JP6189048B2 - Complex - Google Patents

Description

  The present invention relates to a composite in which a painted metal preform and a molded body of a thermoplastic resin composition are joined, and a method for producing the same.

  Metal plates and their press-molded products, or so-called “metal shapes” formed by casting, forging, cutting, powder metallurgy, etc., are indispensable members for manufacturing all industrial products including automobiles. is there. The composite in which the metal base material and the molded body of the resin composition are joined is lighter than a component made of only metal, but has a higher strength than a component made only of resin, such as a mobile phone or a personal computer. Used in electronic equipment. Conventionally, such a composite has been manufactured by fitting a metal base material and a molded body of a resin composition. However, the method for producing a composite by fitting has a large number of work steps and has low productivity. Therefore, in recent years, it is common to manufacture a composite by joining a metal base material and a molded body of a resin composition by insert molding.

  When producing a composite by insert molding, it is important to improve the adhesion between the metal base material and the molded body of the resin composition. As a method for improving the adhesion between the metal shaped material and the molded body of the resin composition, for example, it is proposed to roughen the surface of the metal shaped material before performing insert molding (patent) References 1-3). In the method of patent documents 1-3, the adhesiveness of the aluminum alloy and the molded object of a resin composition is improved by roughening the surface of an aluminum alloy.

JP 2006-027018 A JP 2004-050488 A JP 2005-342895 A

  In the composites described in Patent Documents 1 to 3, the surface of the metal base material is roughened in order to use the anchor effect. As described above, if fine irregularities are formed on the surface of the metal base material for the purpose of anchor effect, a fine gap is likely to be formed between the metal base material and the molded body of the resin composition. For this reason, in the composites described in Patent Documents 1 to 3, the resin composition may not be bonded to the metal base material with sufficient bonding strength.

  This invention is made | formed in view of this point, and an object of this invention is to provide the composite_body | complex with which the molded object of the thermoplastic resin composition is integrated with sufficient high intensity | strength with the metal raw material.

  The inventors of the present invention have joined the metal base material and the thermoplastic resin composition via the organic resin layer, and the degree of expansion and contraction due to heat at the time of molding the metal base material and the thermoplastic resin composition. The present invention has been completed with further consideration.

That is, the present invention relates to the following composites.
[1] Thermoplastic resin composition bonded to a surface of the metal base material and the surface of the paint metal base material by injection molding or thermocompression bonding, and a metal base material and an organic resin layer disposed thereon The organic resin layer contains acid-modified polypropylene, and the molding shrinkage of the thermoplastic resin composition is 1.1% or less, and the linear expansion coefficient of the metal base material The composite, wherein the ratio αp / αm of the linear expansion coefficient αp of the thermoplastic resin composition to αm is 6 or less.
[2] The organic resin layer contains 40% by mass or more of acid-modified polypropylene with respect to the mass of the total resin in the organic resin layer, and the thickness of the organic resin layer is 0.2 μm or more. 1].

Moreover, this invention relates to the manufacturing method of the following composites.
[3] It has a metal base material and a painted metal base material having an organic resin layer disposed thereon, and a molded body of a thermoplastic resin composition bonded to the surface of the paint metal base material. A method for producing a composite, comprising the step of joining a molded body of the thermoplastic resin composition to the surface of the organic resin layer by injection molding or thermocompression bonding, wherein the organic resin layer comprises acid-modified polypropylene. The thermoplastic resin composition has a molding shrinkage of 1.1% or less, and the ratio αp / αm of the linear expansion coefficient αp of the thermoplastic resin composition to the linear expansion coefficient αm of the metal base material is The manufacturing method of the composite_body | complex which is 6 or less.
[4] The organic resin layer includes 40% by mass or more of acid-modified polypropylene with respect to the total resin mass in the organic resin layer, and the thickness of the organic resin layer is 0.2 μm or more. [3] The method for producing the composite according to [3].

  ADVANTAGE OF THE INVENTION According to this invention, the composite body with which the metal raw material and the molded object of the thermoplastic resin composition are integrated with sufficient high intensity | strength through an organic resin layer can be provided.

It is a figure which shows roughly an example of the composite_body | complex which concerns on this invention.

1. Composite The composite according to the present invention has a painted metal shape material and a molded body of a thermoplastic resin composition bonded to the surface thereof. Hereafter, each component of the composite_body | complex which concerns on this invention is demonstrated.

(1) Painted metal shape material The painted metal shape material has a metal shape material and an organic resin layer disposed on the surface of the metal shape material. Hereinafter, each component of the painted metal shape material will be described.

(Metal element)
The kind of metal which comprises a metal raw material is not specifically limited. For example, the metal may be iron, a metal other than iron, or an alloy. Examples of the metal base material include cold-rolled steel sheet, galvanized steel sheet, Zn-Al alloy plated steel sheet, Zn-Al-Mg alloy plated steel sheet, aluminum plated steel sheet, stainless steel sheet (austenite, martensite, ferrite, (Including ferrite and martensite two-phase systems), metal plates such as aluminum plates, aluminum alloy plates and copper plates, press-formed products thereof, castings and forgings such as aluminum die-casting and zinc die-casting, cutting, powder metallurgy These include various metal members formed by, for example. The metal shaped material may be subjected to known coating pretreatments such as degreasing and pickling as necessary.

(Chemical conversion coating)
A chemical conversion treatment film may be disposed between the metal base material and the organic resin layer. The chemical conversion treatment film is disposed on the surface of the metal base material, and improves the adhesion between the metal base material and the organic resin layer and the corrosion resistance of the painted metal base material. The chemical conversion coating may be disposed at least in a region (joint surface) to be joined to the molded body of the thermoplastic resin composition in the surface of the metal raw material, but usually on the entire surface of the metal raw material. Has been placed.

The kind of chemical conversion treatment which forms a chemical conversion treatment film is not specifically limited. Examples of the chemical conversion treatment include chromate treatment, chromium-free treatment, phosphate treatment and the like. The adhesion amount of the chemical conversion film formed by the chemical conversion treatment is not particularly limited as long as it is within a range effective for improving coating film adhesion and corrosion resistance. For example, in the case of a chromate film, the adhesion amount may be adjusted so that the total Cr conversion adhesion amount is 5 to 100 mg / m ² . In the case of a chromium-free film, the amount of adhesion is 10 to 500 mg / m ² for a Ti-Mo composite film, and the amount of adhesion in terms of fluorine or the total metal element in terms of adhesion in a fluoroacid-based film is 3 to 100 mg / m ^2. Can be adjusted. Moreover, what is necessary is just to adjust the adhesion amount of each chemical conversion treatment film so that it may become 0.1-5 g / m < ² > in the case of a phosphate membrane | film | coat.

(Organic resin layer)
The organic resin layer is disposed on the surface of the metal base material (or chemical conversion film). The organic resin layer improves the adhesion between the metal base material and the molded body of the thermoplastic resin composition.

  The organic resin layer contains acid-modified polypropylene. The acid-modified polypropylene is a polypropylene in which a carboxyl group or an anhydride group thereof is introduced into a structural unit of polypropylene. Since the acid-modified polypropylene has a functional group that forms a hydrogen bond with the metal base material such as a carboxyl group, the acid-modified polypropylene has sufficient adhesion to both the metal base material and the molded body of the thermoplastic resin composition. The acid-modified polypropylene may further have other functional groups that hydrogen bond to the metal base material other than the carboxyl group.

  The content of the acid-modified polypropylene is 40% by mass or more with respect to the total resin in the organic resin layer, from the viewpoint of improving the adhesion between the coated metal shape material and the molded body of the thermoplastic resin composition To preferred. When the acid-modified polypropylene content in the organic resin layer is less than 40% by mass, the compatibility between the organic resin layer and the molded article of the thermoplastic resin composition may be lowered. Thereby, there exists a possibility that the joining force of the coating metal shape material and the molded object of a thermoplastic resin composition may not be obtained. The upper limit of the content of the acid-modified polypropylene is not particularly limited.

  The acid value of the acid-modified polypropylene is preferably 1 to 500 mgKOH / g. If the acid value of the acid-modified polypropylene is within the above range, the acid-modified polypropylene itself acts as a surfactant by neutralizing the acid-modified polypropylene when preparing the emulsion described later.

  The acid-modified polypropylene preferably has a melting point in the range of 60 to 120 ° C. and a crystallinity in the range of 5 to 20%. Since the acid-modified polypropylene having a melting point and a crystallinity within the above ranges have high wettability with respect to the surface of the metal base material, an organic resin layer is formed in close contact with the irregularities on the surface of the metal base material. When the melting point of the acid-modified polypropylene is less than 60 ° C. or the crystallinity is less than 5%, the organic resin layer is softened at a relatively low temperature, so that the blocking resistance of the coated metal shaped material may be inferior during storage. There is. On the other hand, when the melting point of the acid-modified polypropylene exceeds 120 ° C. or the degree of crystallinity exceeds 20%, the bondability between the painted metal preform and the molded body of the thermoplastic resin composition may be lowered. Note that the melting point and crystallinity of the acid-modified polypropylene hardly change between the state contained in the paint (before baking) and the state of the organic resin layer (after baking). Therefore, the degree of crystallinity of the acid-modified polypropylene in the organic resin layer can be examined by measuring a later-described coating material containing the acid-modified polypropylene by X-ray diffraction by the Ruland method.

  The acid-modified polypropylene can be prepared, for example, as an acid-modified polypropylene emulsion having acid-modified polypropylene as a dispersoid. The acid-modified polypropylene emulsion can be prepared by preparing an acid-modified polypropylene and then dispersing the acid-modified polypropylene in water. Various surfactants may be added as an emulsifier to the acid-modified polypropylene emulsion.

  Polypropylene is known for the stereoregularity of isotactic, tactic, syndiotactic, hemi-isotactic and stereotactic. The stereoregularity of polypropylene is preferably isotactic from the viewpoint of mechanical properties such as rigidity and impact strength required after molding or durability.

  The weight average molecular weight of polypropylene is preferably in the range of 1000 to 300,000, and more preferably in the range of 5000 to 100,000. When the weight average molecular weight of polypropylene is less than 1000, the strength of the organic resin layer may be reduced. On the other hand, when the weight average molecular weight of polypropylene is more than 300,000, the viscosity increases in the modification step described later, which may make the operation difficult.

  The acid modification of polypropylene is carried out by dissolving polypropylene in toluene or xylene, and in the presence of a radical generator, an α, β-unsaturated carboxylic acid and / or an acid anhydride of α, β-unsaturated carboxylic acid and / or 1 This can be done using compounds having one or more double bonds per molecule. Alternatively, using an apparatus capable of raising the temperature to the softening temperature or melting point of polypropylene, the α, β-unsaturated carboxylic acid and / or α, β-unsaturated in the presence or absence of a radical generator. Carboxylic acid anhydrides and / or compounds having one or more double bonds per molecule can be used. When the polypropylene modification reaction is carried out as a solution in an organic solvent such as toluene and / or xylene, or in a heterogeneous dispersion system carried out in a non-solvent such as an aqueous system, nitrogen substitution is sufficiently performed. There is a need. In this way, acid-modified polypropylene can be prepared.

  The types of radical generator include di-tert-butyl perphthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyethyl hexanoate, tert -Peroxides such as butyl peroxypivalate, methyl ethyl ketone peroxide and di-tert-butyl peroxide, and azonitriles such as azobisisobutyronitrile and azobisisopropionitrile are included. It is preferable that the compounding quantity of a radical generator exists in the range of 0.1-50 mass parts with respect to 100 mass parts of polypropylene. Moreover, it is particularly preferably within the range of 0.5 to 30 parts by mass.

  The types of α, β-unsaturated carboxylic acids or acid anhydrides include maleic acid, maleic anhydride, fumaric acid, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride Contains acid. These compounds may be used alone or in combination of two or more. When two or more compounds are used in combination, the physical properties of the organic resin layer are often improved.

  Compounds having one or more double bonds per molecule include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid- 2-hydroxyethyl, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, (Meth) acrylic acid benzyl, (meth) acrylic acid-2-hydroxybutyl, (meth) acrylic acid benzyl, (meth) acrylic acid glycidyl, (meth) acrylic acid, di (meth) acrylic acid (di) ethylene glycol, Di (meth) acrylic acid-1,4-butanediol, di (meth) acrylic acid-1,6-hexane (Meth) such as all, trimethylolpropane tri (meth) acrylate, glycerin di (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, acrylamide Acrylic acid monomers and styrene monomers such as styrene, α-methylstyrene, paramethylstyrene, and chloromethylstyrene are included. Furthermore, in addition to the above compounds, vinyl monomers such as divinylbenzene, vinyl acetate, and vinyl ester of versatic acid can be used in combination.

  These compounds having a double bond may be used alone or in combination of two or more. It is preferable that the compounding quantity of the compound which has these double bonds exists in the range of 0.1-50 mass parts with respect to 100 mass parts of polypropylene. Especially preferably, it exists in the range of 0.5-30 mass parts.

  Alternatively, the acid-modified polypropylene can be obtained as a commercial product. In addition, the presence of the acid-modified polypropylene in the organic resin layer can be confirmed by ordinary analytical equipment such as NMR, IR, and GC-MS.

  The acid-modified polypropylene may be cross-linked. The cross-linking of the acid-modified polypropylene can be performed by, for example, a cross-linking agent having two or more groups that react with a functional group (such as a carboxyl group) that forms a hydrogen bond with the metal base material in the acid-modified polypropylene. Crosslinking the acid-modified polypropylene is preferable from the viewpoint of improving the strength of the organic resin layer. As the crosslinking agent, a known crosslinking agent used for crosslinking of the acid-modified polypropylene can be used. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, a melamine crosslinking agent, or a crosslinking agent having a metal salt. The amount of the crosslinking agent used is appropriately determined within a range in which both the adhesiveness of the organic resin layer to the metal base material and the effect of crosslinking in the acid-modified polypropylene are obtained.

  The organic resin layer may further contain a resin other than the acid-modified polypropylene described above as long as the effect of the present invention is obtained. When the organic resin layer further contains such other resins, the resin component in the organic resin layer is heated when the molded body of the thermoplastic resin composition is injection-molded or thermocompression bonded to the painted metal shape material. It is more compatible with the plastic resin composition, and the organic resin layer and the thermoplastic resin composition are more strongly bonded. Therefore, it is preferable that the organic resin layer further contains the other resin from the viewpoint of improving the adhesion of the molded body of the thermoplastic resin composition to the organic resin layer. Such other resins are appropriately selected from known resins. Examples of other resins include polypropylene, polyurethane, acrylic resin, acrylic / styrene resin, vinyl acetate, EVA (ethylene-vinyl acetate copolymer resin), fluorine resin, ester resin, and olefins other than polypropylene. Resins, and combinations thereof are included. Content of the said other resin in an organic resin layer should just be a range with which the effect by the mixing | blending of said other resin is acquired, for example, is 0-150 mass parts with respect to 100 mass parts of said acid-modified polypropylene.

  Moreover, the organic resin layer may contain a rust preventive agent. The rust preventive agent improves the corrosion resistance of the painted metal preform and the composite according to the present invention. The kind of rust preventive agent is not specifically limited. Examples of the rust preventive agent preferably include an oxide, hydroxide or fluoride of a metal (valve metal) selected from the group consisting of Ti, Zr, V, Mo and W, or a combination thereof. By dispersing these metal compounds in the chemical conversion film, the corrosion resistance of the painted metal shaped material can be further improved. In particular, these metal fluorides can also be expected to suppress corrosion at film defects by a self-repairing action.

  The organic resin layer may further contain a soluble or hardly soluble metal phosphate or composite phosphate. The soluble metal phosphate or composite phosphate further improves the corrosion resistance of the metal base material by complementing the self-healing action of the metal fluoride. Further, the hardly soluble metal phosphate or composite phosphate is dispersed in the organic resin layer to improve its strength. For example, the soluble or poorly soluble metal phosphate or complex phosphate is a salt such as Al, Ti, Zr, Hf, Zn.

  The organic resin layer may contain a lubricant. The lubricant can suppress the occurrence of galling on the surface of the painted metal profile. The type of lubricant is not particularly limited. Examples of lubricants include organic waxes such as fluorine, polyethylene, styrene, and polypropylene, and inorganic lubricants such as molybdenum disulfide and talc. It is preferable that the compounding quantity of the lubricant in an organic resin layer is 1-20 mass parts with respect to 100 mass parts of total mass of resin in an organic resin layer. When the lubricant is less than 1 part by mass, the generation of galling may not be sufficiently suppressed. On the other hand, when the amount of the lubricant exceeds 20 parts by mass, no significant improvement is observed in the effect of suppressing the generation of galling, and the lubricity is too high and the handleability may be poor.

  The organic resin layer may contain an antifoaming agent. An antifoamer makes it difficult to generate bubbles when preparing a coating for an organic resin layer, which will be described later. The type of the antifoaming agent is not particularly limited, but an appropriate amount of a known silicone-based antifoaming agent may be added as necessary.

  The melting point of the resin composition constituting the organic resin layer is preferably equal to or lower than that of the molded body of the thermoplastic resin composition, and is preferably 60 to 160 ° C., for example. When the melting point of the resin composition is lower than 60 ° C., the organic resin layer is softened at a relatively low temperature, so that the blocking resistance of the coated metal shaped material may be insufficient. If the melting point of the resin composition is higher than 160 ° C., the bondability between the painted metal shape material and the molded body of the thermoplastic resin composition may be insufficient.

  The thickness of the organic resin layer is preferably 0.2 μm or more. When the thickness of the organic resin layer is less than 0.2 μm, the surface of the metal base material may not be uniformly covered. Thereby, the composite having an organic resin layer having a thickness of less than 0.2 μm may cause a fine gap between the metal base material and the molded body of the thermoplastic resin composition. If fine voids are generated, the sealing performance of the composite may be reduced. On the other hand, the upper limit of the thickness of the organic resin layer is not particularly limited, but is preferably 10 μm or less, and more preferably 3 μm or less. Even if the thickness of the organic resin layer exceeds 10 μm, no significant performance improvement is observed, and it is disadvantageous from the viewpoint of productivity and cost.

(2) Molded body of thermoplastic resin composition The molded body of the thermoplastic resin composition is bonded to the surface of the coated metal shaped material (the surface of the organic resin layer on the metal shaped material). The shape of the molded body of the thermoplastic resin composition is not particularly limited as long as it is a shape that is in contact with the joint surface described above in the painted metal base material, and may be appropriately selected depending on the application.

  Examples of the thermoplastic resin composition constituting the molded body include an amorphous resin composition such as a PVC (polyvinyl chloride) resin composition, a PMMA (methacrylic acid) resin composition, or PE (polyethylene). Crystalline resin compositions such as resin-based resin compositions, PP (polypropylene) -based resin compositions, POM (polyacetal) -based resin compositions, and combinations thereof are included. The shape of the molded article of the thermoplastic resin composition is not particularly limited and can be appropriately selected depending on the application.

  The molding shrinkage rate of the thermoplastic resin composition is 1.1% or less. The molding shrinkage of the thermoplastic resin composition can be adjusted by a known method. For example, the molding shrinkage rate can be adjusted by adding a filler or the like to a thermoplastic resin composition containing a thermoplastic elastomer. Further, the mold shrinkage can be adjusted by changing the mixing ratio of the crystalline resin and the amorphous resin.

The molding shrinkage rate (%) of the thermoplastic resin composition is the volume of the molten thermoplastic resin composition (for example, the volume of the thermoplastic resin composition having the melting point of the thermoplastic resin or the cavity of the injection mold). Va, when the volume of a thermoplastic resin composition (for example, a thermoplastic resin composition at room temperature (20 ° C.)) solidified by cooling from the molten state is represented by Vb, is obtained by the following formula.
{(Va−Vb) / Va} × 100

  When the molding shrinkage rate is larger than 1.1%, the molded body of the thermoplastic resin composition may not be sufficiently firmly bonded to the painted metal shape material. The molding shrinkage rate is preferably 0.9% or less and more preferably 0.7% or less from the viewpoint of further increasing the bonding strength of the molded body of the thermoplastic resin composition to the painted metal base material. preferable. For example, the molding shrinkage decreases when the filler content or the amorphous resin content in the thermoplastic resin composition is large.

  When the linear expansion coefficient of the thermoplastic resin composition is αp, the ratio αp / αm of the linear expansion coefficient αp of the thermoplastic resin composition to the linear expansion coefficient αm of the metal base material is 6 or less. When the ratio is greater than 6, the molded body of the thermoplastic resin composition may not be sufficiently firmly bonded to the painted metal shape material. The ratio αp / αm is preferably 4.5 or less from the viewpoint of further increasing the bonding strength of the molded body of the thermoplastic resin composition to the painted metal preform. αm and αp are determined by measuring the amount of dimensional change associated with the temperature change of the material, for example, by TMA (Thermal Mechanical Analysis). For example, αp decreases as the filler content in the thermoplastic resin composition increases.

  The thermoplastic resin composition may further contain components other than the organic resin as long as the effects of the present invention are obtained. Examples of such other components include fillers. It is preferable to add a filler to the thermoplastic resin composition from the viewpoint of adjusting the molding shrinkage of the thermoplastic resin composition and the linear expansion coefficient αp of the thermoplastic resin composition. Moreover, the rigidity of the molded object of a thermoplastic resin composition can be improved by mix | blending a filler with a thermoplastic resin composition.

  The thermoplastic elastomer improves the impact resistance of the molded article of the thermoplastic resin composition. The kind of thermoplastic elastomer is not particularly limited. Examples of thermoplastic elastomers include polyolefin resins, polystyrene resins, and combinations thereof.

  The filler reduces the molding shrinkage of the molded article of the thermoplastic resin composition and improves the rigidity. The kind of filler is not particularly limited, and a known substance can be used. Examples of fillers include fiber fillers such as glass fiber, carbon fiber, and aramid resin; carbon black, calcium carbonate, calcium silicate, magnesium carbonate, silica, talc, glass, clay, lignin, mica, quartz powder, glass sphere Powder fillers such as: pulverized carbon fiber or aramid fiber. A filler may be used independently and may be used in combination of 2 or more type. The filler content in the thermoplastic resin composition is preferably in the range of 5 to 60% by mass, more preferably in the range of 10 to 40% by mass.

  The molding shrinkage rate of the thermoplastic resin composition can also be adjusted by mixing a crystalline resin and an amorphous resin. Generally, the molding shrinkage rate of the crystalline resin is larger than the molding shrinkage rate of the amorphous resin. Therefore, if the mixing ratio of the amorphous resin to the crystalline resin is increased, the molding shrinkage rate of the thermoplastic resin composition can be decreased.

  The manufacturing method of the composite_body | complex which concerns on this invention is not specifically limited. For example, the composite according to the present invention can be produced by the method described below.

2. Method for Producing Composite The composite according to the present invention can be produced, for example, by a method including a step of joining a molded body of a thermoplastic resin composition to the surface of the organic resin layer by injection molding or thermocompression bonding. Such a method includes, for example, (1) a first step of preparing the above-mentioned coated metal preform, and (2) a heated thermoplastic resin composition in contact with the surface of the coated metal preform, And a second step of joining a molded body of the thermoplastic resin composition to the surface of the metal base material. Hereinafter, each step will be described.

(1) 1st process In the 1st process, the above-mentioned paint metal shape material is prepared. Prior to forming the organic resin layer of the painted metal shape material, a chemical conversion treatment film may be formed on the metal shape material. The chemical conversion treatment film can be formed by applying a chemical conversion treatment liquid to the surface of the metal base material and drying it. The method for applying the chemical conversion liquid is not particularly limited, and may be appropriately selected from known methods. Examples of such a coating method include a roll coating method, a curtain flow method, a spin coating method, a spray method, and a dip pulling method. What is necessary is just to set suitably the drying conditions of a chemical conversion liquid according to the composition of a chemical conversion liquid, etc. For example, the metal raw material coated with the chemical conversion treatment solution is put into a drying oven without being washed with water, and heated so that the ultimate temperature of the metal raw material becomes 80 to 250 ° C. A uniform chemical conversion coating can be formed on the surface.

  The painted metal element is produced by forming an organic resin layer on the surface of the metal element. The organic resin layer is produced by applying a coating for the organic resin layer containing the material for the organic resin layer to the surface of the metal base material and heating the applied coating.

  The paint for the organic resin layer contains, for example, the acid-modified polypropylene described above. The coating material for organic resin may further contain the above-described crosslinking agent and other resin, if necessary. Furthermore, the coating material for organic resin may contain a solvent as necessary. The type of the solvent is not particularly limited as long as it is a liquid that can uniformly dissolve or disperse various components in the coating for the organic resin, and is a liquid that evaporates in the process of forming the organic resin layer, preferably water. . For example, the coating for the organic resin layer contains an acid-modified polypropylene-based aqueous emulsion, a non-acid-modified water-based resin emulsion, a crosslinking agent, a rust inhibitor, a lubricant, a stabilizer, and an antifoaming agent. The solid content in the coating for the organic resin layer can be appropriately determined according to the coating property of the coating and the thickness of the coating film to be formed, and is, for example, 5 to 30% by mass. The content of the acid-modified polypropylene in the coating for the organic resin layer can be prepared by, for example, blending an acid-modified polypropylene emulsion and an aqueous resin emulsion not acid-modified.

  The organic resin layer is formed by applying the paint for the organic resin layer to the surface of the metal base material (or chemical conversion film) and evaporating the solvent (water) by, for example, heat drying. The method for applying the coating material for the organic resin layer is not particularly limited, and may be appropriately selected from known methods. Examples of such a coating method include a roll coating method, a curtain flow method, a spin coating method, a spray method, and a dip pulling method. The heating method of the coating material for the organic resin layer applied to the metal base material is not particularly limited. Although the ultimate temperature of the metal base material during heating is not particularly limited, from the viewpoint of forming an organic resin layer closely adhered to the surface of the metal base material (or chemical conversion film), for example, a resin in the organic resin layer The melting point of the composition is preferably 250 ° C. or lower.

(2) Second Step In the second step, the molded body of the heated thermoplastic resin composition is brought into contact with the surface of the painted metal preform, and the thermoplastic resin composition is molded on the surface of the painted metal preform. Join the body. The painted metal shape material may be processed in advance into a desired shape by pressing or the like.

  For example, after the painted metal material prepared in the first step is inserted into the injection mold, the molten thermoplastic resin composition is injected into the injection mold at high pressure (ie, injection molding). That's fine. At this time, it is preferable to provide a gas vent in the injection mold so that the thermoplastic resin composition flows smoothly. The molten thermoplastic resin composition is molded inside the injection mold to form a molded body, and is compatible with the organic resin layer formed on the surface of the metal base material. For this reason, a compatible layer having a nano-order thickness is formed between the thermoplastic resin composition and the organic resin layer. At this time, the temperature of the injection mold is preferably near the melting point of the thermoplastic resin in the thermoplastic resin composition. In addition, the composite obtained by injection molding may be annealed after molding to eliminate internal distortion due to molding shrinkage.

  Alternatively, after setting the painted metal preform prepared in the first step and the molded body of the thermoplastic resin composition in a thermocompression press machine, heat and heat are applied to these painted metal preform and the thermoplastic resin composition. What is necessary is just to apply pressure (that is, heat-pressing). At this time, heating and pressurization may be performed on all or a part of the molded body of the painted metal preform and the thermoplastic resin composition. It is necessary to heat and press at least one or both of the joint surfaces of the molded body of the thermoplastic resin composition and the painted metal base material. Part of the heated and pressurized organic resin layer and part of the thermoplastic resin composition are melted and compatible. For this reason, a compatible layer having a nano-order thickness is formed between the thermoplastic resin molded body and the organic resin layer. The method of heating and the method of pressurizing the molded body of the painted metal base and the thermoplastic resin composition are not particularly limited. Examples of the heating method include heater heating, electromagnetic induction heating, and ultrasonic heating. Examples of the pressurizing method include pressurization by human power, pressurization using a vise and the like.

  Furthermore, the manufacturing method described above may include other steps than the first step and the second step described above as long as the effects of the present invention are obtained.

  By the above procedure, the composite body according to the present invention can be manufactured by joining the molded body of the thermoplastic resin composition to the surface of the painted metal base material.

  As described above, in the present invention, the molding shrinkage of the thermoplastic resin composition is sufficiently small, 1.1% or less. Further, the ratio αp / αm of the linear expansion coefficient αm of the metal base material and the linear expansion coefficient αp of the thermoplastic resin composition is also sufficiently small as 6 or less. Therefore, when the thermoplastic resin composition is joined to the painted metal shape member by heat, the difference between the shrinkage amount of the thermoplastic resin composition and the shrinkage amount of the metal shape material during cooling can be reduced. For this reason, even if the molded body of the thermoplastic resin composition and the metal shape member deviate on the joining surface during cooling, it is considered that this deviation does not affect the joining state of both.

  In addition, the organic resin layer disposed between the molded body of the thermoplastic resin composition and the metal base material is strongly bonded to the metal base material by hydrogen bonding or the like on the one hand, and the thermoplastic resin composition on the other hand. A compatible layer is formed between the molded body and the molded body of the thermoplastic resin composition through the compatible layer. Furthermore, the organic resin layer is considered to have a lower molecular density than the metal base material and the molded body of the thermoplastic resin composition, and thus has a more flexible structure. It is done. For this reason, while the composite is cooled from the temperature at the time of bonding to the room temperature, the organic resin layer is in close contact with both the metal raw material and the molded body of the thermoplastic resin composition, and the above-described strong against both of them. It is believed that the bond is maintained from the time of molding until after molding.

  As described above, in the composite according to the present invention, the organic resin layer and the metal base material, and the organic resin layer and the molded body of the thermoplastic resin composition are firmly bonded, so that the painted metal base Excellent adhesion between the material and the molded body of the thermoplastic resin composition.

  Hereinafter, although this invention is demonstrated in detail with reference to the Example at the time of using a metal plate as a metal raw material, this invention is not limited by these Examples.

1. Fabrication of composite (1) Paint substrate (metal shape material)
A. Paint substrate 1
The surface of SUS430 with a plate thickness of 0.8 mm is No. The finished coating substrate 1 was prepared by finishing four. When the thermal expansion coefficient (αm) of the coated substrate 1 was determined as an average linear expansion coefficient from 20 to 100 ° C. using TMA, the linear expansion coefficient (αm) of the coated substrate 1 was 10 × 10 ⁻⁶ / K. Met.

B. Paint base 2
A cold rolled steel sheet (SPCC) with a plate thickness of 0.8 mm is prepared as a coated base material 2 with a molten Zn-6 mass% Al-3 mass% Mg alloy-plated steel sheet with a coating amount of 45 g / m ² per side. did. The linear expansion coefficient (αm) of the coated substrate 2 was 12 × 10 ⁻⁶ / K.

C. Paint base 3
A cold-rolled steel plate (SPCC) having a plate thickness of 0.8 mm was prepared as a coated base material 3 with a molten Al-9 mass% Si alloy-plated steel plate having a plating adhesion amount of 45 g / m ^{2 on} one side. The linear expansion coefficient (αm) of the coated substrate 3 was 12 × 10 ⁻⁶ / K.

D. Paint base 4
An aluminum alloy plate (A1050) having a plate thickness of 0.8 mm was prepared as the coating substrate 4. The linear expansion coefficient (αm) of the coated substrate 4 was 23 × 10 ⁻⁶ / K.

(2) Preparation of paint Acid-modified polypropylene (PP) resin (A), polyethylene (PE) wax (C), epoxy-based crosslinking agent so that the ratio of the mass of acid-modified polypropylene to the total mass of the resin is 95% by mass. (D) was added to water to prepare a prepaint 1 having a nonvolatile component of 20% by mass. In this prepaint 1, ammonium molybdate (Kishida Chemical Co., Ltd.): 0.5% by mass, zirconium carbonate (Zircosol AC-7; Daiichi Rare Element Chemical Co., Ltd.): 0.5% by mass as a rust preventive agent Silicone-based antifoaming agent (KM-73; Shin-Etsu Chemical Co., Ltd.): 0.05% by mass was prepared, respectively, to prepare paint 1. “Zircozole” is a registered trademark of Daiichi Rare Element Chemical Co., Ltd.

  Similarly, the content of the acid-modified PP resin (A) is 40 parts by mass, the content of the polyurethane (PU) resin (B) is 55% by mass, the acid-modified PP resin (A) The content is 35% by mass, the content of polyurethane (PU) resin (B) is 60% by mass, and the content of polyurethane (PU) resin (B) is 95% by mass. A paint 4 was prepared.

A. Acid-modified polypropylene resin For the acid-modified PP resin (A), a commercially available acid-modified polypropylene (Harden EW-5303; Toyobo Co., Ltd.) having an acid value of 2.0 mgKOH / g was used. “Hard Ren” is a registered trademark of Toyobo Co., Ltd.

B. Polyurethane resin A polyurethane resin emulsion (Superflex 830; Daiichi Kogyo Seiyaku Co., Ltd.) was used as the PU resin (B) for adjusting the ratio of the acid-modified PP to the total mass of the resin. “Superflex” is a registered trademark of Daiichi Kogyo Seiyaku Co., Ltd.

C. Polyethylene wax Polyethylene wax (HYTEC E-9015; Toho Chemical Industry Co., Ltd.) was added in an amount of 5.0% by mass relative to the total mass of the resin. “HYTEC” is a registered trademark of Toho Chemical Co., Ltd.

D. Epoxy-based crosslinking agent A commercially available epoxy-based crosslinking agent (HUX-XW3; ADEKA Corporation) was added in an amount of 3.0% by mass based on the total mass of the resin.

(3) Formation of organic resin layer The coated substrate 1 was immersed in an alkaline degreasing aqueous solution (Surf Cleaner SD-270; Nippon Paint Co., Ltd., pH = 12) at a liquid temperature of 40 ° C. for 1 minute to degrease the surface. Next, the paint 1 is applied to the surface of the degreased coated base material 1 with a roll coater so that the dry film thickness is 2.0 μm, and the coated substrate 1 is applied at a temperature at which the ultimate plate temperature becomes 150 ° C. The coated paint 1 was dried with a hot air dryer to form an organic resin layer. The base material I is a painted metal shape member having this organic resin layer. Moreover, except having changed the coating base material and the coating material as shown in Table 1, the organic resin layer was formed on the surface of the coating base material similarly to the base material I, and the base materials II-VII were produced. Furthermore, the coating base material 2 which does not apply | coat a coating material was prepared as the base material VIII. Table 1 shows the materials and physical properties of the substrates I to VIII. “Surf Cleaner” is a registered trademark of Nippon Paint Co., Ltd.

(4) Thermoplastic resin composition As a polyethylene (PE) resin composition, Nipolon Hard 1000 (injection temperature 230 ° C; Tosoh Corporation) was prepared. This resin composition contains 5% by mass of glass fiber as a filler. This resin composition is referred to as “resin composition i”. “Nipolon Hard” is a registered trademark of Tosoh Corporation.

  Moreover, Novatec PP, BC06C (injection temperature 250 ° C .; Nippon Polypro Co., Ltd.) and Prime Polypro R-350G (injection temperature 250 ° C .; Prime Polymer Co., Ltd.) were prepared as polypropylene (PP) resin compositions. The former does not contain glass fiber, and the latter contains 40% by mass of glass fiber as a filler. The former resin composition is referred to as a resin composition ii, and the latter resin composition is referred to as a resin composition iii. “Novatech” is a registered trademark of Nippon Polypro Co., Ltd., and “Prime Polypro” is a registered trademark of Mitsui Chemicals, Inc.

  Parapet GF (injection temperature 210 ° C .; Kuraray Co., Ltd.) was prepared as an acrylic resin composition (PMMA). This resin composition does not contain a filler (glass fiber). This resin composition is referred to as “resin composition iv”. “Parapet” is a registered trademark of Kuraray Co., Ltd.

  The mold shrinkage of the thermoplastic resin composition is as follows: mold temperature: 60 ° C. at the injection temperature of each resin composition i to iv into a mold having a cavity shape of width 100 mm × length 100 mm × thickness 3 mm. , Holding pressure: molding shrinkage rate of each resin composition i to iv when injection molding of each resin composition i to iv is performed at 80 MPa and cooled to 20 ° C. Moreover, the average linear expansion coefficient from 20 degreeC to 100 degreeC using TMA of each resin composition i-iv was calculated | required as linear expansion coefficient ((alpha) p) of each resin composition i-iv. Table 2 shows the compositions and physical properties of the resin compositions i to iv. A clear melting point of the resin composition iv was not confirmed.

(5) Joining of painted metal shape material and molded body of thermoplastic resin composition Bonding of coated metal mold and thermoplastic resin composition for measuring bonding force by injection bonding Inserting base material I into an injection mold and injecting molten resin composition iii into the cavity of the injection mold Then, as shown in FIG. 1, a composite 1 (reference numeral 13) in which the resin composition iii (reference numeral 12) was joined to the surface of the substrate I (reference numeral 11) by injection molding was produced. The shape of the cavity is width (W1) 30 mm × length (L1) 100 mm × thickness (T1) 4 mm. The shape of the base material I is width (W2) 30 mm × length (L2) 100 mm × thickness (T2) 0.8 mm. The base material I and the resin composition iii are joined at a portion having a length of 30 cm from each other. The composite I was produced by injecting the resin composition iii into the cavity at an injection temperature of 260 ° C. and then cooling and solidifying it. The composites 1 to 8, 12, except that the base material and the resin composition were changed as shown in Table 3 and the injection temperature was changed to the above-described injection temperature of each resin composition. 14 and 15 were produced respectively. Table 3 shows combinations of the base material and the resin composition in each composite.

B. Bonding of Painted Metal Shape and Thermoplastic Resin Composition for Measurement of Bonding Force by Thermocompression Bonding Molded Body of Resin Composition iv 30 mm wide × 100 mm long × 4 mm thick produced by injection molding method As shown in FIG. 1, the base material III having a width of 30 mm, a length of 100 mm, and a thickness of 0.8 mm is overlaid in a region of a width of 30 mm and a length of 30 mm at each end, and is heated to 60 MPa at 0.3 MPa. After pressurizing for 2 seconds, the composite 9 was obtained by cooling and solidifying. Except that the base material and the resin composition were changed as shown in Table 3, composites 10, 11, 13, and 16 were produced in the same manner as composite 9. Table 3 shows combinations of the base material and the resin composition in each composite.

(6) Evaluation of the bonding strength of the composite The molded body and base material of each composite body obtained in (5) above were pulled at a speed of 100 mm / min in a direction parallel to the surface of the base material and opposite to each other. The strength when peeled (peel strength) was measured. The case where the peel strength is less than 1.0 kN is evaluated as “×”, the case where the peel strength is 1.0 kN or more and less than 1.5 kN is evaluated as “Δ”, and the peel strength is 1.5 kN or more. The case of less than 2.0 kN was evaluated as “◯”, and the case where the peel strength was 2.0 kN or more was evaluated as “◎”. The results are shown in Table 3. As for the bonding strength of the composite, “Δ”, “◯” or “「 ”is acceptable.

  As apparent from Table 3, in injection molding or thermocompression bonding, the thermoplastic resin composition has a molding shrinkage of 1.1% or less, and the linear expansion coefficient αp of the thermoplastic resin composition with respect to the metal raw material αm. In the composites 1 to 10 having a ratio (αp / αm) of 6 or less, the molded body of the thermoplastic resin composition was sufficiently firmly bonded to the painted metal shape material.

  On the other hand, in both injection molding and thermocompression bonding, composites 11 and 12 having a linear expansion coefficient ratio αp / αm larger than 6 even when the molding shrinkage of the thermoplastic resin composition is 1.1% or less, In the composite 14 in which the organic resin layer does not contain acid-modified polypropylene, the bonding strength between the molded body of the thermoplastic resin composition and the painted metal base material is inferior, and the molded body of the thermoplastic resin composition is not coated metal element. It did not substantially join the profile. Also, the composite 13 having a molding shrinkage ratio of the thermoplastic resin composition exceeding 1.1% and a linear expansion coefficient ratio αp / αm larger than 6, and composites 15 and 16 in which the organic resin layer itself is not formed. Then, the molded body of the thermoplastic resin composition was not bonded to the painted metal base material.

  The composite containing the painted metal preform according to the present invention has excellent adhesion between the painted metal preform and the molded body of the thermoplastic resin composition. For example, various electronic devices, household appliances, medical devices It is suitably used for automobile bodies, on-vehicle accessories, building materials, and the like.

11 Base Material 12 Resin Composition 13 Composite

Claims (2)

A molded body of a thermoplastic resin composition, which is bonded to the surface of the metal base material and a coated metal base material having an organic resin layer disposed thereon by injection molding or thermocompression bonding. And having
The organic resin layer includes acid-modified polypropylene,
The organic resin layer has a thickness of 0.2 μm or more and less than 1.0 μm,
The ratio αp / αm of the linear expansion coefficient αp of the thermoplastic resin composition to the linear expansion coefficient αm of the metal base material is 6 or less.
Complex. The organic resin layer contains 40% by mass or more of acid-modified polypropylene with respect to the mass of the total resin in the organic resin layer.
The composite according to claim 1.

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