JPH04191044A - Molded product - Google Patents

Abstract

PURPOSE:To obtaon molded product, which hgs cold impact properties and is excellent in heat resistance, rigidity and the like, by a structure wherein the molded product concerned has surface layer, which covers the whole surface of core material and is made of specified propylene-based polymer, ethylene- propylene copolymer and/or inorganic filler. CONSTITUTION:The molded product concerned consists of core material and surface layer, which covers the whole surface of the core material. The surface layer is made of composition consisting of propylene single polymer and/or propylene-based polymer having the copolymerization ratio of ethylene of at least 10wt.%, which has the melt flow rate of 0.1-100g/10min, ethylene-propylene copolymer, which has the copolymerization ratio of propylene of 1.5-40wt.%, the melt flow rate of 0.1-4.0g/0min, the peak melt temperature of 80 deg.C or higher and the ratio of weight average molecular weight to number average molecular weight of 4 or more, and/or inorganic filler. The core material is made mainly of propylene-based resin, the flexural modulus of elasticity of which is 10,000kg/cm<2> or more and the Izod impact strength at 23 deg.C of which is 5.0kg.cm/cm or more.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molded article comprising a core material and a surface layer covering substantially the entire circumference of the core material. More specifically, it is made up of a core material and a surface layer that substantially covers its entire circumference, and it not only has extremely good impact resistance and cold impact resistance, but also has good rigidity and heat resistance. The present invention relates to a molded product having a sandwich structure that has excellent adhesion between a core material and a surface layer.

[Conventional technology]

As is well known, propylene polymers are widely produced industrially because they not only have excellent moldability but also have good properties such as mechanical properties, heat resistance, solvent resistance, and oil resistance.
It is used in many ways as a component for automobiles, electrical equipment, electronic equipment, and other daily necessities.

Furthermore, due to the wide range of properties mentioned above, propylene polymers are expected to improve their functional properties by blending (adding) other synthetic resins, rubbers, and fillers as various second and third components. It is a well-known fact that various polymer blend products have been widely used in the above fields due to improvements in so-called polymer blend technology.

Hereinafter, among the above-mentioned uses, a bumper, which is a part of an automobile exterior material, will be specifically explained as an example.

With the automobile industry's focus on weight reduction, fuel efficiency, and cost reduction, as well as the specialization and differentiation of automobile designs, bumper shapes have become larger and more complex, and metal is being used to give a sense of luxury. Ethylene is added to propylene polymer compositions, especially propylene polymers (polypropylene resins).
Polymer blend products, which are a mixture of one or more of propylene rubber, polyethylene resin, and inorganic fillers, have been widely used and have been proposed in large numbers (for example, JP-A No. 53-64256, 53-6
No. 4257, No. 57-55952, No. 57-1598
No. 41, No. 58-111846).

Sandwich molding is also used in the field of injection molding of thermoplastic resins. In this molding method, the surface layer (
In recent years, this molding method has been used to improve the appearance (sink marks, warpage) of molded products, as it is possible to mold not only the same type of material but also different types of materials used for the skin layer and core material. It is widely used mainly in household electrical equipment, office automation equipment, etc., for the purpose of improving rigidity.

[Invention or problem to be solved]

However, although the bumper using the above-described polymer component has sufficient cold impact resistance, it does not necessarily have sufficient heat resistance, so it is not possible to raise the baking temperature during painting. Further, there are drawbacks such as the inability to reduce the thickness of the molded article (product).

In order to improve the heat resistance, it is possible to increase the amount of inorganic filler added. However, not only the appearance of the obtained product (bumper) is not good, but also the paintability is deteriorated.
In addition, a decrease in impact resistance occurs.

Further, the purpose of the conventional sandwich molding method described above is mainly due to the following reasons.

(1) A foaming agent is used in the core layer to prevent sink marks in thick-walled products such as the housings of home electrical appliances and OA equipment.

(2) Composite reinforced materials such as glass fibers are used in the core layer to improve the dimensional accuracy, prevent warpage, and improve rigidity of home appliances such as TV garnishes and parabolic antennas.

That is, although the conventional sandwich molding method improves the above-mentioned physical properties, there are problems in the physical property balance of cold impact resistance, rigidity, and heat resistance of the resulting molded product.

Based on the above, the present invention is a molded product made of a polypropylene resin composition that does not have these drawbacks, has sufficient cold impact resistance as molded products such as automobile exterior parts, and has excellent heat resistance and rigidity. The purpose is to obtain something.

[Means and effects for solving the problems] The present invention has been made to solve these problems, and its gist is to form a core material with a surface layer that substantially covers the entire surface of the core material. The surface layer has a melt flow rate ['l5K72] of 0, and the conditions in Table 1 are 14.
measured, hereinafter referred to as rMFRJ] is 01 to 100 g/1
"Propylene homopolymer and/or propylene-ethylene random copolymer whose copolymerization ratio of ethylene is at most 10% by weight" [hereinafter referred to as "propylene polymer"] and the copolymerization ratio of propylene is 15 to 40% by weight, and the melt flow rate [:
Measured under conditions 14 in accordance with JIS K7210, hereinafter referred to as rMFRJ] is 0.1 to 4.0 g/10 minutes, the melting peak measured with a differential scanning calorimeter is 80°C or higher, and Weight average molecular weight/ which is an index of molecular weight distribution measured by migration chromatography
The core material is made of an ethylene-propylene copolymer having a number average molecular weight of 4 or more, or a composition consisting of these and an inorganic filler, and the core material has a flexural modulus of IO,000 kg/c.
nf or more and Izot impact strength at 23°C (measured with a notch according to ASTM D256)
It consists of a composition whose main component is a propylene-based resin having a value of 5,0 cm/cm or more, and a propylene-based polymer and ethylene-propylene co-Mea in the surface layer.
Ethylene-
The composition ratio of the propylene copolymer is 25 to 55% by weight, and the composition ratio of the inorganic filler is at most 25 parts by weight based on 100 parts by weight of the total amount of these polymeric substances. The thickness of the surface layer is 100 or less with respect to the thickness of 100, and the thickness of all the surface layers is 0.
．． The molded article is characterized by having a diameter of 2 mm or more.

The present invention will be explained in detail below.

The molded article of the present invention includes a surface layer that substantially covers the entire surface of the core material. The surface layer is made of a propylene polymer and an ethylene-propylene copolymer (described later), or a composition comprising these and an inorganic filler.

(A) Propylene polymer The propylene polymer used in the surface layer of the molded article of the present invention is a propylene homopolymer and/or a propylene-ethylene lantam copolymer. The propylene
The copolymerization ratio of ethylene in the ethylene lantum copolymer is at most 10% by weight, preferably 8.0% by weight or less, and particularly preferably 60% by weight or less. If a propylene-ethylene lantam copolymer with an ethylene copolymerization ratio exceeding 10% by weight is used, the rigidity will be greatly reduced, which is not preferable.

The MFR of the propylene polymer is 0.1~]00g/1
0 minutes, preferably 1.0 to 80 g/10 minutes, particularly preferably 20 to 6 g/l 1 minute. MFR
If less than 0 g/10 minutes is used, not only the moldability will be poor, but also the appearance of the resulting molded product will be poor. On the other hand, if a propylene polymer exceeding 100 g/10 minutes is used, the resulting composition will have poor mechanical properties such as impact resistance.

(B) Ethylene-propylene copolymer Furthermore, the copolymerization ratio of propylene in the ethylene-propylene copolymer used in the present invention is 15 to 40% by weight, and 1
8 to 40% by weight is preferred, particularly 20 to 38% by weight. When an ethylene-propylene copolymer having a propylene content of less than 15% by weight is used, the effect of improving the impact resistance of the resulting composition is poor. On the other hand, 40% by weight
When using ethylene-propylene copolymer exceeding
Although the effect of improving the impact resistance of the resulting composition is good, the composition has insufficient rigidity and is also poor in terms of heat resistance.

Moreover, the MFR of the ethylene-propylene copolymer is 01
-4.0 g/10 minutes, preferably 0.2-40 g/10 minutes, particularly preferably 05-4.0 g/10 minutes. If an ethylene-propylene copolymer having an MFR of less than O, Ig/10 minutes is used, it will be difficult to disperse the resulting composition during kneading and the processability of the composition will be poor. Further, even if a uniform composition is obtained, flow marks, welds, etc. become highly visible on the surface of the molded product, making it impossible to obtain a composition with a good appearance. On the other hand, 4.
If the ethylene-propylene copolymer is used in excess of 0 g/10 minutes, the impact resistance and J54-
The effect of improving water quality is insufficient.

In addition, the Mooney viscosity (ML, 100°C) of the ethylene-propylene copolymer is usually 10 to 1oO
+4, preferably 10-70, particularly preferably 20-70.

Note that the ethylene-propylene copolymer was measured using a differential scanning calorimeter (Differential ScanningC).
alo “imete+.

The melting peak measured by DSC) is 80°C or higher, and 8
The temperature is preferably 0 to 125°C, particularly preferably 85 to 125°C. If the melting peak is less than 80°C, the stiffness and tensile strength of the resulting composition are poor.

In addition, the ethylene-propylene copolymer has a crystallinity of 1% or more, preferably 2 to 30%, as measured by X-rays,
Particularly suitable is 2 to 25%. This crystallinity is 1%
If less than 20% of the ethylene-propylene copolymer is used, the stiffness and tensile strength will be poor. On the other hand, if it exceeds 30%, the impact resistance will be poor.

Furthermore, the ethylene-propylene copolymer has a weight average molecular weight (M /
The number average molecular weight (Mn) is 4 or more, preferably 4 to 8. If an ethylene-propylene copolymer with Mw/Mn of less than 4 is used, the processability of the resulting composition is poor.

(C) Inorganic filler The inorganic filler used in the surface layer of the molded product of the present invention is one widely used in the fields of general synthetic resins and rubbers. The inorganic filler is preferably an inorganic compound that does not react with oxygen or water and does not decompose during kneading and molding. Examples of the inorganic filler include oxides and hydrates (hydroxides) of metals such as aluminum, copper, iron, lead, nickel, magnesium, calcium, barium, zinc, zirconium, molybdenum, silicon, antimony, and titanium. It is broadly classified into compounds such as sulfates, carbonates, silicates, their double salts, and mixtures thereof. Among these inorganic fillers, those in powder form preferably have a diameter of 30 μm or less (preferably 10 μm or less). In the case of fibrous materials, the diameter is 1 to 20 μm (preferably 1 to 15 μm), and the length is 0 to 150 μm (preferably 15 to 150 μm).
m) is desirable. Furthermore, the diameter of the flat plate is 3
The thickness is preferably 0 μm or less (preferably 10 μm or less). Among these inorganic fillers, talc, mica, clay, wollastonite, potassium titanate, calcium carbonate and the like are preferred.

(D+ Composition ratio The surface layer of the molded product of the present invention is made of the propylene polymer and ethylene-propylene copolymer, or a composition in which these polymeric substances and an inorganic filler are uniformly mixed. .

The composition ratio of the ethylene-propylene copolymer in the total amount of polymeric substances is 25 to 55% by weight, and 30 to 5% by weight.
5% by weight is preferred, particularly 30-50% by weight. If the composition ratio of the ethylene-propylene copolymer to the total amount of polymeric substances (i.e., propylene-based polymer and ethylene-propylene copolymer) is less than 25% by weight, the impact resistance of the resulting molded product may deteriorate. do not have. on the other hand,
If it exceeds 55% by weight, the rigidity and heat resistance of the molded product will be poor.

Further, when an inorganic filler is further blended, the composition ratio of the inorganic filler to 100 parts by weight of the total amount of polymeric substances is usually at most 25 parts by weight, and preferably 20 parts by weight or less. Since the composition ratio of the inorganic filler to the total amount of polymeric substances (in parts by weight) exceeds 25 parts by weight, not only the appearance of the obtained molded product is poor, but also the paintability is poor when coating the surface.

fE) Core material The core material of the molded product of the present invention is a composition containing a propylene-based resin as a main component, and specifically, the above-mentioned propylene homopolymer, propylene-ethylene random copolymer (propylene-based polymer), or The main component is propylene, and a small amount (usually 20% by weight or less, preferably 18% by weight)
It is a polymer in which ethylene is block copolymerized as described below or a composition of these polymers, and if necessary, an inorganic filler, a polyamide resin, etc. are added.

The polymer obtained by this block copolymerization is substantially a mixture of a propylene homopolymer and an ethylene-propylene lantum copolymer, which will be described later.

The propylene homopolymer in the mixture contains at most 5.0% by weight (preferably not more than 30% by weight) of components soluble in xylene at a temperature of 30°C. In addition, the MFR of the polymer is generally 2.0~]00g/10
minutes, preferably from 5.0 to 100 g/10 minutes, particularly preferably from 5.0 to 80 g/10 minutes. If a propylene homopolymer having an MFR of less than 2.0/10 minutes is used, the kneading properties will be poor and the moldability of the composition will also be poor. On the other hand, those exceeding 100g/10 minutes,
The impact resistance of the composition is poor.

The copolymerization ratio of propylene in the ethylene-propylene random copolymer in the mixture is 25 to 75% by weight, preferably 30 to 70% by weight, and particularly preferably 30 to 60% by weight. Copolymerization ratio of propylene is 25% by weight
If less than 10% of the ethylene-propylene random copolymer is used, the impact resistance of the composition will be poor. On the other hand, ethylene-propylene random copolymers in which the copolymerization ratio of propylene exceeds 75% by weight are difficult to manufacture, and even if they are obtained, there are problems in terms of the rigidity of molded products.

The ethylene-propylene lantum copolymer contains at most 50% by weight of components insoluble in xylene at a temperature of 30°C.
(preferably 45% by weight or less).

The total MFR of the propylene homopolymer and ethylene-propylene random copolymer is 1.0 to 80 g/10 minutes, preferably 2.0 to 80 g/10 minutes, particularly 2.0 to 60 g/'10 minutes. suitable. The MFR of the total amount of propylene homopolymer and ethylene-propylene random copolymer is 1. If it is less than Og/10 minutes, the kneading properties and moldability are poor. On the other hand, if it exceeds 80 g/'IO, the mechanical properties of the molded product, especially the impact resistance, will be poor.

The flexural modulus of the core material of the present invention (measured according to ASTM D690) is 10.000 kg/cnf or more,
In particular, 12,000 kg/cri or more is preferable. If the flexural modulus is less than 10,000 kg/crt, the effect of improving heat resistance is low.

In addition, the Izot impact strength (according to ASTM D256, with a notch, measured at 23°C) is 5.0 kg.
- Cm/cm or more, especially 5. Qkg-
An/an or higher is desirable. Izot impact strength of less than 50 dazzle cm/cm is not preferable because the impact resistance is significantly reduced.

It is important that the core material of the present invention has both the above-mentioned flexural modulus and Izot impact strength.

If the propylene-based polymer or the polymer obtained by block copolymerizing ethylene and propylene has a flexural modulus of elasticity and an Izot impact strength within the above range, it can be used as is. If these properties do not fall within the above ranges, the inorganic fillers, other polymeric substances, such as ethylene-
It is necessary to blend propylene copolymer, polyamide resin, etc. and adjust it to fall within these ranges.

This polyamide resin has a melting point of 180 to 280°C (preferably 200 to
280°C) and a dry flexural modulus (measured according to the method described above) of 20 to 35XlO"
kg/cffl (preferably 23×103 to 35×1
03 kg/crl) is desirable. The intrinsic viscosity of the polyamide resin (concentration 1 g/cx, cη in 98% concentrated sulfuric acid at 25°C) is determined from the viewpoint of moldability and strength.
Generally it is 10-5.0 (preferably 10-4.0).

Polyamide resins having melting points and flexural modulus within these ranges include polyamide 6-6° polyamide 6
and polyamide MXD6. These polyamide resins are manufactured by Ihonai and Oyanagi.

Manufacturing methods, various physical properties, applications, etc. are described in detail on pages 1 to 56 and pages 74 to 94 of "Ensuring Plastic Encyclopedia" co-edited by Seno (Gihodo, published December 15, 1988). It is something that exists.

The content of the polyamide resin together with the propylene resin is generally 10 to 40% by weight.

When blending the above-mentioned polyamide resin to improve the rigidity of propylene resin, the mutual compatibility of the polymers (resins) is not good, so it is necessary to blend a so-called compatibilizer to ensure uniform mixing. be. As the compatibilizer, propylene polymers, polymers obtained by block copolymerization, or other monomers containing ethylene as a main component (for example, α,β-unsaturated dicarboxylic acids, their anhydrides, methyl methacrylate) Examples include modified products obtained by graft polymerizing α,β-unsaturated dicarboxylic acids or their anhydrides to copolymers with . Furthermore, from the viewpoint of heat resistance and rigidity of the core material, propylene-based polymers or polymers obtained by block copolymerization may be used with α,β-unsaturated dicarboxylic acids (e.g., maleic acid) and their anhydrides (e.g., A modified product obtained by graft polymerization of (maleic anhydride) is suitable.

The blending ratio of the modified substance is generally 30 to 2 parts by weight per 100 parts by weight of the total amount of propylene resin and polyamide resin.
It is 0 parts by weight.

(F) Method for producing the composition When using the above-mentioned compound to produce the surface layer and the core material (in the case of a compound containing an inorganic filler, rubber, or other synthetic resin) in the molded article of the present invention , each component may be mixed uniformly. As mentioned above, even if the surface layer and core material are composed of compositions, or even if the core material does not contain the above-mentioned compositional components, they are generally added in the field of polyolefin resins (especially polypropylene resins). UV absorbers, antioxidants, weathering stabilizers, plasticizers, lubricants, antistatic agents, colorants (pigments)
Additives such as these may be added to the extent that they do not substantially damage the substances contained in the respective compositions or synthetic resins.

To produce the composition, methods commonly used in the field of synthetic resins may be applied.

As for the mixing method, if you use a mixer such as a Henschel mixer to tri-blend, you can use a hini roll mill,
Examples include a method of melt-kneading using a screw extruder, a kneader, and a mixer such as a Banbury mixer. At this time, a more uniform composition can be obtained by triblending the rough composition components and further melt-kneading the resulting mixture. Further, the composition is preferable in terms of handling when producing pellet-like products or molded products described below.

(G) Molding method The above composition, polypropylene resin, or polymer obtained by block copolymerization can be molded by a so-called sandwich molding method, which is commonly practiced in the field of synthetic resins.

As described above, in the sandwich molding method, the surface layer material is injected, then the core material is injected, and finally a small amount of the surface layer material is injected into the gate part.

Regarding the sandwich molding method, see "Mulder Series, The Latest Injection Molding Technology - Its Practice and Applications -" edited by Akari Hiroe.
” (1988, published by Sangen Publishing), pages 137 to 144, are described in detail.

Both the melt kneading and sandwich molding described above are carried out at a temperature at which the polymer materials used, such as the propylene polymer, the polymer obtained by block copolymerization, and the ethylene-propylene copolymer, are melted. Is it necessary? However, if carried out at high temperatures, the polymeric material used may thermally decompose. The melt-kneading temperature and the injection molding temperature may or may not be specified by the packaging machine depending on the type and composition ratio of the respective materials used for the surface layer and core material, and are generally 180 to 3H°C (preferably 190 to 280°C). It is.

(Hr molded product The molded product of the present invention obtained as described above is substantially coated with a surface layer over the entire surface of the core material. Thickness of core material] (Thickness of surface layer relative to l The height is 10 (l or less), and preferably 80 or less.

If the thickness of the surface layer relative to the thickness of the core material exceeds [ll], the rigidity of the resulting molded product will be poor.
There is a problem in terms of heat resistance. Further, the thickness of all the surface layers is preferably 0.020 mm or more, Q, preferably 5 rrrm or more, and particularly preferably 0.8 rrm or more.

If the thickness of all the surface layers is less than 0.2 rmn, it is difficult to cover the entire surface of the core material of the molded product, and the impact resistance and cold impact resistance of the molded product are affected. There's a problem.

The molded product of the present invention is characterized by using a composition of a polypropylene polymer with extremely high impact resistance and an ethylene-propylene copolymer in the surface layer, which has good adhesion to the core material and has extremely high rigidity. By manufacturing the material using the above-mentioned molding method, it has a so-called sandwich structure, and has a balance of impact resistance and heat resistance that cannot be obtained with the commonly used polypropylene resin blend materials. I was able to get what I got.

On the other hand, if the materials used for the surface layer and the core material are reversed, sufficient impact resistance cannot be obtained. The reason for this is the location (starting point) or surface layer of cracks that occur when the sandwich molded product is subjected to impact.
Either that or it propagates through the surface layer.

[Examples and comparative examples]

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the Examples and Comparative Examples, the flexural modulus is ASTM
Measurements were made in accordance with D790 at a bending speed of 2.5 mm/min, and heat distortion temperatures were measured in accordance with ASTM D648 at a load of 4.6 kg/al. Furthermore, the impact strength was measured using a high-speed impact tester (manufactured by Rheometric (R) IOMETRIc), model: Impact tester (Impact 1ette+) -80 [1
0], the impact speed is 5 m/s, and the diameter of the tip of the striking core is 1/
From the stress-strain curve obtained when performing an impact test under the following conditions: 2 inches, the sample holder is 2.5 inches in diameter from the jig, the sample size is 1oOX]00m, the same thickness is 6mm, and the measurement temperature is -30℃. Destructive energy was determined and displayed.

In addition, in the examples and comparative examples, the surface layer (skin layer)
The physical properties of the propylene-based polymer, ethylene-propylene copolymer, and inorganic filler used as the material are shown below.

[(A) Propylene polymer]

As a propylene polymer, MFR or 15g/10
The copolymerization ratio of propylene homopolymer [hereinafter referred to as rPP(A)J] and ethylene is 5. rJN amount%
A propylene-ethylene random copolymer [hereinafter referred to as rPP(B)] having the following properties and an MFR of 10 minutes was used.

[(B) Ethylene-propylene copolymer] Also, as an ethylene-propylene copolymer, the copolymerization ratio of propylene is 38% by weight, and the Mooney viscosity (ML, ]009
Ethylene-propylene copolymer with a temperature of 42 °C and an I+4 MFR of 1.2 g/10 min [melting peak 115 °C, crystallinity 4%.

MY/Mn5. O, hereinafter referred to as rEP(1), J], the copolymerization ratio of propylene is 37% by weight, the Mooney viscosity (ML, ]OO'C) is 48, and 1+
4 Ethylene-propylene copolymer with MFR of 0.9 g/10 min [melting peak 105°C9 crystallinity 20%,
My/Mn 4.8. Hereinafter referred to as rEP(2)J],
The copolymerization ratio of propylene is 24% by weight, the Mooney viscosity (ML, l [l [1°C)] is 12, and the
+4 Ethylene-propylene copolymer with MFR of 4.5 g/10 min [melting peak 110°C, crystallinity 0.7%
, Mr/Mn 5.8. Hereinafter referred to as 1fp(3)J]
Ethylene-propylene copolymer [crystallization degree 0%, MY/M114. l.

rEP(4)J] was used.

[(C) Inorganic filler]

Furthermore, as an inorganic filler, talc with an average particle size of 20 μm and an aspect ratio of 50, and talc with an average particle size of 0
Light calcium carbonate (hereinafter referred to as r Ca CO
3 (1) J], mica having an average particle size of 5.0 μm, and clay having an average particle size of 50 μm.

In addition, the core material (core layer) is mainly composed of propylene,
A polymer obtained by block copolymerizing a small amount of ethylene (hereinafter referred to as rHIPPJ), other polymer materials such as polyamide resin, ethylene terpolymer, and polypropylene resin by graft polymerization with maleic anhydride. The manufacturing method, physical properties, etc. of the modified product and inorganic filler obtained by the method are shown below (excluding those used for the surface layer).

[([1lHIPP] As HIPP, we used HIPP that was manufactured as follows and whose physical properties have been shown. In each case, propylene was homopolymerized using a Ziegler-Natsuta catalyst in a polymerization vessel without using a solvent. Next, ethylene was supplied into the polymerization vessel and ethylene and propylene were copolymerized to produce T-HIPP.The propylene homopolymer in the obtained HIPP was heated at 30°C. The soluble content in xylene was 0% at the temperature, and the insoluble content in xylene was 0% at the temperature of 30'C for both ethylene-propylene random copolymers.Ethylene-propylene in each HIPP obtained Mixing ratio of random copolymer [hereinafter referred to as "component B"], MFR and total H of propylene homopolymer U (hereinafter referred to as "component A")
Table 1 shows the MFR of IPP.

Table 1 [(E) Other polymeric substances] In addition, as other polymeric substances, melt flow index (according to JIS K7210, the conditions in Table 1 are 4)
The copolymerization rate of methyl methacrylate is 20.4% by weight, and the copolymerization rate of maleic anhydride is 4% by weight. Original copolymer [hereinafter referred to as rETJ], 100 parts by weight of a propylene homopolymer with an MFR of 0.6 g/10 min, 0.70 parts by weight of maleic anhydride and 4 parts by weight of Henschel peroxide were mixed and mixed using a Henschel mixer. Tri-blend for 5 minutes using an extruder (diameter 40
+++m, cylinder temperature 180~230°
A modified product (hereinafter referred to as modified PPJ) obtained by kneading into pellets using C), which has an intrinsic viscosity [η] of 2.5 and a flexural modulus when dried of 26 x 103 kg/CI
Polycaprolactam [hereinafter referred to as 1'-PA6J], which is If, was used.

((F) Inorganic filler) Furthermore, heavy calcium carbonate (hereinafter referred to as [Ca C03(2) J]) having an average particle size of 10 μm was used as an inorganic filler.

A propylene polymer, an ethylene-propylene copolymer, and an inorganic filler whose types and amounts are shown in Table 2 were listed and triblended for 5 minutes using a Henschel mixer. Each of the resulting mixtures was passed through a vented twin-screw extruder (
Each composition in the form of pellets was produced by melt-kneading using a pellet (diameter: 30 mm). Table 2 shows the abbreviations of each composition obtained.

Each composition was used as a surface layer of the molded article described below.

In addition, each composition component whose type and blending amount are shown in Table 3 was triblended in the same manner as described above to produce each mixture. Each mixture was melt-kneaded in the same manner as described above (however, the resin temperature varied depending on the type and amount of the components) to produce each component in the form of pellets. Table 3 shows the MFR, flexural modulus, isot impact strength (notched), and abbreviations of each composition obtained. Each composition component was used as a core material of the molded product described below.

Examples 1-9, Comparative Examples 1-7 Table 4 shows the type of each composition. Each of the compositions obtained as described above was applied to a sandwich injection molding machine [West Germany Battenfeld (Baltcnlel+)].
I) using model 8Ml150S-C'l,
First, the material for the surface layer is injection molded, followed by the material for the core material, and then the material for the surface layer (approximately 2% of the surface layer) is injection molded to form a flat plate (400 x 400 mm, thickness
6 mm) was molded. Samples were cut out from the resulting molded product, and the flexural modulus, thermal deformation temperature, and fracture energy were measured. The results are shown in Table 4. Furthermore, Table 4 shows the thickness of the surface layer of each molded product.

〔Effect of the invention〕

The molded product of the present invention exhibits the following effects.

(1) Excellent impact resistance (especially impact resistance at low temperatures).

(2) Good heat resistance.

(3) Excellent rigidity (flexural modulus).

(4) In particular, compared to molded products obtained by commonly used injection molding methods, when molded using the same type of material, impact resistance (including impact resistance at low temperatures),
Excellent balance of heat resistance and rigidity. In particular, it has a good balance of physical properties between heat resistance and impact resistance.

(5) Since the core material can be highly filled with inorganic filler, dimensional accuracy is excellent.

The molded product of the present invention can be used in a wide variety of ways to achieve the effects described above.

Typical uses are shown below.

(1) Bumper, bumper apron, spoiler,
Automotive exterior parts such as side moldings, side air dams, and engine undercovers (2) Motorcycle parts such as front fenders and body covers

Claims (1)

[Claims] It is a molded product consisting of a core material and a surface layer that substantially covers the entire surface of the core material, and the surface layer is made of a propylene homopolymer having a melt flow rate of 0.1 to 100 g/10 minutes and /or a propylene-ethylene random copolymer in which the copolymerization ratio of ethylene is at most 10% by weight, and the copolymerization ratio of propylene 15 to 40%
% by weight, and the melt flow rate is 0.1 to 4.
0 g/10 min, the melting peak measured by differential scanning calorimeter is 80°C or higher, and the crystallinity measured by X-ray is 1.
% or more and 30% or less, and an ethylene-propylene copolymer whose weight average molecular weight/number average molecular weight, which is an index of molecular weight distribution measured by gel permeation chromatography, is 4 or more, or these and an inorganic filler. The core material has a flexural modulus of 1.
0,000 kg/cm^2 or more and an Izod impact strength at 23° C. of 5.0 kg/cm/cm or more, comprising a composition containing a propylene-based resin as a main component, a propylene homopolymer in the surface layer, Propylene-
The composition ratio of the ethylene-propylene copolymer in the total amount of the polymeric substance consisting of the ethylene random copolymer and the ethylene-propylene copolymer is 25 to 55% by weight.
In addition, the composition ratio of the inorganic filler to 100 parts by weight of the total amount of these polymeric substances is at most 25 parts by weight, and the thickness of the surface layer is 100 parts by weight or less relative to the thickness of the core material of the molded article 100 parts by weight. A molded article characterized in that the thickness of all surface layers is 0.2 mm or more.