pigment. The pigment can be appropriately selected according to the required properties. Examples of the pigment include black pigments, white pigments, red pigments, yellow pigments and blue pigments. Various pigments can be included in the adhesive composition at a content selected based on the desired effect, for example, in the range of 0.5 to 30 parts by mass with respect to 100 parts by mass of the urethane prepolymer. .

When the light shielding property is required, a black pigment can be used. Examples of black pigments include carbon black pigments such as carbon black, lamp black, graphite, plant black and bone charcoal; oxides of iron, complex oxides of copper and chromium, complex oxides of copper, chromium and zinc And oxide-based black pigments such as

The content of the black pigment is preferably 0.5 to 10 parts by mass, more preferably 0.8 to 8 parts by mass, and still more preferably 1 to 5 parts by mass with respect to 100 parts by mass of the urethane prepolymer. When the content of the black pigment is 0.5 parts by mass or more, the light shielding property of the adhesive layer formed from the adhesive composition can be easily improved, and the content of the black pigment is 10 parts by mass or less, It becomes easy to adjust the viscosity of the adhesive composition.

Here, the particle size (average primary particle size) of the black pigment is not particularly limited, but may be, for example, 1 to 200 nm or 5 to 100 nm. The average primary particle size in the present specification indicates a numerical value determined by the method described in the examples.

When light reflectivity is required, a white pigment can be used. Examples of white pigments include titanium oxide, zinc oxide, alumina, magnesium oxide, antimony oxide and zirconium oxide.

(Other ingredients)
In the adhesive composition according to the present embodiment, an appropriate amount of a catalyst, an antioxidant, an ultraviolet light absorber, a surfactant, a flame retardant, a filler, and the like may be blended, if necessary.

The catalyst includes, for example, dibutyltin dilaurate, dibutyltin dioctoate, dimethylcyclohexylamine, dimethylbenzylamine and trioctylamine.

(Physical properties)
The open time (bonding possible time) of the adhesive composition according to the present embodiment is preferably 120 seconds or less, and more preferably 60 seconds or less. If the open time is 60 seconds or less, adhesion is likely to develop immediately after bonding with the adhesive composition.

From the viewpoint of improving the coatability to the adherend, the melt viscosity of the adhesive composition according to the present embodiment measured using a rotational viscometer is in accordance with JIS Z 8803 and the method described in the examples. It can be measured. The melt viscosity of the adhesive composition is preferably 10 Pa · s or less at 120 ° C., more preferably 8 Pa · s or less, and still more preferably 7 Pa · s or less. The lower limit value of the melt viscosity is not limited, but may be, for example, 0.5 Pa · s or more at 120 ° C.

[Method of producing reactive hot melt adhesive composition]
The method for producing an adhesive composition according to the present embodiment comprises the step of reacting a polyol compound and a polyisocyanate compound to obtain a urethane prepolymer having an isocyanate group, wherein the polyol compound is based on the total mass of the polyol compound. As a method of containing 50% by mass or more of crystalline polyester polyol.

The adhesive composition according to the present embodiment is produced by reacting a polyol compound and a polyisocyanate compound to obtain a reactive urethane prepolymer, and then mixing it with a component such as a pigment to be blended if necessary. May be In addition, the adhesive composition may be produced while synthesizing the reactive urethane prepolymer by mixing the polyisocyanate compound and the polyol compound, and the component such as the pigment to be blended if necessary. For example, when a pigment is added to the adhesive composition, the adhesive composition may be prepared by the step of reacting a polyol compound and a polyisocyanate compound in the presence of the pigment to obtain a urethane prepolymer. The adhesive composition may be prepared by the step of mixing the urethane prepolymer and the pigment after the reaction of the polyol compound and the polyisocyanate compound in advance to obtain the urethane prepolymer.

Various adherends can be adhered using the reactive hot melt adhesive composition of the present embodiment. The adhesive composition according to the present embodiment can adhere the adherends to each other by applying it to the surface or side of the adherend, and in a shorter time than the conventional reactive hot melt adhesive composition. It is possible to develop excellent initial adhesive strength.

Examples of adherends include metal adherends (SUS, aluminum and the like) and non-metallic adherends (polycarbonate, glass and the like). The adhesive composition according to the present embodiment exhibits excellent adhesive strength not only to nonmetallic adherends but also to metallic adherends. The adhesive composition according to the present embodiment can also be used to bond a flat panel display such as a liquid crystal display and the like to which a double-sided tape has conventionally been used and a backlight unit.

The flat panel display refers to a thin video display having a thin flat screen. Examples of flat panel displays include liquid crystal displays, plasma displays, organic EL displays, FEDs (field emission displays), electronic paper, and the like.

Hereinafter, a method of bonding the flat panel display and the backlight unit using the adhesive composition according to the present embodiment will be described. FIG. 1 is a schematic cross-sectional view showing one aspect of adhesion using the adhesive composition according to the present embodiment.

The flat panel display 10 and the backlight unit 20 are stacked to form a two-layered structure, and the adhesive composition is applied to the inner corner of the side surface of the backlight unit 20 and the exposed upper surface of the flat panel display 10 Thus, the adhesive layer 30 can be formed, and the flat panel display 10 and the backlight unit 20 can be bonded. That is, in the bonding method according to the present embodiment, the side surface of the backlight unit 20 and the exposed upper surface of the flat panel display 10 which are formed by laminating the backlight unit 20 on the upper surface of the flat panel display 10 At a corner, the adhesive layer 30 can be formed using the adhesive composition according to the present embodiment. By using the bonding method, an image display device including a flat panel display and a backlight unit can be manufactured. In addition, since the adhesive composition according to the present embodiment has rapid solidification, it is preferable in the method of manufacturing the image display device from the viewpoint of making the manufacturing process efficient. At this time, when an adhesive composition containing a black pigment is used, adhesion and light shielding can be simultaneously performed. In the case of the bonding method according to the present embodiment, it is possible to reduce the thickness as compared with the method in which the end of the conventional flat panel display and the end of the backlight unit are bonded with a double-sided tape. In addition, when the adhesive composition according to the present embodiment is adhered by the above adhesion method, it may be used for adhesion of a two-layered adherend as shown in one aspect of the above adhesion, and three or more layers You may use for adhesion | attachment of a to-be-adhered body.

The adhesive composition according to the present embodiment is particularly suitable in the above-mentioned bonding method because it has a fast setting property.

Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to these examples.

(Polyol compound)
As a crystalline polyester polyol, PES-1 (polyester polyol obtained by reacting adipic acid and 1,6-hexanediol, number of hydroxyl groups: 2, Mn: 3000), and PES-2 (sebacic acid and 1,1 A polyester polyol obtained by reacting 6-hexanediol, the number of hydroxyl groups: 2, Mn: 5000) was prepared. As an amorphous polyester polyol, PES-3 (a polyester polyol obtained by reacting adipic acid and ethylene glycol, number of hydroxyl groups: 2, Mn: 2000) was prepared. As a polyether polyol, PP2000 (polypropylene glycol, Mn: 2000, "EXENOL 2020" manufactured by Asahi Glass Co., Ltd.) was prepared.

(Polyisocyanate compound)
MDI (diphenylmethane diisocyanate, isocyanate group number: 2, "Millionate MT" manufactured by Tosoh Corp.) was prepared as a polyisocyanate compound.

(Pigment)
As black pigments, carbon black A (particle diameter: 30 to 50 nm), carbon black B (particle diameter 20 to 30 nm), and carbon black C (particle diameter 10 to 20 nm) were prepared. Here, the particle size refers to the average primary particle size. Carbon black is observed using a scanning electron microscope ("XL-30" manufactured by Philips Corporation), and the major axis of 50 primary particles of carbon black is measured from the obtained observation image, and the average value is calculated. Average primary particle size.

Example 1
After mixing 50 parts by mass of PES-1 dehydrated beforehand by a vacuum dryer, 50 parts by mass of PP2000, 21.1 parts of MDI and 3 parts by mass of carbon black A, the mixture is reacted at 110 ° C. for 2 hours, The mixture was further degassed under reduced pressure at 110 ° C. for 2 hours to obtain an adhesive composition containing a urethane prepolymer having an isocyanate group and a black pigment.

(Examples 2 to 8, Comparative Examples 1 to 2)
An adhesive composition was obtained in the same manner as Example 1, except that each component was changed to the type and blending amount shown in Table 1. The numbers in Table 1 mean parts by mass.

Each characteristic of the adhesive composition produced by the Example and the comparative example was evaluated as follows. The results are shown in Table 2.

(Melt viscosity)
An adhesive composition (sample amount at a rotor rotational speed of 50 rpm, 120 ° C using a No. 4 rotor with a B-type viscometer ("TVB-25H" manufactured by Toki Sangyo Co., Ltd.) according to JIS Z 8803 The melt viscosity of 15 g) was measured.

(Solidification ability)
The adhesive composition is applied to a substrate with a width of 1 mm at room temperature (23 ° C., 50% RH) to form an adhesive layer, and then the time taken for tackiness to disappear on the surface of the adhesive layer is measured. The solidifying property was judged. The case where tack was lost within 1 minute was evaluated as "A", the case where tack was lost within 1 minute and 2 minutes was "B", and the case where tack was not lost within 2 minutes was evaluated as "C". .

(Adhesive force)
The adhesive composition is melted at 100 ° C., and in an environment of temperature 25 ° C. and humidity 50%, on a polycarbonate plate 100 mm long × 25 mm wide × 2 mm thick, 12.5 mm long × 25 mm wide × 0. After forming an adhesive layer of 1 mm, a polycarbonate plate of length 100 mm × width 25 mm × thickness 2 mm was crimped onto the adhesive layer to prepare a test piece. In accordance with JIS 6850, using a tester ("Autograph AGS-1kNX" manufactured by Shimadzu Corporation), shear adhesion test of a test piece after 10 minutes and 30 minutes after pressing (Peel speed: 10 mm / min) was performed to measure the initial adhesive strength. Moreover, after leaving a test piece produced in the same procedure to a thermostat at 25 ° C. and 50% RH for 24 hours, a shear adhesion test (peel speed: 10 mm / min) was performed to measure the final adhesion strength.

(Dischargeability)
A syringe container ("PSY-30E" manufactured by Musashi Engineering Co., Ltd.) with an adhesive composition melted at 100 ° C and a precision nozzle ("SHN-0.25N" manufactured by Musashi Engineering Co., Ltd.) with an inner diameter of 0.25 mm attached ), And discharged at a pressure of 300 kPa using a dispenser (“SHOTMASTER 200DS” manufactured by Musashi Engineering Co., Ltd.) preheated to 100 ° C. The case where discharge was possible was evaluated as “A”, and the case where discharge was not possible was evaluated as “C”.

(Light blocking property)
The adhesive composition was melted at 100 ° C. to prepare a test piece of 15 mm long × 40 mm wide × 0.1 mm thick. The test piece was allowed to stand in a thermostat at 25 ° C. and 50% RH for 7 days, and then the OD value was measured with a transmission densitometer (“TM-5” manufactured by Ihara Electronics Co., Ltd.).

The adhesive compositions obtained in Examples 1 to 8 were confirmed to be excellent in rapid solidification and to exhibit adhesion in a short time.

10 ... flat panel display. 20 ... backlight unit, 30 ... adhesive layer.

Claims

A reaction comprising a urethane prepolymer having an isocyanate group, which is a reaction product of a polyol compound and a polyisocyanate compound, wherein the polyol compound contains 50% by mass or more of a crystalline polyester polyol based on the total mass of the polyol compound Hot Melt Adhesive Composition.
The reactive hot melt adhesive composition according to claim 1, wherein the polyol compound comprises 50 to 90% by mass of the crystalline polyester polyol.
The reactivity according to claim 1 or 2, wherein the crystalline polyester polyol has a structure based on a polycarboxylic acid having 6 to 12 carbon atoms and a polyhydric alcohol having 4 to 10 carbon atoms. Hot melt adhesive composition.
The reactive hot melt adhesive composition according to any one of claims 1 to 3, wherein the polyol compound comprises a polyether polyol.
Urethane having a structural unit derived from a polyol compound and a structural unit derived from a polyisocyanate compound, wherein 50% by mass or more of the structural units derived from the polyol compound is a structural unit derived from a crystalline polyester polyol Reactive hot melt adhesive composition containing a prepolymer.
The reactive hot melt adhesive composition according to any one of claims 1 to 5, further comprising a pigment.
An image display apparatus comprising a flat panel display and a backlight unit,
An image display apparatus, wherein the flat panel display and the backlight unit are bonded by the reactive hot melt adhesive composition according to any one of claims 1 to 6.
A process for producing a reactive hot melt adhesive composition containing a urethane prepolymer having an isocyanate group, comprising:
B. reacting the polyol compound and the polyisocyanate compound to obtain the urethane prepolymer having the isocyanate group,
The production method, wherein the polyol compound contains 50% by mass or more of crystalline polyester polyol based on the total mass of the polyol compound.
The production method according to claim 8, wherein the polyol compound contains 50 to 90% by mass of the crystalline polyester polyol.
The method according to claim 8 or 9, wherein the crystalline polyester polyol has a structure based on a polycarboxylic acid having 6 to 12 carbon atoms and a polyhydric alcohol having 4 to 10 carbon atoms. .
The method according to any one of claims 8 to 10, wherein the polyol compound comprises a polyether polyol.
A bonding method for bonding a flat panel display and a backlight unit,
The inner surface of the side surface of the said back light unit and the exposed upper surface of the said flat panel display formed by laminating | stacking the said back light unit on the upper surface of the said flat panel display, The any one of Claims 1-6. A bonding method for forming an adhesive layer by using the reactive hot melt adhesive composition according to one aspect.
The manufacturing method of an image display apparatus which manufactures an image display apparatus using the adhesion method of Claim 12.