JP5064267B2 - Reinforcing sheet and method for reinforcing thin plate - Google Patents

Description

  The present invention relates to a reinforcing sheet and a method for reinforcing a thin plate, and more particularly to a reinforcing sheet and a reinforcing method for reinforcing a thin plate used in various industrial products using the reinforcing sheet.

Conventionally, it is known that a thin plate used for various industrial products is provided with a reinforcing sheet in a portion that needs reinforcement in the thin plate to improve the strength of the portion.
As such a reinforcement sheet, for example, a fusion sheet for reinforcing a thin plate in which a thermosetting resin uncured composition layer including a modified epoxy resin, a filler, a curing agent, and a foaming agent is laminated on a glass cloth is proposed. (For example, refer to Patent Documents 1 and 2). And such a fusion sheet for reinforcing a thin plate is attached to an outer plate steel plate of an automobile or a thin plate steel plate of a home appliance, and these are heated at 180 ° C. for 30 minutes to form a thermosetting resin uncured composition layer. If it hardens and foams, an outer plate steel plate and a thin plate steel plate can be reinforced.
JP-A-8-267665 Japanese Patent Laid-Open No. 9-226061

However, in the reinforcement of thin plates, there is a demand to reinforce at a low temperature and in a short time from the viewpoint of energy saving and improvement of production efficiency in recent years. In addition, from the viewpoint of cost reduction and weight reduction, even when FRP (fiber reinforced plastic) or synthetic resin is used as a thin plate, these cannot be heated to a high temperature, so a reinforcement at a low temperature and in a short time is desired. Is done.
However, since the fusion sheet for reinforcing thin plates described in Patent Documents 1 and 2 is heated at a relatively high temperature for a long time, it is insufficient to meet such a demand.

  Furthermore, since the resin layer of the conventional reinforcing sheet including Patent Documents 1 and 2 is made of a thermosetting resin, it is difficult to achieve both storage stability and low temperature reactivity. That is, when a curing agent having low reactivity is used, the curing agent is difficult to be decomposed at low temperature, so that storage stability is improved, but reinforcement at low temperature and in a short time is difficult. On the other hand, when a highly reactive curing agent is used, the curing agent is easily decomposed at a low temperature, so that it can be reinforced at a low temperature in a short time, but the storage stability is lowered. Therefore, it is difficult to reinforce at a low temperature in a short time while ensuring good storage stability.

  An object of the present invention is to provide a reinforcing sheet that can be reinforced at a low temperature in a short time while ensuring good storage stability, and a thin plate reinforcing method using the reinforcing sheet.

In order to achieve the above object, the reinforcing sheet of the present invention includes a heat-fusible resin layer and a constraining layer laminated on the resin layer, and the resin layer is made of ethylene / alkyl (meth) acrylate. It looks including the ester copolymer filler and a tackifier, wherein the constraining layer is a glass cloth, and characterized in that it is used in the reinforcement of the thin plate.
In the reinforcing sheet of the present invention, it is preferable that the resin layer further includes butyl rubber.

In the reinforcing sheet of the present invention, the resin layer preferably has a Young's modulus at 23 ° C. of 1.0 × 10 ⁷ N / m ² or more.
In the reinforcing sheet of the present invention, the tackifier is preferably a terpene resin .
Also, the reinforcing method of the thin plate of the present invention, the reinforcing sheet described above, by placing a thin plate, and wherein the heating and pressing the resin layer.

According to the reinforcing sheet and the method for reinforcing a thin plate of the present invention, if a resin layer is disposed on a portion of the thin plate that requires reinforcement and heated and pressurized, the resin layer is thermally fused with the thin plate and the constraining layer with good adhesion. . Therefore, it is possible to secure the rigidity of the thin plate and improve the strength of the part.
Moreover, according to the reinforcing sheet and thin plate reinforcing method of the present invention, it is possible to reinforce by heating at a low temperature in a short time while ensuring good storage stability. As a result, it is possible to achieve reliable reinforcement at a low temperature and in a short time while ensuring reliable use of the reinforcing sheet.

The reinforcing sheet of the present invention includes a heat-fusible resin layer and a constraining layer laminated on the resin layer.
In the present invention, the resin layer is formed by molding a heat-fusible resin composition (hereinafter referred to as a heat-fusible resin composition) into a sheet shape.
The heat-fusible resin composition contains an ethylene copolymer, a filler, and a tackifier from the viewpoint of heat-sealing the resin layer in a low temperature range (for example, 60 to 120 ° C.).

The ethylene copolymer is a thermoplastic resin made of a copolymer of ethylene and a monomer copolymerizable with ethylene. For example, ethylene / vinyl acetate copolymer (EVA), ethylene / (meth) acrylic acid Examples thereof include alkyl ester copolymers.
The ethylene / vinyl acetate copolymer is, for example, a random or block copolymer of ethylene and vinyl acetate, preferably a random copolymer.

  Such an ethylene / vinyl acetate copolymer has a vinyl acetate content (based on the MDP method, the same shall apply hereinafter) of, for example, 12 to 50% by weight, preferably 14 to 46% by weight. The flow rate (MFR: compliant with JIS K 6730; hereinafter simply referred to as MFR) is 1-30 g / 10 min, preferably 1-15 g / 10 min, and the hardness (JIS K7215) is, for example, 60-100 degrees. Preferably, it is 70-100 degree | times, softening temperature is 35-70 degreeC, for example, and melting | fusing point is 70-100 degreeC, for example.

The ethylene / (meth) acrylic acid alkyl ester copolymer is, for example, a random or block copolymer of ethylene and (meth) acrylic acid alkyl ester, preferably a random copolymer.
The (meth) acrylic acid alkyl ester is a methacrylic acid alkyl ester and / or an acrylic acid alkyl ester, and more specifically, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic. Propyl acid, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, ( Neo-pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acryl Isooctyl acid, nonyl (meth) acrylate, isono (meth) acrylate , Decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate (Meth) acrylic acid hexadecyl, (meth) acrylic acid heptadecyl, (meth) acrylic acid octadecyl alkyl (meth) acrylates (wherein the alkyl moiety is a linear or branched alkyl having 1 to 18 carbon atoms), etc. Can be mentioned. These (meth) acrylic acid alkyl esters can be used alone or in combination.

Preferred are ethylene / ethyl acrylate copolymer (EEA) and ethylene / butyl acrylate copolymer (EBA).
The ethylene / ethyl acrylate copolymer has an ethyl acrylate content (EA content, MDP method) of, for example, 9 to 35% by mass, preferably 9 to 25% by mass, and MFR is, for example, 0.5 to 25 g / 10 min, preferably 0.5 to 20 g / 10 min, and the hardness (Shore A, JIS K7215 (1986)) is, for example, 60 to 100 degrees, preferably 70 to 100 degrees. Yes, softening temperature (Vicat, JIS K7206 (1999)) is, for example, 35 to 70 ° C., melting point (JIS K7121 (1987)) is, for example, 70 to 100 ° C., and glass transition temperature (DVE method) Is, for example, −40 ° C. to −20 ° C.

  The ethylene / butyl acrylate copolymer has a butyl acrylate content (EB content, DuPont method) of, for example, 7 to 35% by mass, preferably 15 to 30% by mass, and MFR is, for example, 1 to 6 g / 10 min, preferably 1 to 4 g / 10 min, and the hardness (Shore A, ISO 868 or JIS K7215) is, for example, 75 to 100 degrees, preferably 80 to 95 degrees. The softening temperature (Vicat softening point, JIS K7206 or ISO 306) is, for example, 35 to 70 ° C, preferably 40 to 65 ° C, and the melting point (JIS K7121 or ISO 3146) is, for example, 80 to 120 degreeC, Preferably it is 90-100 degreeC.

  When the heat-fusible resin composition contains an ethylene copolymer, the melting point of the heat-fusible resin composition can be set to, for example, 60 to 120 ° C., preferably 70 to 100 ° C., Heat fusion can be performed in such a temperature range (low temperature). In addition, the above-described temperature range is compared with the use temperature of the reinforcing sheet containing the thermosetting resin and the curing agent (the curing temperature, that is, the temperature at which the curing agent decomposes, for example, 150 to 200 ° C.). Is set low.

  As the filler, for example, a reinforcing agent, more specifically, calcium carbonate (for example, heavy calcium carbonate, light calcium carbonate, white glaze etc.), talc, mica, clay, mica powder, bentonite (organite) And silica, alumina, aluminum silicate, titanium oxide, carbon black, acetylene black, aluminum powder, and glass powder (powder). These fillers may be used alone or in combination, and the blending ratio thereof is, for example, 1 to 300 parts by weight, reinforcing property, weight (weight reduction), economical with respect to 100 parts by weight of the ethylene copolymer. From the viewpoint, it is preferably 10 to 200 parts by weight.

  Examples of the tackifier include rosin resins, terpene resins (eg, terpene-aromatic liquid resins), coumarone indene resins (coumarone resins), petroleum resins (eg, C5 petroleum resins, C9 petroleum resin, C5 / C9 petroleum resin, C5 / C6 petroleum resin, etc.) and phenolic resin. These tackifiers can be used alone or in combination.

The melting point of the tackifier is, for example, 50 to 150 ° C., although it depends on the type, blending ratio, and melting point of the ethylene copolymer.
The blending ratio of the tackifier is preferably 1 to 200 parts by weight, preferably 5 to 100 parts by weight with respect to 100 parts by weight of the ethylene copolymer, for example, from the viewpoint of reinforcement and heat-fusibility (adhesiveness). It is.

The heat-fusible resin composition can further contain butyl rubber. By including butyl rubber, vibration damping properties can be improved as well as reinforcing properties.
Butyl rubber is a synthetic rubber obtained by copolymerization of isobutene (isobutylene) and a small amount of isoprene, and its degree of unsaturation is preferably 0.8 to 2.0, and Mooney viscosity is preferably , 30-90 (ML _{1 + 8} , at 125 ° C.).

Butyl rubber can be used alone or in combination of two or more different physical properties.
The blending ratio of butyl rubber is, for example, 10 to 40 parts by weight, preferably 20 to 40 parts by weight with respect to 100 parts by weight of the total amount of the ethylene copolymer and butyl rubber. If the blending ratio of butyl rubber is less than the above range, vibration damping may not be improved sufficiently. Further, when the blending ratio of butyl rubber exceeds the above-described range, although the vibration damping property is improved, the Young's modulus is lowered and the reinforcing property may be insufficiently improved.

In addition to the above-mentioned components, the above-mentioned heat-fusible resin composition may contain, for example, a thixotropic agent (for example, montmorillonite), a lubricant (for example, stearic acid), a pigment, and a scorch inhibitor. Further, known additives such as stabilizers, softeners, plasticizers, anti-aging agents, antioxidants, ultraviolet absorbers, colorants, fungicides, flame retardants, and the like can also be contained in appropriate proportions.
On the other hand, in the present invention, the heat-fusible resin composition does not include any of a curable resin such as an epoxy resin, a crosslinking agent, and a foaming agent from the viewpoint of heat-sealing the resin layer at a low temperature.

The heat-fusible resin composition can be obtained by blending the above-described components at the blending ratio described above, and is not particularly limited, but for example, kneaded by a mixing roll, a pressure kneader, an extruder, or the like. Thus, it can be prepared as a kneaded product.
Thereafter, the obtained kneaded product is not particularly limited, but is rolled into a sheet shape at, for example, 60 to 150 ° C. by, for example, calendar molding, extrusion molding or press molding to form a resin layer.

In addition, the thickness of the rolled resin layer is 0.2-3.0 mm, for example, Preferably, it is 0.5-2.5 mm.
In the present invention, the resin layer formed by rolling as described above has a Young's modulus at 23 ° C. (normal temperature) of, for example, 1.0 × 10 ⁷ N / m ² or more, preferably 5.0. × 10 ⁷ N / m ² or more, usually 1.0 × 10 ¹⁰ N / m ² or less. If the Young's modulus of the resin layer is less than 1.0 × 10 ⁷ N / m ² , sufficient reinforcement may not be obtained.

The Young's modulus is, for example, a resin layer formed by rolling to a thickness of 0.8 mm, cut to 10 mm width × 100 mm length, and this is speeded at 5 mm / min between 50 mm chucks by a universal testing machine. It is calculated by measuring the tensile strength.
In the present invention, the constraining layer constrains the resin layer that is heat-sealed by heating and pressurizing to retain the shape of the heat-sealing layer after heating, and imparts toughness to the heat-sealing layer to improve strength. It is intended. Further, the constraining layer is formed of a sheet-like material that is lightweight and thin, and can be closely integrated with the heat-sealing layer. Examples of such materials include glass cloth, metal foil, synthetic resin nonwoven fabric, and carbon fiber.

  The glass cloth is made of glass fiber and a known glass cloth is used. The glass cloth includes a resin-impregnated glass cloth. As the resin-impregnated glass cloth, the above-described glass cloth is impregnated with a synthetic resin such as a thermosetting resin or a thermoplastic resin, and a known one is used. In addition, as a thermosetting resin, an epoxy resin, a urethane resin, a melamine resin, a phenol resin etc. are mentioned, for example. Examples of the thermoplastic resin include vinyl acetate resin, ethylene / vinyl acetate copolymer (EVA), vinyl chloride resin, EVA / vinyl chloride resin copolymer, and the like. The above-mentioned thermosetting resin and thermoplastic resin can be used alone or in combination, respectively, and thermosetting resin and thermoplastic resin (for example, melamine resin and vinyl acetate resin) are mixed. You can also.

Examples of the metal foil include known metal foils such as an aluminum foil and a steel foil.
Of these, glass cloth is preferably used in consideration of weight, adhesion, strength, and cost.
Moreover, the thickness of a constrained layer is 0.05-2 mm, for example, Preferably, it is 0.1-1.0 mm.

And the reinforcement sheet of this invention can be obtained by bonding together the above-mentioned resin layer and constrained layer. The total thickness of the resin layer and the constraining layer is, for example, 0.3 to 5 mm, preferably 0.6 to 3.5 mm.
In addition, in the obtained reinforcing sheet, if necessary, a separator (release paper) on the surface of the resin layer (the surface opposite to the back surface on which the constraining layer is adhered) until actually used. Can also be attached.

The reinforcing sheet of the present invention is not particularly limited, but is used for reinforcing a thin plate, for example.
The thin plate is not particularly limited as long as it is a thin plate that needs reinforcement, and examples include thin plates used in various industrial products. The material for forming such a thin plate is not particularly limited, and is, for example, metal or resin (including FRP and synthetic resin). Specific examples of such thin plates include automobile pillars, roofs, fenders, hoods, trunks, quarter panels, doors, door handles, door mirrors, and the like. In addition, examples of the thin plate include a casing (casing) of an electric device or a home appliance, and more specifically, a computer, a computer display, a TV, a mobile phone, a game device, a refrigerator, a vacuum cleaner, or the like. It is done.

FIG. 1 is an explanatory view showing an embodiment of a method for reinforcing a thin plate of the present invention, in which the reinforcing sheet of the present invention is disposed on a thin plate and is reinforced by heating and pressurizing a resin layer. ) Is a step of preparing a reinforcing sheet and peeling off the release paper, (b) is a step of arranging the reinforcing sheet on a thin plate, and (c) is a step of heating and pressurizing the resin layer.
Next, an embodiment of a method for reinforcing a thin plate of the present invention, in which the reinforcing sheet of the present invention is placed on a thin plate and reinforced by heating and pressurizing a resin layer, will be described with reference to FIG.

First, in this method, a reinforcing sheet 1 is prepared as shown in FIG.
As for the reinforcing sheet 1, the resin layer 2 and the constraining layer 3 are bonded together, and the release paper 6 is pasted on the surface of the resin layer 2 (the surface opposite to the back surface on which the constraining layer 3 is pasted) if necessary. Has been.
Next, in this method, the reinforcing sheet 1 is disposed on the thin plate 5.
The thin plate 5 is used for the various industrial products described above, and includes, for example, an outer surface that appears in appearance and an inner surface that faces inward and does not appear in appearance.

In order to arrange the reinforcing sheet 1 on the thin plate 5, as shown by the phantom line in FIG. 1 (a), first the release paper 6 is peeled off from the surface of the resin layer 2, and then as shown in FIG. 1 (b). Next, the surface of the resin layer 2 is attached (temporarily fixed or temporarily fixed) to the inner surface of the thin plate 5 having a substantially rectangular shape when viewed from the front.
Thereafter, the reinforcing sheet 1 is heated and pressurized as shown in FIG. Although heating temperature is based also on melting | fusing point and softening temperature of an ethylene copolymer, it is 60-120 degreeC, for example, Preferably, it is 70-100 degreeC. At the same time as or after the heating, the reinforcing sheet 1 is, for example, at a pressure at which the heat-fusible resin composition does not flow out of the sticking position. Pressurize at a pressure of 15 to 10 MPa.

In pressurization, the reinforcing sheet 1 and the thin plate 5 are heated at the same time or after being heated, for example, with a laminator roll, a hand roll (roller), a spatula, etc., for example, at a speed of 5 to 500 mm / min, a pressure of 0.05 to The resin layer 2 is pressure-bonded toward the thin plate 5 side at 0.5 MPa.
Then, the resin layer 2 becomes the heat-sealing layer 4 by the heating described above, and further, the heat-sealing layer 4 is heat-sealed (adhered) with good adhesion to the thin plate 5 and the constraining layer 3 by being pressurized. . Therefore, the strength of the thin plate 5 can be improved by the thermal fusion of the thermal fusion layer 4.

  In addition, since the resin layer 2 does not contain any of a curable resin, a curing agent, and a crosslinking agent, a thin plate can be obtained by heating and pressurizing at a low temperature and in a short time while ensuring good storage stability of the resin layer 2. 5 can be reinforced. As a result, the reinforcing sheet 1 including the resin layer 2 is reliably manufactured, and the thin sheet 5 is reliably reinforced by heating and pressurizing at a low temperature for a short time while ensuring the reliable use of the reinforcing sheet 1. be able to.

Moreover, in the thin plate 5, when it is easy to generate | occur | produce a vibration and it is necessary to prevent the vibration sound resulting from it, etc., if butyl rubber is contained in the resin layer 2, it will improve a damping property with a reinforcement. be able to.
In addition, it can also heat after the above-mentioned heating and pressurization. In such heating, for example, the thin plate 5 is an automobile pillar or the like, and the thin plate 5 and the reinforcing sheet 1 are put into a coating drying furnace used for drying after painting on the pillar.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the examples and comparative examples.
A. Preparation of Reinforcing Sheet In the formulation shown in Table 1, each component was blended on a weight part basis and kneaded with a mixing roll to prepare a kneaded product.

In this preparation, in Example 1 and Comparative Example 3 , an ethylene copolymer, a filler, and a tackifier were kneaded at 100 ° C. In Examples 2 and 3 , the ethylene copolymer, butyl rubber, filler and tackifier were kneaded at 100 ° C. In Comparative Example 1, first, a filler, a tackifier, and a thermosetting resin were kneaded, and after cooling, a curing agent was further added to the kneaded product and kneaded at 80 ° C.

Next, the prepared kneaded material was rolled to a thickness of 0.8 mm and 1.8 mm with a calender roll to form a resin layer. Subsequently, a glass cloth having a thickness of 0.2 mm was bonded to the resin layer as a constraining layer at 100 ° C. to prepare reinforcing sheets having a thickness of 1.0 mm and 2.0 mm, respectively. Further, a reinforcing sheet consisting only of a constraining layer (that is, a reinforcing sheet not provided with a resin layer) was provided as a reinforcing sheet of Comparative Example 2.
B. Evaluation The Young's modulus, the reinforcing property, and the vibration damping property were evaluated as follows for the obtained reinforcing sheets of Examples and Comparative Examples. The results are shown in Table 1.
1) Young's modulus Only the resin layer having a thickness of 0.8 mm formed by rolling in Examples 1 to 3 and Comparative Examples 1 and 3 was cut into a length of 10 mm × 100 mm, and this was cut to 50 mm by a universal testing machine. Young's modulus was calculated by measuring the tensile strength between chucks at a speed of 5 mm / min.
2) Reinforcing test a
The reinforcing sheets (thickness 1.0 mm and 2.0 mm) of Examples 1 to 3 and Comparative Examples 1 and 3 and the reinforcing sheet (thickness 0.2 mm) of Comparative Example 2 are cut into 25 mm width × 150 mm length. And this was each stuck on the aluminum thin plate (product number: A5052) of 0.5 mm thickness x 25 mm width x 150 mm length in a 20 degreeC atmosphere.

Next, in Examples 1 to 3 and Comparative Example 3 , the aluminum thin plate and the reinforcing sheet were heated at 100 ° C. for 5 minutes. Thereafter, the reinforcing sheet was pressed at a speed of 300 mm / min with a 2 kg roller (hand roll) to thermally bond the reinforcing sheet to the aluminum thin plate. This obtained the test piece.
Moreover, in the comparative example 1, the reinforcement sheet was stuck on the aluminum thin plate by pressurizing a reinforcement sheet at a speed | rate of 300 mm / min with a 2 kg roller at room temperature. This obtained the test piece.

And the reinforcement property was evaluated about the test piece immediately after pressurization.
In the evaluation of reinforcing properties, each test piece was supported with a span of 100 mm with the aluminum thin plate facing upward, and the test bar was lowered at a compression speed of 5 mm / min from above in the vertical direction at the center in the longitudinal direction. Then, the bending strength when the heat-fusible layer (the constraining layer in Comparative Example 2) was displaced by 1 mm after the contact with the aluminum thin plate and the bending strength when displaced by 2 mm were evaluated as the reinforcement test a.
3) Reinforcing test b
A test piece was obtained in the same manner as the correction test a except that the test piece immediately after pressing was further heated at 100 ° C. for 10 minutes, and this was evaluated as the reinforcing test b.
4) Reinforcing test c
A test piece was obtained in the same manner as the correction test a except that the test piece immediately after pressurization was further heated at 180 ° C. for 30 minutes, and this was evaluated as a reinforcing test c.
5) Damping test (loss factor)
The reinforcing sheets of Examples 1 to 3 and Comparative Examples 1 and 3 were cut into a size of 10 mm width × 250 mm length, and this was attached to a steel plate having a size of 0.8 mm thickness × 10 mm width × 250 mm length. I attached. Then, these were heated at 100 ° C. for 10 minutes in Examples 1 to 3 and Comparative Example 3 and at 180 ° C. for 30 minutes in Comparative Example 1, to obtain test pieces.

  Thereafter, the loss factor of the secondary resonance point of the test piece at 20 ° C. and a frequency of 200 Hz was measured by the central excitation method.

It is explanatory drawing which shows one Embodiment of the reinforcement method of the thin plate of this invention which arrange | positions the reinforcement sheet of this invention to a thin plate, and reinforces by heating and pressurizing a resin layer, (a) is reinforcement A step of preparing a sheet and peeling off the release paper, (b) shows a step of arranging the reinforcing sheet on a thin plate, and (c) shows a step of heating and pressurizing the resin layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reinforcement sheet 2 Resin layer 3 Constrained layer 5 Thin plate

Claims (5)

A heat-fusible resin layer, and a constraining layer laminated on the resin layer,
The resin layer is viewed contains the ethylene- (meth) acrylic acid alkyl ester copolymer and the filler and a tackifier,
The constraining layer is a glass cloth,
A reinforcing sheet used for reinforcing thin plates .   The reinforcing sheet according to claim 1, wherein the resin layer further contains butyl rubber. The reinforcing sheet according to claim 1, wherein the resin layer has a Young's modulus at 23 ° C. of 1.0 × 10 ⁷ N / m ² or more. The reinforcing sheet according to claim 1, wherein the tackifier is a terpene resin. A reinforcing sheet according to any one of claims 1 to 4 , wherein the reinforcing sheet is disposed on a thin plate, and the resin layer is heated and pressurized.

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