JP5734801B2 - Synthetic leather base fabric and synthetic leather - Google Patents

Description

  The present invention relates to a synthetic leather base fabric and a synthetic leather using the same.

In recent years, automobile interior parts (instrument panels, door trims, seats, ceilings, etc.), railcar / aircraft interior parts (trims, seats, ceilings, etc.), furniture, shoes / footwear / bags, interior / exterior components for building, clothing cover materials -For lining and wall coverings, synthetic leather with excellent durability is often used in place of natural leather and fibrous sheets. For example, aircraft interior parts and automobile interior parts must be lightweight and durable, and must have good fire resistance. In addition to these basic characteristics, some thickness and moderate elasticity There is a demand for a synthetic leather having a feel similar to that of natural leather.
Such synthetic leather has a flexible resin layer for adjusting moderate elasticity and a leather-like appearance on the surface of a fibrous sheet such as a base fabric due to dimensional stability and processability, and wear resistance. Those having an excellent skin layer are generally used.
However, in the synthetic leather having a three-layer structure of the base fabric, the resin layer, and the skin layer, the base fabric, the resin layer, and the resin layer are related to the rigidity and stretchability of the base fabric adhered to the back and the physical properties of the resin layer. However, the adhesive strength is not sufficient, or creases are likely to occur, resulting in problems such as inferior processability when processed into a seat sheet or the like, and a solution has been desired.
Specifically, if the base fabric used for synthetic leather is poorly stretchable, the shape followability is inferior.On the other hand, if knitting is used for excellent stretchability, the resin layer is affected by the stretch of the base fabric. The part stretched during use may be thinner than the originally designed resin layer, and there may be a part where the wear strength is weakened. When it was used, there was a problem that the stretchability was too small and the followability to a mold having a three-dimensional feeling was deteriorated, the sewing process was very complicated, and the productivity was inferior.

In addition, in order to improve the adhesive strength between the base fabric and the resin layer, a technique has been proposed in which knitted knitting having raised hair is used as the base fabric and at least a part of the length of the raised fiber is present in the resin layer ( For example, see Patent Document 1.) According to this method, although the adhesiveness is improved, the strength of the raised fiber is limited, and further improvement is desired. Moreover, the synthetic leather described here is not considered for flame retardancy.
For the purpose of improving flame retardancy, a synthetic leather is proposed in which a base fabric is impregnated with a nitrogen-based or phosphoric acid-based flame retardant (see, for example, Patent Document 2). However, when the thickness or strength of the woven fabric or nonwoven fabric used for the base fabric is not sufficient, for example, when used for a seat sheet, there is a problem that the finish is inferior, and the base fabric is impregnated with a flame retardant. Then, after drying, there is a problem that the process becomes complicated because it is adhered to the resin layer.

JP-A-9-111671 JP 2006-77349 A

  The object of the present invention, which has been made in consideration of the above-mentioned problems of the prior art, is a synthetic leather base fabric having a sufficient thickness and suitable for the production of synthetic leather and excellent in processability, durability and flame retardancy. Another object of the present invention is to provide a synthetic leather having an appropriate elasticity, a touch close to that of natural leather, and excellent durability, flame retardancy, and processability.

As a result of intensive studies, the present inventors have found that the above problems can be solved by using a woven fabric using flame retardant fibers and cellulosic fibers as a base fabric, and have completed the present invention.
That is, the present invention has the following configuration.
The invention according to the first embodiment of the present invention has a double-sided knitted structure using a yarn containing a flame retardant fiber having a limiting oxygen index (LOI value) of 25 or more and a cellulosic fiber, and has a mass of 150 g / m. It is a knitted fabric of ^{2 to} 250 g / m ² , and is a synthetic leather base fabric having a LOI value of 25 or more.

  In the invention according to the second embodiment of the present invention, the flame retardant fiber is at least one selected from aramid fiber, polyphenylene sulfide fiber, and vinyl chloride fiber, and the cellulose fiber is cotton, and The synthetic leather base fabric according to the first embodiment, which is one or more selected from rayon.

The invention according to a third embodiment of the present invention is the synthetic leather base fabric according to the first embodiment or the second embodiment, wherein the knitted body has a pontoroma knitting structure.
The invention according to a fourth embodiment of the present invention is the synthetic leather base fabric according to any one of the first to third embodiments, wherein the knitted body has raised hair.

In the fifth embodiment of the present invention, an aqueous polyurethane adhesive layer and an aqueous polyurethane skin layer are formed on the synthetic leather base fabric according to any one of the first to fourth embodiments of the present invention. In this order.
The sixth embodiment of the present invention is the synthetic leather according to the fifth embodiment, further comprising an aqueous urethane dry foam layer between the aqueous polyurethane adhesive layer and the aqueous polyurethane skin layer.
Seventh embodiment of the present invention, aqueous polyurethane used in the aqueous polyurethane skin layer, 100% modulus ^50N / cm 2 ^~1200N / cm of a is the hardness range of ² film with an aqueous polyurethane capable of forming The synthetic leather according to the fifth embodiment or the sixth embodiment.
Eighth embodiment of the present invention, aqueous polyurethane used in the aqueous polyurethane adhesive layer, an aqueous polyurethane capable of forming the hardness of the film is in the range of ^10N / cm ^{2 ~1000N} / cm 2 at 100% modulus The synthetic leather according to any one of the fifth to seventh embodiments.
9th Embodiment of this invention is the synthetic leather of any one of 5th Embodiment-8th Embodiment in which the said water-system polyurethane contact bonding layer contains a flame retardant.

In the present invention, since a knitted body using a flame retardant fiber and a cellulosic fiber that is a natural fiber and excellent in air permeability and texture is used as a knitted body constituting the base fabric, it is excellent in strength and texture. And it is thought that the flame retardance became favorable.
By making this knitted body into a double-sided knitting structure using flame-retardant fiber yarns and cellulosic fiber yarns, the texture and elasticity are further improved. In the present invention, “a double-sided knitted fabric using a yarn containing a flame-retardant fiber and a cellulosic fiber” is composed of a double-sided knitted fabric and a flame-retardant fiber using a blended yarn containing a flame-retardant fiber and a cellulosic fiber It includes both aspects of a double-sided knitted structure using yarns and yarns made of cellulosic fibers. In the former case, the cellulosic fiber in the blended yarn is carbonized during combustion, so that the burning rate of the knitted body can be delayed. Further, when knitting as separate yarns as in the latter case, for example, knitting is performed so that the flame retardant fiber yarn is exposed on the side where more flame retardancy is required, thereby improving the flame retardance of a specific surface. be able to.
In a preferred embodiment of the present invention, since the structure is a pontoroma knitted structure, a base fabric suitable for a synthetic leather, having a fineness of double-sided knitting and elasticity of rib knitting, excellent in strength, texture and flame retardancy, Become.

  ADVANTAGE OF THE INVENTION According to this invention, the base fabric for synthetic leather which has sufficient thickness and was excellent in the durability suitable for manufacture of synthetic leather and a flame retardance can be provided. Further, by using the synthetic leather base fabric of the present invention, there is provided a synthetic leather having an appropriate elasticity, a feeling close to that of natural leather, and excellent in durability, flame retardancy and processability. be able to.

It is an image partial enlarged view showing one mode of a pontoroma knitting organization. It is a schematic sectional drawing which shows the one aspect | mode of the synthetic leather of this invention. It is a schematic sectional drawing which shows another aspect of the synthetic leather of this invention.

Hereinafter, preferred embodiments of the present invention will be described.
<Fabric for synthetic leather>
First, the synthetic leather base fabric of the present invention will be described.
The base fabric for synthetic leather of the present invention is knitted including a flame retardant fiber having a limiting oxygen index (LOI value) of 25 or more and a cellulosic fiber, and the LOI value of the knitted product is 25 or more. .
That is, the knitted body (knitted fabric) for the base fabric is knitted using two different fiber yarns, and preferably has a double-sided knitted structure.
The limiting oxygen index (LOI value) indicates the oxygen concentration necessary for a thing to continue to burn, and is measured by the method described in JIS K7201. Usually, since the oxygen concentration in the air is about 21.2%, if the LOI value is 25 or more, it can be said that the fiber has good flame retardancy.

(Flame retardant fiber)
The flame retardant fiber used in the base fabric of the present invention is not particularly limited as long as the LOI value is 25 or more. However, from the viewpoint that a knitted body having a flexible and volume feeling can be formed, a flame retardant synthetic fiber is used. Fibers are preferred, and specific examples include aramid fibers including meta-aramid fibers, polyphenylene sulfide fibers, polybenzimidazole fibers, vinylidene chloride fibers, and vinyl chloride fibers. In addition, flame retardant polynosic fibers, flame retardant polyester fibers, flame retardant acrylic fibers, flame retardant rayon fibers, and the like that have been subjected to flame retardant processing and have a LOI value of 25 or more may be used.
Of these, one or more fibers selected from aramid fibers, polyphenylene sulfide fibers, and vinyl chloride fibers are preferable from the viewpoint of flame retardancy and excellent strength and texture when knitted into a base fabric. These fibers are required to have a LOI value of 25 or more. However, the LOI value of the flame retardant fiber used in the present invention is preferably 26 or more, more preferably 28 or more.
The base fabric of the present invention is a knitted body (knitted fabric) knitted with a yarn made of flame-retardant fibers and a yarn made of cellulose-based fibers described later, but the LOI value of the knitted body itself needs to be 25 or more. The amount of the flame retardant fiber used in the knitted body is preferably equal to or more than the amount of the cellulosic fiber used, and the ratio of the flame retardant fiber to the total mass of the yarn constituting the knitted body is 60% by mass or more. More preferably, it is 90 mass% or less.
Moreover, considering that it is a base fabric for synthetic leather used for interior materials for vehicles, it is preferable that the yarn used for knitting the knitted body has a thickness of about 20 to 40.

(Cellulose fiber)
There is no restriction | limiting in particular in the cellulosic fiber used for the base fabric of this invention, Cotton, hemp, cupra, rayon, etc. are mentioned, Preferably it is 1 or more types chosen from cotton and rayon. Usually, cotton and rayon have a LOI value of about 18 and are easily flammable, but by combining with the flame retardant fiber to make a knitted body, the LOI value of the whole knitted body is 25 while taking advantage of the characteristics of cellulosic fibers. Used in such a manner as described above.
By using the cellulosic fiber in combination, the cellulosic fiber is carbonized at the time of combustion, and the burning rate of the knitted body can be delayed.
In order to obtain the above-described delay effect of excellent burning rate due to carbonization without reducing the flame retardancy of the base fabric, it is preferable to use the cellulosic fiber mixed with the flame retardant fiber. That is, in a preferred embodiment of the present invention, the yarn used to produce the knitted body is a blended yarn of flame-retardant fiber and cellulosic fiber, and this structure achieves a LOI value of 25 or more. Is.

As a yarn used when knitting a knitted body having a double-sided knitted structure with the flame retardant fiber and the cellulosic fiber, from the viewpoint of elasticity and strength of the obtained base fabric, a thickness of 20 to 40 (about) The yarn density is preferably about 20/25 mm to 50/25 mm for the yarn and about 15/25 mm to 70/25 mm for the course.
The thus obtained knitted body is preferably mass is in the range of ^{150g / m 2 ~250g / m 2} , and more preferably in the range of ^{175g / m 2 ~225g / m 2} .
The structure of the knitted body is not particularly limited, and it is a blended yarn obtained by twisting flame retardant fibers and cellulosic fibers, and may be a uniform knitted body. A yarn made of flame retardant fibers and a yarn made of cellulose fibers. It is a double-sided knitted structure used separately, and may be a knitted body in which flame retardant fibers are mainly exposed on one side and cellulose fibers are mainly exposed on the other side, but the texture of the knitted body (flexibility) From the viewpoint of superiority, the yarn suitable for knitting the base fabric is a twisted yarn (blend yarn), and also from the viewpoint of improving the flame retardancy effect, a knitted body by a blend yarn of flame retardant fiber and cellulosic fiber It is preferable that
As a preferred embodiment of the double-sided knitted structure, one of the changing structures of the double-sided knitting, a ponterome knitted fabric that is a structure in which double-sided knitting and bag knitting are alternately repeated, has good strength and elasticity. It is preferable from the viewpoint of excellent workability of the obtained synthetic leather. FIG. 1 is a partially enlarged view showing an example of a knitted body 10 having a punched Roman knitting structure. Here, in order to make the knitting state easy to understand, the first yarn 12 and the second yarn 14 are displayed in different colors. For example, the first yarn 12 and the second yarn 14 may be a blended yarn in which a flame-retardant fiber and a cellulosic fiber are used in combination, the first yarn 12 is a yarn made of flame-retardant fiber, and the second yarn The yarn 14 may be knitted as a yarn made of cellulosic fibers. In the knitted body 10 having a pontoroma knitted structure, the first yarn 12 is mainly exposed on one side and the second yarn 14 is mainly exposed on the other side. For example, the flame-retardant fiber yarn is exposed on one side. The knitted body 10 in which the surface on which the flammable cellulosic fibers are exposed is used as the back surface and the surface on which the cellulosic fibers are mainly exposed is protected by the flame retardant fiber layer may be used. Further, blended yarns having the same composition may be used, or two kinds of blended yarns having different blending rates may be used. In any case, it is considered that the flame retardancy of the entire base fabric is improved by using the two types of fibers together.
The synthetic leather base fabric of the present invention is useful for forming synthetic leather because it is excellent in flame retardancy, is excellent in strength and elasticity, and is flexible. Synthetic leather is excellent in strength and processability.
In addition, the base fabric 10 may have raising at least on one side. Brushed can be formed by a conventional method. The adhesiveness and adhesive strength of both are improved by making the surface which has the raising of the base fabric 10, and the water-based urethane contact bonding layer 22 adjacent to contact.

<Synthetic leather>
Next, the synthetic leather of the present invention will be described.
The synthetic leather of the present invention is characterized by having an aqueous polyurethane adhesive layer and an aqueous polyurethane skin layer in this order on the synthetic leather base fabric of the present invention. An aqueous urethane dry foam layer may be further provided between the aqueous polyurethane adhesive layer and the aqueous polyurethane skin layer.
FIG. 2 is a schematic cross-sectional view showing one embodiment of the synthetic leather 16 of the present invention.
The synthetic leather 16 of the present invention comprises a water-based polyurethane adhesive layer 22, a water-based urethane foam layer 20, and a water-based polyurethane skin layer 18 in this order on the surface of the synthetic leather base fabric 10 of the present invention. In the present specification, “provided in this order” means that the adhesive layer 22, the foam layer 20 and the skin layer 18 are present in this order on the base fabric 10, and other layers provided as desired. The existence of is not denied.
The water-based urethane foam layer 20 in the present embodiment is a layer provided as desired depending on the use mode of the synthetic leather. By providing the water-based urethane foam layer 20, the elasticity, flexibility, and shape followability of the synthetic leather 16 are improved. The
A general manufacturing method of the synthetic leather 16 according to this embodiment will be described. First, the aqueous urethane skin layer 18 is provided by applying and drying the aqueous urethane skin layer forming composition on the surface of the release agent layer of the temporary support having the release agent layer. Then, on the formed skin layer 18, a water-based urethane foam layer forming coating liquid thermal expansion bead is dispersed in an aqueous polyurethane resin ^{composition, 50g / m 2 ~500g / m} 2 was coated, dried Then, the coating liquid layer is formed, and then the thermally expanded beads are foamed by heating and drying to form the foamed layer 20 containing bubbles.
A water-based urethane adhesive is applied to the surface of the formed foam layer 20 to form an adhesive layer 22, and the surface having the formed adhesive layer 22 and the substrate (base fabric) 10 are brought into close contact with each other to form an adhesive. The synthetic leather 16 is manufactured by curing the layer 22 and then peeling the temporary support.
By forming a leather-like unevenness (texture pattern) on the surface of the temporary support having the release agent layer, a leather-like unevenness pattern is formed on the skin layer 18, and a synthetic leather 16 having a natural leather-like appearance is obtained. can get.

[Water-based urethane skin layer]
The water-based urethane skin layer is applied to the surface of the release agent layer of the temporary support having a release agent layer, for example, by applying the composition for forming the skin layer with a sealed or open coating head and drying by heating. It is obtained by forming to the thickness.
The temporary support has a release agent layer on the surface, and a desired embossed pattern (uneven pattern) is formed on the surface. For example, when the synthetic leather 16 is a skin material having a natural leather-like appearance, a leather-like uneven pattern may be formed in advance on the surface of the temporary support on the side where the release agent layer is formed. At this time, a leather-like uneven pattern is transferred to the formed skin layer 18 by applying the composition for forming the skin layer to the surface of the temporary support on which the release agent layer is formed.

Examples of the water-based polyurethane used to form the skin layer 18 include polycarbonate-based polyurethane, polyether-based polyurethane, polyester-based polyurethane, and modified products thereof. When long-term durability is required, polycarbonate-based polyurethane is used. Is preferred.
The polyether-based or polycarbonate-based aqueous polyurethane in the present invention may be used alone or in combination with other polyurethane resins as long as the effects of the present invention are not impaired. Such a water-based polyurethane main component is preferably a so-called self-emulsifying water-based polyurethane in which one or two or more hydrophilic carboxyl groups are introduced into a part of the molecular chain to facilitate dispersion in water. The self-emulsifying water-based polyurethane is obtained by neutralizing a prepolymer prepared from a polyether-based or polycarbonate-based diol, a diol-containing low molecular weight material, dimethylolalkylcarboxylic acid and diisocineanate with an alkali or the like according to a conventional method. Thus, it can be obtained by dispersing in water with a nano-sized particle diameter while polymerizing with a diamine chain extender.

The water-based polyurethane suitable for the present invention is a polyether or polycarbonate-based water-based polyurethane alone or a part of the molecular chain of the urethane main agent in the polyether-based and polycarbonate-based mixed or copolymer, It is desirable that 0.01% to 10%, preferably 0.05% to 5%, and more preferably 0.1% to 2% of carboxyl groups are introduced. Sufficient water dispersibility and dry film formability can be obtained within the above mass ratio range.
From the viewpoint of strength, those aqueous polyurethanes preferably have a crosslinked structure. That is, by using a urethane main component having a carboxyl group introduced, the carboxyl group and the crosslinking agent react to form a crosslinked structure, and the peel strength and impact resilience of the resulting polyurethane skin layer are dramatically improved. . As a crosslinking agent for forming a crosslinked structure, conventionally known isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, carbodiimide crosslinking agents, and the like are suitable, and oxazoline-based crosslinking agents are also preferably used. Especially, it is more preferable to use a carbodiimide crosslinking agent from the viewpoint of suppressing hydrolysis of the aqueous polyurethane.
The aqueous polyurethane used in forming the skin layer 18, that hardness measured by JIS K6772 is a water-based polyurethane which can form a film in the range of ^50N / cm ^{2 ~1200N} / cm 2 at 100% modulus it is ^preferred, more preferably in the range of ^{98N / cm 2 ~1176N / cm 2} , and more preferably in the range of ^{196N / cm 2 ~980N / cm 2} . Moreover, it is preferable that the said water-based polyurethane used as a main ingredient when forming a skin layer has the weight average molecular weight measured by GPC method in the range of 50,000-150,000.

The skin layer 18 may contain a colorant in addition to the base resin.
Examples of the colorant include colored organic resin particles in which a colorant is contained in organic resin fine particles selected from urethane resin particles, acrylic resin particles, silicone resin particles, and the like. From the viewpoints of affinity and uniform dispersibility with respect to the polyurethane-based resin, it is preferable to contain polycarbonate-based colored resin particles.
In general, the average particle diameter of such organic resin fine particles is preferably in the range of 0.5 μm to 100 μm, more preferably in the range of 3 μm to 50 μm.

There is no restriction | limiting in particular in the application quantity of the skin layer 18, and a film thickness, Although it selects suitably according to the objective, Generally, as an application quantity before drying from a viewpoint of intensity | strength and an external appearance, it is 50 g / m < ² >. is preferably in the range of to 300 g / ^{m 2,} more preferably in the range of ^{150g / m 2 ~250g / m 2} . The film thickness after drying is preferably about 10 μm to 70 μm, more preferably about 10 μm to 30 μm.

[Water-based urethane foam layer]
A water-based urethane foam layer 20 is provided on the skin layer 18 formed as described above.
Examples of the water-based urethane used for forming the water-based urethane foam layer 20 include polycarbonate-based polyurethane, polyether-based polyurethane, polyester-based polyurethane, and modified products thereof. When long-term durability is required, polycarbonate-based polyurethane is preferable. is there.
The water-based polyurethane used for forming the water-based urethane foam layer 20 is similar to the polyurethane used for forming the skin layer 18 to have water-based physical properties. Those obtained by introducing a hydrophilic carboxyl group are preferred, and in accordance with a conventional method, a prepolymer prepared from a polyether-based or polycarbonate-based diol, a diol-containing low molecular weight material, dimethylolalkylcarboxylic acid, and diisocinenate, After neutralization with an alkali or the like, it can be obtained by dispersing in water with a nano-sized particle size while polymerizing with a diamine chain extender. A water-based urethane main component composed of a polyether-based or polycarbonate-based water-based polyurethane alone or a mixture or copolymer thereof is used as an aqueous dispersion, and is stable for a long period of time without being hydrolyzed in a water-dispersed state. The foam has the advantage of excellent durability and weather resistance.
There is no particular limitation on the method for forming the foamed layer with the aqueous polyurethane introduced with a carboxy group, and a method using a known foaming agent may be used. From the viewpoint of improving the stability, the cloud point of the 5% by mass aqueous solution It is obtained by adding a foaming agent, a foam stabilizer and a crosslinking agent while stirring a water-based polyurethane main component that is forcibly emulsified with a high cloud point surfactant having a temperature of 50 ° C. or higher, and further adding a thickener. A method in which a water dispersion liquid mechanically foamed in a cream form is applied to the surface of the progenitor skin layer 18 and dried is preferable.
The dispersion particle diameter of the aqueous polyurethane in the dispersion of the aqueous polyurethane main component forcedly emulsified with the high cloud point surfactant is 0.1 μm or more in consideration of dry film forming property, uniform structure of the foam, and the like. Is preferable, and more preferably 0.4 μm to 0.8 μm. Furthermore, considering the peel strength, the solid content of the resin is preferably 40% by mass or more, and more preferably 60% by mass or more.

  Next, while stirring the aqueous polyurethane main component, at least a foaming agent, a foam stabilizer, and a crosslinking agent are added, and a thickener is further added. Here, as a foaming agent, it does not cause a chemical change in itself, and by reducing the surface tension of an aqueous urethane dispersion, it is easy to foam by mechanical stirring. Alkylsulfosuccinate sodium, lauryl sulfate Examples include sodium, sodium sulfonates such as sodium alkyldiphenyl ether disulfonate, higher fatty acid ester salts such as sodium oleate, and ether-modified silicone compounds. Among these, they were added to an aqueous polyurethane dispersion and stirred. Sodium sulphosuccinate lauryl ester is preferred because the foaming is good, the foam height does not change over a long period of time, and there is little change in the foam height in an atmosphere at 60 ° C.

  As a foam stabilizer, it is used to prevent bubble breakage by lowering the surface tension of the bubble film during bubble formation, and to stabilize and uniformly refine the bubbles. A higher fatty acid ester having 14 or more carbon atoms Sodium is preferable, and examples thereof include sodium myristate, sodium valmitate, sodium stearate, sodium oleate alone or a mixture thereof. Among these, when added to an aqueous polyurethane dispersant and stirred, foaming is small but uniform and fine foams are formed, and the foam height does not change even when left for a long time. In particular, sodium palmitate is preferred from the standpoint of stability in which the foam height does not change at all. The amount of sodium palmitate added is 0.1 to 10 parts by mass, preferably 1 to 5 parts by mass with respect to 100 parts by mass of the aqueous polyurethane dispersion.

  As the crosslinking agent, those described above are used, and a carbodiimide-based crosslinking agent is preferable. The addition amount of the crosslinking agent is desirably 0.5 parts by mass to 20 parts by mass or more, more preferably 1 part by mass to 10 parts by mass, and further preferably 3 parts by mass with respect to 100 parts by mass of the aqueous polyurethane dispersion. -7 parts by mass. When the addition amount of the crosslinking agent is within the above range, the curing is sufficiently performed, the intended peel strength and impact resilience are obtained, and the deterioration of physical properties due to the remaining unreacted components is suppressed.

  The viscosity of the water-based polyurethane dispersion is required to be a high-viscosity blend due to the stability of the bubbles, and 1,000 Pas to 100,000 mPas with a BH viscometer. Is preferred. As the thickener, water-soluble polymers are generally used, but casein, alginate, arabic gum, carboxylated methylcellulose salt, polyvinyl alcohol, polyvinylpyrrolidone copolymer, polyacrylate, polymethacrylate, polyacrylamide emulsion, Methyl vinyl ether maleic anhydride copolymer, carboxylated styrene butadiene polymer, carboxylated vinyl polymer, polyalkylene oxide, polyphthalic acid emulsion and the like are used. In addition, inorganic thickeners such as montmorillonite, bentonite and clay can be used alone or in combination. These thickeners are hydrophilic, and if the amount used is large, the hardness, hygroscopicity and water retention of the foam will be affected. It is preferable to add 1 part by mass to 5 parts by mass of an oxide polymer or the like.

  In addition to foaming agents, foam stabilizers, oxazoline-based crosslinking agents, and thickeners, aqueous polyurethane dispersions include film-forming aids, pigments, flame retardants, fillers, anti-aging agents, ultraviolet rays, as necessary. Components such as an absorbent and a fragrance can be added.

  When a predetermined component is added to the aqueous polyurethane dispersion and mechanically stirred with air in an ordinary batch stirrer, for example, a Hobart mixer or a hopper, a mechanically foamed dispersion in cream form is obtained. In mass production, a method of stirring continuously while feeding a fixed amount of air with an Oaks mixer, a pin mixer or the like is desirable. As a method of applying the mechanically foamed dispersion liquid to a predetermined substrate, a coating apparatus such as a normal knife coater, comma coater, roll coater, or lip coater can be used.

  In the case of applying this mechanically foamed dispersion, the aqueous polyurethane dispersion may be applied onto the surface layer 18, and after application, drying and heat treatment may be performed, and this application, drying and heat treatment may be repeated twice or more. A foam of any thickness can be formed. When the desired thickness of the foamed layer is 1 mm or more, it is desirable to perform the above step twice or more because physical properties such as rebound resilience and peeling strength due to pressing of the obtained foamed layer are improved.

The drying temperature is preferably 50 ° C to 100 ° C, the drying time is preferably 0.5 minutes to 10 minutes, the heat treatment temperature is 100 ° C to 180 ° C, more preferably 120 ° C to 160 ° C, and the heat treatment time is 0.5 ° C. Minutes to 10 minutes, more preferably 2 minutes to 8 minutes. As a drying method, conventional apparatuses such as hot air drying and far-infrared radiator drying can be used alone or in combination.
A method for forming a foamed layer using such polyether-based or polycarbonate-based water-based polyurethane is described in detail in Japanese Patent No. 4596865, and the technique described here is applied to the formation of the foamed layer in the present invention. be able to.
The foam layer 20 is formed by applying a foam layer forming coating solution obtained by adding thermally expandable beads to a base aqueous polyurethane resin composition on the surface of the skin layer 18 and drying to form a coating solution layer. Then, the foam layer 20 may be formed by expanding the thermally expanded beads present in the coating liquid layer by heating to form voids.

The aqueous polyurethane used in forming the foam layer 20 is preferably made hardness of an aqueous polyurethane capable of forming a film in the range of ^50N / cm ^{2 ~1200N} / cm 2 at 100% modulus, 98 N / more preferably in the range of cm ² ~1176N / cm ^2, and more preferably in the range of ^{98N / cm 2 ~490N / cm 2} . The weight average molecular weight of the water-based polyurethane used as a main agent when forming the foamed layer is preferably in the range of 250,000 to 1,500,000.

Coating weight before drying of the foam layer 20 is preferably ^{50g / m 2 ~500g / m 2} mp range, the method of using the beads, after drying to form a coating liquid layer, by heating The foam layer 20 is formed by expanding the thermally expanded beads present in the coating liquid layer to form voids.

The thermally expanded beads used in the coating liquid for forming the foamed layer are particles in which an organic solvent such as a hydrocarbon solvent is encapsulated in hollow thermoplastic resin particles. The volume increases, and as a result, the foamed layer 20 in which bubbles are contained in the resin matrix (dispersion medium) is formed.
As the thermally expandable beads used in the present invention, any one may be used as long as it expands by heating to form bubbles in the aqueous polyurethane resin matrix and can maintain the state of the formed bubbles. .
Thermally expanded beads are also available as commercial products, such as EXPANSEL series (trade name) manufactured by Nippon Ferrite Co., Ltd., any of which can be used in the present invention.
The addition amount of the thermally expanded beads is preferably 0.5 part by mass to 10 parts by mass, and more preferably 1 part by mass to 7 parts by mass with respect to 100 parts by mass of the aqueous polyurethane resin.

Drying of the coating layer for forming a foam layer when using thermally expanded beads is preferably performed at a temperature in the range of 90 ° C to 130 ° C, and may be performed at a temperature of 100 ° C to 120 ° C. More preferred.
Moreover, in the said foaming layer formation process, it is preferable that the heating temperature for expanding a thermally expanded bead is the range of 130 to 200 degreeC, and it is more preferable that it is the range of 150 to 180 degreeC.

The coating liquid for forming the foam layer may contain a colorant for the purpose of adjusting the appearance. As the colorant used in the foam layer, colored organic fine particles containing various pigments and dyes can be selected and used according to the purpose, but from the viewpoint of design and durability, from organic pigments and inorganic pigments One or more selected or colored organic fine particles containing these pigments are preferred. The aforementioned skin layer may also contain a colorant, and the colorant in the skin layer and the colorant in the foam layer may be the same or different.
Although content of a coloring agent is suitably selected according to a use purpose, it is preferable to contain in 1 mass part-100 mass parts with respect to 100 mass parts of aqueous polyurethane resins which are main ingredients. When a plurality of colorants are contained, the content indicates the total amount of the plurality of colorants.

  In addition, you may use together other additives for the coating liquid for foaming layer formation in the range which does not impair the effect of this invention. Examples of additives that can be used in combination include flame retardants, chain extenders, thixotropy imparting agents, antifoaming agents, leveling agents, and surfactants.

There is no restriction | limiting in particular in the application quantity of the foaming layer 20, and a film thickness, Although it selects suitably according to the objective, Generally, as an application quantity before drying from a viewpoint of intensity | strength and an external appearance, it is 25 g / m < ² >. is preferably in the range of to 500 g / ^{m 2,} more preferably in the range of ^{25g / m 2 ~200g / m 2} . Moreover, the film thickness after drying is preferably about 10 μm to 100 μm, and more preferably about 20 μm to 60 μm.

[Water-based urethane adhesive layer]
A water-based urethane adhesive layer 22 is provided on the surface of the formed foam layer 20.
Examples of the water-based urethane used for forming the water-based urethane adhesive layer 22 include polycarbonate-based polyurethane, polyether-based polyurethane, polyester-based polyurethane, and modified products thereof. When long-term durability is required, polycarbonate-based polyurethane is preferable. is there. Similarly to the water-based polyurethane used for the skin layer and the foamed layer, the water-based polyurethane used for the adhesive layer also has one or more hydrophilic groups in a part of the molecular chain of the urethane main agent in order to have water-based physical properties. Those obtained by introducing a functional carboxyl group are preferred.
In addition, as the aqueous polyurethane used for forming the adhesive layer, various commercially available aqueous polyurethane resins such as Implanil DLU manufactured by Bayer are also applicable.
Water-based polyurethane used to form the adhesive layer, is preferably a water-based polyurethane which can form a film in the range of ^10N / cm ^{2 ~1000N} / cm 2 at 100% modulus hardness, more preferably 98 N / in the range of cm ² ~980N / cm ^2, more preferably in the range of ^{196N / cm 2 ~588N / cm 2} . Moreover, it is preferable that the weight average molecular weight of the water-based polyurethane used as the main agent in forming the adhesive layer is in the range of 10,000 to 70,000.

After forming the skin layer 18 and the foamed layer 20 on the temporary support, an aqueous polyurethane adhesive is coated on the surface of the foamed layer 20 with a hermetic or open coating head, and dried by heating to an adhesive having a desired thickness. A coating liquid layer is formed. Thereafter, the base fabric 10 for synthetic leather is subjected to thermocompression bonding, the adhesive is reacted and cured, and the formation of the adhesive layer 22 and the close contact between the adhesive layer 22 and the base fabric 16 are simultaneously performed.
The heating temperature and the heating time for accelerating the curing reaction are appropriately selected depending on the type of the adhesive, but generally it is preferably in the range of 30 ° C. to 80 ° C., and the heating time is 12 hours to 72 hours. A range is preferable.
The thermocompression bonding is preferably performed by laminating the heating temperature in the range of 100 ° C. to 150 ° C. using a roll nip apparatus.
Moreover, when the base fabric 10 has raised parts on at least one side, the raised fibers are infiltrated into the adhesive coating liquid layer for forming the adhesive layer by bringing the raised side into close contact with the adhesive layer 22, and in this state, the adhesive layer 22. Is cured to further improve the adhesion between them.
Even if a base material is a single | mono layer, it may have a multilayer structure which laminated | stacked the sheet | seat which has a physical property according to the objective.

A cross-linking agent and a cross-linking accelerator may be added to the adhesive composition for the purpose of improving curability. Moreover, you may add a flame retardant for the flame retardance improvement of synthetic leather.
(Crosslinking agent, crosslinking accelerator)
As the crosslinking agent, the described oxazoline crosslinking agent, polyisocyanate crosslinking agent, epoxy crosslinking agent, aziridine crosslinking agent, carbodiimide crosslinking agent, and the like can be used.
Moreover, you may use together the crosslinking accelerator suitable for a crosslinking agent, etc. with a crosslinking agent.

(Flame retardants)
The adhesive layer according to the present invention may contain a flame retardant. In particular, when the synthetic leather of the present invention is used for aircraft or vehicle interior materials, it is preferable to contain a flame retardant because flame retardancy is important as well as strength.
A well-known thing can be used suitably for the flame retardant which can be used for this invention, For example, you may use a metal hydroxide, a phosphorus flame retardant, a nitrogen-phosphorus flame retardant, etc. The flame retardant is also available as a commercial product, and examples thereof include STC powder manufactured by Clariant Japan Co., Ltd.
The flame retardant content is preferably in the range of 1 part by mass to 50 parts by mass with respect to 100 parts by mass of the water-based polyurethane adhesive that is the adhesive main agent.

Coating weight before drying of the adhesive layer-forming coating liquid ^is required to be a ^{50g / m 2 ~500g / m 2} , is preferably ^{100g / m 2 ~200g / m 2} . Moreover, it is preferable that the thickness after drying of an contact bonding layer is about 20 micrometers-100 micrometers, More preferably, it is the range of 30 micrometers-80 micrometers. When the thickness of the adhesive layer is within the above range, a synthetic leather having sufficient elasticity and strength is formed.

  Thus, after the skin layer 18, the foam layer 20, and the adhesive layer 22 are formed on the temporary support, and the adhesive layer 22 and the base fabric 10 are adhered and fixed by the curing of the adhesive layer 22, By peeling the temporary support having the release layer, a synthetic leather 16 having a leather-like uneven pattern on the skin layer 18 and having good elasticity and strength is obtained.

FIG. 3 is a schematic cross-sectional view showing another embodiment of the synthetic leather of the present invention.
In the present embodiment, the synthetic leather 24 includes a water-based urethane adhesive layer 22 and a water-based urethane skin layer 18 in this order on the surface of the base fabric 10.
The synthetic leather 24 of this embodiment has the same configuration as that of the synthetic leather 16 of the above embodiment except that the aqueous urethane foam layer 20 is not provided between the aqueous urethane adhesive layer 22 and the aqueous urethane skin layer 18. .
However, in order to make the synthetic leather 24 have a desired film thickness, elasticity, and strength, the film thicknesses of the skin layer 18 and the adhesive layer 24 are appropriately adjusted.
The preferable film thickness after drying of the skin layer 18 in the synthetic leather 24 of this embodiment is about 10 μm to 70 μm, and more preferably about 10 μm to 30 μm.
Moreover, the film thickness after drying of the adhesive layer 22 is preferably about 20 μm to 100 μm, and more preferably about 30 μm to 80 μm.
The synthetic leather 16 of the present invention uses the synthetic leather base fabric 10 of the present invention, which has a sufficient thickness and has easy processability, durability and flame retardancy suitable for the production of synthetic leather. The skin layer 16 having a desired hue and having a desired concavo-convex pattern (texture pattern) on the surface is provided, and is excellent in strength, durability, and workability. For this reason, it can be suitably used in various fields such as automotive interior materials, railway vehicle / aircraft interior parts, furniture, shoes / footwear / bags, building interior / exterior members, clothing cover materials / linings, sheets, Even in the case of covering the surface of a member having a complicated three-dimensional shape such as a chair, the conformability to the shape is good, a natural wrinkle feeling is obtained, and the same feeling as when natural leather is used. The appearance can be achieved and the durability and flame retardancy resulting from the material can be obtained.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not restrict | limited to these.
[Example 1]
A knitted structure using a blended yarn of 22nd-numbered polyvinyl chloride fiber (LOI value: 28) and 22nd-numbered rayon fiber (LOI value: 19), and having a thickness of 0.8 mm, heavy weight A knitted fabric (knitted fabric) having a thickness of 200 g / m ² was produced to obtain a synthetic leather base fabric 10 of the present invention. The LOI value measured by JIS K7201 of the obtained base fabric 10 was 26.
As a temporary support, a cleaved release paper (Dai Nippon Printing Co., Ltd., DE-41: paper thickness average 140 μm) having a surface release treatment and having a release layer was used.

(Skin layer forming composition)
-100% by weight 100% modulus of water-based non-yellowing polycarbonate polyurethane paint with 588 N / cm ² (Bayer's Implanil DLC-P: trade name)
・ Colored organic resin fine particles (made by Mikuni Dye, SBP color series) 10 parts by mass ・ Solvent (water) 100 parts by mass

The composition for forming the skin layer was sufficiently mixed to obtain a composition for forming the skin layer having a solid content of about 19% by mass.
Using the open coating head coating apparatus, the wet coating amount is 110 g / m ² on the surface of the release layer forming side of the temporary support provided with the release layer. It applied so that it might become. After the coating film was formed, the coating film was dried using a hot air dryer at 100 ° C. for 2 minutes to form a skin layer 18 (film thickness after drying: about 20 μm) on the temporary support.

(Composition for forming foam layer)
・ 100 parts by weight of water-based hardly yellowed polycarbonate polyurethane paint having a 100% modulus of 490 N / cm ² and a solid content of 60% (manufactured by Bayer, Implanil DLU)
・ 4 parts by mass of thermal expansion beads (made by Nippon Ferrite Co., Ltd., Expandel DU120)
・ 3.0 parts by mass of crosslinking agent (Nippon Shokubai Co., Ltd., Epocross WS-500)
・ Thickener 2.0 parts by mass (made by Elementis, Leorate 210)
The intermediate layer forming composition was sufficiently mixed to obtain a foamed layer forming composition having a solid content of about 60% by mass.
On the skin layer 18, the foamed layer forming composition was applied using a knife coat coating apparatus. After the coating film is formed, the coating film is dried using a hot air dryer at 100 ° C. for 2 minutes, and an open-type foaming layer forming coating liquid layer (coating amount: 50 g / m ^{2) is} formed on the skin layer 18. ) Was formed.
The formed laminate having the intermediate layer forming coating liquid layer 18 is heated at 170 ° C. for 2 minutes using a hot air drier to expand the thermally expanded beads, and the foam layer 20 having a thickness of about 75 μm containing bubbles is formed. Formed.

On the surface of the formed foam layer 20, a cross-linking agent (Bayer, Dismodule N3900) with respect to a hardly yellowing water-based polycarbonate polyurethane adhesive (Bayer, Implanil DLU) having a 100% modulus of 245 N / cm ² 3 parts by mass of a non-decabro flame retardant having a pH of 7 to 9 and 2% by mass of an antimony combined flame retardant were added so that the thickness after drying would be 50 μm. It was coated with a coating head and dried at 100 ° C. for 2 minutes to form an adhesive composition layer, thereby obtaining a laminate for forming synthetic leather.
Next, the adhesive layer 22 of the obtained laminate and the base fabric 10 having the pontoroma knitted structure are brought into contact with each other, laminated with a nip device, wound up and maintained at 50 ° C. for 48 hours to cure the adhesive. Reaction was advanced and the base fabric 10 and the contact bonding layer 22 were stuck.
Thereafter, the temporary support was peeled off to obtain the synthetic leather 16 of Example 1 having the adhesive layer 22, the foam layer 20, and the skin layer 18 in this order on the surface of the base material 10.
When the obtained synthetic leather 16 of Example 1 was visually observed, there was no pattern omission due to imperfect transfer on the surface, no glossy appearance, excellent appearance, and good elasticity and feel when pressed with a finger.

[Example 2]
Except that the adhesive layer 22 (thickness: 50 μm) and the skin layer 18 (thickness: 20 μm) were provided on the base fabric used in Example 1, and the water-based urethane foam layer 20 was not provided, the same as in Example 1. Thus, a synthetic resin skin material of Example 2 having a layer structure shown in FIG. 3 was produced.
[Comparative Example 1 and Comparative Example 2]
A knitted fabric (knitted fabric) having a knitted structure of Pontiloma, a thickness of 0.8 mm, and a weight of 200 g / m ² was prepared using polyvinyl chloride fiber (LOI value: 28) having a thickness of 22nd. A base fabric for synthetic leather for Comparative Example 1 was obtained. The LOI value measured by JIS K7201 of the obtained base fabric was 28.
Further, a 22nd-numbered rayon fiber (LOI value: 19) was used to prepare a knitted fabric (knitted fabric) having a knitted structure of Ponchiroma, a thickness of 0.8 mm, and a weight of 200 g / m ² . A base fabric for synthetic leather for 2 was obtained. The LOI value measured by JIS K7201 of the obtained base fabric was 19.
Synthetic resin skin materials of Comparative Example 1 and Comparative Example 2 were prepared in the same manner as in Example 1 except that the base fabric was changed to the comparative base fabric obtained above.

(Evaluation of the synthetic leather obtained)
The obtained synthetic leather was evaluated by the following method. The results are shown in Table 1 below.
1. Flame Retardancy Evaluation Each synthetic leather obtained was subjected to a combustion test according to Part III Appendix F Vertical Method for Airworthiness Examination, and flame retardancy was evaluated according to the criteria shown in Table 1 below.
If it is evaluated as ◎ or ○ according to the criteria shown in Table 1, it is judged to exhibit practically sufficient flame retardancy.

2. Scratch resistance Using a Taber Scratch Tester (manufactured by Tester Sangyo Co., Ltd., HA-201), a test was performed by a standard test method. As a result, the scratch resistance required performance of 2.94N or more was evaluated as “good”, and the one less than 2.94N was evaluated as “poor”.
3. Shape follow-up Synthetic leather parts that cover a wide area of the seat back and a thin surface that covers the side of the seat back in a structure having a seat cushion and a seat back that is a base of a vehicle seat by cutting synthetic leather The seat back was covered and fixed with two pieces of synthetic leather parts having a small width and area, and the shape following property of the seat back of the vehicle seat covered with the synthetic leather was evaluated.
Observe the seat back of the vehicle seat covered with synthetic leather visually, especially the synthetic leather covering the wide area of the curved part along the top of the U-shaped seat back and two sheets corresponding to the side part Check the presence or absence of each wrinkle of fine sewing wrinkles along the seam and relatively large hanging wrinkles formed by waving the synthetic leather itself, and judged according to the following evaluation criteria. . When shape followability is good, wrinkles are unlikely to occur even when a structure having a curved shape such as a seat back of a vehicle seat is covered.
○: Neither sewn wrinkles nor suspended wrinkles were observed. Δ: Sewing wrinkles were observed, but no hanging wrinkles were observed. ×: Both sewn wrinkles and suspended wrinkles were observed.

  From the results of Table 2, the synthetic leathers of Examples 1 and 2 using the synthetic leather base fabric of the present invention are excellent in appearance and feel, and are excellent in all of flame retardancy, scratch resistance, and shape followability. It can be seen that it can be suitably used for aircraft seat materials, vehicle interior materials, furniture, and the like that require flame retardancy and durability. On the other hand, in Comparative Example 1 using only flame retardant fibers as the base fabric, the shape following property is low as compared with the Example, and surprisingly, the flame retardance is also inferior compared with Example 1. It was a thing. In Comparative Example 2 using a flammable base fabric, the flame retardancy was extremely low, and it was a level causing a practical problem.

DESCRIPTION OF SYMBOLS 10 Base fabric for synthetic leather 12 First thread 14 Second thread 16, 24 Synthetic leather 18 Skin layer 20 Foamed layer 22 Adhesive layer

Claims (9)

Has a double-sided knitting structure using yarns comprising limiting oxygen index (LOI value) and 25 more flame retardant fibers and cellulosic fibers, the mass is a knitting of ^{150g / m 2 ~250g / m 2} , the A base fabric for synthetic leather in which the LOI value of the knitted fabric is 25 or more.   2. The flame retardant fiber is one or more selected from aramid fiber, polyphenylene sulfide fiber, and vinyl chloride fiber, and the cellulosic fiber is one or more selected from cotton and rayon. The synthetic leather base fabric described in 1.   The base fabric for synthetic leather according to claim 1 or 2, wherein the knitted body has a pontoroma knitting structure.   The base fabric for synthetic leather according to any one of claims 1 to 3, wherein the knitted body has raised hairs.   The synthetic leather which has a water-based polyurethane contact bonding layer and a water-based polyurethane skin layer in this order on the base fabric for synthetic leather of any one of Claims 1-4.   The synthetic leather according to claim 5, further comprising an aqueous urethane foam layer between the aqueous polyurethane adhesive layer and the aqueous polyurethane skin layer. Aqueous polyurethane used in the aqueous polyurethane skin layer, according to claim 5 or claim 6 which is an aqueous polyurethane capable of forming the hardness of the film is in the range of ^50N / cm ^{2 ~1200N} / cm 2 at 100% modulus Synthetic leather. Any the aqueous polyurethane used in the aqueous polyurethane adhesive layer, a 100% modulus at ^10N / cm 2 ^~1000N / cm Hardness of the film is in the range of ² which is an aqueous polyurethane capable of forming claims 5 to 7 2. Synthetic leather according to item 1.   The synthetic leather according to any one of claims 5 to 8, wherein the water-based polyurethane adhesive layer contains a flame retardant.