JP2016194053A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition which makes it possible to obtain high initial adhesiveness even if polyvinyl chloride and a steel plate are stuck to each other at a low temperature.SOLUTION: The present invention provides an adhesive composition for a polyvinyl chloride laminate steel plate, which is at least two-liquid type adhesive composition comprising a main agent and a curing agent, the main agent comprising a solvent, a polyester resin, an isocyanate compound, a filler, a catalyst and a silane coupling agent.SELECTED DRAWING: None

Description

  The present invention relates to an adhesive composition.

Conventionally, decorative steel plates have been used as materials for buildings and the like.
A decorative steel sheet is generally manufactured by laminating an embossed resin film on a base metal plate, but an adhesive is used between the resin film and the base metal plate during the above lamination. May be.
The present applicant has previously proposed Patent Document 1 as an adhesive composition used in the lamination. Patent Document 1 discloses an adhesive composition for a printed film laminated steel sheet containing a substrate, a curing agent and an adhesion promoter, wherein the substrate is a polyester resin, and the curing agent is a polyisocyanate compound. There is described an adhesive composition for a printed film laminated steel sheet, wherein the adhesion promoter is an amine catalyst and 1,3-bis (N, N-glycidylaminomethyl) cyclohexane.

JP 2008-69232 A

Under such circumstances, an adhesive composition is prepared based on Patent Document 1, and the composition is applied to a steel sheet, which exceeds the softening point of the polyester resin contained in the composition, but the baking temperature is relatively high. Baking at a low temperature, bonding and pressing a polyvinyl chloride sheet and a steel plate to produce a polyvinyl chloride laminated steel plate, the resulting polyvinyl chloride laminated steel plate may have low initial adhesion. It became clear.
Then, an object of this invention is to provide the adhesive composition with which high initial adhesiveness is acquired even if it bonds together a polyvinyl chloride and a steel plate at low temperature.

As a result of intensive studies to solve the above-mentioned problems, the present inventors are at least a two-component adhesive composition having a main agent and a curing agent, and the main agent is a solvent, a polyester resin, a filler, and a catalyst. According to the adhesive composition for a polyvinyl chloride laminated steel sheet containing a silane coupling agent and a silane coupling agent, it has been found that a predetermined effect can be obtained, and the present invention has been achieved.
The present invention is based on the above knowledge and the like, and specifically, solves the above problems by the following configuration.

1. An adhesive composition of at least two-component type having a main agent and a curing agent, wherein the main agent includes a solvent, a polyester resin, a filler, a catalyst, and a silane coupling agent. Adhesive composition.
2. The adhesive composition according to 1 above, wherein the content of the silane coupling agent is 1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polyester resin.
3. The adhesive composition according to 1 or 2 above, wherein the polyester resin is at least one selected from the group consisting of a polyester resin having a softening point of 150 ° C or lower and a polyester resin having a softening point exceeding 150 ° C.
4. The adhesive composition according to any one of the above 1 to 3, wherein the polyester resin contains a polyester resin having a softening point of 150 ° C or lower and a polyester resin having a softening point exceeding 150 ° C.
5. The mass ratio of the polyester resin having a softening point of 150 ° C. or lower to the polyester resin having a softening point of higher than 150 ° C. (polyester resin having a softening point of 150 ° C. or lower / polyester resin having a softening point higher than 150 ° C.) is 2/8. 5. The adhesive composition according to 4 above, which is 8/2 or less.
6. The adhesive composition according to any one of 1 to 5, wherein the main agent further contains a plasticizer.
7. The adhesive composition according to 6 above, wherein the plasticizer is epoxidized linseed oil.
8. The adhesive composition according to 6 or 7 above, wherein a content of the plasticizer is 5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polyester resin.
9. The adhesive composition according to any one of 1 to 8 above, wherein the catalyst is a tin-based catalyst and / or an amine-based catalyst.
10. The adhesive composition according to any one of 1 to 9, wherein the curing agent contains a polyisocyanate compound.

  According to the adhesive composition of the present invention, high initial adhesiveness can be obtained even when polyvinyl chloride and a steel plate are bonded together at a low temperature.

The present invention will be described in detail below.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
Moreover, in this specification, when a component contains 2 or more types of compounds, content of a component points out the sum total of content of 2 or more types of compounds.
The softening point is synonymous with the softening temperature.

[Adhesive composition of the present invention]
The adhesive composition of the present invention (the composition of the present invention)
An adhesive composition of at least two-component type having a main agent and a curing agent, wherein the main agent includes a solvent, a polyester resin, a filler, a catalyst, and a silane coupling agent. It is an adhesive composition.

  Since the composition of this invention takes such a structure, it is thought that a desired effect is acquired. The reason is not clear, but it is presumed that the adhesiveness between the composition of the present invention and the polyvinyl chloride and the steel sheet is increased by containing the silane coupling agent.

  Hereinafter, each component contained in the composition of this invention is explained in full detail.

The composition of this invention has a main ingredient and a hardening | curing agent.
The composition of the present invention is at least a two-component composition. One preferred embodiment of the composition of the present invention is a two-pack type.

(Main agent)
In the composition of the present invention, the main agent contains a solvent, a polyester resin, a filler, a catalyst, and a silane coupling agent.

-Solvent In the composition of this invention, the solvent contained in a main ingredient will not be restrict | limited especially if it is an organic compound (organic solvent) inactive with respect to the other component contained in a main ingredient. For example, alicyclic hydrocarbon compounds such as cyclohexane; naphtha; ketones such as acetone, methyl ethyl ketone (MEK) and methyl isobutyl ketone; aromatic hydrocarbon compounds such as benzene, xylene and toluene; methyl acetate, ethyl acetate, acetic acid Examples include esters such as butyl; ethers such as diethyl ether, tetrahydrofuran, and dioxane.
The solvent is preferably at least one selected from the group consisting of alicyclic hydrocarbon compounds, naphtha and ketones.
The boiling point of naphtha is preferably higher than the softening point of the polyester resin described later. The boiling point of naphtha is preferably 175 to 220 ° C. The boiling point is measured under the condition of 1 atm.

150 mass parts or more and 300 mass parts or less are preferable with respect to 100 mass parts of polyester resins, and, as for content of the said solvent, it is more preferable that it is 200-250 mass parts.
When the solvent contains naphtha, the amount of naphtha can be appropriately adjusted in terms of workability, but is preferably 80 to 10 parts by mass, and 70 to 15 parts by mass in 100 parts by mass of the solvent. Is more preferable.

-Polyester resin The polyester resin contained in the main ingredient in the composition of the present invention is not particularly limited as long as it is a compound having two or more ester bonds.
Further, the polyester resin is not particularly limited for its production. For example, it can be produced by reacting an acid component having a plurality of carboxy groups or acid anhydride groups with a polyol having a plurality of hydroxy groups. The acid component and the polyol are not particularly limited.
The polyester resin can have a carboxy group, an acid anhydride group, or a hydroxy group at the terminal.
As the polyester resin, a commercially available grade can be used.

The polyester resin is preferably at least one selected from the group consisting of a polyester resin having a softening point of 150 ° C. or lower and a polyester resin having a softening point exceeding 150 ° C.
For polyester resins having a softening point of 150 ° C. or lower, the lower limit of the softening point is preferably 50 ° C. or higher.
For polyester resins having a softening point exceeding 150 ° C, the upper limit of the softening point is preferably 170 ° C or less.

  The manufacturer's published (catalog) value was used as the softening point of the polyester resin in the present invention.

  In addition, from the viewpoint that the polyvinyl chloride and the steel plate can be bonded at a lower temperature, higher initial adhesiveness is obtained, and the balance with boiling water resistance is excellent, the polyester resin has a softening point of 150 ° C. or less. It is preferable to use together a polyester resin having a softening point of more than 150 ° C.

  In the case of the above combination, the mass ratio of the polyester resin having a softening point of 150 ° C. or less and the polyester resin having a softening point of more than 150 ° C. (polyester resin having a softening point of 150 ° C. or less / polyester resin having a softening point of more than 150 ° C.) is 2 It is preferably / 8 or more and 8/2 or less, more preferably 3/7 to 7/3.

-Filler The filler contained in the main agent in the composition of the present invention is not particularly limited. For example, silica, calcium carbonate, clay, talc and the like can be mentioned.
Of these, silica is preferable, and amorphous silica and fumed silica are more preferable.
The fillers can be used alone or in combination of two or more.

  The content of the filler is preferably 1 part by mass or more and 10 parts by mass or less, and more preferably 1-5 parts by mass with respect to 100 parts by mass of the polyester resin.

-Catalyst The catalyst contained in the main component in the composition of the present invention is a compound that can accelerate the reaction of the curing agent contained in the composition of the present invention (hereinafter sometimes referred to as a broadly defined curing agent). There is no particular limitation.
The catalyst is preferably a tin-based catalyst and / or an amine-based catalyst. The broadly defined curing agent contains at least a compound described later (strictly defined curing agent), but when the narrowly defined curing agent is an isocyanate compound, the catalyst is preferably a tin-based catalyst and / or an amine-based catalyst. One of them.

  The tin-based catalyst is not particularly limited as long as it is a compound having tin. Examples thereof include dialkyltin dicarboxylic acid esters such as dibutyltin dilaurate and dioctyltin dilaurate.

The amine catalyst is not particularly limited. For example, a compound having at least one selected from the group consisting of an amino group, an imino group, a tertiary amino group and a quaternary ammonium salt (hereinafter sometimes referred to as an amino group or the like) can be mentioned.
The said amino group etc. can be couple | bonded with the hydrocarbon group which may have a hetero atom.
The hydrocarbon group is not particularly limited. For example, an aliphatic hydrocarbon group (either linear, branched, cyclic, or a combination thereof), an aromatic hydrocarbon group, or a combination thereof can be given.
The hetero atom is not particularly limited. For example, an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen are mentioned. A hetero atom may be individual, respectively, or may combine 2 or more types. A hetero atom may optionally replace the carbon atom of the hydrocarbon group. The heteroatom may be bonded to a hydrogen atom or a carbon atom to form a functional group.
Examples of amine-based catalysts include primary amines, secondary amines, tertiary amines, and quaternary ammonium salts.

Moreover, in this invention, a commercial item can be used as an amine catalyst. Examples of such amine-based catalysts include special amines such as urethane catalysts (U-CAT SA series) manufactured by Sun Apro.
The catalysts can be used alone or in combination of two or more.

  The content of the catalyst is preferably 0.01 to 0.1 parts by mass and more preferably 0.01 to 0.05 parts by mass with respect to 100 parts by mass of the polyester resin.

Silane coupling agent The silane coupling agent contained in the main component in the composition of the present invention is not particularly limited as long as it is a compound having a hydrolyzable silyl group or silanol group and a functional group.
Examples of the hydrolyzable silyl group possessed by the silane coupling agent include an alkoxysilyl group. The number of carbon atoms of the alkoxy group that the alkoxysilyl group has can be 1 to 5. The number of alkoxy groups bonded to one silicon atom is preferably 2 or 3.
When the number of alkoxy groups bonded to one silicon atom is 2 or less, the hydrocarbon group that can be bonded to the silicon atom is not particularly limited. For example, an alkyl group is mentioned.
Examples of the functional group that the silane coupling agent has include an epoxy group, an amino group, an imino group (—NH—), and a hydroxy group. Of these, an epoxy group is preferable.
The hydrolyzable silyl group or silanol group and the functional group can be bonded to a hydrocarbon group which may have a hetero atom. A hetero atom and a hydrocarbon group are as defined above.

The silane coupling agent is preferably epoxy silane or amino silane.
As the epoxy silane, for example, glycidyloxyalkyltrialkoxysilane and glycidyloxyalkyldialkoxyalkylsilane are more preferable, and 3-glycidyloxypropyltrimethoxysilane is exemplified.

The aminosilane can have an amino group and / or an imino group. One preferred embodiment of aminosilane having an imino group is mentioned. Examples of aminosilanes having an imino group include N-phenyl-3-aminopropyltrimethoxysilane (KBM-573, manufactured by Shin-Etsu Chemical Co., Ltd.), N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane may be mentioned.
The silane coupling agents can be used alone or in combination of two or more.

  1 mass part or more and 10 mass parts or less are preferable with respect to 100 mass parts of said polyester resins, and, as for content of the said silane coupling agent, it is more preferable that it is 1-5 mass parts.

-Plasticizer In this invention, it is preferable that a main ingredient contains a plasticizer further. A preferable example of the plasticizer is one having a low glass transition temperature (Tg) that can be compatible with the polyester resin. Specific examples include ester plasticizers and epoxy plasticizers.
The plasticizer is preferably an epoxy plasticizer, more preferably epoxidized linseed oil.
Epoxidized linseed oil is not particularly limited as long as it is epoxidized linseed oil.
The plasticizers can be used alone or in combination of two or more.

  The content of the plasticizer is preferably 5 parts by mass or more and 10 parts by mass or less, and more preferably 5 to 8 parts by mass with respect to 100 parts by mass of the polyester resin.

  In the present invention, the main agent can be prepared by mixing the above components.

(Curing agent)
The composition of the present invention has a curing agent (curing agent in a broad sense).
The curing agent (curing agent in a broad sense) included in the composition of the present invention can include at least a curing agent in a narrow sense. The curing agent (curing agent in a broad sense) included in the composition of the present invention may be composed of only a curing agent in a narrow sense.
In the present invention, the hardener in the narrow sense can react with the polyester resin and / or silane coupling agent contained in the main agent, or can react with each other in a narrow sense.
The curing agent in a narrow sense is one of the preferred embodiments that is a compound having a functional group capable of the above reaction.
One of the preferred embodiments is that the hardener in the narrow sense has a plurality of functional groups in one molecule.

The hardener in the narrow sense is not particularly limited as long as it is a compound having a plurality of the above functional groups.
As a functional group, an isocyanate group is mentioned, for example.
One molecule of the hardener in the narrow sense has two or more functional groups, and can be four or less.
The functional group can be bonded to a hydrocarbon group which may have a hetero atom. A hetero atom and a hydrocarbon group are as defined above.

The narrowly defined curing agent is preferably a polyisocyanate compound. The polyisocyanate compound is not particularly limited as long as it is a compound having a plurality of isocyanate groups.
Examples of the polyisocyanate compound include aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and hydrogenated xylylene diisocyanate (H ₆ XDI); diphenylmethane diisocyanate, tolylene diisocyanate (TDI), xylylene Aromatic polyisocyanates such as diisocyanate (XDI); modified products thereof; polyisocyanates having phosphate esters such as tris (phenylisocyanate) thiophosphate; copolymers of polyisocyanate compounds such as copolymers of TDI and HDI Is mentioned.

Examples of the modified body include adducts with triols such as trimethylolpropane and glycerin; isocyanurates; burettes; allophanates.
Examples of commercially available modified products include Takenate D series (Mitsui Chemicals).

  As a commercial item of a tris (phenyl isocyanate) thiophosphate, Desmodur RFE (made by Bayer) is mentioned, for example.

  Examples of the polyisocyanate compound copolymer include Desmodur HL (manufactured by Bayer).

The narrowly defined curing agent is preferably at least one selected from the group consisting of a modified polyisocyanate compound, a polyisocyanate having a phosphate ester, and a copolymer of a polyisocyanate compound.
The hardeners in a narrow sense can be used alone or in combination of two or more.

  The content of the hardener in the narrow sense is preferably 1 to 10 parts by mass and more preferably 1 to 7 parts by mass with respect to 100 parts by mass of the main agent.

-Optional component The composition of this invention can contain an additive further as needed other than the said various components in the range which does not impair the objective of this invention. Examples of the additive include an anti-aging agent, an antioxidant, an adhesiveness imparting agent, a dispersant, and a colorant.
The additive can be added to the main agent and / or the curing agent. Moreover, the composition of this invention may have an additive as 3rd agents other than a main ingredient and a hardening | curing agent.

The composition of this invention can be manufactured by mixing a main ingredient and a hardening | curing agent, for example. The mixing method is not particularly limited.
The main agent can be prepared by mixing the above components.
When using only a hardener in a narrow sense as a hardener, a hardener in a narrow sense can be used as it is as a hardener. When a hardening | curing agent contains arbitrary components other than a hardener in a narrow sense, a hardening | curing agent can be prepared by mixing these.

The composition of the present invention can be used as an adhesive composition for a polyvinyl chloride laminated steel sheet. Specifically, for example, when producing a polyvinyl chloride laminated steel sheet, it can be used as an adhesive for adhering the polyvinyl chloride film and the steel sheet.
The method in particular of apply | coating the composition of this invention to a polyvinyl chloride film or a steel plate is not restrict | limited. For example, a conventionally well-known thing is mentioned.

[Polyvinyl chloride resin laminated steel sheet]
By using the composition of the present invention, it is possible to produce a polyvinyl chloride resin-laminated steel sheet in which the polyvinyl chloride film and the steel sheet are bonded via the composition of the present invention.

The polyvinyl chloride film used when manufacturing the polyvinyl chloride resin laminated steel sheet is not particularly limited. For example, a conventionally well-known thing is mentioned.
The surface of the polyvinyl chloride film may have a texture. The grain is not particularly limited. For example, the embossing may be formed by embossing. According to the composition of the present invention, high initial adhesiveness can be obtained even if the temperature at which the polyvinyl chloride and the steel plate are bonded is lowered. Therefore, after the bonding between the vinyl chloride and the steel plate, Can keep.
The thickness of the polyvinyl chloride film can be 50 μm to 200 μm.

  The steel plate used when manufacturing the polyvinyl chloride resin laminated steel plate is not particularly limited. For example, a conventionally well-known thing is mentioned. The thickness of the steel plate can be 0.2-2 mm.

(Production method of polyvinyl chloride resin laminated steel sheet)
As a manufacturing method of a polyvinyl chloride resin laminated steel sheet, for example,
An application step of applying the composition of the present invention on the steel sheet;
A baking step of baking the steel sheet after the coating step;
On the composition on the steel plate after the baking step, a lamination step of laminating the polyvinyl chloride film to obtain a laminate,
The manufacturing method of the polyvinyl chloride resin laminated steel plate which has a crimping | compression-bonding process which crimps | bonds the said laminated body and obtains a polyvinyl chloride resin laminated steel plate is mentioned.

In the said manufacturing method, the said application | coating process is a process of apply | coating the composition of this invention on a steel plate.
The steel plate used in the coating process is the same as described above.
The composition used in the coating step is not particularly limited as long as it is the composition of the present invention.
The method for applying the composition of the present invention on a steel plate is not particularly limited.
The film thickness of the composition after application can be 2 to 20 μm.

In the said manufacturing method, a drying process can be arbitrarily provided between an application | coating process and a baking process. It is mentioned as one of the preferable aspects that the said manufacturing method has the said drying process further.
A drying process is a process of drying the composition on the steel plate after an application | coating process.
The drying method in the drying step is not particularly limited as long as the solvent can be removed from the composition. For example, a method of drying at room temperature (natural drying) can be mentioned.

A baking process is a process of baking the steel plate after an application | coating process or a drying process.
In the baking process, the method for baking the steel sheet is not particularly limited. For example, a conventionally well-known thing is mentioned.
The temperature (baking temperature) in the baking step can be 250 ° C. or lower, preferably 160 ° C. or lower, more preferably 150 ° C. or lower, and still more preferably lower than 150 ° C.
Since the composition of the present invention is used, the baking temperature can be lowered.
When baking temperature is 160 degrees C or less, the polyvinyl chloride resin laminated steel plate which maintained the state of the polyvinyl chloride film before affixing can be obtained, without deforming a polyvinyl chloride film. In the case where the polyvinyl chloride film has a texture, one of preferred embodiments is that the baking temperature is 160 ° C. or lower.

A lamination process is a process of bonding a polyvinyl chloride film on the composition on a steel plate immediately after a baking process, and obtaining a laminated body.
In the laminating step, the method for bonding the polyvinyl chloride film to the steel plate is not particularly limited. For example, a conventionally well-known thing is mentioned.
In the laminating process, it is preferable that the temperature of the steel sheet after the baking process is maintained at the same level as that in the baking process from the viewpoint of not reducing the initial adhesiveness.

The crimping step is a step of crimping the laminate to obtain a polyvinyl chloride resin laminated steel sheet.
The pressure bonding can be performed using a roller, for example.

Moreover, as another manufacturing method of the polyvinyl chloride resin laminated steel sheet, for example,
An application step of applying the composition of the present invention on the steel sheet;
The manufacturing method of the polyvinyl chloride resin laminated steel plate which has the lamination process of bonding the steel plate after the said application | coating process and the said polyvinyl chloride film with a laminator, and obtaining a polyvinyl chloride resin laminated steel plate is mentioned.

The coating process is the same as described above.
A drying step can optionally be provided between the coating step and the laminating step. The drying process is the same as described above.

The laminating step is a laminating step of obtaining a polyvinyl chloride resin laminated steel sheet by laminating the steel sheet and the polyvinyl chloride film after the coating process or the drying process with a laminator.
The polyvinyl chloride film used in the laminating process is the same as described above.

  In the laminating step, first, the steel plate and the polyvinyl chloride film after the coating step or the drying step are set in a laminator, the steel plate is heated (for example, warm air heating), and after heating, the steel plate and the polyvinyl chloride film are rolled into a roller. It is possible to obtain a polyvinyl chloride resin laminated steel sheet by pressure bonding while bonding together.

  In the laminating step, the heating temperature of the steel plate or the temperature of the pressure bonding can be the same as the above baking temperature.

The heating time can be 20 seconds to 1 minute.
By passing the steel plate and the polyvinyl chloride film between two rubber rolls, the steel plate and the polyvinyl chloride film can be pressure-bonded.
The pressure-bonded polyvinyl chloride resin laminated steel sheet may be cooled with water, for example.

  The polyvinyl chloride resin laminated steel sheet manufactured using the composition of the present invention can be used as, for example, a decorative steel sheet.

  The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.

<Preparation of main agent>
Using each component shown in the “Composition of main ingredient” column in the following Table 1 in the amount (parts by mass) shown in the same table, these were mixed with a stirrer to prepare the main ingredient.

<Production of composition>
Main agent (main agent prepared in the above composition) and curing agent shown in Table 1 below in Table 1 and curing agent: polyisocyanate 1 (polyisocyanate-based curing agent, trade name HAMATITE Y-6410-B. Polyisocyanate 1 The content of the polyisocyanate compound in (curing agent in a broad sense): 46% by mass, NCO group content in the polyisocyanate compound: 30% by mass, manufactured by Yokohama Rubber Co., Ltd. is used in the amount (parts by mass) shown in the same table. These were mixed with a stirrer to produce a composition.

<Manufacture of polyvinyl chloride resin laminated steel sheet>
-Application | coating process Each composition manufactured as mentioned above was apply | coated on the steel plate (length 15cm x width 5cm x thickness 1mm) using the bar coater # 10.

-Drying process The steel plate coated with the composition obtained as described above was placed under normal temperature conditions for 5 minutes to dry the composition.

-Preparation of polyvinyl chloride film A polyvinyl chloride film (length 18 cm x width 7 cm x thickness 50 µm, having a surface with a texture) was prepared.

-Baking process The steel plate after the drying process was put in an oven set at the temperature (140 ° C, 150 ° C, 160 ° C, 250 ° C) at the time of pasting shown in Table 1 and baked for 1 minute. .

・ Lamination process and crimping process Take out the baked steel sheet from the oven, immediately paste the polyvinyl chloride film on the steel sheet to make a laminate (laminating process), and press the laminate with a roller to laminate the polyvinyl chloride resin. A steel plate was produced.

<Evaluation>
The following evaluation was performed using the polyvinyl chloride resin laminated steel sheet manufactured as described above. The results are shown in Table 1.
-Initial adhesiveness The cross-cut of the cross was put into the polyvinyl chloride resin laminated steel plate from the said polyvinyl chloride resin film, and the sample for initial adhesive evaluation was obtained. The width of each side of the cross was 5 mm.
The sample for initial adhesiveness evaluation after cross-cutting was pushed in by 7 mm in the Erichsen test specified in JIS K 6744, and after the pushing, the polyvinyl chloride film (cross portion) was forcibly peeled and observed.

The evaluation criteria of initial adhesiveness are as follows.
A: Forced peeling was attempted, but the polyvinyl chloride film remained in close contact with the steel plate and was not peeled off from the steel plate.
B: A part of the polyvinyl chloride film was peeled off from the steel sheet by forced peeling.
C: The entire polyvinyl chloride film cut into a cross was peeled off from the steel sheet by forced peeling.
A is most excellent in initial adhesiveness, B is somewhat excellent in initial adhesiveness, and C has low initial adhesiveness.

The evaluation criteria for the presence or absence of wrinkles are as follows.
Yes: The surface of the manufactured polyvinyl chloride resin-laminated steel sheet obtained as described above had wrinkles, and the matte state could be maintained.
None: The surface of the manufactured polyvinyl chloride resin-laminated steel sheet obtained as described above was smooth, free of wrinkles, glossy, and could not maintain a matte state.

Boiling water resistance A boiling water resistance test was performed in which the polyvinyl chloride resin-laminated steel sheet produced as described above was immersed in boiling water for 2 hours and then further immersed for 1 day at room temperature.
Next, after the boiling water resistance test, the polyvinyl chloride resin-laminated steel sheet is taken out of the water, and a cross is cut into the polyvinyl chloride resin-laminated steel sheet from above the polyvinyl chloride resin film to obtain a sample for evaluating boiling water resistance. It was. The width of each side of the cross was 5 mm.
The sample for evaluation of boiling water resistance was pushed in by 7 mm in the Erichsen test specified in JIS K 6744. After the pushing, the polyvinyl chloride film (cross portion) was forcibly peeled and observed.

The evaluation criteria for boiling water resistance are as follows.
The case where the polyvinyl chloride film after the pressing did not peel from the steel sheet was indicated as A because it was very excellent in initial adhesiveness.
The case where the cross portion of the polyvinyl chloride film after the pressing peeled off from the steel plate within the range of the height from the upper portion of the extruded portion to 1/3 was indicated as B, indicating excellent initial adhesiveness.
The case where the cross portion of the polyvinyl chloride film after the pressing peeled off from the steel plate from the upper part of the extruded portion to the ridge was regarded as slightly inferior to the initial adhesiveness, and this was indicated as C.
The case where the entire cross portion of the polyvinyl chloride film after the pressing was peeled off from the steel sheet was regarded as having poor initial adhesion, and this was indicated as D.
When the cross section of the polyvinyl chloride film after the pressing was already peeled off from the steel plate before the forced peeling, the initial adhesiveness was very poor and this was indicated as E.

The details of each component used in the main agent and the curing agent (polyisocyanate 1) shown in Table 1 are as follows. The softening points of the polyester resins 1 to 4 used in the examples are the manufacturer's published (catalog) values.

  As shown in Table 1, Comparative Examples 1 and 2 not containing a silane coupling agent had low initial adhesiveness when polyvinyl chloride and a steel plate were bonded together at a low temperature. In particular, when the application temperature was set to 160 ° C., which is lower than the normal application temperature but higher than the softening point of the polyester resin, Comparative Examples 1 and 2 had low initial adhesiveness.

  On the other hand, Examples 1-11 were excellent in initial adhesiveness, even if it bonded together polyvinyl chloride and a steel plate at low temperature (160 degreeC).

  When Examples 1 to 6 are compared, a polyester resin having a softening point of 150 ° C. or less and a polyester resin having a softening point of more than 150 ° C. are used in combination, and as the content of the polyester resin having a softening point of 150 ° C. or less increases, the polyester resin is applied at a lower temperature. It became clear that even when combined, higher initial adhesiveness can be obtained.

  When Example 1 and Example 8 were compared, Example 8 containing a plasticizer was more excellent in initial adhesiveness at a lower temperature.

  When Example 6 was compared with Example 10, it became clear that the smaller the amount of the silane coupling agent, the higher the initial adhesiveness can be obtained even if the bonding is performed at a lower temperature.

  When comparing Examples 1 to 7 with respect to boiling water resistance, Examples 1 to 6 including at least a polyester resin having a softening point exceeding 150 ° C. as the polyester resin were superior to Example 7 in boiling water resistance.

  Further, when Examples 2 and 6 in which a polyester resin having a softening point of 150 ° C. or less and a polyester resin having a softening point exceeding 150 ° C. are used in combination as the polyester resin, the content of the polyester resin having a softening point exceeding 150 ° C. increases. Excellent boiling water resistance.

  Comparing Example 6 and Example 11, the use of aminosilane as the silane coupling agent was superior in boiling water resistance than epoxysilane.

Claims (10)

  An adhesive composition of at least two-component type having a main agent and a curing agent, wherein the main agent includes a solvent, a polyester resin, a filler, a catalyst, and a silane coupling agent. Adhesive composition.   The adhesive composition according to claim 1, wherein a content of the silane coupling agent is 1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polyester resin.   The adhesive composition according to claim 1 or 2, wherein the polyester resin is at least one selected from the group consisting of a polyester resin having a softening point of 150 ° C or lower and a polyester resin having a softening point higher than 150 ° C.   The adhesive composition according to any one of claims 1 to 3, wherein the polyester resin contains a polyester resin having a softening point of 150 ° C or lower and a polyester resin having a softening point exceeding 150 ° C.   The mass ratio of the polyester resin having a softening point of 150 ° C. or less and the polyester resin having a softening point of more than 150 ° C. (polyester resin having a softening point of 150 ° C. or less / polyester resin having a softening point of more than 150 ° C.) is 2/8 or more and 8 The adhesive composition according to claim 4, which is / 2 or less.   The adhesive composition according to claim 1, wherein the main agent further contains a plasticizer.   The adhesive composition according to claim 6, wherein the plasticizer is epoxidized linseed oil.   The adhesive composition according to claim 6 or 7, wherein a content of the plasticizer is 5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polyester resin.   The adhesive composition according to claim 1, wherein the catalyst is a tin-based catalyst and / or an amine-based catalyst.   The adhesive composition according to claim 1, wherein the curing agent includes a polyisocyanate compound.