JP2000212349A - Leathery sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a woodmeal-contg. polypropylene-based resin sheet presenting leathery appearance, in particular appearance resembling that of suede or backskin, for use in footwear, clothing, bags/baggage, and the like. SOLUTION: This leathery sheet comprises 100 pts.wt. of a polypropylene- based resin with a flexural modulus of >=400 kgf/cm2 but <2,000 kgf/cm2 and 40-250 pts.wt. of woodmeal with an average particle size of 10-200 μm; wherein at least one side of the sheet is polished with abrasive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood powder-containing polypropylene resin sheet having a leather-like appearance, particularly an appearance similar to suede or backskin.

[0002]

2. Description of the Related Art Synthetic leather used as a substitute for natural leather is mainly made of vinyl chloride resin, polyamide resin, urethane resin, and its composition is adjusted, foamed, or made to a specific thickness. It is manufactured by using fibers having a cross-sectional shape. Among such various kinds of synthetic leathers, those using a vinyl chloride resin are inexpensive and advantageous in terms of cost, but are inferior in durability, especially in cleaning resistance,
Those using a polyamide resin often have insufficient flexibility. On the other hand, synthetic leather using a urethane-based resin is excellent in various physical properties such as abrasion resistance, flex fatigue resistance, tensile strength and the like, and can be easily adjusted in flexibility, so that footwear, clothing, bags and bags are used. Widely used for such purposes.

[0003] However, synthetic leathers using urethane resins have the disadvantage that they are generally expensive due to the high price of the raw material resin and the complicated manufacturing method of the synthetic leather. Also, Japanese Patent Application Laid-Open No. 10-10238
1, a sheet made of a resin composition obtained by mixing a specific wood powder with a specific ethylene-α-olefin copolymer obtained by polymerization using a metallocene catalyst is used as a crushed abrasive. Discloses a leather-like sheet polished with a. However, the leather-like sheet obtained by this method has an excellent tactile sensation and the like, but is not sufficiently satisfactory in abrasion resistance.

[0004]

The object of the present invention is to provide a leather-like sheet which can be used as a substitute for natural leather, in particular, a backskin or a suede, and which is excellent in design, touch and abrasion resistance.

[0005]

The gist of the present invention is that a flexural modulus is 400 kgf / cm ² or more and 2000 kgf / c.
polypropylene resin of less than m ² , and an average particle diameter of 40 to 250 parts by weight per 100 parts by weight of the resin is 10 to 20.
A leather-like sheet characterized in that at least one side of the sheet is polished with an abrasive, and the sheet has a thickness of 0.1 μm. The grain size of the leather-like sheet and the abrasive, which is 075 to 15 mm, is in the above-mentioned leather-like sheet having a grain size specified in JIS R-6001 and in the range of # 60 to # 400.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The polypropylene resin used in the present invention has a flexural modulus of 4
00kgf / cm ² or more, and less than 2,000 kgf / cm ^2. The flexural modulus is JIS K-7203.
Shall be used. When the flexural modulus is less than 400 kgf / cm ² , the wear resistance becomes insufficient. On the other hand, if the flexural modulus is 2000 kgf / cm ² or more, a suede-like surface state and tactile sensation cannot be obtained. More preferably, the flexural modulus is in the range of 450 to 1500 kgf / cm ² .

As the polypropylene resin, a propylene homopolymer (homopolymer), a copolymer containing propylene as a main component, or a mixture of the above homopolymer and / or copolymer with another polymer ( Polymer blend). More specifically, as the copolymer containing propylene as a main component, propylene and ethylene or other α-olefin, a random copolymer or a block copolymer, or a polyolefin-based copolymer as a trunk polymer. A propylene graft copolymer is exemplified. As the α-olefin copolymerizable with propylene, those having 4 to 12 carbon atoms are preferable. For example, 1-butene, 1-pentene, 1-hexene, 1-hexene
Heptene, 1-octene, 4-methyl-1-pentene,
1-decene and the like, and one kind or a mixture of two or more kinds thereof is used. The mixing ratio of ethylene or α-olefin is preferably 5 to 40% by weight based on propylene.

[0008] Examples of the polyolefin copolymer for the backbone polymer of the propylene graft copolymer include ethylene-propylene rubber, ethylene-butene rubber, and ethylene-propylene-diene rubber. Other polymers that can be mixed with the homopolymer and / or copolymer to give a polymer blend include, for example, styrene-based rubbers such as ethylene-propylene rubber, styrene-butadiene rubber, and styrene-isoprene rubber. Thermoplastic elastomers. This styrenic thermoplastic elastomer is preferably hydrogenated. The amount of the polymer to be mixed is preferably 20 to 80% by weight, particularly preferably 30 to 60% by weight.

The leather-like sheet of the present invention comprises the above-mentioned polypropylene resin and 40 to 250 parts by weight per 100 parts by weight of the resin.
Contains wood parts by weight. If the amount of wood powder is less than 40 parts by weight based on 100 parts by weight of the polypropylene resin,
A suede-like surface state (design / tactile sensation) cannot be obtained even by polishing with an abrasive. Further, when the amount of the wood flour exceeds 250 parts by weight, the viscosity increases when the wood flour and the resin are kneaded, and the surface of the sheet becomes rough during molding by an extruder or the like, Ear cuts are likely to occur, which lowers productivity and decreases the physical properties of the sheet.

Wood powder has an average particle diameter of 10 to 200 μm.
, Preferably 30 to 150 μm. The wood species used as the raw material of the wood flour used in the present invention is not particularly limited, and may be selected from conifers such as pine, fir and hemlock and broadleaf trees such as poplar. As the wood powder, it is preferable to use cutting powder or the like as sawdust (saw dust) which is formed into a powder having an average particle diameter of 10 to 200 μm by dry or wet pulverization or sieving.

When the average particle size of the wood flour exceeds 200 μm, heat generation due to frictional resistance increases during molding with an extruder or the like, and foaming or coloring occurs due to generation of gas due to decomposition of the wood flour. In the case of fine wood flour having an average particle diameter of less than 10 μm, pulverization and sieving are troublesome, and dusting tends to occur during mixing. The average particle diameter of the wood flour is represented as the particle diameter at a point where the integrated value of the weight of each fraction measured by a JIS sieve is 50% of the whole.

The wood flour having an average particle size within the above-mentioned specific range and having 70 wt% or more, preferably 80 wt% or more of the whole wood flour, within the above-mentioned particle size range. It is suitable. The leather-like sheet of the present invention may contain an inorganic filler, a lubricant, a surfactant, an anti-adhesive agent, a pigment, an antibacterial agent and the like, in addition to the above components, as long as the object of the present invention is not impaired.

The leather-like sheet of the present invention is obtained by first forming a sheet and then subjecting at least one side of the obtained sheet to polishing treatment using an abrasive. To form the sheet, for example, after kneading the pellets of the polypropylene resin and the specific wood powder with a Banbury mixer, forming the sheet into a sheet with a heating roll, or twin-screw extrusion kneading with a hot cut device After mixing and pelletizing the polypropylene resin and wood flour using a machine,
The pellets may be formed into a sheet using an extruder equipped with a T-die.

The wood powder may be previously dried with a drier or a hopper drier before kneading with the resin, and when using a twin-screw extruder, the wood powder is dried in-line using a device equipped with a hopper drier. May be. The water content of the wood flour is preferably in the range of 3 to 7% by weight. The molding temperature is preferably in the range of 150 to 200 ° C. The thickness of the sheet is preferably in the range of 0.075 to 15 mm. When the thickness is less than 0.075 mm, the polishing treatment of the sheet becomes difficult. On the other hand, when the thickness exceeds 15 mm, the molding speed decreases and the productivity of the sheet deteriorates. A more preferred sheet thickness is 0.15 to 5 mm.

As the abrasive used to give the sheet-like wood powder-containing polypropylene resin molded article obtained as described above a leather-like, particularly suede-like appearance, a crushed abrasive may be used. preferable. Crushed abrasives are mainly abrasives used for grinding and polishing, such as diamond, corundum, alundum, and carborundum crystal fragments or powders, or by adhering these to cloth, paper, or nonwoven fabric. Crushed thing. Further, an abrasive such as steel wool may be used.

The particle size of the abrasive is JIS R-60
It is preferable to use a particle having a particle size defined by 01 in the range of # 60 to # 400. # 60 abrasive particle size
If it is coarser, the brushed state becomes rough, giving a rough touch, and a good suede-like sheet may not be obtained. On the other hand, if the particle size is smaller than # 400, the raising effect may be insufficient, and the time required for polishing also increases. As a device for performing the polishing treatment, a portable sander or a belt sander can be exemplified. This polishing treatment may be performed in-line after the sheet is formed by an extruder such as a T-die, or may be performed off-line after the sheet is once manufactured and stored.

[0017]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. <Evaluation of flexural modulus of polypropylene resin> JIS
It was measured according to K-7203.

<Evaluation of Sheet> (1) Formability: As shown in Example 1 below, when a test sheet was prepared using a T-die extruder, the ease of molding was evaluated. The evaluation criteria are as follows.・ ・ ・: A sheet having a good appearance was produced without any problem. Δ: A sheet could be prepared, but the appearance was inferior. X: The sheet could not be formed. (2) Tactile sensation: After one side of the test sheet was polished with polishing paper having the particle size shown in Table 1, it was evaluated whether or not it resembled suede by the tactile sensation of the hand. The evaluation criteria are as follows.・ ・ ・: Excellent feel equivalent to natural leather suede. ○ △: There is a suede-like touch, but there is a slight difference from natural leather. Δ: Suede-like touch is felt, but the difference from natural leather is clear. X: No suede-like touch.

(3) Abrasion resistance: One side of a test sheet is polished, and then this surface is subjected to a surface measurement (Shinto Kagaku Co., Ltd.)
(HEIDON-140D manufactured by Heidon Co., Ltd.) under the following conditions, and the degree of wear of the sheet surface was visually evaluated. The conditions and evaluation criteria are as follows. Test conditions ・ Indenter size 20mm diameter ・ Load 300g ・ Indenter moving speed 1m / min ・ Friction frequency 10 reciprocations ・ Steel wool For industrial pad (NO.7448) extra fine finish Evaluation criteria ○ ・ ・ ・ No change in appearance △ ・ ・ ・ Slight Is scratched and changes in appearance are observed. × ・ ・ ・ significantly scratched and the degree of change is large.

Example 1 50 parts by weight of a propylene homopolymer (FY4 manufactured by Mitsubishi Chemical Corporation) and a styrene-based thermoplastic elastomer (Dynalon 13 manufactured by Nippon Synthetic Rubber Co., Ltd.)
20P) 50 parts by weight, wood powder 150 having an average particle size of 70 μm
The parts by weight were kneaded using an internal mixer (MS-3600, Minami-Senju Seisakusho Co., Ltd.) under the conditions of a temperature of 170 ° C., a rotor rotation speed of 50 rpm, and a kneading time of 10 minutes, and a calender roll (Ishikawajima Harima Heavy Industries ( Was manufactured at a temperature of 170 ° C. With respect to this sheet, one side of the sheet was polished using abrasive paper (crushed abrasive) having a particle size of # 180, and the above evaluation was performed. Separately,
A resin mixture having the same composition except that it did not contain wood powder was formed into a sheet under the same conditions, and the flexural modulus of the resin used was measured. The results are summarized in Table 1.

<Example 2> Same as Example 1, except that the amount of wood flour was 100 parts by weight, and one side of the sheet was polished using abrasive paper (crushed abrasive) having a particle size of # 60. Then, a sheet was prepared and evaluated. Further, in the same manner as in Example 1, the flexural modulus of the used resin was measured. The results are summarized in Table 1.

<Comparative Examples 1-2> Sheets were prepared, polished and evaluated in the same manner as in Example 1 except that the amounts and amounts shown in Table 1 were used as the polypropylene resin or wood powder. Further, in the same manner as in Example 1, the flexural modulus of the used resin was measured. The results are summarized in Table 1.

Comparative Example 3 The procedure of Example 1 was repeated except that EG8150 manufactured by Dow Chemical Co., Ltd. manufactured using a metallocene-based catalyst was used as the resin, and the amount of wood powder added was as shown in Table 1. Preparation, polishing and evaluation of the sheet were performed in the same manner. Further, in the same manner as in Example 1, the flexural modulus of the used resin was measured. The results are summarized in Table 1.

[0024]

[Table 1] Abrasive particle size: According to JIS R-6001

[0025]

Industrial Applicability The leather-like sheet of the present invention has a suede-like appearance and feel, has good abrasion resistance, and has excellent performance as synthetic leather, so that it is preferably used as a leather-like sheet. You.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Miyuki Yamashita 2nd Oike, Iwazuka-cho, Nakamura-ku, Nagoya-shi, Aichi F-term (reference) 4F071 AA20 AA74 AA80 BC01 BC08 BC14 BC16 DA17 4J002 AB01X AC085 AC115 BB12W BB14W BB15W BB155 BN06W BP02W FD010 FD090 FD170 FD180 FD310

Claims (3)

[Claims] 1. A polypropylene resin having a flexural modulus of 400 kgf / cm ² or more and less than 2000 kgf / cm ² , and wood powder having an average particle diameter of 40 to 250 parts by weight per 100 parts by weight of the resin and 10 to 200 μm. , Wherein at least one side of the sheet is polished using an abrasive. 2. The leather-like sheet according to claim 1, wherein the thickness of the sheet is 0.075 to 15 mm. 3. The particle size of the abrasive is JIS R-6001.
The leather-like sheet according to claim 1 or 2, wherein the particle size is in the range of # 60 to # 400 with the particle size specified in (1).