JP7061052B2 - Adhesives and laminated sheets using them, and laminated structures - Google Patents

Description

The present invention relates to an adhesive applied to a heat-foamable sheet that forms a carbonized heat insulating layer by increasing temperature, a laminated sheet using the same, and a laminated structure.

Conventionally, in building structures, it has been required to make main structures such as columns, beams, floors, and walls heat-resistant structures for the purpose of protecting the buildings from fire.
As one of the methods for applying a heat-resistant structure, there is a method of coating a base material such as a main structure with a sheet-like member (heat-expandable sheet) that foams (expands) by heat (for example, Patent Document 1, Patent). Document 2 etc.). The heat-foamable sheet is thin and lightweight in normal times, and has the effect of foaming and carbonizing to form a heat insulating layer and exhibiting heat-resistant protection against a temperature rise due to a fire or the like. Such a heat-foamable sheet has a feature that it can be relatively easily installed by simply attaching it with an adhesive or an adhesive, does not require an extra space, and can have a uniform thickness.

Japanese Unexamined Patent Publication No. 8-60763 JP-A-2017-145682

However, when the heat-foamable sheet is attached to the base material via an adhesive or an adhesive, it may be difficult to retain the carbonized heat insulating layer formed by foaming due to heat, and the desired heat-resistant protection is desired. Performance was sometimes difficult to maintain.

As a result of diligent research to solve the above problems, the present inventors have excellent adhesiveness in normal times and excellent drop-off when the temperature rises by containing a specific synthetic resin as an adhesive. The present invention has been completed by finding that sufficient heat-resistant protection can be obtained by demonstrating preventiveness and slip-off prevention.

That is, the present invention has the following features.
1. 1. An adhesive applied to a heat-foamable sheet that forms a carbonized heat insulating layer by increasing temperature.
The adhesive comprises a synthetic resin and a cross-linking agent.
The synthetic resin contains a hydroxyl group-containing acrylic resin and a fluororesin .
An adhesive having a mixing ratio (solid content weight ratio) of the hydroxyl group-containing acrylic resin and the fluororesin of 99.5: 0.5 to 80:20 .
2. 2. A laminated sheet in which a heat-foamable sheet that forms a carbonized heat insulating layer due to an adhesive and a temperature rise is laminated.
The adhesive comprises a synthetic resin and a cross-linking agent.
The synthetic resin contains a hydroxyl group-containing acrylic resin and a fluororesin .
A laminated sheet characterized in that the mixing ratio (solid content weight ratio) of the hydroxyl group-containing acrylic resin and the fluororesin is 99.5: 0.5 to 80:20 .
3. 3. A laminated structure in which an adhesive and a heat-foamable sheet that forms a carbonized heat insulating layer by increasing temperature are laminated on a substrate surface.
The adhesive comprises a synthetic resin and a cross-linking agent.
The synthetic resin contains a hydroxyl group-containing acrylic resin and a fluororesin .
A laminated structure characterized in that the mixing ratio (solid content weight ratio) of the hydroxyl group-containing acrylic resin and the fluororesin is 99.5: 0.5 to 80:20 .

The adhesive of the present invention contains a specific synthetic resin and is used for a heat-foamable sheet that forms a carbonized heat insulating layer by increasing the temperature. It has excellent adhesiveness in normal times and excellent heat resistance when the temperature rises. It is possible to enhance the heat-resistant protection property of the base material by demonstrating the property, the falling-off prevention property and the slip-off prevention property.

It is sectional drawing which shows an example of the laminated sheet of this invention. It is a perspective view which shows an example of the laminated structure of this invention. It is an enlarged sectional view of the part A of FIG.

1. 1. Thermal foaming sheet 2. Adhesive 3. Releasable sheet 4. Base material

Hereinafter, the present invention will be described in detail based on the embodiments thereof.
The adhesive of the present invention is applied to laminating heat-foamable sheets, for example.
-Laminated sheet in which an adhesive and a heat-foamable sheet that forms a carbonized heat insulating layer due to temperature rise are laminated.
-A laminated structure in which an adhesive and a heat-foamable sheet are laminated in order from the substrate surface side,
Can be used as.

The adhesive of the present invention contains a synthetic resin and a cross-linking agent, and the synthetic resin contains a hydroxyl group-containing acrylic resin and a fluororesin. By using such an adhesive, it has excellent adhesiveness, exhibits excellent heat resistance when the temperature rises, exhibits fall-off prevention and slip-off prevention, and provides heat-resistant protection of the base material. Can be enhanced. The mechanism of action is not limited to the following, but the decomposition temperature of the resin skeleton shifts to the high temperature region due to the incorporation of the fluororesin into the resin skeleton formed by the hydroxyl group-containing acrylic resin, resulting in excellent heat resistance. It is considered that the effect of the present invention can be obtained. The adhesive of the present invention also includes an adhesive.

The hydroxyl group-containing acrylic resin is obtained by using a hydroxyl group-containing monomer and an alkyl-containing (meth) acrylic monomer as essential components and, if necessary, copolymerizing with other monomers.

As the polymerization method, a known method may be adopted. For example, solution radical polymerization, suspension polymerization, bulk polymerization, emulsion polymerization and the like can be adopted, and an initiator or the like can also be used at the time of polymerization.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, and 6-hydroxyhexyl (meth). ) Primary hydroxyl group-containing (meth) acrylic monomers such as hydroxyalkyl (meth) acrylate monomers such as acrylates and 8-hydroxyoctyl (meth) acrylates,
Secondary hydroxyl group-containing (meth) acrylic monomers such as 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-chloro2-hydroxypropyl (meth) acrylate, etc.
Tertiary hydroxyl group-containing (meth) acrylic monomers such as 2-hydroxy-2-methylpropyl (meth) acrylate,
Further, glycerol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol (meth) acrylate, caprolactone-modified (meth) acrylic acid ester, N-hydroxyethyl acrylamide and the like can be mentioned, and one of them can be mentioned. Alternatively, two or more types can be used.

Examples of the alkyl-containing (meth) acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, and n. -Propyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl. Examples thereof include (meth) acrylate and cyclohexyl (meth) acrylate, and one or more of these can be used.

Other monomers include, for example,
Carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, and itaconic acid,
Amino group-containing monomers such as dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylate,
Amide group-containing monomers such as (meth) acrylamide and ethyl (meth) acrylamide,
Nitrile group-containing monomers such as acrylonitrile,
Epoxy group-containing monomers such as glycidyl (meth) acrylate,
γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, etc. Hydrolytic silyl group-containing vinyl-based monomer,
Aromatic hydrocarbon-based vinyl monomers such as styrene, methylstyrene, chlorostyrene, vinyltoluene, etc.
Sulfonic acid-containing vinyl monomers such as styrene sulfonic acid and vinyl sulfonic acid,
Chlorine-containing monomers such as vinyl chloride, vinylidene chloride, and chloroprene,
Α-olefins such as ethylene, propylene and isobutylene,
Vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, etc.
Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, etc.
Allyl ethers such as ethyl allyl ether and butyl allyl ether,
Etc., and one or more of these can be used.

In the adhesive of the present invention, the fluororesin used in combination (mixed and used) with the hydroxyl group-containing acrylic resin is not particularly limited, but for example,
(I) Fluorine-containing monomer alone or copolymer,
(Ii) A copolymer of a fluorine-containing monomer, a hydroxyl group-containing monomer, and other polymerizable monomers,
And so on. Further, the fluororesin may be a solvent-based resin such as a solvent-soluble resin or a non-aqueous dispersion resin, or a powder resin, but in the present invention, the solvent-soluble resin is preferable.

Examples of the fluorine-containing monomers of (i) and (ii) include perfluoroolefins such as tetrafluoroethylene, chlorotrifluoroethylene and hexafluoropropylene, and fluoroolefin monomers such as vinyl fluoride and vinylidene fluoride.
Examples thereof include fluoroalkyl group-containing acrylic monomers such as perfluoromethylmethacrylate, perfluoroisononylmethylmethacrylate, 2-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, and trifluoroethyl acrylate. These can be used in one type or two or more types.

Specific examples of the fluorine-containing monomer alone or copolymer of (i) above include polyvinyl fluoride (PVF), polyvinylidene fluoride, polytrifluoroethylene, polychlorotrifluoroethylene, and polytetrafluoroethylene. Monopolymer;
Examples thereof include copolymers such as tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, and ethylene-chlorotrifluoroethylene copolymer.

Further, as described in (i) above, those modified with an acrylic resin can also be used. As such an acrylic resin composite fluorine-containing resin, for example, a mixture and / or a reactant of the acrylic resin and the fluororesin can be used, and in particular, the powdery acrylic resin composite polytetrafluoroethylene is used in the adhesive. It has excellent dispersibility and can further enhance the effect of the present invention.

Examples of the hydroxyl group-containing monomer of (ii) include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, and hydroxypentyl vinyl ether; ethylene glycol monoallyl ether, diethylene glycol monoallyl ether, and triethylene glycol monoallyl. Hydroxyallyl ethers such as ethers; hydroxyl group-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxyethyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. One or more of these can be used.

Examples of other polymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and n-amyl (meth) acrylate. Isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) Alkyl-containing (meth) acrylic monomers such as acrylate; dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylamino (meth) acrylate, aminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, etc. Amino group-containing monomers; carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, maleic acid or its monoalkyl ester, itaconic acid or its monoalkyl ester, fumaric acid or its monoalkyl ester; (meth) acrylamide, ethyl Amid-containing monomers such as (meth) acrylamide; nitrile group-containing monomers such as (meth) acrylonitrile; epoxy group-containing monomers such as glycidyl (meth) acrylate; aromatic vinyl monomers such as styrene, methylstyrene, chlorostyrene and vinyltoluene; Vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate; olefin-based monomers such as ethylene and propylene can be mentioned, and one or more of these can be used as needed.

In the present invention, it is preferable that the fluororesin is a hydroxyl group-containing fluororesin obtained by copolymerizing the above-mentioned (ii) fluorine-containing monomer and a hydroxyl group-containing monomer as essential components and other polymerizable monomers. Thereby, the effect of the invention can be further enhanced. The mechanism of action is not limited to the following, but the hydroxyl group-containing fluororesin is likely to be stably incorporated into the resin skeleton formed by the hydroxyl group-containing acrylic resin, and the decomposition temperature of the resin skeleton is stably set in the high temperature region. It is considered that the resin can be shifted, excellent heat resistance can be exhibited, and the effect of the present invention can be enhanced.

The mixing ratio (solid content weight ratio) of the hydroxyl group-containing acrylic resin and the fluororesin is preferably 99.5 to 0.5 to 80:20 (more preferably 99: 1 to 90:10, more preferably 99: 1 to 90:10). 98: 2 to 92: 8). In such a range, it has excellent adhesiveness in normal times, and can exhibit excellent drop-off prevention property and slip-off prevention property when the temperature rises. When it is below the upper limit of the above range, it shows excellent adhesiveness, and when it is above the lower limit of the above range, it sufficiently exhibits excellent drop-off prevention property and slip-off prevention property when the temperature rises. Can be done.

Examples of the cross-linking agent contained in the adhesive of the present invention include isocyanate group-containing compounds and the like.

Examples of the isocyanate group-containing compound include tolylene diisocyanate compounds such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, and tetra. Xylylene diisocyanate compounds such as methyl xylylene diisocyanate; aromatic isocyanate compounds such as 1,5-naphthalenedi isocyanate and triphenylmethane triisocyanate; hexamethylene diisocyanate, isophorone diisocyanate, and these isocyanate compounds and trimethyl propane and the like. Examples thereof include an adduct form with the polyol compound of the above, a buretto form and an isocyanurate form of these polyisocyanate compounds, and one or more of these can be used.

The mixing ratio of the cross-linking agent is preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight, still more preferably 2 to 5 parts by weight, based on 100 parts by weight of the solid content of the synthetic resin. be. In such a range, the effect of the present invention can be fully exerted. When it is below the upper limit of the above range, it shows excellent adhesiveness, and when it is above the lower limit of the above range, it sufficiently exhibits excellent drop-off prevention property and slip-off prevention property when the temperature rises. Can be done.

In the present invention, the hydroxyl group-containing acrylic resin and the like can be used in combination with a curing catalyst that promotes the reaction of the cross-linking agent. The curing catalyst is, for example, a substance having an action of accelerating the reaction of isocyanate groups to cure. Examples of the curing catalyst include various types such as amine-based catalysts, organometallic-based catalysts, and inorganic-based catalysts.

The adhesive of the present invention is not particularly limited as long as it contains the above synthetic resin and a cross-linking agent, but may also contain known additives. The additive is not particularly limited, but is a filler, a colorant, a diluent, a viscous adhesive, a thickener, a dispersant, an antifoaming agent, a preservative, an antifungal agent, an algae-proofing agent, and an ultraviolet absorber. , Light stabilizers, heat stabilizers, antioxidants and the like.

Among these, examples of the antioxidant include phosphorus-based, sulfur-based, and hindered-type phenol-based antioxidants. These can be used alone or in combination of two or more. By including such an antioxidant, deterioration of the synthetic resin can be suppressed not only in normal times but also when the temperature rises due to a fire or the like, and excellent heat resistance can be exhibited.

Examples of the heat stabilizer include metal soap-based heat stabilizers such as calcium, barium, and zinc. These can be used alone or in combination of two or more. By including such a heat stabilizer, the crosslinkability of the adhesive is improved and excellent heat resistance can be exhibited.

The heat-foamable sheet of the present invention foams as the temperature rises (preferably 200 ° C. or higher, more preferably 250 ° C. or higher) to form a carbonized layer. As the constituent component of the heat-foamable sheet, for example, one containing a resin component, a flame retardant, a foaming agent, a carbonizing agent and a filler is suitable. Among these, the resin component is, for example, a vinyl resin, a polystyrene resin, a polypropylene resin, an acrylic resin, a polyamide resin, a polyurethane resin, a thermoplastic resin such as a vinyl acetate resin, or the like, and the flame retardant is, for example. As a foaming agent, for example, melamine, dicyandiamide, azodicarbonamide, etc., as a carbonizing agent, for example, pentaerythritol, dipentaerythritol, etc., as a filler, for example, talc, calcium carbonate, etc. Examples thereof include zinc oxide and titanium dioxide.

The blending ratio of each component is preferably 50 to 1000 parts by weight of the flame retardant, 5 to 500 parts by weight of the foaming agent, 5 to 600 parts by weight of the carbonizing agent, and filling with respect to 100 parts by weight of the resin component in terms of solid content. The agent is 10 to 300 parts by weight.

The heat-foamable sheet of the present invention may further contain pigments, fibers and the like. As the pigment, a general coloring pigment (organic pigment / inorganic pigment) can be used. Further, expandable graphite, unexpanded vermiculite and the like may be blended in order to further enhance the heat resistance.

The heat-foamable sheet used in the present invention can be produced by a known method. For example, a method of adding an appropriate solvent to a composition containing an appropriate amount of the above-mentioned synthetic resin, flame-retardant agent, foaming agent, carbonizing agent, etc., pouring it into a mold, drying the composition, and then removing the mold; Is applied to the release paper by a heating coating machine and then wound up; a method of processing the composition kneaded by a kneader into a sheet shape by an extrusion molding machine; the composition kneaded by a kneader is put between rolls. A method of supplying and processing into a sheet; a method of pelletizing the composition and then processing it into a sheet by an extrusion molding machine; a calender consisting of a plurality of heat rolls of the composition kneaded with a Banbury mixer, a mixing roll or the like. Examples thereof include a method of rolling and processing into a sheet.

Further, a reinforcing sheet can be laminated on the heat-foamable sheet. Examples of the reinforcing sheet include woven fabric, non-woven fabric, and mesh. By laminating such a reinforcing sheet, it is possible to improve the adhesiveness and adhesion, and further prevent the falling-off prevention property and the slip-off prevention property.

The thickness of the heat-foamable sheet of the present invention may be appropriately set depending on the application site and the like, but is preferably 0.2 mm or more and 10 mm or less, and more preferably 0.5 mm or more and 6 mm or less.

The laminated sheet of the present invention is obtained by forming an adhesive layer with the above-mentioned adhesive on one surface of a heat-foamable sheet. Further, in the laminated sheet (FIG. 1), the surface of the adhesive layer can be covered with a releasable sheet. By forming such a laminated body, the heat-foamable sheet can be easily attached, and the work efficiency is improved.

The releasable sheet protects the adhesive layer during storage or transportation of the laminated sheet of the present invention, and can be easily peeled off from the adhesive layer when the laminated sheet is used. As such a releasable sheet, a known one can be used without particular limitation. Examples thereof include paper or film coated or impregnated with a mold release agent such as silicon, wax or fluororesin, or a synthetic resin film such as polypropylene or polyethylene which does not contain the mold release agent and has a mold release property itself.

The method for manufacturing the laminated sheet is not particularly limited, but a method of applying an adhesive to one surface of a heat-foamable sheet and laminating a releasable sheet on the adhesive, or a method of laminating a releasable sheet on the releasable sheet is applied. Examples thereof include a method of coating and laminating a heat-foamable sheet on the coating. In the above method, when an adhesive is applied and each sheet is laminated on the adhesive, the sheets may be laminated as they are (without being dried) or after being dried. The amount of the adhesive used in this case is not particularly limited, but may be about 25 g / m ² or more and 300 g / m ² or less. Further, the laminated sheet of the present invention may be a wound body in which a long body of the laminated sheet is created and the laminated sheet is wound in a spiral shape. In the case of a wound body, the outer layer may be either a heat-foamable sheet or a releasable sheet, but it is preferable to wind the releasable sheet so as to be on the outer side. Such a wound body can be cut and used according to a required length, and a laminated sheet is unwound from the wound body at the time of construction, the releasable sheet is peeled off to expose the adhesive layer, and the adhesive layer is exposed. Can be used by sticking it toward the base material side. At this time, crimping or the like can be performed as needed.

The laminated structure of the present invention (FIGS. 2 and 3) can be obtained by attaching a heat-foamable sheet to a base material via an adhesive. The base material is not particularly limited as long as it requires heat resistance, but mainly includes materials constituting columns, beams, floors, walls, etc. of building structures, and is formed of, for example, metal. Examples thereof include H steel, steel round pillars, steel square pillars, mortar, concrete, calcium silicate board, gypsum board, calcium carbonate foam board, non-combustible volcanic vitreous multi-layer board, fiber reinforced cement board, lightweight cement board and the like. Further, the surface of the base material may be treated with a rust preventive agent or a rust preventive paint.

In the present invention, by coating such a base material with a heat-foamable sheet via the above-mentioned adhesive, a laminated structure having heat resistance can be obtained.

The coating method is not particularly limited, but for example,
-How to attach the above laminated sheet to the base material,
-A method of applying an adhesive to the base material side and / or the heat-foamable sheet side and adhering as it is,
-A method in which an adhesive is applied to the base material side and / or the heat-foamable sheet side, the adhesive is dried, and then pressure-bonded to bond the adhesive.
And so on. The amount of the adhesive used is not particularly limited, but may be about 25 g / m ² or more and 300 g / m ² or less. When using a laminated sheet in which a releasable sheet, an adhesive, and a heat-foamable sheet are laminated, the releasable sheet may be peeled off and adhered to a base material, and crimping or the like may be performed as necessary. You can also.

Hereinafter, examples will be shown to further clarify the features of the present invention.

(Manufacturing of adhesive)
According to the formulation shown in Table 1, each raw material was mixed by a conventional method and used as an adhesive 1-7.
The following raw materials were used.
-Hydroxy group-containing acrylic resin (solid content 54% by weight, ethyl acetate, containing aromatic hydrocarbon solvent)
-Fluororesin: Fluororesin containing hydroxyl groups (chlorotrifluoroethylene-vinyl ether-hydroxyalkyl vinyl ether, hydroxyl value 52 mgKOH / g, solid content 60% by weight, containing aromatic hydrocarbon solvent)
-Crosslinking agent: Isocyanate compound (tolylene diisocyanate compound, solid content 45% by weight, ethyl acetate solvent)
・ Solvent: Ethyl acetate ・ Additives: Plasticizers, antioxidants, heat stabilizers, catalysts

(Manufacturing of heat foamable sheet)
A raw material mixture containing 100 parts by weight of ethylene-vinyl acetate resin, 75 parts by weight of melamine, 75 parts by weight of dipentaerythritol, 370 parts by weight of ammonium polyphosphate and 105 parts by weight of titanium oxide is sufficiently kneaded using a kneader and then extruded. It was processed into a sheet by a machine to produce a heat-foamable sheet having a thickness of 1 mm.

(Example 1)
1. 1. Adhesive Test 200 g / m ² of Adhesive 1 was applied to one half surface (25 mm × 25 mm) of a heat-foamable sheet (25 mm × 50 mm), and dried at 23 ° C. for 3 hours. Similarly, 100 g / m ² of the adhesive 1 was applied to one side of a steel sheet (150 mm × 70 mm × 1.6 mm) and dried at 23 ° C. for 3 hours.
Next, the adhesive-coated surface of the heat-foamable sheet and the adhesive-coated surface of the steel plate were pressure-bonded and bonded to obtain a test piece. (Note that this test piece is in an embodiment in which one side of the heat-foamable sheet is not adhered to the steel plate (has a non-adhesive portion).)
In the adhesiveness test, the test piece was placed horizontally so that the heat-foamable sheet was on the lower side, the non-adhesive portion of the heat-foamable sheet 1 was bent at 90 °, and the non-adhesive portion of the heat-foamable sheet 1 was bent at the tip of the bent portion of the heat-foamable sheet. A weight of 200 g was suspended, and the time until the heat-foamable sheet was peeled off from the steel plate was measured. The evaluation was performed in the following five stages. The results are shown in Table 2.
A: 2 hours or more B: 1 hour or more and less than 2 hours C: 30 minutes or more and less than 1 hour D: 15 minutes or more and less than 30 minutes E: less than 15 minutes

2. 2. Dropout test 1
100 g / m ² of the adhesive 1 was applied to the entire surface of one side of the heat-foamable sheet (70 mm × 70 mm), and the sheet was dried at 23 ° C. for 3 hours. Similarly, 100 g / m ² of the adhesive 1 was applied to one side of a steel sheet (150 mm × 70 mm × 1.6 mm) and dried at 23 ° C. for 3 hours.
Next, the adhesive-coated surface of the heat-foamable sheet and the adhesive-coated surface of the steel plate were pressure-bonded and bonded to obtain a test piece.
In the dropout test 1, the heat-foamable sheet is horizontally installed so as to be on the lower side, a heater (heater temperature 680 ° C.) is installed at a position 25 mm above the test piece, and the test piece is heated by the heater to form a steel plate. The temperature of the interface between the steel sheet and the heat-foamable sheet when the heat-foamable sheet fell off was measured. The evaluation was performed in the following four stages. The results are shown in Table 3.
⊚: Drop-off temperature 300 ° C or higher ○: Drop-off temperature 280 ° C or higher and lower than 300 ° C Δ: Drop-off temperature 260 or higher and lower than 280 ° C ×: Drop-off temperature less than 260 ° C

3. 3. Dropout test 2
Specimens were obtained in the same manner as in dropout test 1.
In the dropout test 2, the test piece was installed vertically, and the propane gas burner was installed at a position 50 cm laterally from the test piece (heat foamable sheet surface side).
In the dropout test 2, the test piece was heated for 1 minute with a propane gas burner, and the state of the heat-foamable sheet was evaluated. The evaluation was performed in the following three stages. The results are shown in Table 3.
○: Not dropped △: Partially dropped ×: Dropped

(Examples 2 to 5, Comparative Examples 1 to 2)
A test piece was prepared in the same manner as in Example 1 except that the adhesive shown in Table 2 was used, and the adhesiveness test, the dropout test 1 and the dropout test 2 were performed. The evaluation is shown in Table 2.

Claims (3)

An adhesive applied to a heat-foamable sheet that forms a carbonized heat insulating layer by increasing temperature.
The adhesive comprises a synthetic resin and a cross-linking agent.
The synthetic resin contains a hydroxyl group-containing acrylic resin and a fluororesin .
An adhesive having a mixing ratio (solid content weight ratio) of the hydroxyl group-containing acrylic resin and the fluororesin of 99.5: 0.5 to 80:20 . A laminated sheet in which a heat-foamable sheet that forms a carbonized heat insulating layer due to an adhesive and a temperature rise is laminated.
The adhesive comprises a synthetic resin and a cross-linking agent.
The synthetic resin contains a hydroxyl group-containing acrylic resin and a fluororesin .
A laminated sheet characterized in that the mixing ratio (solid content weight ratio) of the hydroxyl group-containing acrylic resin and the fluororesin is 99.5: 0.5 to 80:20 . A laminated structure in which an adhesive and a heat-foamable sheet that forms a carbonized heat insulating layer by increasing temperature are laminated on a substrate surface.
The adhesive comprises a synthetic resin and a cross-linking agent.
The synthetic resin contains a hydroxyl group-containing acrylic resin and a fluororesin .
A laminated structure characterized in that the mixing ratio (solid content weight ratio) of the hydroxyl group-containing acrylic resin and the fluororesin is 99.5: 0.5 to 80:20 .

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