JP2022067626A - Grained artificial leather, manufacturing method of the same, and separate collection method of skin layer of grained artificial leather - Google Patents

Abstract

To provide grained artificial leather which includes an intermediate layer and a skin layer for coating the intermediate layer for forming a grain layer, and which can be separately collected by peeling only the skin layer from the intermediate layer just by simple processing.MEANS: A grained artificial leather includes: a fiber entangled body; an intermediate layer integrated with the fiber entangled body and containing foamed polyurethane; and a skin layer which is laminated on the intermediate layer and whose thickness is 4-20 μm. The skin layer at least includes a first region which contains silicone-modified polyurethane and organic polysiloxane, which comes into contact with the intermediate layer and whose thickness is equal to or greater than 4 μm.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for realizing the recycling and utilization of a material of silver-like artificial leather.

There is known a silver-like artificial leather that has a silver-like appearance similar to natural leather and is used as a skin material for bags, clothing, shoes, and the like. As such a silver-like artificial leather, a fiber entanglement and an intermediate layer including a foamed polyurethane layer and a skin layer coating the intermediate layer for being integrated with the fiber entanglement to form a grain surface layer are provided. It is known to have silver-like artificial leather.

Due to the demand for resource recycling, separate collection has been carried out in the past, in which similar materials are separated and collected from waste. Even in silver-based artificial leather, it is preferable that the materials are separated and collected and recycled as resources. However, in the silver-like artificial leather in which the intermediate layer including the fiber entanglement and the foamed polyurethane layer and the epidermis layer are laminated and integrated, each layer is adhered with a high adhesive force so as not to peel off from each other in the usage environment. Has been sought.

For example, for the purpose of suppressing peeling of the skin layer, the following Patent Document 1 describes silver including a fiber base material and a polyurethane surface film laminated on the surface layer directly on the fiber base material or via another polyurethane layer. Disclosed a leather-like sheet with silver that does not peel off the polyurethane surface even after dropping mono (2-ethylhexyl) phthalate on the surface of the polyurethane surface and leaving it at room temperature for 336 hours. do.

By the way, although it is not a technique for suppressing peeling of the skin layer, the following Patent Document 2 describes adding a silicone-based surfactant to a water-based ink from the viewpoint of improving the storage stability of the water-based ink and the scratch resistance of the printed matter. Is disclosed.

Japanese Unexamined Patent Publication No. 2019-151948 Japanese Unexamined Patent Publication No. 2020-097683

As mentioned above, in the conventional silver-like artificial leather, each layer is adhered to each other with high adhesive force so as not to peel off in the usage environment, and the idea is to separate each layer and separate and collect similar materials. There was no.

INDUSTRIAL APPLICABILITY The present invention is a silver-like artificial leather provided with an intermediate layer and a skin layer for coating the intermediate layer for forming a grain surface layer, and only a simple hot water immersion treatment is performed to remove only the intermediate layer to the skin layer. It is an object of the present invention to provide a silver-like artificial leather that can be peeled off and separately collected.

One aspect of the present invention comprises a fiber entangled body, an intermediate layer containing a foamed polyurethane integrated into the fiber entangled body, and a skin layer having a thickness of 4 to 20 μm laminated on the intermediate layer. , Silicone-modified polyurethane and organic polysiloxane, which is a silver-like artificial leather containing at least a first region of 4 μm or more in contact with an intermediate layer. Such silver-like artificial leather is adhered with a high adhesive force so that the intermediate layer and the epidermis layer do not peel off from each other in the general usage environment of the product using the leather, and at the time of disposal, for example, for example. Only the epidermis layer can be selectively peeled from the intermediate layer by a simple hot water immersion treatment such as immersing in hot water at 90 ° C. for 24 hours (hereinafter, this property is also referred to as hot water peelability). .. Therefore, according to such silver-like artificial leather, only the epidermis layer can be selectively peeled off and separately collected.

Further, it is preferable that the first region contains 3.0% by mass or more of silicon atoms because it is easy to obtain silver-like artificial leather having sufficiently excellent hot water peelability.

Further, it is preferable that the epidermis layer further includes a second region that coats the first region, from the viewpoint of excellent degree of freedom in adjusting the color and surface physical properties.

Further, another aspect of the present invention includes a step of preparing a base material having an intermediate layer including a fiber entanglement and a foamed polyurethane integrated into the fiber entanglement, and a silicone-modified polyurethane and organic on the surface of the intermediate layer. A method for producing silver-like artificial leather, comprising a step of gravure-applying an ink containing polysiloxane and then drying it to form a skin layer containing at least a first region of 4 μm or more.

In addition, another aspect of the present invention includes a step of preparing any of the above-mentioned silver-like artificial leather and a step of immersing the silver-like artificial leather in hot water to peel off the epidermis layer. This is a method for separating and collecting the epidermis layer of silver-like artificial leather. According to such a method, only the epidermis layer can be separated and collected from the intermediate layer forming the grain surface layer.

According to the present invention, in a silver-based artificial leather provided with an intermediate layer and a skin layer for coating the intermediate layer for forming a grain surface layer, only a simple hot water immersion treatment is performed, and only the skin layer is intermediate. A silver-like artificial leather that can be separated from the layer and collected separately can be obtained.

FIG. 1 is a schematic cross-sectional view of the silver-like artificial leather 10 of the embodiment.

Hereinafter, an embodiment of silver-based artificial leather according to the present invention will be described. The silver-like artificial leather of the present embodiment includes a fiber entanglement, an intermediate layer containing foamed polyurethane integrated into the fiber entanglement, and a skin layer having a thickness of 4 to 20 μm laminated on the intermediate layer. The epidermis is a silvered artificial leather containing at least a first region of 4 μm or more in contact with the intermediate layer, which contains a silicone-modified polyurethane and an organic polysiloxane. Hereinafter, the silver-based artificial leather of the present embodiment will be described in detail with reference to the drawings and a typical manufacturing method thereof.

FIG. 1 shows a schematic cross-sectional view of the silver-like artificial leather 10. In FIG. 1, 1 is a fiber entangled product, 2 is an intermediate layer containing foamed polyurethane, and 3 is a first region having a thickness of 4 μm or more in contact with the intermediate layer containing silicone-modified polyurethane and organic polysiloxane. It is an epidermis layer having a thickness of 4 to 20 μm laminated on the intermediate layer containing at least. In the silver-like artificial leather 10 of the present embodiment, the intermediate layer 2 includes a laminated region 2a laminated on the fiber entangled body 1 and an impregnated region 2b impregnated on the fiber entangled body 1. The intermediate layer 2 has a foamed structure having pores v. Further, in the silver-like artificial leather, for example, embossed roll-embossed grain may be formed on the outer surface of the silver-like artificial leather.

Hereinafter, an example of a method for manufacturing silver-like artificial leather according to the present embodiment will be described.

In the method for producing silver-like artificial leather of the present embodiment, first, a base material provided with a fiber entanglement and a foamed polyurethane layer as an intermediate layer integrated with the fiber entanglement is prepared. For example, the base material is manufactured as follows.

The fiber structure of the fiber entanglement is not particularly limited, and examples thereof include a non-woven fabric, a woven fabric, a knitted fabric, or an entanglement obtained by combining them, and preferably a non-woven fabric or an entanglement of a non-woven fabric and a woven fabric.

The resin that forms the fiber entanglement is not particularly limited. Specifically, for example, nylon resins such as 6-nylon, 66-nylon, 610-nylon, 10-nylon, 11-nylon, 12-nylon, 612-nylon; polyethylene terephthalate (PET), modified polyethylene terephthalate, etc. Aromatic polyester resins such as polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polytriethylene terephthalate, polyhexamethylene terephthalate, polypropylene terephthalate, polyethylene naphthalate, polylactic acid, polyethylene succinate, and polybutylene succinate. Polyester resins such as aliphatic polyester resins such as nate, polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvariate copolymer; polypropylene, polyethylene, polybutene, polymethylpentene, chlorine-based polyolefin, ethylene vinyl acetate Polyethylene-based resins such as copolymers and styrene-ethylene copolymers; modified polyvinyl alcohol-based resins formed from modified polyvinyl alcohols containing 25 to 70 mol% of ethylene units; and polyurethane-based elastomers, polyamide-based elastomers, polyesters. Examples thereof include crystalline elastomers such as based elastomers. Among these, nylon-based resins and aromatic polyester-based resins are preferable because they have an excellent balance of various characteristics.

Further, the fineness and morphology of the fiber are not particularly limited. For example, it may be a regular fiber having an average fineness of more than 1 dtex, or an ultrafine fiber having an average fineness of less than 1 dtex, preferably an ultrafine fiber having an average fineness of 0.0001 to 0.1 dtex. Further, the form of the fiber may be a solid fiber or a fiber having pores such as a hollow fiber or a lotus root-like fiber. For the average fineness, a cross section parallel to the thickness of the silver-like artificial leather was magnified 3000 times with a scanning electron microscope (SEM), and fibers were formed from 15 fiber diameters selected evenly. It is obtained as an average value calculated using the density of the resin to be used.

The thickness of the fiber entanglement is not particularly limited, but is preferably, for example, about 0.3 to 3 mm, more preferably about 0.5 to 1.5 mm.

The substrate comprises a fiber entanglement and a polyurethane foam layer integrated into the fiber entanglement.

Such a substrate is, for example, impregnated with a polyurethane solution containing a polyurethane that wet-solidifies the fiber entanglement, and further, after applying a similar polyurethane solution to the surface of the fiber entanglement, with, for example, water or water. It is obtained by wet-coagulating a polyurethane layer containing foamed polyurethane by immersing it in a coagulating solution such as a mixed solvent with DMF.

Further, instead of forming the polyurethane layer containing the foamed polyurethane integrated into the fiber entanglement by the method of wet coagulation, the so-called dry foam surface method is used to entangle the polyurethane layer containing the foamed polyurethane into the fiber entanglement. It may be integrated into. Specifically, a method may be used in which a polyurethane layer containing polyurethane foam is formed on the release paper, and the polyurethane layer containing polyurethane foam formed on the release paper is adhered to the fiber entanglement. In the present embodiment, as a typical example, a method of integrating the foamed polyurethane layer into the fiber entanglement will be described in detail using a method of wet coagulation.

The type of polyurethane that forms the foamed polyurethane is not particularly limited, and specific examples thereof include polyester-based polyurethane, polycarbonate-based polyurethane, polyester-polyester-polycarbonate-based polyurethane, and polyether-based polyurethane. These may be used alone or in combination of two or more.

Further, the foamed polyurethane layer may contain additives such as a coagulation regulator, an antioxidant, a light resistant agent and an antibacterial agent in addition to a colorant such as a pigment as long as the effect of the present invention is not impaired.

Examples of the solvent contained in the polyurethane solution include N, N-dimethylformamide (DMF), cyclohexanone (CHN), tetrahydrofuran (THF), methyl ethyl ketone (MEK), acetone (Ac), dioxane, isopropyl alcohol, toluene, and water. A mixed solvent in which the above is mixed is preferably used.

In the base material, the fiber entanglement is impregnated with the polyurethane solution in advance, the polyurethane solution is applied to the surface of the fiber entanglement, and then the fiber entanglement is immersed in the coagulation liquid to coagulate the inside of the fiber entanglement. Includes polyurethane foam integrated into the fiber entanglement, including an impregnated region in which the polyurethane foam impregnated with the fiber entanglement is integrated with the fiber entanglement, and a laminated region containing the polyurethane foam laminated in the impregnated region. A polyurethane layer is formed.

The thickness of the intermediate layer formed from the polyurethane layer containing the foamed polyurethane is not particularly limited, but is preferably 100 to 600 μm, more preferably 200 to 400 μm. Further, among the intermediate layers, the thickness of the laminated region laminated on the impregnated region is preferably 50 to 500 μm, more preferably 100 to 300 μm. The total thickness of the base material is preferably 800 to 3000 μm, more preferably 1200 to 2000 μm.

Further, the expansion ratio of the foamed polyurethane defined as (volume of the foamed polyurethane) / (actual volume of the polyurethane excluding the pores of the foamed polyurethane) is 1.5 to 5 times, further 3 to 4 times. Is preferable from the viewpoint of excellent hot water peelability. If the foaming ratio of the foamed polyurethane is too low, the hot water does not easily reach the surface in contact with the intermediate layer in the hot water immersion treatment described later, and the time required for peeling becomes long, so that the hot water peelability tends to decrease. There is. Further, if the foaming ratio is too high, the mechanical properties tend to be deteriorated, such as the wear resistance being lowered.

The mass ratio (fiber / polyurethane foam) of the fiber forming the fiber entanglement constituting the silver-like artificial leather is 40/60 to 70/30, and further, 50/50 to 60/40. This is preferable from the viewpoint of excellent balance between texture and morphological stability. If the proportion of polyurethane foam is too high, it tends to have a rubber-like texture, and if the proportion of fibers is too high, morphological stability tends to decrease.

Next, an ink containing a silicone-modified polyurethane and an organic polysiloxane (hereinafter, also simply referred to as a first ink) is gravure-coated on the surface of the foamed polyurethane layer as an intermediate layer of the base material prepared in this manner. Then, by drying, a first region of 4 μm or more, which is contained in the epidermis layer and is in contact with the intermediate layer, preferably in direct contact with the intermediate layer, is formed.

The first ink applied to form the first region contains a silicone-modified polycarbonate-based polyurethane, an organic solvent that dissolves the polyurethane, and an organic polysiloxane compounded as an additive.

The polyurethane forming the first region contains a silicone-modified polyurethane, and it is particularly preferable to mainly use a silicone-modified polyurethane. Specifically, for example, the first region preferably contains 60% by mass or more of the silicone-modified polyurethane, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

Silicone-modified polyurethane is a polyurethane in which a siloxane bond is introduced into the main chain or side chain of the polyurethane. The silicone-modified polyurethane is produced by reacting, for example, a polyol, a chain extender, an active hydrogen group-containing organopolysiloxane, and a polyisocyanate using a known polyurethane production method.

Examples of the silicone-modified polyurethane include silicone-modified polycarbonate-based polyurethane, silicone-modified polyester-based polyurethane, and silicone-modified polyether-based polyurethane, depending on the difference in the polyol component. Among these, silicone-modified polycarbonate-based polyurethane is preferable because it is particularly excellent in durability.

The first region may contain a non-silicone modified polyurethane other than the silicone modified polyurethane as long as the effect of the present invention is not impaired. Specific examples of the polyurethane that has not been modified with silicone include polycarbonate-based polyurethane, polyester-based polyurethane, polyester-polyester-polycarbonate-based polyurethane, and polyether-based polyurethane that have not been modified with silicone. These may be used alone or in combination of two or more.

The first region contains an organic polysiloxane in addition to the silicone-modified polyurethane. The organic polysiloxane is a silicone compound having a siloxane bond in the polymer main chain, and is preferably in the form of an oil. Specific examples of the organic polysiloxane include polydimethylsiloxane or organic modification in which one of the two methyl groups of the siloxane unit (-Si-O-) of the polydimethylsiloxane is replaced with another chemical structure. Examples thereof include polysiloxane and terminal organically modified polysiloxane having another chemical structure added to one end or both ends of polydimethylsiloxane. Examples of other chemical structures include a polyether group, a phenyl group, a polyester group, an alkyl group having 2 to 9 carbon atoms, an aralkyl group and the like. Specific examples thereof include polyether-modified polydimethylsiloxane, phenyl-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, and aralkyl-modified polydimethylsiloxane.

In addition, the first region may contain additives such as colorants such as pigments, light resistant agents, antioxidants, antibacterial agents, and dispersants as long as the effects of the present invention are not impaired. In particular, it is preferable that the first region is colored with a pigment.

The content ratio of the silicone-modified polyurethane contained in the first region is such that the silicon atom content ratio contained in the first region is 1.0% by mass or more, further 2.0% by mass or more. This is preferable from the viewpoint of excellent hot water peelability.

Further, regarding the content ratio of the organic polysiloxane contained in the first region, the silicon atom content ratio contained in the first region is 0.5% by mass or more, further 1.0% by mass or more, particularly 2. It is preferable that the ratio is 0% by mass or more from the viewpoint of excellent hot water removability.

The total content of silicon atoms contained in the first region shall be 3.0% by mass or more, further 3.5% by mass or more, and particularly 4.0% by mass or more. Is preferable from the viewpoint of excellent hot water peelability.

Examples of the solvent contained in the first ink include N, N-dimethylformamide (DMF), cyclohexanone (CHN), tetrahydrofuran (THF), methyl ethyl ketone (MEK), acetone (Ac), dioxane, isopropyl alcohol, toluene, and the like. And a mixed solvent in which water or the like is mixed is preferably used.

The concentration of the silicone-modified polyurethane contained in the first ink is not particularly limited, but is preferably about 5 to 15% by mass.

The method of applying the first ink is not particularly limited, but a method of gravure-coating the first ink on the surface of the intermediate layer using a gravure roll can be mentioned from the viewpoint of easy control of the film thickness. As the gravure roll, the size of the cell engraved on the surface of the gravure roll is preferably 65 to 180 mesh, more preferably 100 to 130 mesh, from the viewpoint that an appropriate amount of ink can be uniformly applied. Further, the gravure coating may be applied in a plurality of stages so as to secure a uniform film thickness.

The amount of the first ink applied is preferably 10 to 40 g / m ² per application, more preferably 15 to 30 g / m ² , and particularly preferably 20 to 25 g / m ² . By repeating the application, the thickness of the first region is adjusted. The total coating amount of the first ink for forming the first region may be 50 to 250 g / m ² , more 100 to 200 g / m ² , and particularly 120 to 150 g / m ² . preferable. By applying the first ink to the surface of the intermediate layer in such a coating amount and drying the solvent, a first region of 4 μm or more in contact with the intermediate layer is formed. The drying conditions are appropriately adjusted according to the type of solvent and the like, and examples thereof include conditions for drying in about 5 to 30 seconds in a hot air dryer set at 100 to 120 ° C.

The thickness of the first region thus formed is 4 μm or more, preferably 5 μm or more, and more preferably 6 μm or more. The upper limit is 20 μm, which is the upper limit of the thickness of the epidermis layer. When the thickness of the first region is less than 4 μm, the hot water peelability is lowered.

In addition, the epidermis layer may further include a second region that coats the first region, if necessary. By further containing such a second region, the degree of freedom in adjusting the color and surface physical properties is improved, which is preferable.

In the second region, the surface of the first region contains the same ink as the first region, or an ink or non-polyurethane containing a polyurethane different from the first region, which does not contain silicone-modified polyurethane or organic polysiloxane. It is formed by gravure-applying an ink containing a resin (hereinafter, also simply referred to as a second ink) and then drying it. The second region is formed by the same method except that the second ink is used instead of the first ink.

Similarly, the second region may contain additives such as colorants such as pigments, lightfasteners, antioxidants, antibacterial agents, and dispersants as long as the effects of the present invention are not impaired. In particular, it is preferable that the second region is also colored with a pigment.

The total thickness of the epidermis layer including at least the first region is 4 to 20 μm, preferably 4 to 15 μm, and more preferably 8 to 15 μm. When the total thickness of the epidermis layer is less than 4 μm, the effect of protecting the surface and imparting wear resistance tends to be insufficient, and when it exceeds 20 μm, the texture becomes hard or the texture becomes hard. The bending resistance is low, and the embossing property due to embossing is low.

In this way, a silver-like artificial leather having an intermediate layer and a skin layer forming a grain surface layer can be obtained. In addition, after forming the epidermis layer on such silver-like artificial leather, an embossed pattern may be imparted to the surface thereof by embossing with an embossed roll having heated grain. The shape of the embossed roll on the surface is not particularly limited, but for example, an embossed roll having an uneven height difference of about 20 to 100 μm is preferably used. Further, as the surface temperature of the embossed roll, a temperature at which the shape of the embossed roll can be appropriately transferred and an opening having a small diameter is likely to remain is appropriately selected. Specifically, for example, the temperature is preferably 150 to 190 ° C, more preferably 160 to 180 ° C.

Such silver-like artificial leather is a silver-like artificial leather provided with an intermediate layer and a skin layer forming a grain surface layer, and by immersing in hot water, only the skin layer is peeled off and collected separately. It is a silver-like artificial leather that can be made.

Specifically, for example, when immersed in hot water at 90 ° C., only the epidermis layer can be selectively peeled from the intermediate layer. Specifically, when immersed in hot water at 90 ° C., it is preferably completely peeled off in 12 hours, further 8 hours, particularly 4 hours. In addition, peeling means that, for example, a gap is formed in at least a part between the intermediate layer and the epidermis layer, and the epidermis layer can be easily peeled from the portion with a light force. The higher the temperature of the hot water, the shorter the time it can be peeled off, so it is appropriately selected, but it is preferably 80 ° C. or higher, more preferably 90 ° C. or higher. It may also be processed with steam.

On the other hand, in such a silver-like artificial leather, the epidermis layer does not peel off and maintains a strong adhesive force to the intermediate layer in the general usage environment of the product. Specifically, it is a promotion test under high temperature and high humidity conditions, for example, it does not peel off even if it is left in a constant temperature and constant humidity bath such as 80% RH at 90 ° C. for 4 weeks.

By peeling off the epidermis layer in this way, the epidermis layer can be separated and collected. The recovered epidermis layer can be reused as a raw material for ink by dissolving it again. Since the peeled epidermis layer is peeled off only by immersing it in hot water, it can be recovered without causing deterioration such as a significant decrease in the molecular weight of polyurethane. For example, when the polystyrene-equivalent molecular weight of the recovered polyurethane of the epidermis layer is measured by GPC, deterioration can be suppressed so that the retention rate of the weight average molecular weight is 80% or more. Therefore, it can be reused as a material for forming an epidermis layer when manufacturing silver-like artificial leather.

The silver-like artificial leather of the present embodiment described above is preferably used as a surface material of a product that comes into contact with the human body, such as a clothing material, a shoe upper material, a back lining material of a backpack, and the like. ..

Hereinafter, the present invention will be described in more detail with reference to Examples. The scope of the present invention is not limited to these examples.

[Example 1]
After melt-spinning a sea-island type composite fiber consisting of 45 parts by mass (sea component) of 6-nylon (sea component) and 55 parts by mass (island component) of polystyrene, stretching it three times, applying a fiber oil agent, and mechanically crimping it. , Drying to produce crimped fibers.

The obtained crimped fibers were cut to 51 mm to form 3dtex staples to form webs. Then, the web was subjected to needle punching of about 500 punches / cm ² alternately from both sides thereof to obtain a non-woven fabric of a sea-island type composite fiber. The weight of the obtained non-woven fabric of the sea-island type composite fiber was 350 g / m ² , and the apparent specific gravity was 0.17.

Then, the non-woven fabric of the sea-island type composite fiber was treated with a 4% aqueous solution of polyvinyl alcohol, compressed to a thickness of about 1.3 mm and fixed, and the surface was buffed and smoothed. Then, the smoothed non-woven fabric of the sea-island type composite fiber was impregnated with a polyurethane solution containing mainly polyester-based polyurethane. Further, the same polyurethane solution was applied to the surface in an amount of 100 g / m ² in solid content, and then immersed in a mixed solution of DMF / water to wet-coagulate the porous polyurethane foam. The polyurethane solution was a solution having a concentration of 13% by mass containing polyester-based polyurethane as a main component and dimethylformamide (hereinafter referred to as DMF) as a solvent.

Then, the non-woven fabric of the sea-island type composite fiber to which the foamed polyurethane was applied was immersed in hot toluene to elute and remove the island component, and the sea-island type composite fiber was converted into a hollow fiber. In this way, a base material containing a non-woven fabric and a polyurethane foam layer integrated with the non-woven fabric was obtained. According to observation with a microscope, the thickness of the polyurethane foam layer was 300 μm. The foaming ratio of the foamed polyurethane layer was 3.7 times.

On the other hand, by adding 10% by mass of one-terminal polyether-modified polydimethylsiloxane to a polyurethane solution containing 11% by mass of silicone-modified polycarbonate-based polyurethane containing a red pigment and containing DMF as a solvent, the one-terminal polyether-modified polydimethylsiloxane is added to the polyurethane solid content. A first ink was prepared. The content ratio of the silicon atom contained in the first region formed by evaporating and drying the first ink was 4.7% by mass. The content ratio of silicon atoms contained in the first region is a fluorescent X-ray apparatus using a film prepared by spreading 1.0 g of ink on an aluminum dish and drying it at 120 ° C. for 2 hours under vacuum as a sample. Measurement was performed using ZSX Primun-μ (manufactured by Rigaku Co., Ltd.).

Then, the epidermis layer was formed by applying the first ink to the surface of the foamed polyurethane layer using a 150 mesh gravure roll so that the thickness after drying was about 16 μm. The entire epidermal layer is the first region and includes the first region of 16 μm. Then, using an embossed roll having 18 convex portions / mm ² having an average depth of 60 μm and having a fine uneven pattern on the entire surface, the mold is used at a temperature of 170 ° C., a pressure of 15 kg / cm, and a processing speed of 1.5 m / min. By pressing, an embossed pattern including an uneven surface was formed. In this way, silver-like artificial leather was manufactured.

The thickness (film thickness) of the epidermis layer was measured as follows. Three places of the cross section selected evenly from the obtained silver-like artificial leather were observed with a scanning electron microscope (SEM) at a magnification of 400, and images were taken. Then, in each of the three images, the thickness of the epidermis layer and the thickness of the first region were measured at 5 points at intervals of 50 μm, and the average thickness of the epidermis layer in each image was obtained. Then, the average value of the average thickness of the epidermis layer obtained from the three images was further calculated. The average value of the thickness of the epidermis layer thus obtained was taken as the thickness of the epidermis layer.

Then, a piece of vertical 7 cm × horizontal 4.5 cm was cut out from the obtained silver-like artificial leather to prepare a test piece. Then, the obtained test piece was immersed in hot water at 90 ° C. contained in a wide-mouthed bottle, and left in a dryer at 90 ° C. for 24 hours. Then, after 24 hours, the silver-like artificial leather was taken out from hot water and judged according to the following criteria.
A: The epidermis layer was completely exfoliated from the intermediate layer.
B: A gap was partially formed between the epidermis layer and the intermediate layer, and it was easily peeled off by pinching it with a finger and peeling it off.
C: The intermediate layer and the epidermis layer were not separated at all.

Further, the obtained artificial leather with silver was left in a constant temperature and humidity chamber of 80% RH at 90 ° C., taken out after 4 weeks, and judged according to the following criteria.
A: The intermediate layer and the epidermis layer were not separated at all.
B: Peeling was observed between the intermediate layer and the epidermis layer.

The results are shown in Table 1.

[Example 2]
Silver-like artificial leather in the same manner as in Example 1 except that the ink was applied so that the thickness after drying was about 16 μm, but the ink was applied so that the thickness after drying was about 8 μm. Was manufactured and evaluated. The results are shown in Table 1.

[Example 3]
Instead of impregnating the non-woven fabric of Kaijima-type composite fiber with a polyurethane solution containing polyester-based polyurethane as the main component, polyurethane containing a polymer polyol unit in which polycarbonate diol and polyester diol are mixed at a molar ratio of 60:40 is mainly used. A silver-based artificial leather was produced and evaluated in the same manner as in Example 1 except that it was impregnated with the polyurethane solution containing it. The results are shown in Table 1.

[Example 4]
A silver-based artificial leather was produced and evaluated in the same manner as in Example 1 except that the ratio of one-ended polyether-modified polydimethylsiloxane to the polyurethane solid content contained in the first ink was changed from 10% by mass to 3% by mass. bottom. The results are shown in Table 1.

[Example 5]
Examples except that the ratio of one-ended polyether-modified polydimethylsiloxane to the polyurethane solid content contained in the first ink was changed from 10% by mass to 4% by mass, and the dried film thickness of 16 μm was adjusted to 4 μm. A first region was formed on the surface of the foamed polyurethane layer in the same manner as in 1. Then, the same ink as the first ink prepared in Example 1 is used as the second ink on the surface of the first region, and the second ink is applied so that the thickness after drying becomes 4 μm, and the ink is dried. By doing so, a second region was formed. Other than these, silver-like artificial leather was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 6]
Examples except that the ratio of one-ended polyether-modified polydimethylsiloxane to the polyurethane solid content contained in the first ink was changed from 10% by mass to 23% by mass, and the dried film thickness of 16 μm was adjusted to 4 μm. A first region was formed on the surface of the foamed polyurethane layer in the same manner as in 1. Then, the same ink as the first ink prepared in Example 1 is used as the second ink on the surface of the first region, and the second ink is applied so that the thickness after drying becomes 8 μm, and the ink is dried. By doing so, a second region was formed. Other than these, silver-like artificial leather was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 7]
The same as in Example 1 except that a non-modified polydimethylsiloxane was blended in place of the one-terminal polyether-modified polydimethylsiloxane contained in the first ink, and the dried film thickness of 16 μm was adjusted to 8 μm. A first region was formed on the surface of the foamed polyurethane layer. Then, the same ink as the first ink prepared in Example 1 is used as the second ink on the surface of the first region, and the second ink is applied so that the thickness after drying becomes 8 μm, and the ink is dried. By doing so, a second region was formed. Other than these, silver-like artificial leather was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 8]
The same ink as the first ink prepared in Example 1 is used as the second ink, and the second ink is applied to the surface of the first region so that the thickness after drying is 4 μm, and the ink is dried. A second region was formed by. Other than these, silver-like artificial leather was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
The silicone-modified polycarbonate-based polyurethane contained in the first ink is changed to a non-modified polycarbonate-based polyurethane, and the first ink containing no single-ended polyether-modified polydimethylsiloxane is used to obtain a film thickness of 8 μm after drying. The first region was formed. Then, the same ink as the first ink prepared in Example 1 is used as the second ink on the surface of the first region, and the second ink is applied so that the thickness after drying becomes 4 μm, and the ink is dried. By doing so, a second region was formed. Other than these, silver-like artificial leather was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 2]
A first region having a film thickness of 16 μm after drying was formed using a first ink containing no single-ended polyether-modified polydimethylsiloxane. Other than these, silver-like artificial leather was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Referring to Table 1, the silvered tone obtained in Examples 1 to 8 provided with a skin layer containing a first region having a thickness of 4 μm or more and containing silicone-modified polyurethane and organic polysiloxane, which is in direct contact with the intermediate layer. When the artificial leather was immersed in hot water at 90 ° C. for 24 hours, all the epidermis layers were peeled off. In Example 4 in which the silicon atom content was 2.8% by mass, the exfoliation did not occur naturally, but the exfoliation was performed by pulling with a light force. On the other hand, the silver-based artificial leather of Comparative Example 1 containing no silicone-modified polyurethane or organic polysiloxane and containing no silicon atom did not peel off even when immersed in hot water at 90 ° C. for 24 hours. Further, the silver-based artificial leather of Comparative Example 2, which contains silicone-modified polyurethane but does not contain organic polysiloxane and has a low silicon atom content, does not peel off even when immersed in hot water at 90 ° C. for 24 hours. rice field.

1 Fiber entanglement 2 Intermediate layer 2a Laminated area laminated on fiber entanglement 1 b Impregnated area impregnated on fiber entanglement 1 3 Epidermis layer 10 Silver-like artificial leather v Vacancies

Claims (6)

A fiber entanglement, an intermediate layer containing a foamed polyurethane integrated into the fiber entanglement, and a skin layer having a thickness of 4 to 20 μm laminated on the intermediate layer are provided.
The skin layer is a silver-like artificial leather containing at least a first region having a thickness of 4 μm or more in contact with the intermediate layer, which contains a silicone-modified polyurethane and an organic polysiloxane. The silver-like artificial leather according to claim 1, wherein the first region contains 3.0% by mass or more of silicon atoms. The silver-like artificial leather according to claim 1 or 2, wherein the epidermis layer is peeled off from the intermediate layer when immersed in hot water at 90 ° C. for 24 hours. The silver-like artificial leather according to any one of claims 1 to 3, wherein the epidermis layer further includes a second region that coats the first region. A step of preparing a base material having an intermediate layer containing a fiber entanglement and a polyurethane foam integrated into the fiber entanglement, and a step of preparing the substrate.
The surface of the intermediate layer is gravure-coated with an ink containing a silicone-modified polyurethane and an organic polysiloxane, and then dried to form a skin layer containing at least a first region having a thickness of 4 μm or more. A method for manufacturing artificial leather with silver, which is characterized by this. The step of preparing the silver-like artificial leather according to any one of claims 1 to 4.
A method for segregating and recovering the skin layer of silver-like artificial leather, which comprises a step of peeling the skin layer from the intermediate layer by immersing the silver-like artificial leather in hot water.

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