JP4866700B2 - Polypropylene leather - Google Patents

Description

  The present invention relates to a polypropylene-based synthetic leather, and more particularly to a polypropylene-based synthetic leather used for various uses such as stationery, various cases, packaging, furniture, construction, and automobile interiors.

  Conventionally, olefin-based synthetic leather (olefin-based leather) has been used for applications such as stationery, various cases, packaging, furniture, construction, and automobile interiors. And as a soft olefin resin used for such an olefin type synthetic leather, an olefin type thermoplastic elastomer, a styrene type thermoplastic elastomer, an ethylene-vinyl acetate copolymer, an ethylene- (meth) α olefin copolymer Etc. are known. However, in the olefin synthetic leather obtained using such a soft olefin resin, there is a problem that the scratch resistance is not sufficient, and the soft olefin resin has a low softening point. There was a problem that it was inferior to return. Therefore, in order to improve heat resistance, in the olefin-based synthetic leather used for automobile interiors exposed to high temperature environment, general-purpose polypropylene (isotactic polypropylene, syndiotactic polypropylene and Olefin-based synthetic leather obtained by adding (random polypropylene) has been used, but since a large amount of general-purpose polypropylene was added to obtain sufficient heat resistance, the flexibility of the resulting synthetic leather was impaired. . Further, a soft polypropylene resin composition containing the general-purpose polypropylene and atactic polypropylene has been studied and disclosed.

For example, in JP-A-3-148551 (Patent Document 1), (A) the number average molecular weight obtained in the presence of a specific catalyst is 25000 or more, and the weight average molecular weight (Mw) and the number average molecular weight (Mn From 10 to 90% by weight of a polypropylene-soluble polypropylene having a ratio Mw / Mn of 7 or less, and 90 to 10% by weight of a polypropylene-soluble polypropylene having a melt index of 0.1 to 4 g / 10 minutes. A flexible polypropylene composition is disclosed. And in such patent document 1, an atactic polypropylene is described as (A) component and an isotactic polypropylene is described as (B) component.
Further, in JP-A-10-71683 (Patent Document 2), an isotactic polypropylene is formed on a base sheet made of high-density polyethylene, a thermoplastic elastomer, a colorant, and an inorganic filler. A decorative sheet in which a soft polypropylene resin film having a composite three-dimensional structure composed of a mixed system of atactic polypropylene is laminated is disclosed. However, the soft polypropylene composition described in Patent Document 1 and the decorative sheet described in Patent Document 2 do not necessarily have sufficient heat resistance or flexibility. There was a problem that a product with sufficiently high heat resistance could not be obtained. In particular, when the decorative sheet or the like is used for an automobile interior used in a high temperature environment, since a large amount of general-purpose polypropylene is contained in order to obtain sufficient heat resistance, flexibility cannot be obtained and synthesis is performed. It was not suitable for use as leather. In addition, in such a soft polypropylene composition and decorative sheet, when it is a synthetic leather used for applications such as automobile interiors and furniture, when it touches the human body, it adheres to lipids secreted from the human body and the human body. There was a problem that the oily substance in the cosmetics swelled or wrinkled.
Japanese Patent Laid-Open No. 3-14851 Japanese Patent Laid-Open No. 10-71683

  The present invention has been made in view of the above-described problems of the prior art, and provides a polypropylene-based synthetic leather capable of exhibiting a good balance of flexibility, heat resistance, scratch resistance, and wear resistance at a high level. The purpose is to do.

  As a result of intensive studies to achieve the above object, the present inventors have obtained a polypropylene resin composition sheet layer obtained by adding general-purpose polypropylene to atactic polypropylene, in the polypropylene resin composition sheet layer. By setting the mass ratio of atactic polypropylene to the above-mentioned general-purpose polypropylene to be atactic polypropylene / general-purpose polypropylene = 90/10 to 60/40, the balance between heat resistance and flexibility, which are contradictory properties, is improved and obtained. It has been found that it is possible to impart high heat resistance, flexibility, scratch resistance and wear resistance by laminating a resin layer and a surface layer made of an ionomer resin, and the present invention has been completed. .

  In addition, as a result of further research, the present inventors synthesized a specific resin by adding a specific resin to at least one of the resin layer and the surface layer in order to improve the interlayer adhesion between the resin layer and the surface layer. While maintaining excellent appearance as leather, it can impart high oil resistance and scratch resistance, while maintaining the above-mentioned flexibility, heat resistance and scratch resistance at a high level in a balanced manner, and lipid It has also been found that swelling, wrinkles and the like caused by the above can be sufficiently prevented.

That is, the polypropylene synthetic leather of the present invention is a polypropylene synthetic leather comprising a base material layer, a resin layer, and a skin layer, wherein the resin layer is made of a polypropylene resin, and includes atactic polypropylene and general-purpose polypropylene. mass ratio is made polypropylene resin composition is atactic polypropylene / general purpose polypropylene = 90 / 10-60 / 40, the skin layer is Ri Do from an ionomer resin, the resin layer, at least one layer of the skin layer 1 to 10 parts by mass of at least one selected from high-hydroxyl polyester resin and hydrogenated terpene resin is added to 100 parts by mass of the resin component .

  Moreover, as the polypropylene-based synthetic leather according to the present invention, the surface of the surface layer has a thickness of 1 to 30 μm made of at least one surface treatment agent selected from the group consisting of polyurethane resins and fluoroacrylic resins. It is preferable to further include a surface protective layer.

  Furthermore, as the polypropylene-based synthetic leather according to the present invention, a bromine-based flame retardant, an antimony-based flame retardant, a metal hydroxide, a phosphorus-based flame retardant, and nitrogen-phosphorus are formed on at least one of the resin layer and the skin layer. It is preferable that 1-50 mass parts of at least 1 type of flame retardant selected from the group which consists of a system flame retardant is added with respect to 100 mass parts of resin components.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the polypropylene-type synthetic leather which can exhibit a softness | flexibility, heat resistance, abrasion resistance, and abrasion resistance with a high level with sufficient balance.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

[Resin layer]
The resin layer according to the present invention comprises a polypropylene resin composition comprising a polypropylene resin composition containing at least one general-purpose polypropylene selected from the group consisting of isotactic polypropylene, syndiotactic polypropylene and random polypropylene, and atactic polypropylene. It is a resin composition sheet layer, Comprising: The mass ratio of the said atactic polypropylene contained in the said polypropylene resin composition sheet layer and the said general purpose polypropylene is atactic polypropylene / general purpose polypropylene = 90 / 10-60. It is a layer which becomes / 40.

  The isotactic polypropylene contained as a general-purpose polypropylene in the polypropylene resin composition according to the present invention is not particularly limited and may be any known polypropylene as long as all asymmetric carbons have the same absolute configuration. Can be used.

  In addition, the syndiotactic polypropylene contained as a general-purpose polypropylene in the polypropylene resin composition according to the present invention is not particularly limited, and may be any known polypropylene as long as the absolute configuration of asymmetric carbon is alternately arranged. Can be used.

Moreover, it does not restrict | limit especially as said random polypropylene contained as a general purpose polypropylene in the polypropylene resin composition concerning this invention, A well-known thing can be used suitably. Examples of such random polypropylene include propylene-ethylene random polypropylene, random polypropylene containing a highly compatible rubber component, and random polypropylene graft-polymerized with maleic anhydride.

  The atactic polypropylene contained in the polypropylene resin composition according to the present invention is not particularly limited, and any known polypropylene can be used as long as it is a polypropylene in which asymmetric carbons are arranged at random.

In the polypropylene resin composition sheet layer according to the present invention, a mass ratio of the atactic polypropylene to the general-purpose polypropylene is atactic polypropylene / general-purpose polypropylene = 90/10 to 60/40. When the mass ratio of such atactic polypropylene is less than the above lower limit, the flexibility of the obtained polypropylene synthetic leather is lowered. On the other hand, when the upper limit is exceeded, the heat resistance of the obtained polypropylene synthetic leather is lowered. In the present invention, the above-mentioned general-purpose polypropylene which is a high-melting-point polyolefin which is completely compatible with the atactic polypropylene which is a soft polyolefin is contained, and the mass ratio (atactic polypropylene / general-purpose polypropylene) is 90/10 to 10/10. By setting the ratio to 60/40, it is possible to impart heat resistance and flexibility, which are contradictory performances in the prior art, to the obtained polypropylene resin composition sheet layer in a balanced manner. In addition, such a polypropylene resin composition sheet layer is one in which the atactic polypropylene and the general-purpose polypropylene are completely compatible with each other, and therefore, from an olefin-based synthetic leather made of a conventional olefin-based thermoplastic elastomer. Furthermore, it is possible to impart excellent surface scratch resistance.

  The mass ratio of the atactic polypropylene contained in the resin layer and the general-purpose polypropylene is more preferably atactic polypropylene / general-purpose polypropylene = 70/30 to 80/20. By setting it as such a mass ratio, in the obtained polypropylene-type synthetic leather, it exists in the tendency for a softness | flexibility, heat resistance, and abrasion resistance to be achieved with a higher level with sufficient balance.

  Moreover, as a resin layer concerning this invention, 1-30 mass parts of resin components whose glass transition temperature is 20-60 degreeC lower than the said polypropylene resin composition are contained with respect to 100 mass parts of said polypropylene resin compositions. It is preferable. Since the glass transition temperature of the polypropylene resin composition used in the present invention is around −5 ° C., it is preferable to select a resin component of −25 to −65 ° C.

  Thus, it becomes possible to improve the cold resistance of the polypropylene-type synthetic leather obtained by containing the resin component whose glass transition temperature is 20-60 degreeC lower than the said polypropylene-type resin composition. The polypropylene synthetic leather thus obtained is useful as a polypropylene synthetic leather for automobile interiors used in cold districts such as North America.

  Thus, the resin component is not particularly limited as long as it has a glass transition temperature lower by 20 to 60 ° C. than the polypropylene resin composition. For example, a polyethylene resin (HDPE, LLDPE, LDPE, etc.); Ethylene-α olefin copolymer; olefin rubber (EPR, EPDM, etc.); styrene rubber (SEBS, SEPS, SBR, HSBR, SEBC, etc.), nitrile rubber; olefin thermoplastic elastomer; styrene thermoplastic elastomer; It is possible to use an ethylene-vinyl acetate copolymer; an ethylene- (meth) acrylic ester copolymer or the like. Among these resin components, while improving the cold resistance, the compatibility of the resin component and the polypropylene resin composition is improved, and the balance between flexibility and scratch resistance derived from the compatibility is achieved. From the viewpoint of further improvement, it is preferable to use olefin rubber and olefin thermoplastic elastomer.

  As described above, the content of the resin component is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the polypropylene resin composition. If the content of such a resin component is less than the lower limit, the resulting polypropylene synthetic leather tends not to exhibit the intended cold resistance, whereas if the upper limit is exceeded, the resulting polypropylene synthetic leather has heat resistance. Tend to decrease.

  In the resin layer according to the present invention, in addition to the above-described components, as necessary, fluorine fibrils, antioxidants, weather resistance improvers, fillers, antistatic agents, pigments, dispersants, light stabilizers. A foaming agent or the like can be added.

  In addition, the thickness of the resin layer according to the present invention is appropriately selected depending on the use of the obtained polypropylene synthetic leather, but is generally preferably 50 to 1000 μm. If the thickness of the resin layer is less than the lower limit, the volume as a synthetic leather tends to be lacking. On the other hand, if the thickness exceeds the upper limit, the flexibility as a synthetic leather tends to be lowered.

  Moreover, the resin layer concerning this invention can also be made into a foaming layer as needed. By using a foamed layer in this way, there is a tendency that flexibility, weight reduction, and improvement in volume feeling can be achieved. Thus, when making a polypropylene resin composition sheet layer into a foaming layer, a foaming agent is added in a polypropylene resin composition.

  Examples of the foaming agent include pyrolytic chemical foaming agents such as azodicarboxamide, oxybisbenzene hydrazide, benzenesulfonyl hydrazide, P-toluenesulfonyl hydrazide, diazoaminobenzene, dinitropentamethylenetetramine, azobisisobutyronitrile. One or more selected foaming agents can be used in combination. It is also possible to use a foaming aid in combination with the foaming agent, and examples of such foaming aids include zinc white, tribasic metal sulfate, and stearic acid.

The addition amount of the foaming agent is appropriately selected depending on the foaming ratio of the foamed layer. For example, when the foaming ratio is 3 to 15 times, 2 to 20 parts by weight with respect to 100 parts by weight of the polypropylene resin composition. It is mentioned to make it the addition amount of a grade. When the resin layer is a foamed layer, the thickness is preferably about 50 to 3000 μm.
[Surface layer]
The surface layer according to the present invention uses an ionomer resin having a special structure in which molecules of ethylene-methacrylic acid copolymer or ethylene-acrylic acid copolymer are intermolecularly bonded with metal ions such as sodium and zinc. Is done. The thickness of the surface layer is appropriately set depending on the use of the polypropylene synthetic leather and the like, but is about 10 to 100 μm.
In the resin layer and the surface layer according to the present invention based on the olefin resin, even if an adhesive layer is provided between the layers, the adhesion with each layer tends to be insufficient. By improving this adhesion, scratch resistance and oil resistance can be improved, and appearance defects such as peeling of the surface layer and the base material layer can be prevented.
As a method for improving the adhesion, generally, a corona treatment or a plasma treatment is performed on the adhesion surface of the resin layer or the surface layer, or a primer layer is provided. As the primer, chlorinated polyolefin, polyester, one-component polyurethane, two-component polyurethane, etc. are used, and in consideration of adhesion and weather resistance, a two-component reactive type polyurethane made of non-yellowing isocyanate and polycarbonate polyol is preferable. in use. In the present invention, a conventionally used method may be adopted as described above, but the number of processes is increased at the manufacturing stage, which is not preferable in terms of production efficiency.

In the present invention, by adding 1 to 10 parts by mass of the highly hydroxylated polyester resin or hydrogenated terpene resin to 100 parts by mass of the resin component of each layer, at least one of the resin layer and the surface layer is added. Adhesion can be improved, and the manufacturing process can be simplified.

If the addition amount is less than 1 part by mass, the adhesion performance is not improved, and if it exceeds 10 parts by mass, hydrolysis resistance and cold resistance are lowered, which is not preferable.

  Further, at least one of the resin layer and the surface layer according to the present invention is selected from the group consisting of a bromo flame retardant, an antimony flame retardant, a metal hydroxide, a phosphorus flame retardant, and a nitrogen-phosphorus flame retardant. It is preferable to contain 1-50 mass parts of said at least 1 type of flame retardant with respect to 100 mass parts of said polypropylene resin compositions or ionomer resins.

  The brominated flame retardant, the antimony flame retardant, the metal hydroxide, the phosphorus flame retardant, or the nitrogen-phosphorus flame retardant is not particularly limited, and a known one can be used as appropriate. For example, examples of the metal hydroxide include magnesium hydroxide and aluminum hydroxide, and examples of the phosphorus flame retardant include phosphate ester and red phosphorus. Examples of the nitrogen-phosphorus flame retardant include ammonium polyphosphate and guanidine flame retardant. Among these flame retardants, it is particularly preferable to use a phosphate ester from the viewpoint of cost and imparting higher flame retardancy.

  Moreover, it is preferable that content of such a flame retardant is 1-50 mass parts with respect to 100 mass parts of the said polypropylene resin composition or ionomer resin. By setting it as such content, it becomes possible to give high flame retardancy to the obtained polypropylene-based synthetic leather, and to be able to clear the flame retardance standard required in automotive applications. is there. From the viewpoint of further improving the obtained polypropylene-based synthetic leather, it is effective to impregnate the base material described later with the flame retardant.

  Thus, by including the flame retardant in at least one of the resin layer and the surface layer, the resulting polypropylene-based synthetic leather has a high degree of flexibility, heat resistance and scratch resistance in a well-balanced manner, There exists a tendency for a flame retardance to improve more. Therefore, the polypropylene-based synthetic leather thus obtained is given flame retardancy comparable to that of polyvinyl chloride-based synthetic leather, polyurethane-based synthetic leather, etc., and is used, for example, for automobile interiors. Useful as polypropylene-based synthetic leather.

[Base material layer]
It does not restrict | limit especially as a base material used for the base material layer concerning this invention, The well-known base material which can be used for manufacture of an olefin type synthetic leather can be used suitably. Examples of such a substrate include woven fabric, knitted fabric, and non-woven fabric. Examples of such a woven or knitted material include polyamide fiber, polyester fiber, acrylic fiber, polypropylene fiber, cotton, rayon, or a blended yarn thereof. Examples of the type of the knitted fabric include double-sided knitted fabric and tenshi knitted fabric, and examples of the woven fabric include plain woven fabric, twill woven fabric, and satin woven fabric. Moreover, it is also possible to use a soft foam sheet for the substrate. Examples of such a flexible foam sheet include polypropylene foam, electron beam cross-linked polypropylene foam, polyethylene foam, and polyurethane foam.

  Moreover, as a base material layer which consists of such a base material, the thickness of 100-2000 micrometers generally used can be used.

[Surface protective layer]
In the polypropylene synthetic leather of the present invention, a surface protective layer having a thickness of 1 to 30 μm composed of at least one surface treatment agent selected from the group consisting of polyurethane resins and fluoroacrylic resins is provided on the surface of the surface layer. It is preferable to further provide.

  In conventional polypropylene-based synthetic leather, when used for applications such as automobile interiors and furniture, when the human body touches, lipids secreted from the human body and oily substances in cosmetics adhere to the surface of the polypropylene-based synthetic leather. As a result, the surface swelled, wrinkles, blisters and the like were generated, and the beauty was impaired. Furthermore, conventional polypropylene-based synthetic leather is inferior in scratch resistance compared to PVC or polyurethane-based synthetic leather. Therefore, in the polypropylene-based synthetic leather of the present invention, by providing the surface protective layer further on the surface of the polypropylene-based resin composition sheet layer, the oil resistance is improved, the lipid secreted from the human body, the oiliness in cosmetics It is possible to sufficiently prevent the polypropylene-based synthetic leather from swelling due to the substance, further mineral oil, and the like, and to further improve the scratch resistance.

  The polyurethane-based resin used as a surface treating agent in the present invention is not particularly limited, and may be contained in a molecular structure obtained by reacting a known bifunctional polyol and a known diisocyanate as appropriate as a main component. A polyurethane-based resin having a urethane group can be used. Examples of such polyurethane resins include silicon-modified polyurethane resins. Among such polyurethane-based resins, a silicon-modified polyurethane resin (for example, trade name “RESAROID LU-4305” manufactured by Dainichi Seika Co., Ltd.) is used from the viewpoint of further improving oil resistance and scratch resistance. It is preferable.

  Further, the fluoroacrylic resin used as the surface treating agent in the present invention is not particularly limited, and for example, a fluoroacrylic resin obtained by adding an isocyanate crosslinking agent to a fluoroacrylic prepolymer or a one-component fluorine An acrylic resin etc. are mentioned. Among such fluoroacrylic resins, from the viewpoint of further improving oil resistance and scratch resistance, fluoroacrylic prepolymers (for example, product names “Defenser TR-301”, “Defenser TR— 306 "etc.) is preferably used with a fluoroacrylic resin obtained by polymerizing an isocyanate cross-linking agent (for example, product name" Bernock DN-950 "manufactured by Dainippon Ink, Inc.).

  Moreover, as thickness of such a surface protective layer, it is preferable that it is 1-30 micrometers (preferably 2-10 micrometers). When the thickness of the surface protective layer is less than 1 μm, the surface protective layer becomes too thin, and it tends to be difficult to impart the desired sweat resistance to the polypropylene-based synthetic leather, while when it exceeds 30 μm, There exists a tendency for the softness | flexibility as a synthetic leather to fall.

  In addition, the polyurethane resin or the fluoroacrylic resin may include an antioxidant, a neutralizer, an ultraviolet absorber, a light stabilizer, an antistatic agent, a pigment, a dye, an antifungal agent, and an alga as necessary. An agent, a foaming agent, a lubricant and the like can be blended.

[Polypropylene-based synthetic leather]
The polypropylene synthetic leather of the present invention comprises the base material layer, the resin layer, and a surface layer. Such a polypropylene-based synthetic leather of the present invention can exhibit flexibility, heat resistance, scratch resistance and wear resistance at a high level in a well-balanced manner.

  The polypropylene synthetic leather of the present invention preferably further includes the surface protective layer on the surface layer. Thus, when the said surface protective layer is further provided, it becomes possible to exhibit the outstanding sweat resistance with respect to the lipid etc. which are secreted from a human body etc.

Hereinafter, a production method suitable for producing the polypropylene-based synthetic leather of the present invention will be described.
The production method suitable for producing the polypropylene-based synthetic leather of the present invention is basically a surface layer, a step (A) for producing a resin layer, and the resin layer and the surface layer are bonded, This is a method including a step (B) of obtaining a polypropylene-based synthetic leather comprising a base material layer, a resin layer, and a surface layer by bonding the resin layer and the base material.

  In the step (A) for producing the surface layer and the resin layer, the mass ratio of the atactic polypropylene and at least one general-purpose polypropylene selected from the isotactic polypropylene, the syndiotactic polypropylene, and the random polypropylene is used. The atactic polypropylene / the general-purpose polypropylene = 90/10 to 60/40, and after adding the various additives as necessary, kneading them well, the resulting polypropylene series A resin layer is manufactured using the resin composition, and a surface layer is manufactured using an ionomer resin.

  The molding method of the resin layer and the surface layer in the step (A) is not particularly limited, and a known molding method such as a calendar method, a T-die extrusion method, a coating method using a release paper or the like can be appropriately employed.

  In addition, when the resin layer or the surface layer is produced by adopting the calendar method, it is preferable to add a known lubricant or the like in order to increase the roll lubricity. As such a lubricant, organic acid metal salts, organic fatty acids, metal oxides, phosphoric acid compounds and the like can be used. Examples of such organic acid metal salts include higher fatty acid salts of metals (zinc stearate, barium stearate, calcium stearate, zinc laurate, zinc oleate, dibutyltin dilaurate, dibutyltin stearate). It is done.

  Further, in order to further improve the cold resistance of the obtained polypropylene-based synthetic leather, the resin layer has a glass transition temperature of 20 to 60 than that of the polypropylene-based resin composition with respect to 100 parts by mass of the polypropylene-based resin composition. 1-30 mass parts of polyolefin resins having a low temperature may be added.

  In the step (B), an adhesive is applied to the surface layer or the surface of the resin layer, or both layers, and both layers are laminated, heated, pressurized and integrated, and then the back surface of the resin layer or the base material Applying the adhesive on the surface or both layers, laminating and laminating the resin layer and base material layer, and applying heat and pressure after bonding, the base material and the polypropylene resin composition sheet do not deviate Is made of a base material layer, a resin layer, and a surface layer by heating with a temperature condition of about 130 to 200 ° C. and pressurizing with a crest roll and embossing. Get synthetic leather.

  Although it does not restrict | limit especially as an adhesive agent used in a process (B), Ethylene-vinyl acetate copolymer type | system | group emulsion, a polyvinyl chloride paste, a 2 liquid type polyurethane adhesive etc. are mentioned, A viewpoint that higher adhesiveness is obtained. Therefore, it is preferable to use a two-component polyurethane adhesive. Further, from the viewpoint of further improving the adhesiveness, a primer layer may be provided on the back surface of the surface layer or both surfaces of the resin layer, or a corona discharge treatment or a plasma treatment may be performed.

  When the primer layer is provided in this way, chlorinated polyolefin, polyester, one-component reactive polyurethane, two-component reactive polyurethane, or the like can be used as the primer. Among such primers, from the viewpoint of adhesion and weather resistance, non-yellowing isocyanate (for example, product name “Rezaroid LU-3017” (isocyanate cross-linking agent) manufactured by Dainichi Seika) and polycarbonate polyol (for example, large It is preferable to use a two-component reactive polyurethane made by Nissei Kasei Co., Ltd. and trade name “Rezaroid LU4304” (polyurethane prepolymer). Further, the thickness of such a primer layer is preferably in the range of 1 μm to 30 μm. Moreover, it does not restrict | limit especially as a method of the said corona discharge process or a plasma process, A well-known method can be used suitably.

  Providing the primer layer or performing plasma treatment or the like increases the production process and is not preferable in terms of productivity. Therefore, in the present application, at least one of the resin layer and the skin layer is selected from a high hydroxyl group polyester resin and a hydrogenated terpene resin for at least one of the resin layer and the skin layer. It is preferable that 1-10 mass parts is added with respect to 100 mass parts of resin components.

  Moreover, as conditions of the heating and pressurization performed after bonding each layer, it is preferable that the temperature condition is about 120 to 170 ° C. and the pressure is about 1 to 10 kgf.

  In the step (B), the base material and the resin layer integrated with the surface layer are bonded and laminated to such an extent that they do not deviate, and then heated at a temperature of about 130 to 200 ° C., Pressing with a crest roll and embossing. By pressing with such a crest roll, the base material layer and the resin layer integrated with the surface layer can be integrated to produce a polypropylene-based synthetic leather, and the surface layer can be made of leather or the like. An embossed pattern can be applied.

  Moreover, as a method for producing a polypropylene synthetic leather further provided with the surface protective layer suitable as the polypropylene synthetic leather of the present invention, it may be provided after embossing or the like, or not embossed or the like. It may be provided in stages.

  In the step (C), at least one surface treatment agent selected from a polyurethane resin and a fluoroacrylic resin is applied to the surface of the surface layer, and a surface protective layer is applied to the surface of the polypropylene resin composition sheet layer. Form.

  In the step (C), the method for applying the surface treatment agent is not particularly limited, and a known method can be appropriately employed. For example, a method using a device such as a printing machine or a bar coater, a roller, a brush, and the like And a method of applying by spraying with a sprayer or the like. In addition, in this invention, it is preferable to apply | coat the said surface treating agent so that the thickness after drying may be set to 1-30 micrometers.

  Further, before performing such coating, the adhesion between the surface protective layer and the surface layer is improved to improve the scratch resistance and oil resistance, and appearance defects due to peeling of the surface protective layer can be prevented. In view of the above, at least one selected from the group consisting of a high hydroxyl group polyester resin and a hydrogenated terpene resin is used as the resin component 100 mass by providing a primer layer on the surface layer, performing a corona discharge treatment or a plasma treatment, It is preferable to add 1 to 10 parts by mass with respect to parts.

  Moreover, in a process (C), in order to form a surface protective layer on the surface of the said surface layer, after apply | coating a surface treating agent, it is preferable to make it dry and harden | cure at 60-150 degreeC temperature conditions.

  As mentioned above, although an example of the manufacturing method by a calendar method was demonstrated in manufacturing the polypropylene synthetic leather of this invention, the method of manufacturing the polypropylene synthetic leather of this invention is not restricted to this.

  For example, after extruding the surface layer and the resin layer, lamination bonding may be performed using an adhesive as described above. Alternatively, two or more co-extrusion molding machines may be used to extrude the surface layer and the resin layer at the same time, and laminate and integrate together with the molding. By adopting such a method, it becomes possible to laminate and integrate the three layers simply by applying an adhesive to the base material, and the production efficiency can be improved.

  In the step (A), the resin layer is manufactured as described above. However, the resin layer can be manufactured as a foamed sheet as follows.

  As a method for producing a polypropylene resin composition sheet as a foam sheet, the foaming agent is added to the polypropylene resin composition, and if necessary, additives such as a lubricant and a flame retardant are blended and kneaded. A method of producing a foamed sheet by heating the resulting mixture after molding the resulting mixture to obtain a foamable sheet can be mentioned.

  As the kneading method, known methods can be appropriately employed, and examples thereof include a method using a pressure kneader, a roll, a Banbury mixer, a static mixer, a screw type extruder, and the like. Moreover, you may knead what dry-blended each component previously.

  The molding method of the foamable sheet is not particularly limited, and a known molding method such as a calendar method or a T-die extrusion method can be appropriately employed. A foamable sheet having a desired thickness can be obtained by such a molding method. When molding the foamable sheet, it is preferable to perform the molding by appropriately adjusting the temperature conditions so that the foaming agent does not foam. For example, when adopting the calendar method, the molding temperature is set to 100 to 150 ° C. It is preferable to prepare.

  The temperature at which the foamable sheet is heated is not particularly limited as long as it is equal to or higher than the thermal decomposition temperature of the foaming agent, and is usually 160 to 220 ° C. In addition, after bonding a resin layer to a base material, such a heating may be performed and the said foamable sheet may be foamed, and you may make it foam before bonding with a base material layer or a surface layer.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

Each compound in Tables 1 and 2 was extruded using a two-layer, two-layer single-screw extruder so that the total thickness was 0.25 mm with a skin layer of 0.03 mm and a resin layer of 0.22 mm. Laminated with a base fabric coated with a two-component urethane adhesive as an adhesive on the surface of a base material made of Tetron-Rayon knitted fabric with a thickness of 0.4 mm, and the surface layer is processed with unevenness using a crest roll at a temperature of 170 ° C. To obtain a polypropylene-based synthetic leather composed of a skin layer, a resin layer, and a base material layer. Moreover, Examples 1-4, 6-8, and Comparative Examples 1-4 formed the 10-micrometer surface protective layer using the gravure coating machine for the silicone modified polyurethane.

Ionomer resin: High Milan 1652 (Mitsui DuPont Chemical)
Highly hydroxylated polyester: ZFN300 (Nippon Zeon)
Atactic polypropylene: Tough selenium T3712 (manufactured by Sumitomo Chemical)
General-purpose polypropylene: Noblene W151 (manufactured by Sumitomo Chemical)
Polyolefin resin: Engage 8137 (manufactured by DuPont Dow)
Foaming agent: PO208K (manufactured by Dainichi Seika Kogyo)
Light stabilizer: LP-63P (Asahi Denka Kogyo)
Evaluation was made as follows: Scratch resistance Plane friction (Gakushin type friction fastness tester) load 500 g, friction cloth: cotton canvas No. 6 ◎: No change over 50000 times ○: Change after 10000 times △ : Changed at 1000 times ×: Changed at 500 times or less ・ Flexibility Tactile evaluation was carried out ◎: Very good ○: Good △: Slightly hard ×: Hard, heat resistance 120 ° C. × 400 hours after surface layer ◎: No change ○: Almost no change △: With change ×: Significant change ・ Cold resistance -30 ℃ x 1 hour, immediately drop 800g iron ball from 15cm height ◎: No change ○: Almost no change △: Some cracks are generated ×: All cracks are generated ・ Place gauze impregnated with oleic acid on the surface of sweat-resistant polypropylene synthetic leather, Let stand for 3 days, then 90 ° C x 1 After drying for a while, using a silicon tube, the number of friction was evaluated at a load of 500 g. ◎: No change at 5000 times or more ○: Change at 2000 times △: Change at 500 times ×: Change at 100 times or less Example 1 -8, Adekastab FP-2100 (manufactured by Asahi Denka Kogyo Co., Ltd.) as a flame retardant is added to the skin layer in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the resin component, and a combustion test is performed based on the MVSS302 method. As a result, the burning rate of the obtained synthetic leather could be suppressed to 81 mm / min or less. Even if it added over 50 mass parts, the suppression improvement of the combustion rate was not seen.

  In Examples 4 to 8, a polyolefin-based resin is added to the intermediate layer to improve flexibility. However, a highly hydroxylated polyester is added to at least one of the skin layer and the resin layer to improve adhesion between the layers. By improving, it became possible to prevent a decrease in wear resistance.

  As described above, according to the present invention, it is possible to provide a polypropylene-based synthetic leather that can exhibit flexibility, heat resistance, and scratch resistance at a high level in a well-balanced manner.

  Therefore, since the polypropylene-based synthetic leather of the present invention has a flexible texture, it is useful as a synthetic leather (leather) used in various applications such as stationery, various cases, packaging, furniture, construction, and automobile interiors. It is.

Claims (4)

A polypropylene synthetic leather consisting of a base material layer, a resin layer, and a skin layer,
The resin layer is made of polypropylene resin, and the skin layer is made of a polypropylene resin composition in which the mass ratio of atactic polypropylene to general-purpose polypropylene is atactic polypropylene / general-purpose polypropylene = 90/10 to 60/40. Ri There Do from ionomer resin,
At least one selected from a high hydroxyl group polyester resin and a hydrogenated terpene resin is added to at least one of the resin layer and the skin layer in an amount of 1 to 10 parts by mass with respect to 100 parts by mass of the resin component. Characteristic polypropylene synthetic leather. 2. The polypropylene-based synthetic leather according to claim 1 , further comprising a surface protective layer made of polyurethane resin or fluoroacrylic resin having a thickness of 1 to 30 μm on the surface of the skin layer. At least one kind of flame selected from the group consisting of a bromo flame retardant, an antimony flame retardant, a metal hydroxide, a phosphorus flame retardant, and a nitrogen-phosphorus flame retardant is provided on at least one of the resin layer and the skin layer. The polypropylene-based synthetic leather according to claim 1 or 2 , wherein 1 to 50 parts by mass of a flame retardant is added to 100 parts by mass of the resin component. The polypropylene-based synthetic leather according to any one of claims 1 to 3 , wherein the resin layer is a foam layer.