JP3194813B2 - Sandwich resin molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sandwich resin molded article comprising a core material and a surface layer substantially covering the entire surface thereof, and more particularly, to a core material and substantially covering the entire surface thereof. It has excellent adhesion to polyurethane and other paints without the need for special pre-treatments or primers. Is also good,
The present invention relates to a resin molded product having extremely excellent cold shock resistance, excellent rigidity and heat resistance, and having a sandwich structure with good adhesion between a core material and a surface layer.

[0002]

2. Description of the Related Art When a polypropylene polymer is used for an automobile part, for example, a bumper, not only impact resistance and rigidity but also good paintability are required. However, since these requirements cannot be satisfied by the polypropylene polymer alone, a propylene-ethylene block copolymer is used for the purpose of improving impact resistance, or an ethylene-propylene rubber is used alone or in the propylene block copolymer. And the like have been proposed.

[0003] On the other hand, since polypropylene does not have a polar group, its coatability is originally poor, and it has been proposed to mix polypropylene or the like modified with a compound having a polar group to improve coatability. If the amount is too large, there is a problem that rigidity is reduced. In such a formulation,
Since the blending amount and the like are determined by considering the balance between the two characteristics, it is difficult to sufficiently satisfy both characteristics.
Usually, at the time of coating, first, the surface of the object to be coated is treated with trichloroethane vapor, then a primer is applied, and thereafter, for example, urethane paint is applied.

As a plastic molded body, a so-called sandwich molded body in which a core material and the entire surface thereof are covered is known (see, for example, JP-A-2-251446 and JP-A-4-191444). JP 2
JP-A-251446 discloses a molded article in which a core material is a styrene-based resin modified with a hydroxy group, an epoxy group, or the like, and a surface layer is formed of a composition of polyphenylene ether and polyamide.
Alternatively, a molded product in which a core material is a modified olefin resin and a surface layer is made of polyester and rubber is disclosed.

On the other hand, Japanese Patent Application Laid-Open No. 4-194444 discloses a molded article comprising a surface layer comprising a specific impact-resistant polypropylene polymer composition and a core comprising a highly rigid propylene-based polymer. Have been.

[0006]

In recent years, the use of trichloroethane and some primers has tended to be restricted due to environmental problems. However, in the case of molded articles of the same material from the surface to the inside, there is no need to use a trichloroethane vapor treatment or primers for automobile parts. It is difficult to sufficiently satisfy the rigidity, impact resistance, and paintability required for molded articles such as those described above. Also, even if a primer is used, without special pretreatment such as vapor treatment with trichloroethane, the coating film comes off when coming into contact with a solvent or fuel (especially a mixture of gasoline and alcohol, commonly called gasohol). There is a problem.

In the case of a sandwich resin molded product, the resin material can be changed between the surface and the inside.
The sandwich molded product described in Japanese Patent No. 51446 has a problem that the low-temperature impact resistance is not sufficient, and that a large product is inferior in moldability and expensive in material. Further, the molded article described in JP-A-4-19104 does not pay attention to the improvement of paintability, and there is a problem that the paintability is not sufficient even from the viewpoint of its composition.

Accordingly, the present invention solves the above-mentioned problems of the conventional sandwich molded product and has practically sufficient cold shock resistance, heat resistance, rigidity, etc. as molded products for automobile exterior parts and the like. In addition to being able to apply a paint such as a polyurethane-based paint directly to the molded product without practical pretreatment or primer treatment in a state that is practically satisfactory, it is also resistant to the use of primer without special pretreatment. An object of the present invention is to provide a sandwich molded product having good gasohol properties.

[0009]

Means for Solving the Problems The present invention has solved the above-mentioned problems, and the gist of the present invention is a formed article comprising a core material and a surface layer substantially covering the entire surface of the core material. (A) 30 to 80% by weight of a propylene-based polymer (B) 5 to 50% by weight of a modified propylene-based polymer (C) 15 to 40% by weight of an ethylene-α-olefin copolymer rubber and D) An oligomer having a functional group at a terminal, comprising a composition comprising 0.1 to 20% by weight, wherein the core material has a flexural modulus of 1
Izod impact strength of more than 5,000 kg / cm ² is 5.0
It is a sandwich resin molded product composed of a composition mainly containing a propylene-based polymer of not less than kg · cm / cm ² .

Hereinafter, the present invention will be described more specifically. The surface layer of the sandwich molded product of the present invention comprises a propylene-based polymer, a modified propylene-based polymer, an ethylene / α-olefin copolymer rubber and an oligomer having a terminal functional group, or a composition comprising these and an inorganic filler. Consists of

(A) Propylene Polymer The propylene polymer blended in the composition of the present invention includes a propylene homopolymer, a block copolymer of propylene as a main component with ethylene and / or an α-olefin, and It is selected from random copolymers of propylene with ethylene and / or α-olefin as a main component. In any of these block copolymers and random copolymers, the copolymerization ratio of ethylene and α-olefin is 20% by weight or less as a total amount thereof, preferably 1% or less.
5% by weight or less. The α-olefin preferably has 4 to 12 carbon atoms, and typical examples of such α-olefin include butene-1, hexene-1, 4-methylhexene-1 and octene-1. Among such propylene-based polymers, it is preferable to use the block copolymer and the random copolymer.

The propylene polymer has a melt flow rate (MFR) (measured under condition 14 in accordance with JIS K7210) of usually 1.0 to 100 g / 10 min.
-80 g / 10 min is desirable, and 2.0-60 g / 10 min is particularly preferred. When a propylene polymer having an MFR of less than 1.0 g / 10 minutes is used, not only does the kneadability with the modified propylene polymer tend to deteriorate, but also the moldability of the obtained composition may deteriorate. , Conversely, MF
It is not preferable to use a propylene polymer having an R of more than 100 g / 10 minutes, since the mechanical strength of the obtained composition tends to decrease.

(B) Modified propylene polymer The propylene polymer used for producing the modified propylene polymer blended in the composition of the present invention is exactly the same as the above-mentioned propylene polymer except for MFR. (However, it need not be the same as the propylene-based polymer component A). Instead of the propylene-based polymer,
For example, a mixture of a propylene homopolymer and an ethylene-propylene copolymer rubber described below in a composition ratio described below can also be used. The preferred propylene content of the copolymer rubber is 20 to 50% by weight.

In producing the modified propylene polymer of the present invention using a propylene homopolymer and an ethylene-propylene copolymer rubber, the total amount of the propylene homopolymer and the ethylene-propylene copolymer rubber is The proportion of the ethylene-propylene copolymer rubber in the total is usually at most 40% by weight, and 1 to 40% by weight.
Is preferred, and particularly preferably 2 to 35% by weight. When the proportion of the ethylene-propylene-based copolymer rubber in the total amount of the propylene homopolymer and the ethylene-propylene-based copolymer rubber exceeds 40% by weight, the adhesion strength to the coating film is good, but the This is not preferred because not only flow marks are generated on the surface but also the gloss tends to decrease.

The melt flow rate (MFR) of the propylene polymer is usually from 0.01 to 100 g / 10 min, and from 0.01 to 80 g / min, from the viewpoints of moldability, mechanical properties of the resulting composition and the like. 10 minutes is preferred, especially 0.0 minutes
Those having 2 to 60 g / 10 minutes are preferred.

The modified propylene-based polymer of the present invention comprises a mixture of the propylene-based polymer or a mixture of the propylene-based polymer with an ethylene-α-olefin copolymer rubber, such as a carboxyl group, a hydroxyl group, an amino group or an epoxy group. Modified with an unsaturated compound having a functional group selected from A propylene-based polymer not modified with these functional groups has poor coatability and cannot achieve the above-mentioned object of the present invention.

Examples of the unsaturated compound having a carboxyl group used for modification in the present invention include monobasic unsaturated carboxylic acids and dibasic unsaturated carboxylic acids, and metal salts, amides, imides and the like of these unsaturated carboxylic acids. Esters and anhydrides. Of these, the monobasic unsaturated carboxylic acid usually has at most 30 carbon atoms, and particularly preferably 25 or less. Representative examples of monobasic unsaturated carboxylic acids include acrylic acid, methacrylic acid, and crotonic acid. Representative examples of dibasic unsaturated carboxylic acids and derivatives thereof include maleic acid, fumaric acid, itaconic acid and nadic acid as dibasic unsaturated carboxylic acids, and maleic anhydride and nadic anhydride as their anhydrides. And tetrahydrophthalic anhydride, monoethyl or diethyl maleate and glycidyl methacrylate as esters thereof, and maleimide as imide. Of these unsaturated carboxylic acids or derivatives thereof, anhydrides of dibasic unsaturated carboxylic acids are preferred, and maleic anhydride is particularly preferred.

The unsaturated compound having a hydroxyl group used for modification in the present invention includes a compound having at least one unsaturated bond and containing a hydroxyl group. Examples of such a compound include hydroxypropene, hydroxybutene, dihydroxybutene, hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl crotonate, and pentahydroxyhexyl acrylate.

As the unsaturated compound having an amino group used for the modification in the present invention, various unsaturated compounds having an amino group or a substituted amino group can be used, but from the viewpoint of industrial availability, For example, N, N-dimethyl-2-aminoethyl methacrylate, allylamine, aminostyrene, aminopropyl methacrylate and the like are preferable.

The unsaturated compound having an epoxy group used for the modification in the present invention includes unsaturated glycidyl esters, unsaturated glycidyl ethers, epoxy alkenes and the like, for example, glycidyl (meth) acrylate, allyl glycidyl ether, 3,4-epoxybutene, 3,4-epoxy-1-pentene and the like can be mentioned.

If the amount of the functional group-containing unsaturated compound used in the above-mentioned modification is too small, the coatability on the surface layer obtained from the composition containing the obtained modified propylene polymer may be deteriorated. On the other hand, if the amount is too large, the improvement effect according to the amount used cannot be obtained, but rather the original properties of the propylene-based polymer may be impaired. 0 to
It is preferred to use 10 parts by weight.

The modification of the propylene polymer in the present invention includes a copolymer of the unsaturated compound having the above functional group, but graft modification is preferred. As an example of such a modification method, there is a method in which a propylene-based polymer, the above-mentioned unsaturated compound having a functional group and a radical initiator are mixed and heat-treated. This heat treatment can be performed at a temperature of about 150 to 300 ° C. using an extruder, a kneader, a Banbury mixer, or the like. As another method, there is a method in which a propylene polymer, the unsaturated compound having a functional group and the radical initiator are dissolved in an organic solvent and heated. Still another method is a method of copolymerizing or graft-polymerizing a propylene-based polymer during production.

The radical initiator used in the above modification includes diculumi peroxide, benzoyl peroxide, di-tert-butyl peroxide, 2,5
-Dimethyl-2,5-di (tertiary-butylperoxy)
Organic peroxides such as hexane, 2,2'-vir (t-butylperoxyisopropyl) benzene, and tertiary-butylperoxybenzoate. The amount of the radical initiator is not particularly limited, but is preferably 0.001 to 1 with respect to 100 parts by weight of the propylene polymer.
0.0 parts by weight.

(C) Ethylene / α-olefin copolymer rubber The ethylene / α-olefin copolymer rubber compounded in the surface coating layer of the sandwich resin molded product of the present invention is preferably not substantially crystalline. It is a copolymer rubber of at least ethylene and α-olefin having at most 6 carbon atoms. As the α-olefin, propylene and butene-1 are preferred. The copolymer rubber may be a copolymer of ethylene and the α-olefin, and further contains ethylene and propylene as main components and copolymerizes a small amount (generally, 10% by weight or less) of a monomer described below. A multi-component copolymer rubber obtained by the above method may be used. Such monomers include linear or branched chains containing two double bonds at the terminal such as 1,4-pentadiene, 1,5-hexadiene and 3,3-dimethyl-1,5-hexadiene. Linear or branched diolefins having only one double bond at the terminal, such as diolefins, 1,4-hexadiene and 6-methyl-1,5-heptadiene, or bicyclo [2,2,1] -heptene- And cyclic diene hydrocarbons such as 2 and its derivatives.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the ethylene / α-olefin copolymer rubber is generally from 10 to
140, preferably 15 to 130, particularly 2
0-120 is preferred. If the Mooney viscosity is less than 10, the moldability is improved, but not only the effect of improving the impact resistance is low, but also delamination may occur when the molded product is gate-cut. On the other hand, Mooney viscosity is 1
When a material exceeding 40 is used, not only dispersion during kneading is difficult, but even if a uniform composition is obtained, the surface of the obtained molded article has noticeable flow marks and weld lines. It is not preferable because the appearance is inferior.

The copolymerization ratio of propylene in the ethylene / α-olefin copolymer is preferably from 20 to 70% by weight, more preferably from 20 to 60% by weight, particularly preferably from 20 to 60% by weight.
~ 55% by weight is preferred. When a copolymer rubber having a copolymerization ratio of propylene of less than 20% by weight is used, the resulting composition may have poor heat resistance, and the effect of improving impact resistance may not be sufficient. When the polymerization ratio exceeds 70% by weight, the rigidity of the composition is insufficient, and there is a possibility that a problem may occur in the resulting molded article in terms of scratch resistance.

(D) Oligomers Having a Functional Group at the Terminal The oligomers having a functional group at the terminal in the present invention are:
An oligomer which is a liquid rubber or waxy solid and has a functional group at at least one terminal in one molecule. Here, the functional group includes a hydroxy group, an amino group, a carboxyl group, an epoxy group, a thiol group, and the like, and may include two or more of these as long as they do not react with each other. Among these, it is desirable to include a hydroxy group or an amino group in view of affinity with the urethane paint.

The oligomer having a functional group at the terminal has a number average molecular weight of 10,000 or less, preferably 8,000.
0 or less, more preferably 6,000 or less. Note that the lower limit is about 1,500. Number average molecular weight is 1
If it exceeds 000, no improvement in the paintability is observed and the effect of addition is not obtained.

As the oligomer having a functional group at the terminal, those having an unsaturated bond therein are generally available at low cost. Iodine value of the oligomer (100 g oligomer)
The number of g of iodine added therein) is preferably 0 or more and 50 or less, more preferably 0 or more and 30 or less, and even more preferably 0 or more and 10 or less. When the iodine value is lower, the adhesive strength between the resin composition molded article of the present invention and the urethane paint is excellent, and particularly, even in a region where the peeling speed is high, good coating film adhesion is exhibited.

These oligomers having a functional group at the terminal can be used singly or as a mixture of two or more. Specific examples of the oligomer having a functional group at the terminal in the present invention include polybutadiene (the polymerization mode may be either 1,2- or 1,4-, and in the latter case, the double bond may be either cis or trans. Polyisoprene, isobutylene-isoprene copolymer (butyl rubber), polybutane, butadiene-acrylonitrile copolymer, styrene-butadiene copolymer (either block or random), petroleum resin, and An oligomer which is partially or completely hydrogenated and has a number average molecular weight of 10,000 or less and having a functional group at at least one terminal in one molecule.

The oligomer having a terminal functional group can be produced by a known method. Hydroxy-terminated hydrogenated 1,4-polybutadiene (trade name: Polytail H, manufactured by Mitsubishi Chemical Corporation)
Polytail HA, hydroxy-terminated hydrogenated polyolefin manufactured by Idemitsu Petrochemical Co., Ltd. Epol, hydroxy-terminated 1,2-polybutadiene manufactured by Nippon Soda Co., Ltd. Nisso-PBG-1000, hydroxy group manufactured by Nippon Soda Co., Ltd. Terminal hydrogenated 1,2-polybutadiene NiSSO-PB GI-1000 trade name, Ube Industries, Ltd. amino group terminal acrylonitrile-butadiene rubber Hycar-ATBN trade name, etc. are easily available,
It can be suitably used.

(E) Inorganic Filler The inorganic filler optionally added to the surface layer of the molded article of the present invention is widely used in the field of general synthetic resins and rubbers. As such an inorganic filler, an inorganic compound which does not react with oxygen and water and which does not decompose during kneading and molding is preferably used. Such inorganic fillers, for example, aluminum, copper,
Oxides of metals such as iron, lead, nickel, magnesium, calcium, barium, zinc, zirconium, molybdenum, silicon, antimony and titanium, hydrates (hydroxides), sulfates, carbonates and silicates Such compounds, double salts thereof, and mixtures thereof are roughly classified.

Of these inorganic fillers, the powdery ones have a diameter of 30 μm or less (more preferably 10 μm or less).
Are preferred. For fibrous materials, the diameter is 0.1
２０20 μm (more preferably 0.1 to 15 μm),
The length is 1.0 to 150 μm (more preferably, 1.0 to 10 μm).
0 μm) is preferred. Further, it is preferable that the flat plate has a diameter of 30 μm or less (more preferably 10 μm or less). Of these inorganic fillers, talc, mica, clay, wollastonite, potassium titanate, calcium carbonate and the like are preferred.

Composition Ratio The surface layer constituting the sandwich resin molded product of the present invention comprises:
A composition comprising the propylene polymer (A), the modified propylene polymer (B), the ethylene / α-olefin copolymer rubber (C) and the oligomer having a functional group at the terminal (D), or a high molecular weight thereof; It is composed of a composition in which a substance and an inorganic filler are uniformly mixed.

The proportion of the component (A), ie, the propylene polymer (A), in the composition constituting the surface layer of the sandwich resin molded product of the present invention is 30 to 80% by weight, preferably 35 to 75% by weight. Particularly preferably 40 to 75% by weight
It is. If the proportion of the propylene-based polymer in the composition is less than 30% by weight, the rigidity of the obtained surface layer is lowered, which is not preferable. Is not preferred because it falls.

The component (B) occupying in the composition constituting the surface layer of the present invention, that is, the composition ratio of the modified propylene polymer is 5.0 to 50% by weight, preferably 5.0 to 40% by weight. And particularly preferably 7.0 to 40% by weight. If the composition ratio of the modified propylene polymer in the composition is less than 5.0% by weight, the coatability of the obtained surface layer is not good. Conversely, even if it is more than 50% by weight, depending on the amount used, Not only is it not possible to exert the effect of improving the coating properties and weather resistance, but also the mechanical strength of the resulting composition tends to decrease, which is not preferred.

The composition of the component (C), ie, the ethylene / α-olefin copolymer rubber, to be incorporated in the composition constituting the surface layer of the present invention is 15 to 40% by weight, preferably 1 to 40% by weight.
It is 5 to 35% by weight, particularly preferably 18 to 35% by weight. When the composition ratio of the component (C) is less than 15% by weight, the improvement in impact resistance at low temperatures is not satisfactory. On the other hand, when it exceeds 40% by weight, the rigidity and heat resistance of the composition are reduced and the flow during molding is reduced. It is not preferable because it tends to cause marks.

The component (D) occupying in the composition constituting the surface layer of the present invention, that is, the composition ratio of the oligomer having a functional group at a terminal is 0.1 to 20% by weight, and 0.5 to 20% by weight. Is preferred, and particularly preferably 0.5 to 15% by weight.
When the composition ratio of the component (D) is less than 0.1% by weight, no improvement in coating adhesion, particularly gasohol resistance is observed. Conversely 20
If the amount is more than 10% by weight, the mechanical strength of the obtained molded product is undesirably reduced.

The composition ratio of the inorganic filler arbitrarily compounded in the composition constituting the surface layer of the present invention is usually the same as that of the components (A), (B), (C) and (D). Is at most 20 parts by weight, based on 100 parts by weight of
Less than parts by weight is preferred. When this composition ratio exceeds 20 parts by weight, not only the appearance of the obtained molded product is poor, but also
Poor paintability when painting on the surface. The effect of improving the rigidity and heat resistance of the surface layer obtained by blending the inorganic filler is obtained. In order to obtain such effects, the components (A), (B), (C) and (D) It is preferable to add 1.0 part by weight or more to the total amount of 100 parts by weight.

Core Material The core material of the sandwich resin molded product of the present invention is a scrap resin (hereinafter referred to as “recycled resin”) of the propylene polymer or the recovered polypropylene resin molded product.
Or, it is composed of a resin composition containing it as a main component. The MFR of this propylene-based polymer or recycled resin is 1.
0 to 80 g / 10 min is preferable, and 2.0 to 60 g / 10 min.
Is more preferred. If the MFR is less than 1.0 g / 10 minutes, the kneadability and moldability tend to be inferior, and if it exceeds 80 g / 10 minutes, the mechanical properties, especially impact resistance, of the molded article tend to be inferior.

The recycled resin is a recycled material of a polypropylene resin molded product. In particular, a recycled material of a molded product having a urethane or acrylic colored resin coating film on its surface can be used. Things can of course be used. The amount of the colored resin coating film derived from the urethane or acrylic paint in the recycled material constituting the core material is preferably 10% by weight or less, more preferably 8% by weight or less. If the mixing ratio of the resin coating film exceeds 10% by weight, the molded article tends to have poor impact resistance, which is not preferable.

The core material in the present invention is composed of only the propylene polymer or the recycled resin, or is composed of a composition containing these as main components, that is, at least 50%. In the latter case, the remainder can be an ethylene / α-olefin copolymer or an inorganic filler constituting the surface layer.

The core material of the present invention has a flexural modulus (ASTM D
690) is more than 10,000 kg / cm ² , particularly preferably more than 11,000 kg / cm ² . If the flexural modulus is less than 10,000 kg / cm ² , the effect of improving heat resistance is not sufficient. In addition, Izod impact strength (ASTM
Notched according to D256, measured at 23 ° C)
Is not less than 5.0 kg · cm / cm, especially 6.0 kg · cm
/ Cm or more is desirable. Izod impact strength is 5.
If it is less than 0 kg · cm / cm, the impact resistance is significantly reduced, which is not preferable.

When the composition comprising the propylene-based polymer or recycled resin has a flexural modulus and an Izod impact strength within the above ranges, it can be used as it is. When higher physical properties are desired, the ethylene / α-olefin copolymer and the inorganic filler may be blended in a range of less than 50%.

Method for Producing the Composition In the molded article of the present invention, when the above-described composition is used for producing the surface layer and the core material, the respective components may be uniformly mixed. The parts may be mixed in advance to produce a so-called masterbatch, and the masterbatch and the remaining components may be mixed. In this case, a UV absorber, an antioxidant, a weather resistance stabilizer, a plasticizer, a lubricant, an antistatic agent, a colorant (pigment), etc. which are generally added in the field of polyolefin resin (particularly, polypropylene resin). Additives may be added in a range that does not substantially impair the substance of each composition or synthetic resin.

In order to produce the composition used in the present invention, a method generally used in the field of synthetic resins may be applied. Examples of the mixing method include a method of dry blending using a mixer such as a Henschel mixer and a method of melt-kneading using a mixer such as a roll mill, a screw type extruder, a kneader and a Banbury mixer. At this time, a more uniform composition can be obtained by dry blending the composition components in advance and further melting and kneading the resulting mixture. The composition is preferably in the form of pellets in terms of handling when producing a molded product described below.

Molding Method The molded article of the present invention can be molded by a so-called sandwich molding method generally practiced in the field of synthetic resins, for example. Sandwich molding method,
As described above, the material of the surface layer is injected, the material of the core material is subsequently injected, and finally a small amount of the material of the surface layer is injected into the gate portion. This sandwich molding method is described in "Mulder Series, Latest Injection Molding Technology-Its Practice and Application-", edited by Akira Hiroe (1988, published by Sanko Shuppan Co., Ltd.), No. 137.
Pp. 144-144.

In the case of the above-mentioned melt-kneading and in the case of sandwich molding, it is necessary to carry out at a temperature at which the polymer material such as a propylene polymer to be used is melted. However, when carried out at a high temperature, the polymer material used may be thermally decomposed. Although the melt-kneading temperature and the injection molding temperature cannot be specified unconditionally depending on the type and composition ratio of each material used for the surface layer and the core material, it is generally 180 to 300 ° C, preferably 190 to 280 ° C. is there.

Molded Article The molded article of the present invention obtained as described above is substantially covered with a surface layer over the entire surface of the core material.
The thickness of the surface layer with respect to the thickness 100 of the core material is 100 or less, particularly preferably 80 or less. Core thickness 10
If the thickness of the surface layer with respect to 0 exceeds 100, not only the rigidity of the obtained molded product is not good but also the heat resistance is insufficient. The thickness of all surface layers is 0.2
mm or more, more preferably 0.3 mm or more, and particularly preferably 0.5 mm or more. If the thickness of all the surface layers is less than 0.2 mm, it may be difficult to cover the entire surface of the core material of the obtained molded product,
In addition, the impact resistance and cold impact resistance of the molded product may be insufficient.

The feature of the molded article of the present invention is that not only the surface layer can be coated with a paint such as a polyurethane paint without special pretreatment or primer treatment,
A method for molding a material having good gasohol resistance when using a primer, a polymer composition having extremely high impact resistance, good adhesion between a core material and a surface layer, and high rigidity as described above. It has a so-called sandwich structure, and cannot be generally obtained with commonly used polypropylene-based resin blend materials. Polyurethane-based paint without special pretreatment or primer treatment In addition to being able to apply the paint, it was possible to obtain a product that had good gasohol resistance when using a primer without special pretreatment, and that had a balance between impact resistance and heat resistance. It is. If the material used for the surface layer and the material used for the core material are reversed, it is not possible to obtain a material having a sufficient balance of paintability, impact resistance and heat resistance. The reason for this is that the physical properties of the surface layer dominate the impact resistance and heat resistance rigidity of the sandwich molded article.

[0051]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but it goes without saying that the scope of the present invention is not limited to these Examples. In Examples and Comparative Examples, the flexural modulus was ASTM D79.
According to 0, the bending speed is measured under the condition of 2.5 mm / min,
Further, the heat distortion temperature was measured under a load of 4.6 kg / cm ² according to ASTM D648. Furthermore, the impact strength is measured with a high-speed impact tester [ROMEME
TRIC) Model Impact Tester (Impac)
t tester) -8000] and the impact velocity is 5
m / sec, diameter of tip of hammer 1/2 inch, sample receiving jig diameter 2.5 inches, sample size 100 × 10
The fracture energy was obtained from a stress-strain curve obtained when an impact test was performed under the conditions of 0 mm, the same thickness of 6 mm, and the measurement temperature of -30 ° C., and displayed.

Further, a cross-cut test was conducted on a flat molded product (4
Polyurethane paint (Nippon Bee Chemical Co., Ltd., trade name R255, metallic red) is applied to the surface of 00 × 200 mm, thickness 6 mm so that the thickness when dried becomes 20 to 30 μm, and left for about 15 minutes, The coating was dried at 90 ° C. for 30 minutes, and then left in a constant temperature room (temperature 23 ° C., humidity 55%) for 48 hours to obtain a coated product. On the coating surface of the obtained coating material, 100 grids were cut at 1 mm intervals, and the adhesive tape was completely adhered to the grid by finger pressure, and the adhesive tape was rapidly peeled off at an angle of 45 degrees. The operation was repeated twice, and the ratio of the cross section of the remaining coating film was determined.

In Examples and Comparative Examples, (A) to (A) were used as the surface layer (skin layer) and the core material (core layer).
Physical properties of the polymer (E) and the inorganic filler are shown below. In the gasohol resistance test, a primer (Nippon Bee Chemical Co., Ltd., trade name: RB291) was applied to the flat molded product.
Is applied so as to have a thickness of 15 to 20 μm, left for about 10 minutes, dried at 80 ° C. for 30 minutes, and then coated with a polyurethane paint (Nippon Bee Chemical Co.,
R255 Metallic Red (trade name) was applied and dried to obtain a coated product. The obtained coating material was cut into strips of 30 × 65 mm so as to have an equal cross section, and immersed in gasohol (gasoline 90% by volume, ethyl alcohol 10% by volume) at room temperature for 60 minutes to recoat the coating. Was observed.

(A) Propylene-based polymer MFR is 15 g / 10 min, and ethylene content is 8.
8% by weight of a propylene / ethylene block copolymer [hereinafter referred to as “PP (1)”] and an MFR of 20 g /
Propylene homopolymer [hereinafter referred to as “PP”
(2) "] and a propylene / MFR having an MFR of 17 g / 10 min and an ethylene content of 3.1% by weight.
An ethylene random copolymer [hereinafter referred to as “PP (3)”] was used.

(B) Ethylene / α-olefin copolymer rubber Mooney viscosity (ML _{1 + 4} , 100 ° C., hereinafter the same) is 36.
And an ethylene / propylene copolymer rubber having a propylene copolymerization ratio of 38% by weight (hereinafter referred to as “EPR”).
(1) "and an ethylene / propylene copolymer rubber having a Mooney viscosity of 60 and a copolymerization ratio of propylene of 27% by weight (hereinafter referred to as" EPR (2) ").

(C) Modified propylene polymer 100 parts by weight of a propylene homopolymer having an MFR of 0.5 g / 10 min, 2,5-dimethyl-2,5-di (tert-butyl-peroxy) hexane 0.011 part by weight and 0.375 part by weight of maleic anhydride were added to a Henschel mixer and dry blended for 5 minutes. The obtained mixture is supplied to a non-vent type extruder (diameter 40 mm) equipped with a full flight type screw, and a kneading reaction is performed while melting in a temperature range of 220 to 240 ° C. to obtain a modified olefin resin [hereinafter referred to as “modified resin ( 1) ").

The same propylene polymer as described above was used, and 0.05 parts by weight of benzoyl peroxide and 5 parts by weight of glycidyl methacrylate were added to a Henschel mixer for 100 parts by weight, and dry blending was performed for 5 minutes. went. This is supplied to the extruder, and 170-1
A kneading reaction is carried out while melting in a temperature range of 90 ° C. to obtain a modified olefin resin [hereinafter referred to as “modified resin (2)”].
Was manufactured.

To 85 parts by weight of a propylene homopolymer having an MFR of 0.5 g / 10 min and 15 parts by weight of an ethylene / α-olefin copolymer rubber having a Mooney viscosity of 20 were added 0.5 parts by weight of 2,2-bis ( t-Butylperoxyisopropyl) benzene and 4 parts by weight of 2-hydroxyethyl methacrylate were added to a Henschel mixer and dry blended for 5 minutes. The extruder temperature is 170-200.
A modified olefin-based resin (hereinafter referred to as "modified resin (3)") was produced at a temperature of 550C.

1 part by weight of dicumyl peroxide and 5 parts by weight were added to 85 parts by weight of a propylene homopolymer having an MFR of 0.5 g / 10 min and 15 parts by weight of an ethylene / α-olefin copolymer rubber having a Mooney viscosity of 20. Of N, N'-dimethyl-2-aminoethyl methacrylate was added to a Henschel mixer and dry blended for 5 minutes. This was used to produce a modified olefin-based resin [hereinafter referred to as “modified resin (4)”] at an extruder temperature of 165 to 200 ° C. as described above.

(D) Oligomers having a functional group at the terminal wax-like hydrogenated hydrogenated 1,4-polybutadiene at both ends, 1,4-bond 80%, number average molecular weight 2,80
0, an iodine value of 1.5, and an average number of hydroxy groups of 2.3 (hereinafter referred to as "oligomer (1)").

Both ends aminated butadiene-nitrile rubber, acrylonitrile content 16.5%, number average molecular weight 4,000, iodine value 330, amine equivalent 900 (hereinafter referred to as "oligomer (2)").

(E) Inorganic Filler As an inorganic filler, talc having an average particle size of 2.0 μm and an aspect ratio of 5.0, and an average particle size of 0.5
μm light calcium carbonate (hereinafter “CaCO
₃ (1) ”), mica having an average particle size of 5.0 μm was used.

(F) Core Material The core material may include, as another synthetic resin mixed with the above-mentioned surface layer other than the same polymer, several types of polypropylene bumpers recovered from end-of-life vehicles (different in shape, painted and unpainted) Was mixed as a recycled material (hereinafter referred to as a recycled material (A)). When its physical properties were confirmed, the MFR was 9.0 g / 1.
The bending elastic modulus was 9,000 kg / cm ² and the Izod impact strength was 45 kg / cm ² . Further, 0.9% by weight of the urethane-based coating film was mixed in the recycled material (A).

A padless instrument panel (a type in which PVC leather and foam were not bonded) collected from a scrap car was pulverized by a pulverizer and used as a recycled material (hereinafter referred to as a recycled material (B)). When its physical properties were confirmed, the MFR was 10.3 g / 10 min, the flexural modulus was 23,500 kg / cm ² , and the Izod impact strength was 6.4 kg · cm / cm ² . In addition, 0.4% by weight of an acrylic paint film is contained in the recycled material (B).
Was mixed in.

The talc (average particle size is 2.0 μm and aspect ratio is 5.0) is added to the recycled material (A).
After dry blending, 20% by weight was melt-kneaded using a screw extruder and used as a recycled material (hereinafter referred to as a recycled material (D)). When its physical properties were confirmed, the MFR was 7.3 g / 10 min, the flexural modulus was 16,500 kg / cm ² , and the Izod impact strength was 3
It was 5 kg · cm / cm ² . Further, 0.7% by weight of a urethane-based coating film was mixed in the recycled material (C).

The respective polymers and inorganic fillers shown in Table 1 were mixed and dry blended in advance using a Henschel mixer for 5 minutes, and the resulting mixtures were biaxially vented at a resin temperature of 200 ° C. Melt kneading was carried out using an extruder (diameter 30 mm) to produce pellet-shaped compositions. Table 1 shows abbreviations of the obtained compositions. Each composition was used as a surface layer of a molded article described below.

Further, the respective components shown in Table 2 are shown in Table 2 by dry blending in the same manner as described above.
Each mixture was prepared. Each of the obtained mixtures was melt-kneaded in the same manner as described above (the resin temperature varies depending on the type and amount of the composition components) to produce each of the pellet-shaped composition components. Table 2 shows the MFR, flexural modulus, Izod impact strength (with notch), and abbreviations of the obtained compositions. Each composition component was used as a core material of a molded product described below.

Examples 1 to 12 and Comparative Examples 1 to 7 Tables 3 and 4 show the types of the respective compositions. Each composition obtained as described above was sandwiched with a sandwich injection molding machine [Battenfeld, West Germany].
d), model BM850S-C], the material of the surface layer is injection-molded first, then the material of the core material is injection-molded, and then the material of the surface layer (about 2% of the surface layer) is injection-molded. And
A flat molded product (400 × 200 mm, thickness 6 mm) was molded. A sample was cut out from the obtained molded product, and the flexural modulus, heat deformation temperature, fracture energy, and grid test were measured. The results are shown in Tables 3 and 4. further,
Tables 3 and 4 show the thickness of the surface layer of each molded product.

[0069]

[Table 1]

[0070]

[Table 2]

[0071]

[Table 3]

[0072]

[Table 4]

[0073]

As described above, the molded article of the present invention has the following effects. (1) Adhesion with paints such as polyurethane paints, that is, paintability is excellent. (2) Gasohol resistance after coating is excellent. (3) Excellent impact resistance (particularly impact resistance at low temperatures). (4) Good heat resistance. (5) Excellent rigidity (flexural modulus). (6) In particular, when molded using the same type of material as compared with a molded product obtained by a commonly used injection molding method, the molded article has higher impact resistance (including low-temperature impact resistance), heat resistance and rigidity. The balance is excellent. In particular, the physical properties of heat resistance and impact resistance are well balanced. (7) Since the core material can be highly filled with the inorganic filler, the dimensional accuracy is excellent.

The molded product of the present invention can be used in various fields to exhibit the above effects. Typical applications are as follows. (1) Automotive exterior parts such as bumpers, bumper aprons, spoilers, side moldings, and side air dams. (2) Motorcycle parts such as front fenders and body covers.

Continued on the front page (72) Inventor Koichi Tajima 3-2 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Showa Denko KK Kawasaki Resin Research Laboratory (72) Inventor Akira Ko Katagiri 3- Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa 2 Showa Denko Co., Ltd. Examiner at Kawasaki Resin Laboratory Hiroaki Hirai (56) References JP-A-6-305097 (JP, A) JP-A-7-26044 (JP, A) JP-A-6-145436 (JP, A) JP-A-6-145440 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (3)

(57) [Claims] 1. A molded article comprising a core material and a surface layer substantially covering the entire surface of the core material, wherein the surface layer comprises: (A) 30 to 80% by weight of a propylene polymer (B A) a modified propylene polymer of 5 to 50% by weight; (C) an ethylene-α-olefin copolymer rubber of 15 to 40% by weight; and (D) a functional group-terminated oligomer of 0.1 to 20% by weight. Wherein the core material is composed of a composition containing a propylene polymer having a flexural modulus of 10,000 kg / cm ² or more and an Izod impact strength of 5.0 kg · cm / cm ² or more as a main component. Sandwich resin molded product. 2. The method according to claim 1, wherein the surface layer comprises the components (A), (B),
The sandwich resin molded product according to claim 1, comprising a composition containing (E) an inorganic filler in an amount of 20 parts by weight or less based on 100 parts by weight of the total amount of (C) and (D). 3. The modified propylene-based polymer is obtained by modifying a propylene-based polymer with an unsaturated compound having at least one functional group selected from a carboxyl group, a hydroxyl group, an amino group, and an epoxy group. 3. The sandwich resin molded product according to 1 or 2.