JP5536579B2 - Automotive seat member and resin composition for producing the sheet member - Google Patents

Description

  The present invention relates to an automobile seat member and a resin composition for producing the seat member. In particular, the present invention relates to an automobile seat member (particularly an automobile interior seat member) in which the occurrence of whitening is not noticeable and a resin composition for producing the sheet member.

  Conventionally, a polyolefin resin that is lightweight and easy to mold has been generally used as a material for forming an automobile seat member (particularly, an automobile interior sheet member). This polyolefin resin is formed and processed as a sheet member of chromatic color, white color, gray color, or the like by being molded with or without a colorant. Such a sheet member is a sheet having a uniform sheet thickness with respect to the entire sheet plane, a sheet formed by combining a thick part and a thin part, a sheet having a bent part, depending on the assembly position inside the automobile, In general, the sheet is manufactured in various shapes such as a sheet having protrusions on one or both sides.

  Automobile seat members are manufactured from flat sheets by molding methods such as molding using rolls or molding using a mold, but stress such as shearing force is locally applied to the sheet during molding. In such a case, a phenomenon called “whitening” (a phenomenon in which a white streaky discolored region appears on the surface of the molded product) may occur. This “whitening” is generally considered to be a mild cracking phenomenon that occurs partially inside the molded body formed from the sheet when local stress is applied to the sheet. Whitening may remain even after the application of a typical stress. Such a whitened molded article is usually not a problem with respect to physical properties such as strength, but may be seen as a defective part in the appearance, and at least there is a sense of incongruity, so it is regarded as a defective product. There are many cases. In addition, after the automobile seat member is molded from the sheet, it is assembled to a support member inside or outside the automobile. Similarly, stress such as shearing force may be locally applied to the sheet member during the assembly. In this case, the “whitening” phenomenon may occur for the same reason.

  The whitening phenomenon at the time of molding of automobile parts is not limited to sheet members, but sheet members are whitened because they receive the stress applied at the time of assembling them inside or outside the automobile with a thin sheet thickness. In particular, automotive interior seat members that are becoming thinner due to the weight reduction of automotive parts, which have recently been strongly demanded, are more likely to be whitened when assembled to a support member inside the automobile. Therefore, countermeasures are desired.

  Patent Document 1 discloses a propylene polymer composition for automobile interior parts, which is difficult to be whitened and comprises a propylene copolymer having a specific chemical composition and physical properties and a small amount of a higher fatty acid amide. This propylene polymer composition is described as being a whitening-resistant propylene polymer composition for automobile interior parts in which whitening of a molded body is difficult to occur due to an extrusion pin attached to a mold during injection molding. Therefore, the present invention incorporates a small amount of a higher fatty acid amide, presumably functioning as a lubricant, in a propylene copolymer having a specific chemical composition and physical properties as a molding material in the production of automobile interior parts by molding. It is understood that the invention is based on the knowledge that the use of the propylene polymer composition made possible makes it possible to suppress the occurrence of whitening in automobile interior parts during the production of the molded body.

JP-A-8-302149

  The propylene polymer composition for automotive interior parts having difficulty in whitening described in Patent Document 1 is the occurrence of whitening of a molded product at the time of molding, a propylene-based copolymer having a specific chemical composition and physical properties, and a small amount of high-grade polymer. The propylene polymer is characterized by being suppressed by using a propylene polymer composition containing a fatty acid amide, but the propylene polymer used is limited to a non-generic propylene polymer having a specific chemical composition and physical properties. However, there is a problem that practical utility is limited.

  The present invention uses a general-purpose propylene polymer that does not require specific requirements for chemical composition, physical properties, etc. as a polyolefin resin as a base material. An object of the present invention is to provide a polyolefin resin composition capable of solving the problem of whitening during assembly to a support member.

  The inventor of the present invention has proposed a “specification” proposed by the invention described in Patent Document 1 as a method for solving the problem of whitening at the time of molding operation of an automobile seat member (particularly interior seat member) or assembling the automobile seat member Instead of `` suppressing the occurrence of whitening by using a combination of resin and lubricant '', the problem caused by the occurrence of whitening can also be solved by a method that does not reveal the whitening phenomenon that occurred during the molding operation or assembly to the support member of an automobile. The research was conducted on the assumption that this is possible. This assumption is based on the fact that, as described above, the whitening that occurs in the molded article of the polyolefin resin composition has been confirmed empirically that it does not affect the practical physical properties of the molded article as long as it normally appears. This is an assumption that has been taken into account.

  As a result of the above research, the present inventor used a polyolefin resin that has been conventionally used for manufacturing automobile seats as a polyolefin resin material, and contained a small amount of a specific light shielding pigment. By using a polyolefin resin composition, even when a local stress is applied during the molding of a sheet-like molded product or when it is assembled to a support member of an automobile, the appearance of whitening is not observed in appearance. The present inventors have found that a member can be obtained and have reached the present invention.

  Therefore, the present invention comprises an automobile having a flexural modulus of 900 MPa or more, comprising 0.3 to 5 parts by mass of titanium dioxide and 0.03 to 2 parts by mass of black pigment with respect to 100 parts by mass of polyolefin resin. It exists in the polyolefin resin composition for sheet | seat members (especially automotive interior sheet | seat member) manufacture.

  The present invention also resides in an automobile seat member (particularly an automobile interior sheet member) produced using the polyolefin resin composition of the present invention.

  In the polyolefin resin composition for producing an automobile seat member of the present invention, a highly versatile polyolefin resin that has been conventionally used for producing an automobile sheet member can be used as the polyolefin resin substrate. Even when an automobile sheet member (particularly an automobile interior sheet member) manufactured using a polyolefin resin composition has a whitening phenomenon therein, the occurrence of the whitening phenomenon on the surface of the sheet member may become obvious. Absent. Therefore, even when a highly versatile polyolefin resin is used, it is possible to effectively suppress the occurrence of defective products during molding of a sheet molded body or when assembled to a support member inside or outside an automobile.

  A preferred embodiment of the polyolefin resin composition for producing an automobile seat member of the present invention is as follows.

(1) Content of the black pigment with respect to 1 mass part of titanium dioxide exists in the range of 0.05-0.5 mass part.
(2) It further contains 0.05 to 5 parts by mass of a chromatic pigment as a total amount with respect to 100 parts by mass of the polyolefin resin.
(3) The polyolefin resin is a propylene-ethylene block copolymer.
(4) The flexural modulus is in the range of 900 to 1500 MPa.
(5) The color difference (ΔL) between the whitened area generated when a load of 110 N is applied to a test sheet piece (80 mm × 40 mm × 2.0 mm) prepared from the polyolefin resin composition and the non-whitened area of the test sheet piece It is within 10.0.

  Preferred embodiments of the automobile seat member of the present invention are as follows.

(1) The thickness of the thinnest part is in the range of 1.0 to 2.4 mm.
(2) The thickness of the thinnest part is in the range of 1.2 to 1.8 mm.
(3) The sheet member is in contact with the support member disposed with an interval of at least 80 mm.

  Next, detailed description will be given of various components contained in the polyolefin resin composition for producing an automobile seat member of the present invention.

[Polyolefin resin]
Examples of the polyolefin used in the present invention include polypropylene and polyethylene, and polypropylene is preferred. Polypropylene, which is generally distributed in the market and used as a raw material for producing automobile seat members (particularly, automobile interior sheet members), is a block copolymer (propylene) of a main amount of propylene and a relatively small amount of ethylene. -Ethylene block copolymer) in many cases. Therefore, as the polypropylene used in the present invention, such a propylene-ethylene block copolymer is preferable.
Moreover, when the polyolefin to be used is a molded body, it is necessary that the flexural modulus be 900 MPa or more. For this reason, a polyolefin generally used for manufacturing an automobile seat member (particularly, an automobile interior sheet member) is used. However, if it is polyolefin which shows such a bending elastic modulus, it does not necessarily need to be general polyolefin.
In addition, as polyolefin, unused polyolefin (virgin polyolefin) can be used, but pulverized polyolefin molded product that was not made into a product as a rejected product, polyolefin molding once used as a product and then discarded A pulverized body can also be used.

[titanium dioxide]
Although there is no special limitation in the titanium dioxide used by this invention, It is preferable that they are rutile type titanium dioxide generally used for various uses, or anatase type titanium dioxide. As described above, titanium dioxide is used in an amount in the range of 0.3 to 5 parts by mass with respect to 100 parts by mass of the polyolefin resin.

[Black pigment]
Examples of the black pigment used in the present invention include carbon black and iron black. As described above, the black pigment is used in an amount in the range of 0.03 to 2 parts by mass with respect to 100 parts by mass of the polyolefin resin. Further, the amount of black pigment used is preferably a relatively small amount relative to the amount of titanium dioxide used. For example, the content of the black pigment relative to 1 part by mass of titanium dioxide is in the range of 0.05 to 0.5 parts by mass. It is especially preferable to set it as the quantity.

  When manufacturing a colored sheet member as an automobile sheet member (particularly an automobile interior sheet member), a chromatic pigment is combined in addition to the titanium dioxide and the black pigment. As chromatic pigments, petals, ultramarine blue, cobalt blue, titanium yellow, cobalt yellow, cobalt blue, cobalt green, and other inorganic chromatic pigments, quinacridone red, polyazo yellow, anthraquinone red, anthraquinone yellow, polyazo red, Organic chromatic pigments such as Azo Lake Yellow, Phthalocyanine Blue, Phthalocyanine Green, Isoindolinone Yellow, Quinacridone Red, Permanent Red, Para Red, Toluidine Maroon, Bend Gin Yellow, Fast Sky Blue, Brilliant Carmine 6B, etc. Or they are used in combination.

  In the resin composition for manufacturing an automobile seat member of the present invention, it is preferable that both titanium dioxide and the black pigment are dispersed in a highly dispersed state. For this reason, it is preferable to select and add a known dispersant such as higher fatty acid, higher fatty acid amide, higher fatty acid metal salt (metal soap), glycerin ester, polyethylene wax, polypropylene wax and the like. A particularly preferred dispersant is magnesium stearate.

  The resin composition for producing an automobile sheet member of the present invention can further contain various elastomers and known additives as necessary. Examples of such known additives include fillers (eg, talc), lubricants, antistatic agents, surfactants, nucleating agents, ultraviolet absorbers, antioxidants, and flame retardants.

  Examples of the automobile sheet member manufactured using the resin composition of the present invention include a sheet having a uniform sheet thickness for all sheet planes, a sheet formed by combining a thick part and a thin part, and a sheet having a bent part. In addition, sheet members having various shapes such as a sheet having protrusions on one or both sides of the sheet can be exemplified.

  In particular, the resin composition of the present invention is an automobile sheet (particularly an automobile interior sheet) in which the thickness of the thinnest portion having the smallest thickness is in the range of 1.0 to 2.4 mm (particularly 1.2 to 1.8 mm). ) To be used advantageously. In particular, the present invention is particularly advantageously used when the automobile seat is an interior sheet that is assembled inside the automobile without being supported (backed) by the hard base material over the entire surface of the automobile. That is, when the automobile interior sheet is supported only at its peripheral edge or when it is supported by a support material made of a hard material that is partially in contact, whitening is likely to occur during the assembly operation. The composition can be advantageously used when it is such an interior sheet.

  Examples of automobile seat members manufactured using the resin composition of the present invention include instrument panels, door trims, pillar burnishes and the like for interior parts, and bumpers and side stone guards for exterior parts.

[Example 1] (interior sheet colored in beige)
To 100 parts by mass of a polypropylene resin substrate (a pulverized product of an injection-molded product of a propylene-ethylene block copolymer), titanium dioxide (0.970 parts by mass), a stem (0.080 parts by mass), titanium yellow (0. 670 parts by mass), iron black (0.060 parts by mass), and magnesium stearate (0.10 parts by mass), and then heat-melted and injection molded to prepare a test sheet for the pigment-containing resin composition. A piece (80 mm × 40 mm × 2.0 mm) was prepared.
The flexural modulus (measured according to the method described in JIS 7171, the same applies hereinafter) of this pigment-containing resin composition was 1304 MPa.

[Example 2] (Interior sheet colored beige)
100 parts by mass of a polypropylene resin base material (the same as that used in Example 1), titanium dioxide (2.000 parts by mass), valve stem (0.135 parts by mass), titanium yellow (1.070 parts by mass) ), Iron black (0.35 parts by mass), and magnesium stearate (0.10 parts by mass), and then melted by heating, injection molded, and a test sheet piece (80 mm) of the pigment-containing resin composition. X 40 mm x 2.0 mm).
The flexural modulus of this pigment-containing resin composition was 1324 MPa.

[Example 3] (Interior sheet colored in beige)
100 parts by mass of a polypropylene resin base material (the same as that used in Example 1), titanium dioxide (3.200 parts by mass), valve stem (0.190 parts by mass), titanium yellow (1.530 parts by mass) ), Iron black (0.63 parts by mass), and magnesium stearate (0.10 parts by mass), and then melted by heating, injection-molded, and a test sheet piece (80 mm) of the pigment-containing resin composition. X 40 mm x 2.0 mm).
The flexural modulus of this pigment-containing resin composition was 1355 MPa.

[Example 4] (Interior sheet colored in beige)
100 parts by mass of a polypropylene resin base material (the same as that used in Example 1), titanium dioxide (3.890 parts by mass), valve stem (0.265 parts by mass), titanium yellow (1.970 parts by mass) ), Iron black (0.850 parts by mass), and magnesium stearate (0.10 parts by mass), and then melted by heating, injection-molded, and a test sheet piece (80 mm) of the pigment-containing resin composition. X 40 mm x 2.0 mm).
The flexural modulus of this pigment-containing resin composition was 1377 MPa.

[Example 5] (Interior sheet colored beige)
100 parts by mass of a polypropylene resin base material (the same as that used in Example 1), titanium dioxide (5.000 parts by mass), valve stem (0.325 parts by mass), titanium yellow (2.550 parts by mass) ), Iron black (1.125 parts by mass), and magnesium stearate (0.10 parts by mass), and then melted by heating, injection molded, and a test sheet piece of pigment-containing resin composition (80 mm). X 40 mm x 2.0 mm).
The flexural modulus of this pigment-containing resin composition was 1377 MPa.

[Example 6] (interior sheet colored light gray)
100 parts by mass of a polypropylene resin base material (same as that used in Example 1), titanium dioxide (1.000 parts by mass), valve stem (0.050 parts by mass), titanium yellow (0.030 parts by mass) ), Carbon black (0.200 parts by mass), ultramarine (0.030 parts by mass) and magnesium stearate (0.10 parts by mass), and then melted by heating and injection molded to obtain a pigment-containing resin. A test sheet piece (80 mm × 40 mm × 2.0 mm) of the composition was prepared.
The flexural modulus of this pigment-containing resin composition was 1314 MPa.

[Example 7] (Interior sheet colored light gray)
100 parts by mass of a polypropylene resin base material (the same as that used in Example 1), titanium dioxide (2.750 parts by mass), valve stem (0.130 parts by mass), titanium yellow (0.090 parts by mass) ), Carbon black (0.485 parts by mass), ultramarine (0.090 parts by mass) and magnesium stearate (0.10 parts by mass), and then melted by heating and injection molded to obtain a pigment-containing resin. A test sheet piece (80 mm × 40 mm × 2.0 mm) of the composition was prepared.
The flexural modulus of this pigment-containing resin composition was 1348 MPa.

[Example 8] (interior sheet colored light gray)
100 parts by mass of a polypropylene resin base material (the same as that used in Example 1), titanium dioxide (4.100 parts by mass), valve stem (0.165 parts by mass), titanium yellow (0.130 parts by mass) ), Carbon black (0.675 parts by mass), ultramarine (0.13 parts by mass) and magnesium stearate (0.10 parts by mass), and then melted by heating and injection molded to obtain a pigment-containing resin. A test sheet piece (80 mm × 40 mm × 2.0 mm) of the composition was prepared.
The flexural modulus of this pigment-containing resin composition was 1338 MPa.

[Example 9] (Interior sheet colored in beige)
100 parts by mass of a polypropylene resin base material (propylene-ethylene block copolymer virgin material), titanium dioxide (3.200 parts by mass), valve stem (0.125 parts by mass), titanium yellow (0.130 parts by mass) , Iron black (0.56 parts by mass) and magnesium stearate (0.10 parts by mass) were mixed, heated and melted, injection molded, and a pigment-containing resin composition test sheet piece (80 mm × 40 mm). × 2.0 mm).
The flexural modulus of this pigment-containing resin composition was 978 MPa.

[Example 10] (interior sheet colored in beige)
100 parts by mass of a polypropylene resin base material (the same as that used in Example 9), titanium dioxide (2.100 parts by mass), valve stem (0.089 parts by mass), titanium yellow (0.900 parts by mass) ), Iron black (0.40 parts by mass) and magnesium stearate (0.10 parts by mass), and then melted by heating, injection-molded, and a test sheet piece of pigment-containing resin composition (80 mm × 40 mm × 2.0 mm).
The flexural modulus of this pigment-containing resin composition was 1004 MPa.

[Example 11] (interior sheet colored light gray)
100 parts by mass of a polypropylene resin base material (the same as that used in Example 9), titanium dioxide (2.500 parts by mass), valve stem (0.100 parts by mass), titanium yellow (0.320 parts by mass) ), Carbon black (0.330 parts by mass) and magnesium stearate (0.10 parts by mass), and then melted by heating, injection-molded, and a test sheet piece of pigment-containing resin composition (80 mm × 40 mm × 2.0 mm).
The flexural modulus of this pigment-containing resin composition was 962 MPa.

[Evaluation of whitening]
(1) Measuring method of whitening start load The whitening start load was measured using the test sheet piece of the pigment-containing resin composition prepared in each of Examples 1 to 8. The whitening start load was placed on the upper surface of the opening of a ring-shaped frame (inner diameter: 100 mm) supported by four legs, and the test sheet was framed at each corner (4 points). A cylindrical load applicator having a tip diameter of 3.3 mm is brought into contact with the upper surface of the opening of the test sheet piece, and then applied to the load applicator while gradually increasing the load (applying). The recorded load is recorded by autograph). At the same time, the lower surface of the test sheet piece was visually observed from the lower side of the test sheet piece, the occurrence of whitening was confirmed, and the load when the whitening occurred was confirmed.
In addition, as a test sheet piece for reference, a test sheet piece was also prepared from a pulverized product of a propylene-ethylene block copolymer injection molded product used as a polypropylene resin base material in Example 1 alone.

(2) Evaluation result Table 1 shows the load at the time when the occurrence of whitening measured by the method of (1) was observed.

Table 1
────────────────────────────────────
Test sheet piece Whitening generation load (unit: N)
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Control test sheet piece 111
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Example 1 166
Example 2 168
Example 3 183
Example 4 201
Example 5 201
Example 6 183
Example 7 188
Example 8 200
────────────────────────────────────

(3) Summary of Evaluation Results Test sheet pieces obtained from the pigment-containing resin composition exhibiting a flexural modulus according to the present invention were obtained by using the same resin base material and adding no pigment (control test). Compared with the sheet piece), the load at which the occurrence of whitening is observed is remarkably large, so it can be determined that the occurrence of whitening is suppressed.

Claims (8)

0.970 to 5 parts by mass of titanium dioxide, 0.030 to 2.550 parts by mass of titanium yellow , 0.050 to 0.325 parts by mass of a petite, and 100 parts by mass of propylene-ethylene block copolymer A flat sheet member for an automobile comprising 0.03 to 2 parts by mass of a black pigment, having a flexural modulus in the range of 900 to 1500 MPa, and a thickness of the thinnest part in a range of 1.0 to 2.4 mm. Polyolefin resin composition for production.   The polyolefin resin composition according to claim 1, which is used for producing an automobile interior sheet member.   The polyolefin resin composition according to claim 1 or 2, wherein the content of the black pigment is in the range of 0.05 to 0.5 parts by mass with respect to 1 part by mass of titanium dioxide. The polyolefin resin composition according to any one of claims 1 to 3, further comprising 0.05 to 5 parts by mass of a chromatic pigment as a total amount with respect to 100 parts by mass of the propylene-ethylene block copolymer . A planar sheet member for automobiles, wherein the thickness of the thinnest portion, which is a molded product of the polyolefin resin composition according to any one of claims 1 to 4, is in the range of 1.0 to 2.4 mm. The planar sheet member for an automobile according to claim 5, which is an automobile interior sheet member. The planar sheet member for an automobile according to claim 5, wherein the thinnest portion has a thickness in the range of 1.2 to 1.8 mm. The planar sheet member for an automobile according to any one of claims 5 to 7, wherein the sheet member is in contact with a support member disposed at an interval of at least 80 mm.