JP2899675B2 - Polypropylene resin for pasting synthetic type and pasting synthetic type method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin material for a laminated synthetic product used for interior parts for automobiles and the like, and a method of laminating a synthetic resin. More specifically, the present invention relates to a polypropylene resin for simultaneous shaping and laminating, and a laminating method for laminating the same, which can maintain excellent texture of the skin material after molding.

(Prior art) In recent automobile interior materials, door trims, quarter trims and other trims, as well as skins and core materials used as various types of instrument panel pillars, synthetic composite products of appearance and luxurious appearance. There is an increasing demand for good texture. As a method of manufacturing these laminated synthetic products, in addition to a method of manually applying a skin material to a core material using an adhesive, the skin material and the core material resin are formed in the same mold and simultaneously integrally molded. There is a way to do that.
As the simultaneous shaping and laminating process, the plasticized resin is injected into the mold with the mold with the skin material closed, and the shaping and laminating are performed simultaneously, or the skin material is mounted. There is a method in which the mold is closed while supplying or after supplying the plasticized resin into the mold with the mold opened, and shaping and bonding are performed simultaneously. Conventionally, these simultaneous shaping, the polypropylene used for the pasting synthetic type is for general injection molding,
According to JISK6758, the melt flow index (hereinafter, also referred to as “MFI”) measured at a temperature of 230 ° C. and a load of 2.16 kg was within a fluidity range of 0.01 to 100 g / 10 minutes.

(Problems to be Solved by the Invention) However, when a conventional polypropylene resin is used for the simultaneous imprinting and laminating type, the texture of a molded product may be deteriorated. In such a molding method, the resin temperature is 200 to 250 ° C., and the resin supply or mold clamping pressure is 50 to
1,000 kg / cm ² is required. That is, when the resin flows through the mold, the heat of the high-temperature resin is transmitted to the skin, and the skin itself becomes hot. Also, high shear stress occurs when the resin flows,
High pressure is required to spread the resin over the entire surface of the mold with a uniform thickness. On the other hand, since a thermoplastic resin material is mainly used as the skin material, permanent deformation often occurs when molded under high temperature and high pressure. This deformation specifically appears as a textured flow of the skin material, hair frays, crushing of the foam, and the like, and the texture of the laminated synthetic product is significantly reduced. Until now, various methods have been devised for improving the texture of the skin material in the simultaneous shaping and laminating type. For example, a method of patterning the surface of the mold in contact with the skin to prevent grain flow (JP-A-59-83633, JP-A-60-212343), maintaining the cushioning property by improving the back layer of the skin material (JP-A-59-159342, JP-A-60-212342, JP-A-61-13)
9425), but it is not related to the change of high-temperature and high-pressure molding conditions that cause the texture to deteriorate, and it is difficult to significantly improve the texture because it is not a fundamental measure.

(Means for Solving the Problems) The inventors of the present application have conducted intensive studies on the development of a molding material that significantly reduces the reduction in texture by the simultaneous shaping and laminating method in a mold, and as a result, have reached the invention described below. First, we examined the causes of the reduction in the texture during molding.
It became clear that it was due to stretching. In particular, it has been found that when these factors work simultaneously, the texture decreases synergistically. The present inventors have studied to reduce heat, pressure, and stretching generated during molding from the resin material side for the core material,
Extremely high fluidity than generally known for molding, i.e., a melt flow index of 120 to 800 g /
It has been found that when a polypropylene resin having a fluidity of 10 minutes is used as the core resin, the texture of the skin material of the skin-pasted synthetic product is significantly reduced.

The polypropylene resin in the present invention is a homopolymer of propylene or propylene and ethylene and / or
Or a copolymer with butene having a fluidity with a melt flow index of 120 to 800 g / min. If the melt flow index is less than 120 g / 10 minutes, a high molding pressure is required because the shear stress during the flow of the resin during molding is large. If the melt flow index is more than 800 g / 10 minutes, the mechanical properties of the polymer, particularly the impact strength, are so low that they cannot be put to practical use even in the state of being combined with the skin material.

As a method to obtain a highly fluidized polypropylene resin,
There is a method of producing by controlling the molecular weight by polymerization. Further, there is also a method of producing by reducing the molecular weight by decomposition with an organic peroxide or heat after polymerization, and as the organic peroxide, 2,5-dimethyl-2,5-tbutylperoxyhexane, 2,5-dimethyl Dialkyl peroxides such as -2,5-tbutylperoxyhexene-8, 2,5-dimethylhexane-2,5-
Among dihydroperoxides, p-menthane hydroperoxides, ketone peroxides and peroxyesters, those having a half-life at 100 ° C. of more than 10 hours are suitable.

One or more commonly known additives for polypropylene such as an antioxidant, an ultraviolet ray inhibitor, a nucleating agent, a copper damage inhibitor, a flame retardant and the like may be added to the polypropylene resin. Further, one or more of generally known inorganic fillers for polypropylene resin such as calcium carbonate, talc, barium sulfate, wollastonite, and glass fiber may be filled. Also, generally well-known pigments for polypropylene such as carbon may be added.

Examples of the skin material used in the present invention include vinyl chloride leather lined with nylon cloth, a material obtained by laminating a foamed sheet of polypropylene or urethane to a vinyl chloride-based leather, or a knitted material using a nylon or polyester material (for example, tricot). ), A woven fabric (for example, moquette), a nonwoven fabric, a knitted fabric, a woven fabric, a nonwoven fabric and a foamed sheet made of polypropylene, urethane, or the like.

As the pasting synthetic method of the present invention, the skin material is placed in a mold for molding, and after closing the mold, the thermoplastic resin heated and melted is injected into the mold from the gate of the mold to form the skin material. Or by laminating and laminating, or by placing a skin material between the upper and lower molds, supplying the thermoplastic resin melt with the upper and lower molds not closed, and combining the upper and lower molds. A method of bonding and integrating the skin material and the thermoplastic resin is exemplified.

〔The invention's effect〕

As described above, when the polypropylene material and the molding method according to the present invention are used, it is possible to obtain a laminated synthetic product having an extremely good hand holding property. It has become possible to provide quality, low-cost products.

(Examples) Examples of the present invention will be described below, but the present invention is not necessarily limited to these examples. In addition, evaluation of the laminated synthetic product was performed by the following method.

Hand holding level evaluation method Grain flow of skin material in molded products. Hair follicles and foam collapse were evaluated visually or by touch with a 10-point scale. A level of 10 completely retains the texture of the skin material before molding, and a level of 1 completely loses the original texture. 8 that can withstand use as an automotive interior material
It is of the above level.

Impact test evaluation method As shown in Fig. 1, 50mm x 50mm cut out from molded product
Place the gun barrel (2) on the test piece (4), drop the load (1) from above onto the gun barrel (2), and set the minimum load (1) when the test piece (4) is broken. The fracture height was defined as the height of the fracture, and the fracture energy was calculated from the following equation.

Breaking energy (kg-cm) = Load (kg) x Breaking height (c
m) Examples 1-2: Polypropylene resin for general injection molding (Sumitomo Noblen)
AZ564, Sumitomo Chemical Co., Ltd. MFI = 30, ethylene propylene copolymer) 100 parts by weight of an organic peroxide of the following formula (I)
0.1 parts by weight and supply to the hopper of the injection molding machine,
Decomposition was performed in a cylinder to obtain a polypropylene resin having an MFI of 400 g / 10 minutes. Using this polypropylene resin as the core material resin, polypropylene foam PPAM1503 manufactured by Toray Industries, Inc.
Simultaneous shaping with Kyowa Leather Co., Ltd. skin material with 0 (expansion ratio 15 times) bonded to leather made of vinyl chloride resin. Paste composite form was performed.

A box mold having a height of 200 mm x 200 mm x 50 mm was used as a molding die, and a skin material was bonded to the outer surface. The molding machine was a rigid 100T press having a horizontal injection unit, and a molten resin was injected into the mold through a gate in the mold.

Table I shows the evaluation, results, and the impact test results of the molded product's texture when molded at the minimum molding pressure that can faithfully reproduce the shape of the mold with an even resin thickness. Indicated.

Comparative Examples 1-2 Polypropylene resin for general injection molding (Sumitomo Noblen
AZ564, manufactured by Sumitomo Chemical Co., Ltd., MFI = 30, ethylene. (Propylene copolymer) as the core material resin, and simultaneous molding and laminating with Kyowa Leather Co., Ltd., in which Toray Co., Ltd. polypropylene foam PPAM15030 (expansion ratio: 15 times) is bonded to vinyl chloride resin leather. Using the molding machine and the mold shown in Example 1 under the conditions shown in Table 1, the texture was significantly reduced.

Example 3 Polypropylene resin for general injection molding (Sumitomo Noblen)
AZ564, Sumitomo Chemical Co., Ltd. MFI = 30, ethylene. The same organic peroxide as in Example 1 was added to propylene copolymer).
Example 1 was prepared by mixing and decomposing 2 parts by weight of a core resin.
The same shaping and laminating were performed at the minimum pressure that could be molded using the same skin material, molding material and mold as shown in (1). Table 1 shows the evaluation results. In each case, a molded product having a feeling close to that of the skin material before molding was obtained.

Comparative Example 3 A laminated composite was prepared in the same manner as in Example 3 except that the amount of the organic peroxide used was changed to 0.04 parts by weight. Table 1 shows the results.

Comparative Example 4 A material of MFI1800 obtained by mixing 0.5 parts of an organic peroxide with the same polypropylene resin raw material as in Example 1 was used, and was pasted under the conditions shown in Table 1 using the same skin material equipment mold as in Example 1. The composite molding was performed, and the hand holding and the impact strength were evaluated. The feeling retention was at a very good level, but the impact strength was so low that it could not withstand practical use.

Example 4 Using the same core material resin as in Example 1, a skin material made by Kyowa Leather Co., Ltd. was obtained by laminating a soft urethane foam (expansion ratio: 20 times) to a polyester-based tricot under the conditions shown in Table 1. And the simultaneous shaping and laminating was performed. Hand holding was remarkably good.

Comparative Examples 5 to 6 Using the same polypropylene resin as in Comparative Example 1 as the core material, and using the same skin material as in Example 5 under the conditions shown in Table 1, a simultaneous shaping and laminating was performed to evaluate the feeling retention. I did it. The feeling was significantly reduced.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of an impact test apparatus according to the present invention. (1) Load (2) Shooting tip (3) Tip R 1/2 inch (4) Test piece (5) Test piece support

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masato Matsumoto 2-10-1, Tsukahara, Takatsuki-shi, Osaka Sumitomo Chemical Industries Co., Ltd. (72) Inventor Nobuhiro Usui 2-1-1 Tsukahara, Takatsuki-shi, Osaka Sumitomo Inside Chemical Industry Co., Ltd. (72) Inventor Shigeyoshi Matsubara 2-10-1, Tsukahara, Takatsuki-shi, Osaka Sumitomo Chemical Industry Co., Ltd. (56) References JP-A-62-134231 (JP, A) JP-A-60- 212313 (JP, A) JP-A-62-267344 (JP, A) JP-A-62-263241 (JP, A) JP-A-61-155437 (JP, A)

Claims (1)

(57) [Claims] 1. A method for producing a laminated synthetic product comprising a skin material and a core material resin, wherein a polypropylene resin having a melt flow index of 120 to 800 g / 10 minutes is used as the core material resin. Pasting composite method.