KR20080008214A - Polyurethane resin and application thereof - Google Patents

Abstract

A polyurethane resin is provided to realize excellent close contact property and adhesion to a film and a low melting point, and to allow solvent-free coating work at low temperature. A polyurethane resin(c) is obtained by reacting a polyol with a polyisocyanate, wherein the polyol comprises at least 80 mol% of a polyester polyol(a) based on 100 wt% of the total polyol components. Based on 100 mol% of the total acid components of the polyester polyol, at least 80 mol% thereof includes benzene-o-dicarboxylic acid and/or benzene-m-dicarboxylic acid. Based on 100 mol% of the total alcohol components of the polyester polyol, at least 50 mol% thereof includes dialcohol components having 2 or 3 C8 or lower alkylene groups bound to each other by way of an ether bond. The polyester polyol has an average terminal OH functionality of 0.55-5 mol/kg. The polyisocyanate(b) comprises at least 70 wt% of diisocyanates having no cyclic structures in their structures and having a molecular weight of 250 or less based on 100 wt% of the total polyisocyanate components.

Description

Polyurethane resin and its application {POLYURETHANE RESIN AND APPLICATION THEREOF}

The present invention has a high adhesiveness and adhesion to an aluminum foil, a film or a sheet (hereinafter, these three may be referred to as a 'film'), and is a polyurethane suitable as a resin component of a paint, an ink composition or an adhesive composition. The present invention relates to an adhesive composition capable of thin film coating obtained using a resin, the urethane resin, a film laminating method and a film laminate using the adhesive composition.

A paint, an ink composition, and an adhesive composition which have high adhesiveness and adhesiveness to a film are aromatic polyester resins containing the terephthalic acid component or an isophthalic acid component, or the polyester resin (hereinafter, may mean 'polyester polyol'). Urethane resin or urethane urea resin which consists of these is used.

In the coating method of the said adhesive composition, when an adhesive composition is a solventless type (type which does not contain a solvent), the said adhesive composition is a film form, linear form, or a point in a molten state of comparatively high temperature exceeding 100 degreeC. It is extruded into a shape and coated on a film. On the other hand, in the type in which an adhesive composition contains a solvent, resin for adhesives is coated in the state melt | dissolved in the organic solvent, or disperse | distributed to water, and the solvent component is volatilized after that.

However, if the resin used for the adhesive composition is a relatively low molecular weight polyester resin having an average of about 0.4 to 4 mol / kg of hydroxyl groups at the molecular terminal, it is 10 Pa · s at a relatively low temperature of 100 ° C. or less even in a solvent-free state. It may become the following viscosity. In this case, the adhesive composition can be melt-coated in a thin film form over a large film area. The method using this solvent-free adhesive composition does not require energy in order to dry a solvent, and since it does not use an organic solvent, it is evaluated as a method with less environmental load.

For example, for the purpose of obtaining a laminate of films using an adhesive composition, a squeeze roll is a method in which the adhesive composition can be coated in a thin film shape with a film thickness of about 0.5 to 5 μm over a large area without using an organic solvent. A coating method is employed, and an adhesive composition suitable for this coating method is disclosed in the following Patent Documents 1 to 3 and Japanese Patent Application 2005-189329.

[Patent Document 1] Japanese Patent Application Laid-Open Publication No. 08-60131

[Patent Document 2] Japanese Patent Laid-Open No. 2002-249745

[Patent Document 3] Japanese Patent Publication No. 2003-321664

A relatively low molecular weight aromatic polyester resin having a high adhesion to a film is a urethane resin prepared as a polyol component, a modification of the aromatic polyester resin from a polyisocyanate to a urethane urea resin, or a hydroxyl group at the molecular end When using a relatively high molecular weight aromatic polyester resin having a thickness of about 0.04 to 0.4 mol / kg as an adhesive composition capable of thin-film melt coating over a large area without using an organic solvent, Coating was difficult because the side and melt viscosity were too high.

In addition, the conventional adhesive composition suitable for the said squeeze roll coat system is, for example, as described in Patent Document 1 and Patent Document 3, in order to improve the adhesiveness and adhesion to the aluminum foil, an inorganic acid, an organic acid or Contains acid anhydrides. The acid and the like have a side effect of promoting hydrolysis of the polyester resin as a main component of the adhesive composition by degrading the resin by having a hydrolysis catalysis of an ester bond. As described in Patent Literature 2 and Patent Literature 3, in order to reduce the melt viscosity of the resin, a polyol component other than the aromatic polyester polyol is mixed in a large amount unless the inorganic acid, organic acid or acid anhydride of the glass is not contained. The adhesive composition which consists of polyester polyols has a problem that adhesiveness and adhesiveness with respect to a film are not enough.

Under the above circumstances, a polyester having a specific composition can be coated with a thin solvent-free coating having a low melt viscosity and a large area, regardless of whether a phthalic acid component is contained at a high concentration as an acid component constituting the polyester resin. Resin is disclosed in Japanese Patent Application 2005-189329. This polyester resin shows high adhesiveness to a film, even if it does not contain the inorganic acid, organic acid, or acid anhydride of glass.

However, when the polyester resin described in Japanese Patent Application No. 2005-189329 is used as the polyester polyol (main agent) of the adhesive composition, the problem of requiring a long time for the curing like other conventional adhesive compositions. There was. When the catalyst which accelerates hardening reaction of the said polyester resin is used, shortening of the time required for hardening of the said polyester resin is easy. However, in this case, the usable time (port life) of an adhesive composition became short and it was a problem from the point of practical use.

Therefore, the method of using a solvent-free adhesive composition is evaluated as a method which requires no dry energy of a solvent or a method with less environmental load from not using an organic solvent, but melts a solvent-free adhesive composition, The method of coating to a larger area has not progressed much in the field of the film | membrane which especially high adhesiveness is calculated | required.

Accordingly, an object of the present invention is to provide a polyurethane resin useful as a polyester polyol (topic) of an adhesive composition having high adhesion and adhesion to a film, low melt viscosity, and which can be solvent-free at low temperatures. In addition, another object of the present invention is to provide an adhesive composition made of the polyurethane resin, the curing time is shortened without shortening the usable time, a method of laminating a film using the adhesive composition and a laminate of the film It is.

The above object is achieved by the following invention. That is, the present invention is a polyurethane resin obtained by reacting a polyol and a polyisocyanate,

When the said polyol makes 100 mol% of all polyols, at least 80 mol% of this is polyester polyol (a) (Hereinafter, it may only be called "polyol (a).), And the polyol (a) of When total acid component is 100 mol%, at least 80 mol% of this is a benzene-o-dicarboxylic acid (phthalic acid) component and / or a benzene-m-dicarboxylic acid (isophthalic acid) component,

When the total alcohol component of the polyol (a) is 100 mol%, at least 50 mol% of the polyalcohol (a) is a dialcohol component having 2-3 alkylene groups bonded to each other via an ether bond,

The said polyol (a) has 0.55-5 mol / kg average of hydroxyl groups in a molecule terminal,

The said polyisocyanate is a polyisocyanate containing at least 70 mass% of diisocyanate (b) of the molecular weight 250 or less which does not have a ring structure in the structure when all polyisocyanate is 100 mass%, The polyurethane resin characterized by the above-mentioned. Provide (c).

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to comply with the said prior art request, the present inventors discovered that the polyurethane resin (c) of this invention has high adhesiveness with respect to a film, and has low melt viscosity at the same time. That is, the polyurethane resin of this invention can make the melt viscosity in 80 degreeC into 10 Pa * s or less.

It should be further noted that the polyurethane resin (c) of the present invention has a melt viscosity at 80 ° C. of the same composition as the polyol (a) used for producing the polyurethane resin (c) (that is, the acidity used). The powder and the polyol component are the same) and can be made lower than the melt viscosity of the polyester polyol (a ') having the same molecular weight as the polyurethane resin (c).

When the polyurethane resin (c) of the present invention is compared with the polyol (a '), in the present invention, it is considered that the melt viscosity of the polyurethane resin (c) side is considerably high. Resin (c) was found not only to increase the melt viscosity in most cases, but also surprisingly, that the melt viscosity was lower than that of the polyol (a ').

Furthermore, the said polyurethane resin (c) was used as a main component (that is, 50-100 mass% of a main body) of the main composition (I) of the adhesive composition which consists of a hardening | curing agent (II) which has a main component (I) and a polyisocyanate as a main component. The adhesive composition was found to shorten the time required for curing even without using a curing catalyst.

Furthermore, it discovered that the said adhesive composition was a thin film coating about 0.5-5 micrometers in the large area of a film, and was an adhesive composition suitable for the squeeze roll coat system which manufactures a film laminated body.

Furthermore, in the adhesive composition of the said invention, 50-100 mass% of said main body (I) is made into the polyurethane resin (c) whose melt viscosity in said 80 degreeC is 10 Pa * s or less, and a hardening | curing agent (II) The isocyanate group content is at least 10% by mass, the stoichiometric ratio (isocyanate group / hydroxyl group) of the end groups of the main ingredient (I) and the curing agent (II) is 1.0 to 5.0, and the nonvolatile content is at least 98% by mass. When the composition is substantially free of an organic solvent, the adhesive composition was found to be particularly suitable for the lamination processability of the film and the adhesiveness property of the laminate.

ADVANTAGE OF THE INVENTION According to this invention, the polyurethane resin which has high adhesiveness and adhesiveness with respect to a film, is low in melt viscosity, and is solvent-free at low temperature is provided.

In addition, the polyurethane resin is useful as a subject of an adhesive composition in which curing time is shortened without shortening the usable time, and by using the adhesive composition, a method of laminating a film having a low environmental load and a film laminate are provided. can do.

Embodiment of the Invention

Next, the present invention will be described in more detail with reference to preferred embodiments.

When the polyol (a) used for production of the polyurethane resin (c) of the present invention is 100 mol% in total acid component, at least 80 mol% of the acid component must be phthalic acid component and / or isophthalic acid component. There is. When the said phthalic acid component and / or isophthalic acid component are less than 80 mol% of all the acid components, adhesiveness with respect to the film of the polyurethane resin (c) obtained can fall. Regarding the adhesiveness to the film of the polyurethane resin (c), the higher the ratio of the phthalic acid component in the total acid component is, the more preferable. Preferably, the ratio of the phthalic acid component is at least 90 mol%, particularly preferably in the total acid component. It is 100 mol%.

In addition, in order to lower the melt viscosity of the obtained polyurethane resin (c) and to improve the solubility of the polyurethane resin (c) in an organic solvent, the phthalic acid component is more preferable than the isophthalic acid component as the acid component constituting the polyol (a). Many are preferable, and most preferably, the phthalic acid component in an acid component shall be 100 mol%. Phthalic acid, phthalic anhydride, and / or its alkyl ester are mentioned as an acid component effective as a phthalic acid component. Moreover, isophthalic acid and / or its alkyl ester are mentioned as an acid component effective as an isophthalic acid component. In addition, as an acid component which can be copolymerized, conventionally existing acid, Preferably dibasic acid can be used.

Although the polyol (a) used for manufacture of the polyurethane resin (c) of this invention is a polyester polyol which consists of the said acid component and alcohol component, when the total alcohol component is 100 mol%, at least 50 mol% of it This C8 or less alkylene group needs to be the dialcohol component couple | bonded with 2-3 by the ether bond. When the alcohol component is less than 50 mol% or an alkylene group having 8 or less carbon atoms is not bonded through an ether bond, the melt viscosity of the polyol (a) is increased. Therefore, Preferably, content of the said dial alcohol component is at least 70 mol% of all the alcohol components, Especially preferably, it is 100 mol%.

In addition, when the said dialcoal component is an alcohol component in which the alkylene group of 8 or more carbon atoms of 3 or more is couple | bonded with an ether bond, the heat resistance of the polyurethane resin (c) obtained through a polyol (a) falls, Deterioration by heat of the polyurethane resin (c) at the time of melt coating becomes remarkable. Therefore, the said dialcohol component of the polyol (a) which comprises the polyurethane resin (c) of this invention is C8 or less alkylene which comprises the said dialcohol component from the heat resistance of the polyurethane resin which can be obtained. It is preferable that the ether bond number which couple | bonds the group is 1.

In addition, when the said dialcoal component consists of an alkylene group which has C8 or more, the more the molecular weight, the lower the content in the polyol (a) of the phthalic acid component which is an acid component can be obtained through a polyol (a). The adhesiveness to the film of the polyurethane resin (c) which exists is inferior. Therefore, in adhesiveness with respect to a film, it is preferable that carbon number of the alkylene group which comprises the said alcohol component is 8 or less.

As a dialcohol component which the C8 or less alkylene group which comprises at least 50 mol% at the time of making 100 mol% of all the components of the said alcohol component couple | bonded via an ether bond, for example, diethylene In addition to glycol, triethylene glycol, dipropylene glycol and triethylene glycol, one or two ring opening additions of ethylene oxide, propylene oxide, tetrahydrofuran, etc., to alkylene glycol having 8 or less carbon atoms can be used. . In addition, as an alcohol component which can be copolymerized, although the conventional alcohol component can be used conventionally, Preferably it is glycol which has two hydroxyl groups.

Moreover, it is preferable that the polyol (a) used for manufacture of the polyurethane resin (c) of this invention is a polyester polyol which has 0.55-5 mol / kg average of a hydroxyl group in a molecule terminal. When hydroxyl content is more than 5 mol / kg, adhesiveness with respect to the film of the polyurethane resin (c) which can be obtained falls. On the other hand, when the hydroxyl content of the polyol (a) is less than 0.55 mol / kg, the melt viscosity of the obtained polyurethane resin (c) becomes high, and when it is set as an adhesive composition, it becomes difficult to apply thin film to a large area without a solvent.

The manufacturing method of the polyol (a) used for manufacture of the polyurethane resin (c) of this invention can apply the conventional manufacturing method of the conventional polyester resin. That is, the polybasic acid and / or its alkyl ester and the polyhydric alcohol can be obtained by polycondensation at 140 to 250 ° C. in the presence of an esterification catalyst and optionally in the presence of an antioxidant. have. Although the conventional thing can be used conventionally as an esterification catalyst, an alkoxy titanium system is preferable. As an antioxidant, although a conventional thing can be used conventionally, the thing of a phosphite ester type is preferable.

Polyisocyanate (b) used for manufacture of the polyurethane resin (c) of this invention is a diisocyanate of 250 or less molecular weight which does not have a ring structure in a carbon skeleton. As preferable diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4- or 2,4,4-trimethyl hexamethylene diisocyanate, a lysine diisocyanate, etc. are mentioned, for example.

In manufacture of the polyurethane resin (c) of this invention, active hydrogen containing compounds, such as a polyol other than the above, can also be used. However, the amount used is less than 20 mol% in the total polyol. When the proportion of other active hydrogen-containing compounds increases, the adhesiveness and adhesion to the film of the polyurethane resin (c) to be obtained decrease or the melt viscosity increases. Therefore, Preferably the ratio of the other active hydrogen containing compound is 10 mol% or less of a total polyol component, More preferably, it is 0 mol%. As another active hydrogen containing compound, a conventionally well-known polyol, polyamine, etc. can be used as a polyurethane resin raw material.

Although polyisocyanate of that excepting the above can also be used in manufacture of the polyurethane resin (c) of this invention, the said other polyisocyanate is less than 30 mass% of all polyisocyanate. When the proportion of other polyisocyanates increases, the melt viscosity of the polyurethane resin (c) obtained increases. Therefore, the usage-amount of other polyisocyanate becomes like this. Preferably it is 15 mass% or less, More preferably, it is 0 mass%. As other polyisocyanate, conventionally known polyisocyanate, multimer of polyisocyanate, adduct of polyisocyanate, terminal isocyanate type prepolymer, etc. can be used as a polyurethane resin raw material.

The conventional method for producing a polyurethane resin can be applied to the method for producing a polyurethane resin (c) of the present invention. That is, the above-mentioned polyol (a) and active hydrogen-containing compounds such as other conventional polyhydric alcohol compounds and polyvalent amine compounds, and the aforementioned polyisocyanate (b) and conventionally existing polyisocyanate compounds as necessary It can be obtained by carrying out heavy addition reaction at normal temperature-250 degreeC in the presence of a urethanization catalyst coexistence as needed and also in the presence of an organic solvent coexistence as needed. Although a conventional thing can be used conventionally as a urethanation catalyst, the thing of a 1st tin salt type | system | group is preferable.

In the production of the polyurethane resin (c), it is preferable that an organic solvent is not used if a substantially solvent-free adhesive composition is obtained. However, an organic solvent may be used if necessary, followed by organic conventional methods. The solvent can also be removed. Although the conventional thing can be used conventionally as an organic solvent, Ketone type and / or ester type is preferable.

When the main body (polyol) (I) used for the adhesive composition of this invention makes 100 mass% of all the polyols, 50-100 mass% of it is the polyurethane resin (c) of the said invention. When the main body (I) used for the adhesive composition of this invention makes the whole polyol 100 mass%, 0-50 mass% of it can be made into another polyol component, However, when the ratio of the said other component increases, The adhesiveness and adhesiveness with respect to the film of an adhesive composition fall. Therefore, the ratio of the said other component becomes like this. Preferably it is 20 mass% or less, More preferably, it is 0 mass%.

The hardening | curing agent (polyisocyanate) (II) used for the adhesive composition of this invention is polyisocyanate whose content of an isocyanate group is at least 10 mass%. When content of an isocyanate group is less than 10 mass%, the compounding quantity of the hardening | curing agent required for hardening increases, As a result, content of a polyurethane resin (c) is reduced and adhesiveness and adhesiveness with respect to the film of an adhesive composition fall. As polyisocyanate of hardening | curing agent (II), the conventionally well-known polyisocyanate compound of the isocyanate group content can be used at least 10 mass%.

As for the subject (I) and hardening | curing agent (II) used for the adhesive composition of this invention, the stoichiometric ratio (isocyanate group / hydroxyl group) of a terminal group (hydroxyl group, an isocyanate group) is 1.0-5.0, Preferably it is 1.5-3.0. If the stoichiometric ratio of the end group is less than 1.0, the curing of the adhesive composition is insufficient. On the other hand, if the stoichiometric ratio of the end group exceeds 5.0, a large amount of water is required for curing, and thus a long time is required for curing. in need. Moreover, since content of a polyurethane resin (c) is reduced, the adhesiveness and adhesiveness of the adhesive composition with respect to a film fall.

If necessary, the adhesive composition of the present invention is conventionally used as a colorant, dispersant, surfactant, foaming agent, antifoaming agent, viscosity regulator, leveling agent, stabilizer, ultraviolet absorber, coupling agent, antiblocking agent, catalyst, etc. Possible time extension, a plasticizer, a filler and the like can be blended and obtained. Particularly, catalysts have been conventionally added for the purpose of shortening the curing time, but have been accompanied with the disadvantage of shortening the usable time. Even when using a catalyst, the adhesive composition of this invention becomes possible to reduce the usage amount conventionally, and is useful for extension of a usable time.

It is preferable that the adhesive composition of this invention is non-volatile content at least 98 mass%, and does not contain the organic solvent substantially. The term 'substantially' does not include 100% by mass of nonvolatile matters, such as trace amounts of mixed water, carbonic acid gas produced by the reaction of polyisocyanate with water, and alcohol content produced when a coupling agent is added. This is because the case is considered.

As a method of laminating | stacking a film using the adhesive composition of this invention, the conventional conventional lamination method can be applied. Basically, after mixing the main material (I) and hardening | curing agent (II) by heat-melting, and preparing an adhesive composition, an adhesive composition is coated on a film, and then the other film or sheet | seat or plate shape, and the base material of other forms, It is a method of pasting and bonding, and then curing and aging under normal temperature or heating conditions, but if necessary, the adhesive composition may be coated on both sides of the film, and in order to promote the leveling of the coated adhesive composition prior to pasting, You may install the leaving process.

As a method for preparing the adhesive composition of the present invention, a device for automatically metering and dispensing the main body (I) and the curing agent (II) into a mixer with a separate pump, and using a device for mixing and discharging each time, the adhesive composition is used for each time It is preferable to mix and prepare. Since the adhesive composition which mixed and prepared the main material (I) and hardening | curing agent (II) starts hardening reaction immediately after mixing preparation, and becomes a viscosity gradually, it is not preferable to make it into a large quantity.

As a coating method of the adhesive composition of this invention, a conventionally well-known coating method can be applied.

Specifically, a squeeze roll coat method, a reverse roll coat method, a curtain flow coat method, a knife coat method, etc. are mentioned. The coating film thickness and coating method of an adhesive composition differ according to the characteristic of a film base material (coated film), and the required adhesive performance. For example, when the film base material is thin, the surface of the adhesive surface has high smoothness and does not require a relatively high adhesive strength, the coating film thickness of the adhesive composition is generally 1 to 5 µm, and the coating method in this case is a squeeze roll coat. The manner is preferred. Moreover, when the film base material is thick, the smoothness of an adhesive surface is bad, and the use which requires comparatively high adhesive strength is desired, the coating film thickness of an adhesive composition is generally 5-100 micrometers, and the system other than a squeeze roll coat system is also preferable.

As the film base material laminated | stacked using the adhesive composition of this invention, the polyolefin represented by the conventionally well-known surface treatment, polypropylene, polystyrene, polyvinyl chloride, polyvinyl alcohol, its ethylene copolymer, 6 nylon as needed Various plastic films, such as polyamide represented by the above, polyesters represented by polyethylene terephthalate (PET), and foams thereof, and various conventionally known polymer coating agents represented by polyvinylidene chloride are coated on their surfaces. , A film base material having an inorganic layer such as metal deposition, silica deposition, alumina deposition, etc., a metal material represented by aluminum foil, copper foil, or the like, as well as woven fabrics, nonwoven fabrics, paper, etc., are single or pre-laminated substrates. .

Among them, aluminum foil and PET are film substrates exhibiting excellent adhesiveness of the adhesive composition of the present invention, and the laminate using such a film substrate is a laminate characterized by the present invention.

EXAMPLE

Hereinafter, the present invention will be described in more detail with reference to Synthesis Examples, Examples, Comparative Examples and Reference Examples.

Synthesis Example a-1 to a-10

<Production Method of Polyol (a1: Synthesis Example a-1)>

Into the flask, 538 g of phthalic anhydride, 462 g of diethylene glycol and 1 g of triphenylphosphite were mixed, heated to 230 ° C. for 5 hours while stirring under a nitrogen stream, and the esterification reaction was carried out with water flowing out. . 0.1 g of the tetra-n-butoxy titanium polymer was mix | blended at the time when water outflow stopped, and it heated up at 250 degreeC, condensed under reduced pressure of 10 Torr, and obtained the polyol (a1) of 1.9 mol / kg of hydroxyl concentration. Melt viscosity at 80 degrees C of this polyol (a1) was 0.9 Pa.s.

<Production Method of Polyol (a2: Synthesis Example a-2)>

Like polyol (a1), polyol (a2) having a hydroxyl concentration of 1 mol / kg was obtained from 554 g of phthalic anhydride and 446 g of diethylene glycol. The melt viscosity at 80 degrees C of this polyol (a2) was 5 Pa.s.

<Production Method of Polyol (a3: Synthesis Example a-3)>

Like polyol (a1), polyol (a3) having a hydroxyl concentration of 1.8 mol / kg was obtained from 603 g of isophthalic acid and 462 g of diethylene glycol. The melt viscosity at 80 degrees C of this polyol (a3) was 12 Pa.s.

<Production Method of Polyol (a4: Synthesis Example a-4)>

Like polyol (a1), polyol (a4) having a hydroxyl concentration of 5.3 mol / kg was obtained from 429 g of phthalic anhydride and 571 g of diethylene glycol. The melt viscosity at 80 degrees C of this polyol (a4) was 0.2 Pa.s.

<Production Method of Polyol (a5: Synthesis Example a-5)>

Like polyol (a1), polyol (a5) having a hydroxyl concentration of 0.50 mol / kg was obtained from 568 g of phthalic anhydride and 432 g of diethylene glycol. The melt viscosity at 80 degrees C of this polyol (a5) was 12 Pa.s.

<Production Method of Polyol (a6: Synthesis Example a-6)>

Like polyol (a1), polyol (a6) having a hydroxyl concentration of 2.1 mol / kg was obtained from 603 g of terephthalic acid and 462 g of diethylene glycol. The melt viscosity at 80 degrees C of this polyol (a6) was 60 Pa.s. On the other hand, the molten state at 80 ° C. of the resin was a heterogeneous system in which some crystal components were dispersed.

<Production Method of Polyol (a7: Synthesis Example a-7)>

Like polyol (a1), polyol (a7) having a hydroxyl concentration of 2.1 mol / kg was obtained from 538 g of phthalic anhydride and 463 g of neopentyl glycol. The melt viscosity at 80 degrees C of this polyol (a7) was 430 Pa.s.

<Production Method of Polyol (a8: Synthesis Example a-8)>

Like polyol (a1), polyol (a8) having a hydroxyl concentration of 2 mol / kg was obtained from 559 g of adipic acid and 441 g of 1,4-butanediol. Melt viscosity at 80 degrees C of this polyol (a8) was 0.2 Pa.s.

<Production Method of Polyol (a9: Synthesis Example a-9)>

Like polyol (a1), polyol (a9) having a hydroxyl concentration of 1 mol / kg was obtained from 583 g of adipic acid and 417 g of 1,4-butanediol. Melt viscosity at 80 degrees C of this polyol (a9) was 0.5 Pa.s.

The above polyols a1 to a9 are shown in Table 1 below.

Table 1

(Abbreviated)

APA: phthalic anhydride

IPA: isophthalic acid

TPA: Terephthalic Acid

AA: adipic acid

DEG: Diethylene Glycol

NPG: Neopentylglycol

BD: 1,4-butanediol

Example c1 To c4 , Comparative example c1 To c6  <Polyurethane Resin (c)>

Example c1 (polyurethane resin c1)

Into the flask, 1,053 g of polyol (a1) and 73.4 g of hexamethylene diisocyanate were mixed and subjected to a polyaddition reaction at 75 ° C. for 8 hours while stirring under a nitrogen stream to obtain a polyurethane resin (c1) having a hydroxyl concentration of 1 mol / kg. Got it. Melt viscosity at 80 degreeC of this resin was 4 Pa.s.

Example c2 (polyurethane resin c2)

Like the polyurethane resin (c1), a polyurethane resin (c2) having a hydroxyl concentration of 1 mol / kg was obtained from 1,053 g of the polyol (a1) and 90.8 g of lysine diisocyanate. Melt viscosity at 80 degrees C of this resin was 5.7 Pa.s.

Comparative Example c1 (Polyurethane Resin c3)

Like the polyurethane resin (c1), a polyurethane resin (c3) having a hydroxyl concentration of 1 mol / kg was obtained from 1,053 g of the polyol (a1) and 94.6 g of isophorone diisocyanate. Melt viscosity at 80 degrees C of this resin was 15 Pa.s.

Comparative Example c2 (Polyurethane Resin c4)

Like the polyurethane resin (c1), a polyurethane resin (c4) having a hydroxyl concentration of 1 mol / kg was obtained from 1,053 g of polyol (a1) and 105.2 g of 4,4'-diphenylmethane diisocyanate. Melt viscosity at 80 degrees C of this resin was 18 Pa.s.

Example c3 (polyurethane resin c5)

Like the polyurethane resin (c1), a polyurethane resin (c5) having a hydroxyl concentration of 0.50 mol / kg was obtained from 1,053 g of a polyol (a2) and 42.4 g of hexamethylene diisocyanate. Melt viscosity at 80 degrees C of this resin was 9 Pa.s.

Example c4 (polyurethane resin c6)

Like the polyurethane resin (c1), a polyurethane resin (c6) having a hydroxyl concentration of 1 mol / kg was obtained from 1,053 g of polyol (a3) and 65.3 g of hexamethylene diisocyanate. Melt viscosity at 80 degrees C of this resin was 9.5 Pa.s.

Comparative Example c3 (Polyurethane Resin c7)

Like the polyurethane resin (c1), a polyurethane resin (c7) having a hydroxyl concentration of 1 mol / kg was obtained from 1,053 g of a polyol (a4) and 347.8 g of hexamethylene diisocyanate. Melt viscosity at 80 degreeC of this resin was 6.5 Pa.s.

Comparative Example c4 (Polyurethane Resin c8)

Like the polyurethane resin (c1), a polyurethane resin (c8) having a hydroxyl concentration of 1 mol / kg was obtained from 1,053 g of a polyol (a6) and 89.2 g of hexamethylene diisocyanate. Melt viscosity at 80 degrees C of this resin was 51 Pa.s. On the other hand, the molten state at 80 ° C. of the resin was a heterogeneous system in which some crystalline components were dispersed.

Comparative Example c5 (Polyurethane Resin c9)

Like the polyurethane resin (c1), since it is impossible to stir at 75 ° C, the temperature is 120 ° C, and the polyurethane resin (c9) having a hydroxyl group concentration of 1 mol / kg from 1,053 g of polyol (a7) and 89.2 g of hexamethylene diisocyanate is used. ) Melt viscosity at 80 degrees C of this resin was not measurable (greater than 500 Pa.s).

Comparative Example c6 (Polyurethane Resin c10)

Like the polyurethane resin (c1), a polyurethane resin (c10) having a hydroxyl concentration of 1 mol / kg was obtained from 1,053 g of polyol (a8) and 81.6 g of hexamethylene diisocyanate. Melt viscosity at 80 degrees C of this resin was 1 Pa.s.

For reference, the melt viscosity at 80 ° C. of the polyester polyols (a2, a5, a9) in which these polyurethane resins and hydroxyl group concentrations are close is shown in Table 2-2.

Table 2-1

(Abbreviated)

HDI: hexamethylene diisocyanate

LDI: Lysine Diisocyanate

IPDI: isophorone diisocyanate

MDI: 4,4'-diphenylmethane diisocyanate

Table 2-2

(Abbreviated)

HDI: hexamethylene diisocyanate

<Method of preparing the compounding subject (a2-9)>

750 g of polyol (a2) and 250 g of polyol (a9) were mixed to obtain a compounding agent (a2-9). The hydroxyl concentration of the said compounding subject was 1 mol / kg.

<Method for producing hardener (IIa)>

Takeda Yakuhin High School Takeate D-165N 500g and Japanese Polyurethane Colonate HX 500g were mixed to obtain a curing agent (IIa). The isocyanate group concentration of the said hardening | curing agent was 5.3 mol / kg (isocyanate group content 22 mass%).

<Method for producing hardener (IIb)>

865 g of Asahi Kasei Duranate TPA-100 and 135 g of a polyol (a1) were mix | blended with the flask, and it carried out the polyaddition reaction at 75 degreeC for 8 hours, stirring, under nitrogen stream, and obtained hardening | curing agent (IIb). The isocyanate group concentration of the said hardening | curing agent was 4.5 mol / kg (isocyanate group content 19 mass%).

Example  1 to 5, Comparative example  1-12 <Adhesive Composition>

As a main subject, the polyols (a2, a5, a9), blended polyols (a2-9), polyurethane resins (c1 to c10), and curing agents (IIa and IIb) obtained in the above synthesis examples were mixed in the formulations shown in Table 3, , The adhesive composition of the present invention and the comparative example was obtained.

[Evaluation results]

Table 3-1

Table 3-2

Table 3-3

The evaluation method of evaluation in the above table is as follows.

(Hydroxyl concentration)

The evaluation target was measured based on JIS K 0070.

(Isocyanate group concentration)

The evaluation object was measured based on JISK1603.

(Melt viscosity)

The melt viscosity in 80 degreeC was measured for the evaluation object by the BM-type rotational viscometer.

(Paintability)

Coating aptitude at the time of thin film coating with a squeeze roll coater of 2 micrometers thickness was evaluated.

○: Good appearance, △: Abnormal appearance (poor coating smoothness), ×: Coating impossible

(Aluminum foil adhesiveness)

About 25 micrometers thick aluminum foil, an adhesive composition was thin-film-coated, it bonded together with the corona surface-treated linear low density polyethylene resin of 60 micrometers in thickness, and after 7 days at 40 degreeC, the coating film in 25 degreeC The peeling state at the time of peeling off from an aluminum foil for every linear low density polyethylene resin was evaluated.

○: substrate breaking, ×: easy peeling, ND: no coating, so no data

(PET adhesiveness)

For PET having a thickness of 25 μm, the adhesive composition was coated with a thin film having a thickness of 2 μm, bonded with a corona surface-treated linear low density polyethylene resin having a thickness of 60 μm for reinforcement of the coating film, and after 7 days at 40 ° C., 25 Peeling strength at the time of peeling off a coating film from PET for every linear low density polyethylene resin in ° C was evaluated.

○: substrate breaking, X: easy peeling, ND: no coating, so no data

(Curable)

In evaluation of PET adhesiveness, it peeled at 40 degreeC and the time of three days passed, and the hardening state of the adhesive composition was evaluated.

○: good curing (no adhesion), ×: non-hardening (adhesion), ND: no coating because no coating

As mentioned above, according to this invention, the polyurethane resin which has a high adhesiveness with respect to a film especially, has a low melt viscosity, is excellent in thin-film coating aptitude, and has a short hardening time at the time of setting it as a composition with polyisocyanate is provided. . Such a resin is useful for various applications and is particularly suitable as a resin for an adhesive that gives high adhesion to a film.

Claims (6)

In the polyurethane resin obtained by reacting a polyol and a polyisocyanate, When the said polyol makes 100 mol% of all polyols, at least 80 mol% of it is a polyester polyol (a), and when the total acid component of the said polyester polyol (a) is 100 mol%, At least 80 mol% is a benzene-o-dicarboxylic acid component and / or a benzene-m-dicarboxylic acid component, When the total alcohol component of the polyester polyol (a) is 100 mol%, at least 50 mol% thereof is a dialcohol component having 2-3 alkylene groups bonded to each other via an ether bond. The said polyester polyol (a) has 0.55-5 mol / kg average of hydroxyl groups in the molecular terminal, The said polyisocyanate is a polyisocyanate containing at least 70 mass% of diisocyanate (b) of the molecular weight 250 or less which does not have a ring structure in the structure when 100 mass% of all polyisocyanates are included, The polyurethane resin ( c). The polyurethane resin (c) according to claim 1, wherein a melt viscosity at 80 ° C. is 10 Pa · s or less. The melt viscosity at 80 ° C. of the polyurethane resin (c) has the same composition as the polyester polyol (a) used in the production of the polyurethane resin (c), and the polyurethane resin (c). Polyurethane resin (c) lower than the melt viscosity of the polyester polyol having the same molecular weight as. In the adhesive composition which consists of the main body (I) which has a polyol as a main component, and the hardening | curing agent (II) which has a polyisocyanate as a main component, When the total amount of the above-mentioned main ingredient (I) is 100 mass%, 50-100 mass% of it is the polyurethane resin (c) in any one of Claims 1-3, and the said hardening | curing agent (II) Isocyanate group content is at least 10 mass%, The stoichiometric ratio (isocyanate group / hydroxyl group) of the terminal group of the said main ingredient (I) and the said hardening | curing agent (II) is 1.0-5.0, non-volatile content is at least 98 mass%, and is substantially free of an organic solvent, It is characterized by the above-mentioned. Adhesive composition. A lamination method comprising laminating a plurality of films or sheets using the adhesive composition according to claim 4. The plurality of films or sheets are laminated | stacked using the adhesive composition of Claim 4. The laminated body characterized by the above-mentioned.