TW201936837A - Hot-melt polyurethane adhesive film and layered fibrous structure - Google Patents

Abstract

Use is made of a hot-melt polyurethane adhesive film that comprises a first hot-melt polyurethane layer, a second hot-melt polyurethane layer, and a third polyurethane layer, which is interposed between the first hot-melt polyurethane layer and the second hot-melt polyurethane layer, wherein the third polyurethane layer has a higher softening temperature than the first hot-melt polyurethane layer and the second hot-melt polyurethane layer.

Description

   Hot-melt polyurethane adhesive film and laminated fiber structure   

The present invention relates to a hot-melt polyurethane adhesive film and a laminated fibrous structure formed by bonding fiber substrates to each other.

The hot-melt polyurethane adhesive film is used to adhere fiber substrates to each other. For example, it is known that a shoe upper (upper material) of a sports shoe has a hot-melt polyurethane adhesive film between a low-density mesh knitted fabric and an apparent A stacked body is formed between fibrous base materials like artificial leather having a higher density than the mesh knitted fabric, and the stacked body is hot-pressed to adhere the artificial leather to the surface of the mesh knitted fabric.

The conventional hot-melt polyurethane adhesive film is designed to be rapidly melted when it reaches a predetermined temperature in the hot-pressing step, and to be rapidly solidified if it reaches a predetermined temperature or lower. For example, the following Patent Document 1 discloses a polyurethane hot-melt polyurethane adhesive, which is a thermally adhesive polyurethane film containing the following as a main component: Thermoplastic diurethane obtained by the reaction of a family of diisocyanates, aromatic diisocyanates, polymer diols, and chain extenders; as a melt viscosity behavior, it is sensitive to temperature, and has softness at low temperatures, Thermoplastic polyurethane adhesive with good chemical resistance, dry cleaning resistance, heat resistance, and good bonding strength.

In addition, the following Patent Document 2 discloses a film for bonding automotive interior materials, in which an outer layer and an inner layer are made of a polyethylene resin, and an intermediate layer is a synthetic material having a melting point higher than that of the polyethylene resin by 30 ° C or more. Resin composition. In addition, Patent Document 2 discloses a resin in which nylon and ethylene-vinyl alcohol are copolymerized as an intermediate layer. However, since the polyethylene-based resin-based bonding film has high rigidity, the fiber structure obtained by bonding the mesh knitted fabric and artificial leather having an apparent density higher than that of the mesh knitted fabric is hardened. Because of its low moisture permeability, it cannot be used as a shoe upper.

Advance technical literature Patent literature

Patent Document 1 Japanese Patent Application Laid-Open No. 7-97560

Patent Document 2 Japanese Unexamined Patent Publication No. 7-68721

For example, in order to adhere artificial leather with few voids and high apparent density to the surface of a mesh knitted fabric with low fiber density, many voids, and low apparent density, a hot-melt polyurethane adhesive is intended. The film is in between, and the bonding is performed by a one-stage hot pressing step. Since the hot-melt polyurethane adhesive will preferentially invade the side of the mesh knitted fabric, the hot-melt polyurethane The adhesive becomes difficult to penetrate to the side of the artificial leather, so the anchor effect is deviated, and it is difficult to perform the bonding in a manner that maintains a high bonding strength. Therefore, it is necessary to work on the steps as follows: At the beginning, after the hot-melt polyurethane adhesive is sufficiently infiltrated into the artificial leather through the first stage of hot-pressing treatment, the hot-melt polyurethane is already made. The artificial leather penetrated by the formate adhesive is superimposed on the surface of the mesh knitted fabric, and is subjected to the second stage of hot pressing treatment, thereby adjusting the distribution of the two materials by the hot-melt polyurethane adhesive. Maintain high bonding strength.

An object of the present invention is to provide a heat that can easily maintain a high bonding strength when bonding substrates having different apparent densities, which are likely to cause differences in penetration of hot-melt polyurethane adhesives, to adhere to each other. A melted polyurethane adhesive film, and a laminated fibrous structure formed by using the fibrous base materials having different apparent densities as bonding substrates using the same.

An aspect of the present invention is a hot-melt polyurethane adhesive film, comprising: a first hot-melt polyurethane layer; a second hot-melt polyurethane layer; 1 the third polyurethane layer between the hot-melt polyurethane layer and the second hot-melt polyurethane layer; and the softening temperature of the third polyurethane layer is higher than Softening temperatures of the first hot-melt polyurethane layer and the second hot-melt polyurethane layer. In the case of such a hot-melt polyurethane adhesive film, between the first hot-melt polyurethane layer and the second hot-melt polyurethane layer, which contribute to the adhesion, A third polyurethane layer with a high softening temperature is arranged, and the third polyurethane layer becomes a barrier layer, which suppresses the first hot-melt polyurethane layer and the second hot-melt polymerization during heating. The urethane layers are mixed together due to the force imparted at the time of adhering, and the first hot-melt polyurethane layer or the second hot-melt polyurethane layer will only penetrate into Opposed substrates facing each other. Accordingly, the hot-melt polyurethane of each hot-melt polyurethane layer can be sufficiently penetrated into each of the substrates to be bonded, and a high bonding strength can be maintained.

In addition, if the softening temperature of the third polyurethane layer is higher than the softening temperature of the first hot-melt polyurethane layer by 20 ° C or more, the first hot-melt polyurethane layer can be made. From the viewpoint of sufficiently penetrating into the adhered substrate facing the first hot-melt polyurethane layer, it is preferable.

The softening temperature of the third polyurethane layer is 20 ° C or more higher than the softening temperature of the first hot-melt polyurethane layer and the softening temperature of the second hot-melt polyurethane layer. From sufficiently enabling the first hot-melt polyurethane layer to penetrate into the adhered substrate opposite to the first hot-melt polyurethane layer, and to enable the second hot-melt polyurethane It is preferable that the ester layer sufficiently penetrates the substrate to be adhered to the second hot-melt polyurethane layer.

When the softening temperature of the first hot-melt polyurethane layer is higher than the softening temperature of the second hot-melt polyurethane layer by 5 ° C or more, the first hot-melt polyurethane layer is made softer. The formate layer is opposed to the substrate having a low apparent density, and the second hot-melt polyurethane layer is opposed to the substrate having a high apparent density, so that each of the hot-melt polyamine groups can be made. It is preferable that the formate layer penetrates into each adhered substrate in a well-balanced manner.

In addition, if the thickness of the third polyurethane layer is 10 to 110 μm, sufficient strength is maintained in the hot-pressing step so that it is not easily broken, and the laminated layer obtained by adhering the substrates to each other is not made. From the viewpoint of hardening the texture of the fiber structure, it is preferable.

In addition, when the 100% modulus of the third polyurethane layer at 25 ° C is 2 to 7 MPa, the point of never hardening the texture of the laminated fiber structure obtained by adhering the adhered substrate to each other is from the point that Look, is better.

In addition, the storage modulus E ′ of the third polyurethane layer at 140 ° C. is 2 to 30 MPa, because it is not easily damaged during hot pressing and exhibits a sufficient barrier effect. good.

Furthermore, another aspect of the present invention is a hot-melt polyurethane adhesive film, comprising: a first hot-melt polyurethane layer; and a second hot-melt polyurethane layer; and The first hot-melt polyurethane layer has a softening temperature higher than that of the second hot-melt polyurethane layer. According to such a hot-melt polyurethane adhesive film, the first hot-melt polyurethane layer is caused to face the adhered substrate having a low apparent density, and the second hot-melt polymer is formed. The urethane layer is opposed to the adhered substrate having a high apparent density, and it is preferable from the point that each hot-melt polyurethane layer can penetrate into the adhered substrate in a balanced manner. .

Furthermore, another aspect of the present invention is a laminated fibrous structure formed by bonding two fibrous substrates having different apparent densities from each other using the hot-melt polyurethane adhesive film. According to such a laminated fiber structure, it is possible to maintain high adhesion strength of two fiber substrates having different apparent densities. In particular, even when the apparent density of one of the two fibrous substrates is 1.5 times or more the apparent density of the other fibrous substrate, the fibrous substrates have a large difference in apparent density. Even after the bonding, a high bonding strength can be maintained.

According to the present invention, it is possible to obtain a hot-melt polyurethane adhesive film and a laminated fiber structure that maintains high adhesion strength by using the same and then adhering two fiber substrates having different apparent densities; the The hot-melt polyurethane adhesive film can easily maintain high adhesive strength when adhering substrates having different apparent densities to each other.

1, 21‧‧‧ the first hot-melt polyurethane layer

2. 22‧‧‧ 2nd Hot Melt Polyurethane Layer

3‧‧‧ 3rd polyurethane layer

10, 30‧‧‧ hot-melt polyurethane adhesive film

11‧‧‧ Fiber substrate with low apparent density

12‧‧‧ fiber substrate with high apparent density

FIG. 1 is a schematic cross-sectional view of a hot-melt polyurethane adhesive film 10 according to a first embodiment.

FIG. 2 is a schematic explanatory diagram for explaining a state in which fibrous substrates having different apparent densities are adhered using the hot-melt polyurethane adhesive film 10.

FIG. 3 is a schematic cross-sectional view of a hot-melt adhesive film 30 according to a second embodiment.

Forms used to implement the invention     [First Embodiment]    

The hot-melt polyurethane adhesive film of the first embodiment will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a hot-melt polyurethane adhesive film 10 according to a first embodiment. As shown in FIG. 1, the hot-melt adhesive film 10 has a three-layer structure including a first hot-melt polyurethane layer 1, a second hot-melt polyurethane layer 2, and the like. A third polyurethane layer 3 is interposed between the first hot-melt polyurethane layer 1 and the second hot-melt polyurethane layer 2.

Each of the first hot-melt polyurethane layer, the second hot-melt polyurethane layer, and the third polyurethane layer is made of a polyurethane having a softening temperature. Composition of layers. Then, the first hot-melt polyurethane layer and the second hot-melt polyurethane layer are adhesive layers that exhibit hot-melt properties by heating. The softening temperature of the third polyurethane layer is higher than the softening temperature of the first hot-melt polyurethane layer and the second hot-melt adhesive layer. A polyurethane layer that is melted by heating.

In the hot-melt adhesive film 10, between the first hot-melt polyurethane layer 1 and the second hot-melt polyurethane layer 2 which contribute to the adhesion, a third, which is not easily melted, is arranged. Polyurethane layer 3. Referring to FIG. 2, by using such a layer structure, for example, when a fibrous base material 12 having high fiber density and high apparent density like artificial leather is used, a hot-melt polyurethane adhesive film 10 is used. After the thermal compression bonding step by hot pressing, and then to the fiber base material 11 having a low fiber density and a low apparent density like a mesh knitted fabric, the third polyurethane layer 3 becomes a barrier. Layer to prevent the first hot-melt polyurethane layer 1 and the second hot-melt polyurethane layer 2 from being mixed together, so that the first hot-melt polyurethane layer 1 can penetrate into the fiber The base material 11 penetrates the second hot-melt polyurethane layer 2 to the fiber base material 12. Therefore, the hot-melt polyurethane does not tend to penetrate into the fiber base material 11 having a low apparent density like a mesh knitted fabric, and the hot-melt polyurethane can sufficiently penetrate into the artificial substrate, A fibrous substrate 12 having a leather-like apparent density.

The softening temperature of the third polyurethane layer is higher than the softening temperature of the first hot-melt polyurethane layer by 20 ° C or more. In the thermal compression bonding step generally using a hot-melt adhesive film, from The barrier effect of the third polyurethane layer is sufficiently exerted, and it is preferable that the first hot-melt polyurethane layer can sufficiently penetrate into the substrate to be opposed to the first hot-melt polyurethane layer. . The softening temperature of the third polyurethane layer is higher than the softening temperature of the first hot-melt polyurethane layer and the second hot-melt polyurethane layer by 20 ° C or higher. In the thermal compression bonding step using the hot-melt polyurethane adhesive film, the first hot-melt polyurethane layer can be sufficiently penetrated into the substrate to be opposed thereto, and the first 2 It is preferable that the hot-melt polyurethane layer sufficiently penetrates into the substrate to be opposed thereto.

The softening temperature of the first hot-melt polyurethane layer and the softening temperature of the second hot-melt polyurethane layer may be the same temperature or different temperatures, depending on each hot-melt polyamine. The type of substrate to which the urethane layer is attached is appropriately selected to a preferred softening temperature. For example, as shown in FIG. 2, when the first hot-melt polyurethane layer 1 is made to face the fiber substrate 11 having a low apparent density, and the second hot-melt polyurethane layer 2 is made In the case of a fiber base material 12 having a high apparent density, the softening temperature of the first hot-melt polyurethane layer 1 relative to the fiber base material 11 having a low apparent density is increased, and the surface softness is lowered. The softening temperature of the fibrous base material 12 relative to the second hot-melt polyurethane layer 2 is from the point that the hot-melt polyurethane layers can penetrate into the fibrous base materials in a well-balanced manner. Is better. In this case, the softening temperature of the first hot-melt polyurethane layer 1 is preferably higher than the softening temperature of the second hot-melt polyurethane layer 2 by 5 ° C or more, and more preferably 10 times higher. Above ℃.

The softening temperature of the first hot-melt polyurethane layer and the second hot-melt polyurethane layer functioning as an adhesive layer is 100 to 140 ° C, and further about 110 to 135 ° C. In general, under the bonding conditions generally used with a hot-melt polyurethane adhesive film, it can be rapidly melted or softened, and sufficient bonding strength can be imparted to the laminated structure obtained by bonding the bonded substrates to each other. From the point of view, it is better.

The softening temperature of the third polyurethane layer functioning as a barrier layer is 145 to 195 ° C, and more preferably 150 to 160 ° C. Generally, a hot melt polyurethane is used. The bonding conditions of the acid-ester adhesive film are preferable from the viewpoint that they do not melt and soften moderately. When the softening temperature of the 3rd polyurethane layer is too high, there exists a tendency for it to become hard and a handle will fall.

The third polyurethane layer having a thickness of 10 to 110 μm, and further to 20 to 70 μm, will maintain sufficient strength during hot pressing, and will not cause a laminate obtained by adhering the adhered substrates to each other. From the viewpoint of hardening the texture of the structure, it is preferable.

The thicknesses of the first hot-melt polyurethane layer and the second hot-melt polyurethane layer are appropriately selected depending on the type of the substrate to be adhered, and are, for example, 20 to 300 μm. Further, It is preferable that it is 30-250 micrometers from the point which can maintain sufficient adhesive strength.

The 100% modulus of the third polyurethane layer at 25 ° C. is 2 to 7 MPa, further 2.5 to 5.5 MPa, and particularly 3.0 to 4.5 MPa, which never makes the adhered substrates adhere to each other. From the viewpoint of the hardening of the laminated structure, it is preferable. When the 100% modulus of the third polyurethane layer at 25 ° C. is too low, the third polyurethane layer becomes weak and easily peels off from the third polyurethane layer. Then, the strength becomes insufficient. When the 100% modulus is too high, the third polyurethane layer becomes hard, and the texture of the obtained laminated structure tends to harden.

The 100% modulus of the first polyurethane layer and the second polyurethane layer at 25 ° C is 2 to 7 MPa, further 2.5 to 5.5 MPa, and particularly 3.0 to 4.5 MPa. It is preferable from the point which does not harden the feel of the laminated structure obtained by adhering a to-be-adhered base material to each other.

In addition, the storage modulus E ′ of the third polyurethane layer at 140 ° C. is 2 to 30 MPa, and further 2 to 5 MPa, which is less likely to be damaged during hot pressing and exhibits the first hot melt polymerization. It is preferable that the urethane layer and the second hot-melt polyurethane layer do not mix together with a sufficient barrier effect. In addition, the storage modulus E 'of the first polyurethane layer and the second polyurethane layer at 140 ° C is preferably one which cannot be measured because it is melted at 140 ° C.

The hot-melt polyurethane adhesive film of the first embodiment described above has a three-layer structure including a first hot-melt polyurethane layer and a second hot-melt adhesive. Layer and the third polyurethane layer; as long as the effect of the present invention is not impaired, the inner layer may further include other layers if necessary.

    [Second Embodiment]    

The hot-melt polyurethane adhesive film of the second embodiment will be described with reference to the drawings. Fig. 3 is a schematic cross-sectional view of a hot-melt polyurethane adhesive film 30 according to a second embodiment. As shown in FIG. 3, the hot-melt polyurethane adhesive film 30 has a two-layer structure including a first hot-melt polyurethane layer 21 and a second hot-melt polyurethane.基 carboxylic acid ester layer 22.

The difference between the hot-melt polyurethane adhesive film 30 of the second embodiment and the hot-melt polyurethane adhesive film 10 of the first embodiment is that it does not have a third polyurethane The point of the formate layer and the softening temperature of the first hot-melt polyurethane layer must be higher than the softening temperature of the second hot-melt polyurethane layer. By adopting such a layer structure, for example, a fibrous base material with high fiber density and high apparent density, such as artificial leather, is bonded to the fibrous base material, such as artificial leather, through a heat bonding step by hot pressing using the hot melt adhesive film 30. In the case of a knitted fabric-like fiber base material having a low fiber density and a low apparent density, the first hot-melt polyurethane layer having a high softening temperature and difficult to melt and a fiber base having a low apparent density are used. The second hot-melt polyurethane layer with high softening temperature and easy melting is opposed to the fibrous base material with high apparent density, so that each hot-melt polyurethane layer can be well-balanced. Ground penetrates into each fiber substrate.

In the hot-melt polyurethane adhesive film of the second embodiment, the softening temperature of the first hot-melt polyurethane layer is higher than the softening temperature of the second hot-melt polyurethane layer. When the temperature is higher than or equal to 10 ° C and further higher than or equal to 10 ° C, the hot-melt properties of each hot-melt polyurethane layer can be adjusted to allow the first hot-melt polyurethane layer to sufficiently penetrate into the opposite side of the hot-melt polyurethane layer. It is preferable that the base material sufficiently infiltrates the second hot-melt polyurethane layer into the opposite base material to be bonded.

The softening temperature of the first hot-melt polyurethane layer is 115 to 140 ° C, and further about 120 to 135 ° C. The softening temperature of the second hot-melt polyurethane layer is, If the temperature is 100 to 130 ° C, and further to about 105 to 125 ° C, the hot melt polyurethane adhesive film is generally used to quickly melt or soften the bonding conditions under the bonding conditions of the hot melt polyurethane adhesive film, and each hot melt polyamine is adjusted. The hot-melt property of the urethane layer allows the first hot-melt polyurethane layer to sufficiently penetrate into the substrate to be opposed to the first hot-melt polyurethane layer, and the second hot-melt polyurethane layer to be sufficient. It is preferable that the ground penetrates into the opposite substrate to be adhered.

In the hot-melt polyurethane adhesive film of the second embodiment, the thicknesses of the first hot-melt polyurethane layer and the second hot-melt polyurethane layer are also determined in accordance with The type of the substrate to be adhered is appropriately selected. For example, 20 to 300 μm, and further 30 to 250 μm are preferable from the viewpoint of maintaining sufficient adhesive strength.

The hot-melt polyurethane adhesive film of the second embodiment described above has a two-layer structure including a first hot-melt polyurethane layer and a second hot-melt layer. Polyurethane layer; as long as the effect of the present invention is not impaired, the inner layer may further include other layers as necessary.

    [Specific examples of the first hot-melt polyurethane layer, the second hot-melt polyurethane layer, and the third polyurethane layer]    

The polyurethane having a softening temperature for forming each layer described in the first embodiment and the second embodiment is a thermoplastic polyurethane. With the thermoplastic polyurethane, the softening of each layer of the first hot-melt polyurethane layer, the second hot-melt polyurethane layer, and the third polyurethane layer can be adjusted. Temperature, melt viscosity.

The thermoplastic polyurethane can be obtained by a polymerization method of a polymer polyol, a polyisocyanate, and a thermoplastic polyurethane which reacts with a chain elongator; the polymerization method of the thermoplastic polyurethane is It is performed by conventionally known bulk polymerization, solution polymerization, aqueous dispersion polymerization, and the like. Among these, from the viewpoint of good volume reaction efficiency, block polymerization is preferred. The method of bulk polymerization is not particularly limited, and examples thereof include the production of a urethane by reacting a polymer polyol and a polyisocyanate under appropriate reaction conditions (for example, a reaction at 80 ° C. for 4 hours). A prepolymer, and a chain extender is added to the obtained urethane prepolymer to polymerize a polyurethane; a polymer polyol, a polyisocyanate, and a chain extender One-shot method of polymerization is performed simultaneously.

In addition, the thermoplastic polyurethane is a polyurethane obtained by reacting as a main component the following: a bifunctional polymer polyol (to maintain thermoplasticity without forming a branched structure ( Polymer diol), bifunctional polyisocyanate (diisocyanate), and chain extender; as long as it is in a range that can maintain sufficient thermoplasticity without impairing the effect of the present invention, a trifunctional or more functional compound can be used as a raw material if necessary .

Specific examples of the polymer polyol that can be used in the production of thermoplastic polyurethanes include, for example, polyether polyols (polyether glycols), polyethylene glycols, polypropylene glycols, and polybutadienes. Aliphatic polyether glycols such as alcohols and polytetramethylene glycols. These can be used alone or in combination of two or more. Among these, the case where the polyether polyol is contained in a polyol of 60% by mass or more is preferable from the viewpoint of excellent hydrolysis resistance.

In terms of the number average molecular weight of the polymer polyol, 500 to 5000, further 600 to 4500, and particularly 700 to 4000 are preferable. When the number average molecular weight of the polymer polyol is too low, the flexibility tends to decrease, and when it is too high, the mechanical properties tend to decrease.

Specific examples of the polyisocyanate include benzene diisocyanate, toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and naphthalene diisocyanate. Isocyanates, xylylene diisocyanate and other aromatic diisocyanates; hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl methane diisocyanate Isocyanates, tetramethyl xylylene diisocyanate and other aliphatic diisocyanates or cycloaliphatic diisocyanates; 4,4'-diphenylmethane diisocyanate dimers and terpolymers Polymerized diphenylmethane diisocyanate and the like.

These can be used alone or in combination of two or more.

Examples of the chain elongating agent include low-molecular compounds having a molecular weight of 400 or less, which have two hydrogen atoms capable of reacting with an isocyanate group in the molecule, which have been conventionally used in the production of polyurethane. Specific examples of the chain extender include, for example, hydrazine, ethylene diamine, propylene diamine, xylylene diamine, isophorone diamine, and piperazine. And its derivatives, phenylenediamine, tolylenediamine, xylenediamine, dihydrazine adipate, dihydrazide isophthalate, hexamethylenediamine, 4,4'-diamine Diamine compounds such as phenylphenylmethane, 4,4'-dicyclohexylmethanediamine; ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexane Diols, bis (β-hydroxyethyl) terephthalate, 3-methyl-1,5-pentanediol, cyclohexanediol, xylylene glycol, 1,4-bis Diol compounds such as (β-hydroxyethoxy) benzene and neopentyl glycol; amino alcohols such as aminoethanol and aminopropanol. These may be used alone or in combination of two or more.

In addition to the above-mentioned chain elongation agents, monoamine compounds such as ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, tertiary butylamine, and cyclohexylamine may be used in combination to adjust the molecular weight, or ε may be used in combination. -Aminohexanoic acid (6-aminohexanoic acid), γ-aminobutanoic acid (4-aminobutanoic acid), aminocyclohexanecarboxylic acid, aminobenzoic acid and the like, and introduce carboxyl groups To the end.

In terms of the reaction ratio of the polymer polyol, chain extender, and polyisocyanate, the isocyanate index is preferably 0.85 to 1.1, and more preferably about 0.9 to 1.0. Equivalent ratio of the hydroxyl group in the polyol of the molecular polyol and the active hydrogen group of the chain extender. When the isocyanate index is high, the softening temperature of the thermoplastic polyurethane tends to be high; when the isocyanate index is low, the softening temperature is low, and the mechanical properties are lowered, and then the strength is lowered.

Thermoplastic polyurethanes can also be blended with additives as needed. Specific examples of additives include: known antioxidants such as hindered amines and hindered phenols; benzotriazoles and dibenzenes Ketone series, three Series of lightfasteners; colorants such as pigments and dyes.

The thermoplastic polyurethane used to form the first hot-melt polyurethane layer, the second hot-melt polyurethane layer, and the third polyurethane layer, as long as It is a combination that satisfies the above-mentioned softening temperature, and its type, monomer composition, and the like are not particularly limited.

    [Next method]    

The hot-melt polyurethane adhesive film described in the first embodiment and the second embodiment is preferably used for the penetration of the adhesive through the anchoring effect and subsequent apparent densities which are different from each other. The adhered substrates are adhered to each other. The type of the substrate to be bonded is not particularly limited, and examples thereof include knitted fabrics such as nonwoven fabrics, woven fabrics, and mesh knitted fabrics, artificial leather, and porous resin films.

In particular, a fibrous substrate having a different apparent density, such as a nonwoven fabric and a woven fabric, a nonwoven fabric and a knitted fabric, an artificial leather and a fabric, and an artificial leather and a knitted fabric, is used as a bonded substrate, and such fiber substrates are bonded to each other This will achieve a particularly significant effect. The artificial leather is a fibrous base material obtained by impregnating an elastic polymer such as polyurethane with a fibrous base material such as a nonwoven fabric. More specifically, it is preferable to use two fiber substrates each having an apparent density of one fiber substrate of 1.3 times or more and 1.5 times or more of the apparent density of the other fiber substrate. What happened next.

Next, there can be mentioned: forming a stacked body in which a hot-melt polyurethane adhesive film is interposed between two adhered substrates, and heating and pressing while applying heat and pressure through a heat roller Proceed with the next method. The surface temperature of the hot-pressed and hot-rolled molds is suitable according to the softening temperature of the first hot-melt polyurethane layer, the second hot-melt polyurethane layer, and the third polyurethane layer. select. Generally, it is suitable to set it in the range of 100 ~ 160 ° C.

A laminated fibrous structure obtained by bonding two fibrous substrates having different apparent densities to each other using such a hot-melt polyurethane adhesive film is because it is adhered with a polyurethane. Therefore, it retains cushioning properties and is excellent in softness. Therefore, it can be preferably used as a shoe upper material, especially as a shoe upper material.

Examples

The present invention will be specifically described by way of examples. Furthermore, the scope of the invention is not to be construed as being limited in any way by these embodiments.

Initially, the evaluation method of the properties of the thermoplastic polyurethane is described in the following summary.

    <Evaluation of softening temperature and storage modulus at 140 ° C>    

Using a dynamic viscoelasticity measuring device (FT Rheospectra DVE-V4 manufactured by Rheology), a test piece of thermoplastic polyurethane having a width of 5 mm, a length of 30 mm, and a thickness of 250 μm was fixed between chucks spaced at a distance of 20 mm to measure the area 30. Dynamic viscoelastic behavior was measured under the conditions of ~ 300 ° C, heating rate 3 ° C / min, strain 5μm / 20mm, and measurement frequency 10Hz. Then, in the spectrum of the obtained storage modulus (E ′), the temperature at the intersection of the tangent lines inclined before and after melting in a region where E ′ decreases as the thermoplastic polyurethane is melted is set as Softening temperature. The storage modulus E 'at 140 ° C was read.

    <Evaluation of 100% modulus>    

A film having a width of 25 mm × a length of 150 mm × a thickness of 100 μm obtained using a thermoplastic polyurethane was used in accordance with JIS K7311 using a tensile tester (manufactured by Tensilon ORIENTEC Co., Ltd.) at a head speed of 100 mm / min. 100% modulus was measured.

    (Examples 1 to 12, Comparative Examples 1 to 4)    

Using thermoplastic polyurethanes TPU1 to TPU6 having a softening temperature shown in Table 1 below, the films were melt-extruded through a T die to produce films of each thickness shown in Table 1. In addition, a polyethylene laminated film was produced. The polyethylene laminated film was laminated with a low-density polyethylene (LDPE) having a density of 0.921 g / cm ³ as shown in Table 1 as a first hot-melt adhesive layer and a second heat-welded layer. An adhesive layer and a high-density polyethylene (HDPE) having a density of 0.954 g / cm ³ were formed as the third hot-melt adhesive layer.

Then, each of the thermoplastic polyurethane films shown in Table 1 was used as the first hot-melt polyurethane layer (L1), the second hot-melt polyurethane layer (L2), and The third polyurethane layer (L3) is stacked so as to have a layer structure as shown in Table 2 below to form a stacked body of a thin film. Then, the film stack was thermocompression-bonded under a condition of a pressure of 5 kg / cm ² for 30 seconds by a flat-plate hot press, thereby producing hot-melt adhesive films used in the respective examples and comparative examples. Furthermore, in Examples 1, 3-6, 8-10, and Comparative Examples 1, 2 using TPU1, the surface temperature of the flat-plate hot press was set to 120 ° C; in Example 2 using TPU2 In 7, 7, 11, 12 and Comparative Example 3, the surface temperature was set to 140 ° C. In addition, in addition to Comparative Examples 2 and 3, L1 and L2 were each a film having a thickness of 100 μm. In Comparative Examples 2 and 3, a film having a thickness of 200 μm was directly used as a hot-melt polyurethane adhesive film.

Then, a stack is formed, and the stack is a fluffing type artificially treated with a film of each polyurethane hot-melt adhesive between two sides having a thickness of 1.0 mm and an apparent density of 0.6 g / cm ³ . A leather sheet is overlapped with a double-knitted mesh knitted fabric with a thickness of 3.0 mm and an apparent density of 0.3 g / cm ³ . Moreover, in Example 11 and Example 12, L1 of TPU2 was made to oppose a mesh knitted fabric, and L1 of TPU1 was made to oppose a standing type artificial leather sheet.

Then, the stacked body was subjected to thermocompression bonding using a flat-plate hot press under a condition of a pressure of 5 kg / cm ² for 60 seconds. In addition, in the flat hot press, in Example 1, 3-6, 8-10, and Comparative Examples 1 and 2 using TPU1, the surface temperature was set to 120 ° C, and in Example 2 using TPU2 In 7, 7, 11, 12 and Comparative Example 3, the surface temperature was set to 140 ° C. In Comparative Example 4, the surface temperature was set to 115 ° C. Then, it was made to cool at room temperature for 1 day, and the laminated fiber structure was obtained.

Then, the adhesion strength and feel of each of the obtained laminated fiber structures were evaluated according to the following evaluation methods. The results are shown in Table 2.

    <Adhesive strength>    

The tensile strength of the laminated fiber structure was measured using a tensile tester (Tensilon ORIENTEC (strand)). Specifically, in the same manner as in the production of the laminated fibrous structure, when a sample for bonding strength measurement is produced, the sample size is set to a width of 30 mm × a length of 150 mm, and at the time of thermal compression bonding, the end portion in the longitudinal direction is about 30 mm, A non-adhesive portion is provided between the standing fleece type artificial leather sheet and the double comb rassel type mesh knit. Thereafter, both ends in the width direction were trimmed to remove the overflow portion of the adhesive during pressing, and a test piece having a width of 25 mm × a length of 150 mm was produced. Then, each end portion of the non-adhered portion of the test piece was sandwiched between each chuck above and below a tensile testing machine set to an initial interval of 25 mm, and a tensile test was performed at a tensile speed of 50 mm / minute to obtain an elongation. -A graph of peel strength. Then, from the obtained graph, the portion excluding the initial peak is divided into five intervals, the minimum value of the peak in each interval is read, and the average of the five data obtained is used as the adhesion strength.

    <Feel evaluation>    

A test piece obtained by cutting a laminated fiber structure into a 200 mm length by 200 mm length was produced. Then, from a person skilled in the art of artificial leather, five functional inspectors were selected to touch the test piece, and the following criteria were used to determine the softness.

A: The cushioning property of the mesh knitted fabric and the feel of the artificial leather are sufficiently maintained, and the softness is extremely high.

B: The cushioning property of the mesh knitted fabric and the feel of the artificial leather are substantially maintained, and it has a standard softness as a general sneaker upper material.

C: Although there is a rebound feel of resin-like materials, as a general sneaker upper material, it has a feel that is acceptable to a certain extent.

D: Uneven wrinkles are generated at the time of bending, the resin has a strong springback feeling, and lacks flexibility.

As shown in Table 1, the first hot-melt polyurethane layer, the second hot-melt polyurethane layer, and the first hot-melt polyurethane layer and the first hot-melt polyurethane layer interposed therebetween were used. 2 The third polyurethane layer between the hot-melt polyurethane layers; and the softening temperature of the third polyurethane layer is higher than the softening temperature of other adhesive layers The laminated fiber structure of Examples 1 to 11 followed by the urethane adhesive film has a higher bonding strength than the hot-melt polyurethane bonding using only the first hot-melt polyurethane layer. The laminated fiber structure of Comparative Examples 1 to 3 followed by the agent film. The first hot-melt polyurethane layer and the second hot-melt polyurethane layer are used, and the first hot-melt polyurethane layer is more than the second hot-melt polyurethane layer. The laminated fibrous structure of Example 12 followed by the hot-melt polyurethane adhesive film with a high softening temperature of the formate layer was also a laminated fibrous structure having a higher bonding strength than Comparative Examples 1 to 3. In addition, as shown in Comparative Example 4, when an adhesive film composed of a polyethylene layer was used, a laminated fiber structure having poor adhesion strength and hand feeling was obtained.

Claims (12)

    A hot-melt polyurethane adhesive film includes a first hot-melt polyurethane layer, a second hot-melt polyurethane layer, and a first hot-melt polyamine interposed therebetween. A third polyurethane layer between the polyurethane layer and the second hot-melt polyurethane layer; and the softening temperature of the third polyurethane layer is higher than that of the first polyurethane layer Softening temperature of the hot-melt polyurethane layer and the second hot-melt polyurethane layer.         For example, the hot-melt polyurethane adhesive film of claim 1, wherein the softening temperature of the third polyurethane layer is higher than the softening temperature of the first hot-melt polyurethane layer by 20 Above ℃.         For example, the hot-melt polyurethane adhesive film of claim 2, wherein the softening temperature of the third polyurethane layer is higher than the softening temperature of the first hot-melt polyurethane layer and the soft temperature of the first hot-melt polyurethane layer. The softening temperature of the second hot-melt polyurethane layer is higher than 20 ° C.         The hot-melt polyurethane adhesive film according to claim 1, wherein the softening temperature of the first hot-melt polyurethane layer is higher than the softening temperature of the second hot-melt polyurethane layer. Above 5 ° C.         For example, the hot-melt polyurethane adhesive film of claim 1, wherein the softening temperature of the third polyurethane layer is 145 to 195 ° C, and the first hot-melt polyurethane layer and The softening temperature of the second hot-melt polyurethane layer is 100 to 140 ° C.         The hot-melt polyurethane adhesive film according to claim 1, wherein the thickness of the aforementioned third polyurethane layer is 10 to 110 μm.         For example, the hot-melt polyurethane adhesive film of claim 1, wherein the 100% modulus of the third polyurethane layer at 25 ° C is 2 to 7 MPa.         For example, the hot-melt polyurethane adhesive film according to claim 1, wherein the storage modulus E 'of the third polyurethane layer at 140 ° C is 2 to 30 MPa.         A hot-melt polyurethane adhesive film, comprising: a first hot-melt polyurethane layer and a second hot-melt polyurethane layer; and the first hot-melt polyurethane layer The acid layer is higher in softening temperature than the second hot-melt polyurethane layer.         A laminated fibrous structure is formed by bonding two fibrous substrates having different apparent densities from each other by using the hot-melt polyurethane adhesive film according to any one of claims 1 to 9.         For example, the laminated fiber structure of claim 10, wherein the apparent density of one of the two fiber substrates is 1.5 times or more the apparent density of the other fiber substrate.         For example, the laminated fiber structure of claim 10, wherein one of the aforementioned two fiber substrates is a knitted fabric, and the other is an upper material of an artificial leather shoe.