JP4890380B2 - Multi-layer steel plate reinforcement - Google Patents

Description

  The present invention relates to a steel plate reinforcement used to reinforce a thin steel plate such as an automobile steel plate.

  Automotive steel sheets are becoming thinner for the purpose of weight reduction, and generally 0.6 to 0.8 mm steel sheets are used. For this reason, a steel plate reinforcing material is attached to a portion where strength is required for reinforcement.

  Such a steel plate reinforcing sheet is usually attached in the vehicle body assembly process. Generally, after being applied to an oil-surfaced steel plate, it passes through an electrodeposition coating process and is cured when the electrodeposition paint is baked to exhibit reinforcement.

  The current steel plate reinforcement uses glass cloth and metal foil on the surface, so the sheet edge is exposed during work, and the worker is injured by the glass cloth and metal foil on the surface. There is.

In addition, with the recent complication of vehicle design, there are some parts that cannot be pasted due to poor followability to curved surfaces with conventional reinforcing sheets using glass cloth. Further, there is a problem that after hardening, the difference between the hardening shrinkage and the coefficient of thermal expansion of the reinforcing sheet is concentrated, the distortion is concentrated and the steel sheet is distorted, thereby deteriorating the appearance of the vehicle body. Currently, measures such as “put a slit” as in Patent Document 1 and “resolve the distortion of the steel sheet by making the shape of the sheet such that the distortion escapes” have been taken. Depending on the case, the distortion may not be resolved. In addition, the user has a problem that the number of parts to be managed increases because the shape of the slit / sheet differs for each vehicle type / part. Furthermore, since punching is required, there is a problem that waste is generated, and improvement is desired.
JP 2005-349703 A

  Therefore, the present invention does not use dangerous glass cloth or metal foil, improves the followability to the curved surface at the time of pasting, in any sheet shape without slitting or processing into a specific sheet shape An object of the present invention is to provide a reinforcing material that is free from distortion even when pasted, and that has solved the problems in the prior art.

  The present invention (1) includes at least 1) a reinforcing layer containing a thermosetting resin, a thermoplastic resin, and a thermosetting agent and cured by heating, 2) an intermediate layer having thermoplasticity, and 3) thermosetting. A multilayer steel plate reinforcing material comprising a resin, a thermoplastic resin, and a thermosetting agent, and having an adhesive layer that is cured by heating and adheres to the steel plate.

  The present invention (2) is the multilayer steel plate reinforcing material of the invention (1), wherein the thermoplastic resin of the reinforcing layer of 1) is an acrylic resin.

  The invention (3) is the invention (1) or (2), wherein the thermoplastic resin of the intermediate layer of 2) contains at least one of polyolefin, styrene elastomer, olefin elastomer, polyamide resin and polyester resin. This is a multilayer steel plate reinforcement.

  The present invention (4) is the multilayer steel plate reinforcing material according to any one of the inventions (1) to (3), wherein the thermosetting resin of the adhesive layer of 3) is liquid at room temperature.

  The present invention (5) is a multilayer steel plate reinforcing material in a form in which the multilayer steel plate reinforcing material according to any one of the inventions (1) to (4) formed into a sheet is wound into a roll shape. .

  The present invention (6) reinforces the steel sheet by drawing out the multilayer steel plate reinforcing material from the rolled form of the invention (5), cutting it into an arbitrary length and shape, and affixing to the steel sheet and heat curing. It is a method to do.

  The present invention (7) is a construction in which a steel plate is reinforced using the multilayer steel plate reinforcing material according to any one of the inventions (1) to (5).

According to the present invention, the following steel plate reinforcing sheet can be obtained.
・ Since no glass cloth or metal foil is used, workers are not injured.
・ Since there is no constraining layer such as glass cloth or metal foil, it can follow curved surfaces.
-Since the thermoplastic layer of the intermediate layer absorbs the distortion generated due to the shrinkage when the reinforcing layer is cured and the thermal expansion coefficient with the steel sheet during cooling, the distortion after curing is small.
-There is no need to insert slits to reduce distortion, or to calculate the distortion and punch it into a specific shape.
-Since it is not necessary to arrange the shape for each application site, the product can be supplied to the user side in roll form and cut to any length on the user side, leading to a reduction in the number of parts.

  The multilayer steel plate reinforcing material of the present invention includes at least 1) a reinforcing layer containing a thermosetting resin, a thermoplastic resin, and a thermosetting agent and cured by heating, 2) an intermediate layer having thermoplasticity, and 3). It contains a thermosetting resin, a thermoplastic resin, and a thermosetting agent, and has an adhesive layer that is cured by heating and adheres to the steel sheet, and does not use a constraining layer such as a glass cloth that is normally used. . The reinforcing layer of the present invention has both functions of a constraining layer using a current glass cloth or the like and a reinforcing layer containing a thermosetting resin.

  The reinforcing layer 1) is a flexible sheet before being cured, but is cured by heating and exhibits a reinforcing property. Because it does not use the normally used glass cloth, it is a flexible sheet before curing and can be applied to various curved surfaces, and it exhibits reinforcement by heating and curing at the baking temperature of the paint. is there.

  Further, the intermediate layer of 2) is plasticized when the reinforcing layer of 1) is heat-cured, so that the effect of curing shrinkage generated when the reinforcing layer of 1) is heat-cured and contracts, and the steel plate being cooled and reinforced. By absorbing the difference in the coefficient of thermal expansion of the layers, it has the function of not distorting the steel sheet.

  The adhesive layer 3) has adhesiveness at room temperature and can be attached to a steel plate, and has a function of curing and adhering when the reinforcing layer 1) is heat-cured.

  The multilayer steel plate reinforcing material of the present invention is basically composed of the three layers 1) to 3) above. For example, a primer layer for interlayer adhesion, a surface layer for designability, and the like may be laminated. This will be described in more detail below.

《Reinforcement layer》
The reinforcing layer of configuration 1) is made of a composition containing a thermosetting resin, a thermoplastic resin, and a thermosetting agent, and is a flexible sheet before curing, but is cured by heating and exhibits reinforcing properties.

  Typical examples of the thermosetting resin include acrylic, unsaturated polyester, and epoxy resins. However, the thermosetting resin is not particularly limited, and any one may be used in view of performance.

  Here, examples of the acrylic thermosetting resin include a urethane (meth) acrylate resin, an epoxy (meth) acrylate resin, and a polyester (meth) acrylate resin, but are not limited to these. Or two or more of them may be used. Examples of the unsaturated polyester thermosetting resin include orthophthalic acid unsaturated polyester resin, isophthalic acid unsaturated polyester resin, and bisphenol unsaturated polyester. When acrylic or unsaturated polyester is selected as the thermosetting resin, examples of the thermosetting agent include azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, azobis. Azo curing agents such as cyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, azobiscyanovaleric acid, persulfate curing agents such as ammonium persulfate and sodium persulfate, benzoyl peroxide, cumene hydroperoxide, lauryl Examples thereof include peroxide-based curing agents such as peroxides and redox-based curing agents such as ammonium persulfate-sodium sulfite. The amount of these thermosetting agents used is usually selected in the range of 0.01 to 10 parts by weight, preferably 0.05 to 3 parts by weight per 100 parts by weight of the thermosetting resin. The curing temperature can be controlled by the type of thermosetting agent in accordance with the baking temperature of the paint. For example, when benzoyl peroxide is used, curing is completed by heating at 120 ° C. for about 30 minutes.

  On the other hand, the epoxy thermosetting resin is not particularly limited. For example, bisphenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, tetrabromobisphenol A, 4,4′-biphenol, 2,2 Biphenols such as' -biphenol, polyhydric phenols such as dihydroxybenzene and dihydroxynaphthalene, terpene diphenol, tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane Examples thereof include solid or liquid epoxy resins such as glycidyl etherified products derived from phenolic compounds such as alicyclic epoxy resins, glycidylamine epoxy resins, glycidyl ester epoxy resins, and the like. Not. Preferred are glycidyl etherified products derived from bisphenol A and bisphenol F, and these may be used alone or in combination of two or more. The thermosetting agent is not particularly limited, but a latent curing agent is preferable. As the latent curing agent, for example, Lewis acid complex, dicyandiamide, imidazole compound, acid anhydride curing agent, phenol novolac, aromatic polyamine, amino resin, organic acid hydrazide, diaminomaleonitrile, melamine derivative, polyamine salt, amine imide compound, Examples include molecular sieve encapsulated curing agents and microencapsulated curing agents, and more preferred are dicyandiamide and organic acid hydrazide. These may be used alone or in combination of two or more. May be. The compounding ratio of the epoxy resin and the curing agent is not particularly limited because it varies greatly depending on the combination. Usually, the ratio calculated from the epoxy equivalent is used as a guide. For example, an epoxy resin having an epoxy equivalent of 190 (Epicoat 828, Japan Epoxy Resin) Is preferably 3 to 10 parts by weight for dicyandiamide and 10 to 30 parts by weight for adipic acid dihydrazide with respect to 100 parts by weight of the epoxy resin.

  The thermoplastic resin is used for supporting the thermosetting resin in a matrix before curing and molding the resin into a flexible sheet. The thermoplastic resin is not limited as long as it has good compatibility with the thermosetting resin and does not impair the reinforcing property, but among the various thermoplastic resins, the acrylic resin has good compatibility with various thermosetting resins. In addition, the reinforcing property can be imparted as compared with other resins. Acrylic resins are, for example, (meth) acrylic acid ester homopolymers and copolymers, (meth) acrylic acid esters and 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid, (meth) acrylamide and the like Can be mentioned. In particular, a copolymer having polymethyl methacrylate (PMMA) or methyl methacrylate (MMA) as a main monomer is preferable. The blending ratio of thermoplastic resin / thermosetting resin is preferably 80/20 to 5/95 (wt%), more preferably 40/60 to 20/80 (wt%). If the thermoplastic resin component is 5% by weight or less, it is difficult to form a sheet, and if it is 80% by weight or more, it is difficult to form a flexible sheet. Moreover, you may mix | blend another thermoplastic resin, natural rubber, synthetic rubber, etc. as needed.

  The composition which concerns on a reinforcement layer may contain components other than a thermosetting resin, a thermoplastic resin, and a thermosetting agent as needed. For example, the filler is added as necessary for the purpose of preventing curing shrinkage during heat curing and imparting reinforcing properties. Examples of the filler include calcium carbonate, talc, silica, mica, clay, titanium oxide, inorganic fillers such as sepiolite and wollastonite, and organic fillers such as cellulose fiber and vinylon fiber. These may be used alone or in combination. When added, the addition amount is 10 parts to 500 parts, preferably 80 parts to 250 parts, based on 100 parts by weight of the total of the thermoplastic component and the thermosetting resin / curing agent. If it is 500 parts or more, the moldability deteriorates. Furthermore, flame retardants, anti-aging agents, pigments, dyes, and the like can be blended as necessary.

  If the thickness of the reinforcing layer is too thin, no reinforcing force can be obtained, and if it is too thick, it is contrary to the weight reduction which is the original purpose, but it is not particularly limited, but a range of 100 μm to 2000 μm is preferable.

Forming Method As a forming method of the reinforcing layer, a normal method can be applied. For example, after kneading the above material using a kneader such as a Banbury mixer, a pressure kneader, or a twin screw extruder, the sheet is molded to a target thickness using a calendar or an extruder.

《Middle layer》
The intermediate layer of the configuration 2) is mainly composed of a thermoplastic resin. By plasticizing at the baking stage of the paint, it absorbs the effects of curing shrinkage that occurs when the reinforcing layer is heat-cured and the difference in thermal expansion coefficient between the steel plate being cooled and the reinforcing layer, so that the steel plate is not distorted. Has work.

  The intermediate layer is plasticized and solidified during heating and cooling, respectively. In order to efficiently absorb the distortion of the steel sheet, it is important to plasticize at 180 ° C. or less, which is the curing temperature of the paint. The composition is not particularly limited, and may be a mixture of a plurality of materials or a multilayer using a plurality of materials as long as the above thermoplastic requirements are satisfied. For example, there are a method of mixing a liquid material such as liquid rubber with a filler and a method of using a thermoplastic resin. Among these, it is preferable to use a thermoplastic resin in order to impart thermoplasticity to the intermediate layer. Among them, in particular, polyethylene, ethylene / vinyl acetate copolymer, ethylene / glycidyl methacrylate copolymer, polypropylene, polyolefin such as maleic acid modified polyolefin, styrene / isoprene / styrene copolymer, styrene / butadiene / styrene copolymer. Since olefin elastomers such as styrene elastomer such as ethylene / butene 1 copolymer, ethylene / propylene copolymer, polyamide resin, polyester resin, etc. have a melting point or softening point of 180 ° C. or less, By using these materials for the intermediate layer, both low strain and reinforcement can be achieved.

  The composition which concerns on an intermediate | middle layer may contain components other than a thermoplastic resin as needed. For example, you may mix | blend a filler, a flame retardant, anti-aging agent, a softening agent etc. as needed.

  Although the thickness of the intermediate layer is not particularly limited, it is desirable that the thickness is thinner in view of weight reduction and economy, but if the thickness is too thin, the intermediate layer cannot absorb strain well. Moreover, since it will reduce reinforcement property when it becomes too thick, 10 micrometers-500 micrometers are preferable.

As a forming method of the forming method intermediate layer, a normal film forming method can be applied. For example, the above materials are kneaded with a twin screw extruder or the like, and a sheet is molded to a target thickness using a T die, an inflation die, a calendar, or the like.

<Adhesive layer>
The adhesive layer of Configuration 3) has adhesiveness so as to be in close contact with the steel plate before heating, and adheres firmly to the steel plate by heat curing. The adhesive layer is made of a thermosetting resin, a thermoplastic resin, and a thermosetting agent. The thermosetting resin and the thermosetting agent are selected from the same range as that of the reinforcing layer, but it is preferable to select a thermosetting resin that is liquid at room temperature in order to develop initial tackiness. The thermoplastic resin is not particularly limited as long as it is compatible with the thermosetting resin and does not impair the curability and adhesiveness. However, in order to sufficiently exhibit the oil surface adhesiveness, both ethylene and vinyl acetate are used. Polymers, ethylene / ethyl acrylate copolymers, styrene / isoprene / styrene copolymers, and hydrogenated products thereof, styrene / butadiene / styrene copolymers, and hydrogenated products thereof are preferred. The thermoplastic resin may be used alone or as a mixture of several kinds. The ratio of the thermosetting resin to the thermoplastic resin is not particularly limited, but is preferably 10% by weight / 90% by weight to 90% by weight / 10% by weight from the balance between initial tackiness and oil surface adhesion.

  The composition which concerns on an contact bonding layer may contain components other than a thermosetting resin, a thermoplastic resin, and a thermosetting agent as needed. For example, a filler may be added to reduce shrinkage during bake hardening. As with the reinforcing layer, calcium carbonate, talc, silica, mica, clay, titanium oxide, inorganic fillers such as sepiolite and wollastonite, and organic fillers such as cellulose fiber and vinylon fiber are used. One or more of these fillers can be added. A tackifier may be added for the purpose of improving the initial adhesive strength. Examples of the tackifier include rosin resin, terpene resin, petroleum resin, coumarone resin, and styrene resin, and are selected in consideration of compatibility with thermosetting resins and thermoplastic resins and adhesive properties. In addition, you may mix | blend a flame retardant, an anti-aging agent, etc. as needed.

  The thickness of the adhesive layer is not particularly limited, but is preferably in the range of 50 μm to 400 μm. When it is 50 μm or less, there is a possibility that sufficient oil level adhesion cannot be obtained depending on the amount of oil adhering to the steel plate. On the other hand, when the thickness is 400 μm, the load increases in terms of cost.

Forming Method As a forming method of the adhesive layer, a normal method can be applied. For example, after kneading the above material using a kneader such as a Banbury mixer, a pressure kneader, or a twin screw extruder, the sheet is molded to a target thickness using a calendar or an extruder.

Manufacturing method of multi-layer steel plate reinforcing material The multi-layer steel plate reinforcing material of the present invention is a method of laminating sheets of each layer of 1), 2) and 3) formed separately, or an extruder directly on the formed other layer. It is multi-layered by using a method such as stacking with a calendar. The multilayered sheet may be cut into an appropriate size as it is, but can be wound up in a roll and provided to the user. At this time, release paper or the like can be used to protect the adhesive layer.

Application method and application of multi-layer steel plate reinforcing material The multi-layer steel plate reinforcing material of the present invention is affixed to an oil level body of an automobile and cured at the time of paint baking, whereby the reinforcing layer and the adhesive layer are cured, and the reinforcing layer is sufficiently reinforced. The adhesive layer exhibits adhesiveness with the oil surface steel plate. Further, the intermediate layer absorbs distortion during heat curing and cooling, and maintains the design of the appearance of the automobile.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, the numerical value regarding the mixing | blending in a table | surface means a "weight part" unless there is particular notice.

  Each of the reinforcing layer and the adhesive layer was kneaded with a pressure kneader according to the formulation shown in the table, and then processed into a sheet shape with each thickness using an extruder. The intermediate layer was extruded with a T-die. A reinforcing layer, an intermediate layer, and an adhesive layer were cut into a size of 80 mm × 150 mm, three layers were sandwiched between glass plates of the same size, and heat-pressed under conditions of 80 ° C. and a load of 1 kg to prepare a sample. With respect to the produced steel plate reinforcing sheet, the reinforcing force and the steel plate distortion were evaluated.

Reinforcing force is measured by applying a reinforcing sheet to the entire surface of a 25 mm x 150 mm x 0.8 mm oil surface steel plate (rust-preventing oil 1.0 g / m ² , cold rolled steel plate) and then baking the sample at 180 ° C for 30 min. It was a piece. With the reinforcing sheet affixing surface of the test piece facing down, two positions 25 mm inside from both ends are supported by a support point of 25 mm width, and the resistance when pushing 1 mm from the steel plate side with a 25 mm pressure wedge at the center Reinforcing power was used. The pushing speed was 1 mm / min.

Steel sheet strain was measured by applying a reinforcing sheet to a 25 mm x 200 mm x 0.6 mm oil-surfaced steel sheet (rust-preventing oil 1.0 g / m ² , cold-rolled steel sheet) with a size of 25 mm x 150 mm and a load of 22.1 N. A sample that was press-bonded (with both ends of the steel sheet left by 25 mm) and baked at 180 ° C. × 30 min was used as a test piece. The test piece was placed on a horizontal table with the steel plate portion facing down, and the distance between the opposite end and the horizontal table when the one end was fixed to a horizontal plane was taken as the strain value.

Diamond 3109: Acrylic resin (Mitsubishi Rayon)
Purple light UV7000B: Urethane acrylate (manufactured by Nihon Gosei)
Lipoxy VR90: Epoxy acrylate (made by Showa Polymer)
Epicoat 828: Epoxy resin (made by Japan Epoxy Resin)
Perhexa C (C): Organic peroxide (manufactured by NOF Corporation)
DDA: latent curing agent (dicyandiamide)
Microace P4: Talc (Nippon Talc Co., Ltd.)
Knightyard G: Wollastonite (manufactured by NYCO)

Septon 2063: Styrene-ethylene-propylene-styrene copolymer resin (Kuraray)
Bond First E: GMA (glycidyl methacrylate) -containing PE resin (manufactured by Sumitomo Chemical)
Prime Polypro F-744: Random PP (made by Prime Polymer)
Versamide 973: Polyamide resin (manufactured by Cogris Japan Ltd.)
Byron GM415: Polyester resin (manufactured by Toyobo Co., Ltd.)
Melting point measurement conditions: DSC-60 manufactured by Shimadzu Corporation Temperature increase rate 10 ° C / min
Softening point measurement conditions: ASTM D3236-73

EVAFLEX45X: Ethylene-vinyl acetate copolymer (Mitsui DuPont)
Aerosil R972: Silica (made by Nippon Aerosil)
Perhexa C (C): Organic peroxide (manufactured by NOF Corporation)

Claims (7)

  At least 1) a reinforcing layer containing a thermosetting resin, a thermoplastic resin and a thermosetting agent and cured by heating, 2) an intermediate layer having thermoplasticity, 3) a thermosetting resin, a thermoplastic resin and heat A multilayer steel plate reinforcing material comprising a curing agent, and an adhesive layer that is cured by heating and adheres to the steel plate.   The multilayer steel plate reinforcing material according to claim 1, wherein the thermoplastic resin of the reinforcing layer of 1) is an acrylic resin.   The multilayer steel plate reinforcing material according to claim 1 or 2, wherein the thermoplastic intermediate layer 2) contains at least one of polyolefin, styrene elastomer, olefin elastomer, polyamide resin and polyester resin.   The multilayer steel plate reinforcing material according to any one of claims 1 to 3, wherein the thermosetting resin of the adhesive layer of 3) is liquid at normal temperature.   The multilayer steel plate reinforcing material which is the form which wound up the multilayer steel plate reinforcing material as described in any one of Claims 1-4 shape | molded in the sheet form, and was made into the shape of a roll.   A method of reinforcing a steel sheet by drawing out a multilayer steel plate reinforcing material from the roll-shaped form according to claim 5 and cutting it into an arbitrary length and shape, followed by sticking to the steel sheet and heat curing.   The construction which reinforced the steel plate using the multilayer type steel plate reinforcement according to any one of claims 1 to 5.