JPH06143336A - Multilayered injection-molded body and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide weight-saved multilayered injection-molded body equipped with soft feeling and manufacturing method thereof. CONSTITUTION:The multilayered injection-molded body having hollow metal part 2 inserted within, surface made of olefin-based or styrene-based thermoplastic elastomer layer 4 and rigid injection-molded propylene-based resin layer 3 interposed between the metal part and the surface layer so as to be laminated to one another and the manufacturing method thereof are provided.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention provides a soft feel,
Multi-layer injection with hollow metal parts inserted inside, which can be used for lightweight, furniture, daily necessities, interior parts in transportation equipment such as aircraft, ships, automobiles, steering wheels, handles, knobs, grips, etc. TECHNICAL FIELD The present invention relates to a molded body and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a laminated body having a soft surface and a light weight, for example, a steering wheel, has a metal core having a diameter of 9 to 10 mm, and is surrounded by polypropylene (PP) or polyvinyl chloride. (PV
C), foamed polyurethane (urethane integral skin foam), or the like coated with a relatively hard synthetic resin material has been used. However, in recent years, a soft steering wheel has been demanded from the viewpoints of safety, improvement in feel when grasped, and improvement in operability. In addition, the weight reduction of steering wheels has come to be paid attention to with the provision of airbags and the like.

[0003]

However, the above-mentioned conventional techniques have not been able to provide a lightweight and soft steering wheel that satisfies these requirements in all respects. That is, for example, the one using the urethane integral skin foam has a problem that the metal core and the surface soft material are separated during the grip operation. In addition, there is a problem of environmental destruction due to CFC gas when urethane is foamed. Besides, the molding cycle is long,
There are drawbacks in cost and mass productivity due to defects such as poor yield, and there are various problems that the obtained product is not sufficiently lightened. In addition, there is also one in which a thermosetting adhesive is applied to the metal core and a soft layer of PVC, polyurethane or the like is formed on the outer surface thereof, but cleaning in the bonding work step, application of the adhesive, curing and the like are complicated. There
There was a problem in mass productivity. In addition, there is a problem that the grip feeling is not sufficiently improved and the weight reduction is unsatisfactory.

[0004]

[Means for Solving the Problems]

SUMMARY OF THE INVENTION The present inventors have conducted various studies to solve the above problems, in forming a metal insert molded article in which the surface of a metal part is coated with a soft material, a hollow metal part and By using a specific soft material, and by interposing a specific hard resin layer between the hollow metal parts and the soft material on the surface, the surface gives a soft feel, is excellent in handle operability, and Since the hard resin material can firmly bond the soft material and the hollow metal part without using an adhesive, the peeling phenomenon does not occur even during the grip operation, and the hollow metal part is used. According to the knowledge that the steering wheel can be sufficiently reduced in weight because the hard resin material layer is partially substituted for the above, the present invention has been completed. It is.

That is, the present invention "has a hollow metal part inserted inside and a surface of an olefin-based or styrene-based thermoplastic elastomer layer, and a hard injection-molded propylene-based resin layer is interposed between them. It is a multi-layer injection-molded article "characterized in that it is laminated.

According to another aspect of the present invention, "a hollow metal part is inserted into a mold, and then a hard propylene-based resin is injection-molded into the mold to form the metal part with a hard propylene-based resin. And then coating the surface of the propylene-based resin with an olefin-based or styrene-based thermoplastic elastomer by injection molding.

[Detailed Description of the Invention] [1] Multilayer injection-molded article (1) Constituent material (a) Hollow metal part As a hollow metal part to be inserted into the multilayer injection-molded article of the present invention, iron is used. Various metals such as aluminum, stainless steel and the like can be mentioned, and particularly in the case of a steering wheel, a high-strength steel of ordinary steel (having a tensile strength of 35 kg / mm ² or more) processed into a hollow pipe shape is preferable. The pipe preferably has an outer diameter of about 4 to 17 mm in terms of strength and handle operability.

(B) Propylene-based resin The propylene-based resin used as an intermediate layer between the hollow metal part and the olefin-based or styrene-based thermoplastic TPE layer in the multilayer injection-molded article of the present invention is a propylene homopolymer. Or, other α-olefins containing propylene as a main component, aromatic vinyl monomers, unsaturated carboxylic acids or derivatives thereof, random with polymerizable monomers such as vinyl ester, block or graft copolymers, and the like. To be

In addition to these polymers, inorganic fillers such as glass fiber, carbon fiber, potassium titanate fiber, metal whiskers, talc and mica, polyphenylene ether resin, polyamide resin, saturated polyester resin, polycarbonate resin, polyphenylene sulfide resin. JIS-K720 by blending engineering resin such as
The elastic modulus according to 3 is 3,000 to 170,000 Kg / c
m ² , preferably 40,000 to 120,000 Kg / cm
^The propylene-based resin adjusted to ² can be preferably used. At this time, the preferable blending amount of the engineering resin is 5 to 50% by weight. A propylene-based resin containing various additional components may be used as long as it has such physical properties.

(C) Olefin-based or styrene-based thermoplastic elastomer As the olefin-based or styrene-based thermoplastic elastomer (hereinafter simply referred to as "TPE") used in the multilayer injection-molded article of the present invention, The following can be mentioned.

Olefin-based TPE The olefin-based TPE is a blend of an olefin-based resin such as polypropylene or polyethylene and an olefin-based rubber such as ethylene / propylene-based rubber (EPR) or ethylene / butene-based rubber (EBR). Specific examples thereof include "Thermoran" manufactured by Mitsubishi Petrochemical Co., Ltd., "Milastomer" manufactured by Mitsui Petrochemical Co., Ltd., "Sumitomo TPE" manufactured by Sumitomo Chemical Co., Ltd., "Santoprene" manufactured by Nippon Monsanto Co., Ltd., and the like.

Styrene-based TPEs Styrene-based TPEs include styrene / butadiene block copolymers, styrene / isoprene block copolymers, hydrogenated derivatives of these copolymers (styrene / ethylene / butylene / styrene copolymers, styrene / styrene copolymers). Elastomers containing (ethylene / propylene / styrene copolymer) as a compounding component, and specifically, "Lavalon" manufactured by Mitsubishi Petrochemical Co., Ltd., "Sumitomo TPE-SB" manufactured by Sumitomo Chemical Co., Ltd., and "Elastomer manufactured by Aron Kasei Co., Ltd.""AR","ToughTech" manufactured by Asahi Kasei Kogyo Co., Ltd., and the like.

As such a TPE, the above TPE can be used as it is, or a foamed product of the TPE can be used. From the viewpoint of moldability and soft feel, the A hardness of JIS-K6301 is preferable. 10-80,
Particularly preferably, it is 20 to 60. Further, TPE containing various additional components may be used as long as it has such physical properties.

(D) Arbitrary Constituent Material In addition to the essential constituent materials of (a) to (c) above, the following constituents are added as optional constituent materials for the purpose of improving the designability, grip feeling, operability, etc. It is preferable to use a coating layer forming material and / or a leather layer forming material.

Coating Layer Forming Material Materials used for forming the coating layer include a primer and a paint. Specific examples of the primer include "Primac 1100" manufactured by NOF Corporation, "MEX-5440" manufactured by Sakai Chemical Co., Ltd., and the like. As the paint, specifically, "Suncoat Grace V" manufactured by Nagashima Paint Co., Ltd. and "MEX-6" manufactured by Sakai Chemical Co., Ltd.
047 "and the like can be illustrated.

Material for forming leather layer As a material used for forming the leather layer, there is natural or artificial leather, and specifically, cowhide (steer, cow, kip, calf) having a thickness of about 1 mm. Etc.), natural leather such as sheep leather, and synthetic leather such as vinyl chloride resin synthetic leather and polyurethane synthetic leather.

(2) Structure (a) Indispensable Constituent Layers The multilayer injection-molded product of the present invention, for example, a steering wheel is basically made of the above-mentioned essential constituent materials (a) to (c). However, if necessary, it is coated or coated with any of the constituent materials of (d) above.

That is, the multilayer injection molded article of the present invention, for example,
The overall structure of the steering wheel 1 is as shown in FIG. 1, but the internal structure thereof is as shown in FIG.
Hollow metal core 2 with an outer diameter of 12 mm and an inner diameter of 8 mm
Having a thickness of 2-10 mm, preferably 3-8, which is inserted inside and is coated on the outside by injection molding.
mm of propylene-based resin layer (hard layer) 3 is formed, and the outside of the propylene-based resin layer is coated by injection molding with a thickness of 3 to 10 mm, preferably 4 to 8 m.
The olefin-based or styrene-based thermoplastic elastomer layer (soft layer) 4 of m is formed.

(B) Arbitrary Constituent Layers On the surface of the multilayer injection molded article having such a structure, for example, the steering wheel 1, if necessary, a coating comprising a primer layer and / or a coating film as shown in FIG. By forming the layer 5 or the leather layer 5 having a thickness of about 1 mm, it is possible to further improve the designability, the grip feeling and the operability.

[II] Production of multilayer injection-molded article (1) Production step The multi-layer injection-molded article of the present invention can be produced by various methods, among which the following first step and second step
It is preferable to manufacture by going through steps.

(A) First step: A hollow metal part to be inserted is fixed in a mold, and a hard propylene resin is injection-molded in the mold to obtain a wall thickness of the propylene resin layer. Is 2-10
The surface of the metal part is coated so as to have a thickness of 3 mm, preferably 3 to 8 mm.

(B) Second step Next, the molded body obtained in the first step is transferred into another mold and fixed therein, and a soft olefin-based or styrene-based TPE is injection-molded again. Therefore, the wall thickness of the olefin-based or styrene-based TPE is 3 to 10 mm, preferably 4
The surface of the propylene-based resin is coated to have a thickness of 8 mm.

(2) Manufacturing conditions As an injection molding machine used in the injection molding in the first step and the second step, a generally used in-line screw type machine and the like can be mentioned. Typical injection molding conditions are as shown in Table 1 below.

[0024]

[Table 1]

In the injection molding, foaming the TPE layer is an effective means because a molded product having a softer touch can be obtained. The foaming is performed by a conventional method using a physical foaming agent or a chemical foaming agent.
The volume may be about 2 to 2 times.

(3) Coating Step / Leather Covering Step On the surface of the molded body obtained in the first step and the second step,
Further, it is preferable to form a coating layer and / or a leather coating layer.

Coating Process The coating here is generally performed by applying a paint after the primer treatment. The coating method is a conventional method, usually by spraying, using the above-mentioned primer and paint.

Leather coating step The formation of the leather coating layer is generally carried out by coating a leather in which an adhesive or pressure-sensitive adhesive is applied to a part or the whole of the molded body,
As shown in FIG. 6, the seam is sewn to form a sewn portion 8 for finishing.

[0029]

EXAMPLES In order to further explain the multilayer injection-molded article of the present invention and the method for producing the same, the present invention will be specifically described with reference to Examples and Comparative Examples. The raw materials used in the examples and the evaluation methods for the obtained injection-molded articles are as follows.

(1) Raw Materials (a) Metal Parts As a hollow metal part, high-tensile steel processed into a hollow pipe shape having an outer diameter of 12 mm and an inner diameter of 8 mm was used.

(B) Propylene resin P-1 : "Mitsubishi Polypro MA3" (M
FR 11 g / 10 min, density 0.90 g / cm ³ ) 40% by weight of glass fiber having a diameter of 10 μm and length of 3 mm and 10% by weight of maleic anhydride modified polypropylene were blended and kneaded at 230 ° C. in a granulator. Composition (MFR 5 g /
10 minutes, density 1.21 g / cm ³ , JIS-K7203
Flexural modulus of 80,000 Kg / cm ² ).

P-2 : “Mitsubishi Polypro BC3B” manufactured by Mitsubishi Petrochemical Co., Ltd. (MFR 9 g / 10 minutes, density 0.90 g / c)
m ³ ) poly 2,6-dimethyl-1,4-phenylene ether manufactured by Nippon Polyether Co. (having an intrinsic viscosity of 0.3 dl / g measured in chloroform at 30 ° C.)
25% by weight, 40% by weight of glass fibers having a diameter of 10 μm and a length of 3 mm were mixed and kneaded at 250 ° C. in a granulator (MFR 6 g / 10 min, density 1.30 g / c
m ³ , flexural modulus 110,000 Kg / cm ² ).

(C) Olefin-based or styrene-based thermoplastic elastomer TPS-1: Styrene-based TPE, "Lavalon T-331C" manufactured by Mitsubishi Petrochemical Co., Ltd. (density 0.9 g / cm ³ , JIS
-A hardness 28). TPS-2: Styrene-based TPE, "Lavalon MJ-4300C" manufactured by Mitsubishi Petrochemical Co., Ltd. (density 0.9 g / cm ³ , J
IS-A hardness 45). TPO-1: Olefin-based TPE, “Thermoran 3551” manufactured by Mitsubishi Petrochemical Co., Ltd. (density 0.9 g / cm ³ , JI
S-A hardness 55).

(2) Evaluation method Grip slip test Using the measuring device shown in FIG. 3, the shaded portions 1a, 1b, 1c of the steering wheel 1 shown in FIG.
Clamp from four sides using the pressing tools shown in (a) and (b), and rotate at a load applied acceleration of 5 to 10 seconds / 90 degrees for 3
A torque of 5 kg was applied. After that, when the torque was removed, the one in which the grip returned to the original state was rated as good, and the one that did not return to the original state was rated as bad.

Grip feel test panel 86 people (46 men, 40 women, age 19-)
In a monitor test of 52 years old, when 80% or more of people are considered to be good, on the basis that the one that can be judged to be easy to fit in the hand and to have appropriate elasticity when the obtained molded product is lightly gripped is good. Only when it is judged, it is assumed that the steering wheel performance of the present invention is satisfied.
And

Handle operability test In a monitor test with the same personnel configuration as the above-mentioned grip feel test, when the handle is gripped strongly in the actual handle operation, there is an appropriate repulsive force without bottoming and there is a firm feeling. 8 is a standard to make something that is felt good.
Only when 0% or more of the people were judged to be good, the steering wheel performance of the present invention was satisfied, and it was evaluated as ◯, and the other cases were evaluated as x.

Example 1First step Processed into a hollow pipe with an outer diameter of 12 mm and an inner diameter of 8 mm
Hollow metal parts made of high-strength steel with a cavity inner diameter of 22 mm
Mounted in a mold, then hard propylene resin (P-
2) is injection molded so that the surface of this hollow metal part is
Coated with 5 mm of the resin. The injection molding conditions at this time are
Molding temperature 220 ℃, injection pressure 700Kg / cm ², Mold temperature
It was 30 ° C. and the cooling time was 30 seconds.

Second step The obtained molded body is mounted in a mold having a cavity inner diameter of 30 mm, and then styrene-based TPE (TPS-1) is injection-molded to make the surface of the hard propylene-based resin layer thick. Is 4
mm of the styrenic TPE. The injection molding conditions at this time are as follows: molding temperature 220 ° C., injection pressure 650 Kg / c
m ² , mold temperature was 30 ° C., and cooling time was 50 seconds.

Leather Covering Step The obtained molded body was covered and sewn with cowhide natural leather having an average thickness of 1 mm so as to have the shape shown in FIG.

Evaluation Regarding the product performance of the steering wheel thus obtained, the performance evaluation of three items of a grip idle test, a grip feeling test and a steering wheel operability test was carried out, and the results are shown in Table 2.

Example 2 First Step In the first step of Example 1, the mold was moved to the cavity inner diameter 2
Use a 0 mm mold and hard propylene resin (P-
The same procedure was performed, except that the same (P-1) was used instead of 2) and the coating was performed with a thickness of 4 mm. Second step In the second step of Example 1, styrene-based TPE (TP
The same thickness (TPS-2) is used instead of S-1) and the wall thickness is 5 m.
It carried out similarly except having coated by m. Leather coating process The same process as in Example 1 was performed. Evaluation The same process as in Example 1 was performed. The results are shown in Table 2.

Example 3 First Step The same process as the first step of Example 2 was carried out. Second step In the second step of Example 2, styrene-based TPE (TP
Olefin-based TPE (TPO-1) instead of S-2)
Was performed in the same manner except that was used. Leather coating process The same process as in Example 2 was performed. Evaluation The same process as in Example 2 was performed. The results are shown in Table 2.

Example 4 First Step The same process as the first step of Example 2 was carried out. Second step: The obtained molded body is mounted in a mold having a cavity inner diameter of 30 mm, and then 95 parts by weight of styrene-based TPE (TPS-2) and a blowing agent "FineBlow S" manufactured by Mitsubishi Petrochemical Co., Ltd.
20N ”5 parts by weight of a blended material was used for injection molding, and a wall thickness of 5 mm was obtained while foaming 1.3 times.
Injection molding conditions at this time, the molding temperature 220 ° C., injection pressure primary 20 Kg / cm ^2, and the secondary 15 Kg / cm ² and a low-pressure, mold temperature 30 ° C., and a foaming short shot method cooling time 80 seconds . Leather coating process The same process as in Example 2 was performed. Evaluation The same process as in Example 2 was performed. The results are shown in Table 2.

Example 5 First Step The same process as the first step of Example 2 was carried out. Second step The second step was performed in the same manner as the second step of Example 2. Coating process The surface of the obtained molded body was painted and finished under the following conditions. Pretreatment: Wiping with isopropyl alcohol Primer: “MEX-5440” manufactured by Sakai Chemical Co., Ltd .: Thinner methyl ethyl ketone (MEK): Thickness 7 μm Drying: Temperature Normal temperature: Time 60 minutes Coating material: Main agent Sakai Chemical Co., Ltd. “MEX-604”
7 ": Curing agent" F-3 "manufactured by Sakai Chemical Co., Ltd .: Solvent thinner: Coating thickness 20 µm Baking: Temperature 80 ° C: Time 30 minutes Evaluation was carried out in the same manner as in the same process of Example 2. The results are shown in Table 2.

Comparative Example 1 First Step In the first step of Example 1, the mold was set to the cavity inner diameter 3
Use a 0 mm mold and hard propylene resin (P-
The same procedure was performed except that 1) was coated with a wall thickness of 9 mm. The second step was omitted. Leather coating process The same process as in Example 1 was performed. Evaluation The same process as in Example 1 was performed. The results are shown in Table 2.

Comparative Example 2 The first step was omitted. Second step: A high-tensile steel hollow metal part processed into a hollow pipe shape with an outer diameter of 12 mm and an inner diameter of 8 mm is mounted in a mold with a cavity inner diameter of 30 mm, and then styrene-based TPE (TPS-
2) was injection molded and coated with a wall thickness of 9 mm. The injection molding conditions at this time are the same as the conditions of the second step of the first embodiment. Leather coating process The same process as in Example 1 was performed. Evaluation The same process as in Example 1 was performed. The results are shown in Table 2.

[0047]

[Table 2]

[0048]

The multilayer injection molded article according to the present invention, for example,
The steering wheel has a hollow metal part inside and is formed so as to be gradually softened toward the outside, and a surface layer composed of a soft olefin-based or styrene-based thermoplastic elastomer is formed on the outside. , Gives a soft feel when grasped, improves the handle operability, and moreover, the force given to the grip at the time of grip operation is not directly transmitted to the hollow metal parts, and the hollow metal parts and the surface soft material There is no problem of peeling between the gaps. Further, unlike the case of polyurethane foam, there is no problem of environmental destruction due to CFC gas. Furthermore, since the molding cycle is short and the yield is good, it is excellent in cost and mass productivity, and it is also possible to use hollow metal parts. Since a part of it is replaced with a hard propylene resin layer,
There is a remarkable effect that the weight of the multilayer injection-molded article can be reduced.

[0049]

[Brief description of drawings]

FIG. 1 is a perspective view of a steering wheel according to an embodiment of the present invention.

2 is a steering wheel A shown in FIG.
-A cut-away perspective view taken along line A-section.

FIG. 3 is a plan view of an apparatus for measuring a steering wheel grip slip test.

FIG. 4 is a plan view showing a measurement portion of a steering wheel that measures a grip slip test.

5 (a) and 5 (b) are a plan view and a partial side view of a push tool for clamping the steering wheel of FIG.

FIG. 6 is a partial plan view showing a sewn portion by a leather winding work test.

[0050]

[Explanation of symbols]

1 Steering Wheel 2 Hollow Metal Parts 3 Propylene Resin Layer (Hard) 4 Olefinic or Styrene Thermoplastic Elastomer Layer (Soft Layer) 5 Coating Layer and / or Leather Coating Layer 6 Grip Idling Test Measuring Device 7 Press Tool 8 Sewing department

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Claims (6)

[Claims] 1. A hollow metal part inserted inside and a surface of an olefin-based or styrene-based thermoplastic elastomer layer, and a hard injection-molded propylene-based resin layer is interposed and laminated between them. Characterized by that
Multi-layer injection molding. 2. The multilayer injection-molded article according to claim 1, wherein the surface is coated. 3. The multilayer injection-molded article according to claim 1, whose surface is coated with a natural or artificial leather. 4. A hollow metal part is inserted into a mold, and a hard propylene resin is injection-molded into the mold to coat the metal part with a hard propylene resin.
Next, a method for producing a multilayer injection-molded article, characterized in that the surface of the propylene-based resin is injection-molded with an olefin-based or styrene-based thermoplastic elastomer to cover the surface. 5. The method for producing a multilayer injection-molded article according to claim 4, further comprising coating the surface of a coating obtained by injection-molding an olefin-based or styrene-based thermoplastic elastomer. 6. The method for producing a multilayer injection-molded article according to claim 4, wherein the surface of the coating obtained by injection-molding the olefin-based or styrene-based thermoplastic elastomer is further coated with a natural or artificial leather.