JPH0899387A - Adhesive structure and metal laminate using the same - Google Patents

Abstract

PURPOSE: To obtain sufficient adhesiveness as a laminate without damaging appearance by constituting the laminate of an aminosilane coupling agent layer and a compsn. containing a specific linear polyester resin and a polyfunctional isocyanate compd. or a compd. wherein the isocyanate group of the polyfunctional isocyanate compd. is blocked. CONSTITUTION: An adhesive structure consists of an aminosilane coupling agent layer and a compsn. containing a specific linear polyester twain with a glass transition point of 60 deg.C or higher and a polyfunctional isocyaute compd. or a compd. wherein the isocyanate group of the polyfunctional isocyanate compd. is blocked. A laminate is produced by using the adhesive structure according to a process wherein a solution of an aminosilane coupling agent is applied to a base metal panel and dried to form a primer layer and an adhesive compsn. containing the linear polyester resin and the polyfunctional isocyanate compd. or the blocked isocyanate compd. is applied to the primer layer to be dried and a synthetic resin film is laminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin film such as a vinyl chloride film (hereinafter abbreviated as a vinyl chloride film) or a synthetic resin sheet (hereinafter abbreviated as a synthetic resin film (sheet)) and a metal plate at a low temperature. Relates to a urethane-based adhesive composition that gives excellent adhesive performance in the lamination, and a metal laminate using the same.

[0002]

2. Description of the Related Art Heretofore, as an adhesive used for producing a metal laminate by laminating a synthetic resin film and a metal plate, a combination of a polyester polyol and a polyisocyanate compound has been known.

However, in the case of producing a laminate using such an adhesive, it was necessary to laminate at an extremely high temperature, for example, 200 ° C. or higher in order to obtain sufficient adhesive strength. When laminated at such a high temperature, an unusual pattern is formed on the film, or when an embossed pattern is formed on a synthetic resin film (sheet) such as a vinyl chloride film (sheet), this embossed pattern is erased. However, there is a problem that the external appearance is spoiled and the appearance is lost.

On the other hand, when laminating at a low temperature so as not to impair the appearance, there is a problem in that the adhesive performance as a laminate is insufficient and it cannot be put to practical use.

[0005]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above-mentioned drawbacks.

[0006]

Means for Solving the Problems That is, the present invention comprises an aminosilane coupling agent layer (A), a linear polyester resin (b1) having a glass transition point of 60 ° C. or higher, a polyfunctional isocyanate compound (b2) or a polyfunctional isocyanate compound. Compound (b) in which isocyanate is blocked
And 3) (hereinafter, abbreviated as blocked isocyanate) and a composition layer (B) containing the same, and a metal laminated body using the adhesion composition.

That is, by simply combining the linear polyester resin (b1) having a glass transition point of 60 ° C. or higher, the polyfunctional isocyanate compound (b2) or the blocked isocyanate compound (b3), sufficient adhesive strength can be obtained in low temperature lamination. In addition, the aminosilane coupling agent (A) alone cannot firmly bond the synthetic resin film (sheet) to the metal plate.

In the present invention, the aminosilane coupling agent (A) is applied as a primer on a metal plate in advance and dried, and the linear polyester resin (b1) and the polyfunctional isocyanate compound (b2) are applied on the coating film. Alternatively, it is important to coat and dry the composition (B) containing the blocked isocyanate compound (b3) and laminate the synthetic resin film (sheet). Although it is possible to add the aminosilane coupling agent (A) to the composition obtained by mixing the linear polyester resin (b1), the polyfunctional isocyanate compound (b2) or the blocked isocyanate compound (b3), , An aminosilane coupling agent (A), the linear polyester resin (b1), and a polyfunctional isocyanate compound (b2)
Alternatively, the compatibility with the blocked isocyanate compound (b3) is poor, and the adhesive solution often separates before coating or the viscosity of the adhesive solution significantly changes during storage. By using the aminosilane coupling agent (A) as a primer, the above problems can be avoided,
Synthetic resin film (sheet) -It is now possible to firmly bond metal plates.

The aminosilane coupling agent (A) used in the present invention is a trialkoxysilane having an amino group such as 3-aminopropyltriethoxysilane and N-β (aminoethyl) γ-aminopropyltrimethoxysilane. There is.

When the aminosilane coupling agent (A) is applied and dried as a primer, the coating amount during drying is preferably 0.001 to 0.15 g / m ² ,
0.01 to 0.10 g / m ² is more preferable. If the coating amount at the time of drying is less than 0.001 g / m ² , the adhesiveness will not be improved so much. If it is more than 0.15 g / m ² , the boiling resistance is lowered.

The solvent for dissolving the aminosilane coupling agent (A) is preferably toluene, isopropyl alcohol or the like. In addition, if water is contained, it is not preferable because it discolors with time and a white precipitate is formed, so it is desirable to remove water. Also, after melting, it is necessary to be careful not to store it in a place of high temperature and high humidity or in a place exposed to light.

The linear polyester resin (b1) having a glass transition point of 60 ° C. or higher used in the present invention is obtained by reacting a polybasic acid or its ester compound with a polyhydric alcohol. Specifically, isophthalic acid, terephthalic acid,
Naphthalene dicarboxylic acid, phthalic anhydride, adipic acid,
Azelaic acid, sebacic acid, succinic acid, glutaric acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride,
There are maleic anhydride, itaconic anhydride and ester compounds thereof, and these can be used alone or in combination of two or more.

Specific examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-butylene glycol and 1,4-. There are cyclohexanedimethanol, trimethylolpropane, glycerin, 1,9-nanonediol, 3-methyl-1,5-pentanediol, pentaerythritol and the like, and these can be used alone or in combination of two or more.

The linear polyester resin (b1) used in the present invention has a glass transition point of 60 ° C. or higher. 60 ° C
When it is below, the processability, heat resistance and boiling resistance are poor.

The molecular weight of the linear polyester resin (b1) used in the present invention is 1,000 to 100,000, preferably 5,000 to 20,000. Molecular weight is 1000
If it is less than 100, the cohesive force is small and the adhesive strength and processability are insufficient. If it is 100000 or more, an unreacted isocyanate compound is likely to remain in the reaction, and the synthesis itself is difficult.

The polyfunctional isocyanate compound of the present invention (b
As 2), a mixture of a low molecular weight isocyanate compound, a polyurethane polyisocyanate obtained by reacting a low molecular weight isocyanate compound with water or a polyhydric alcohol, and a low polymer which is a dimer or trimer of a low molecular weight isocyanate. And is generally called an adduct body or an addition body.

Examples of the low molecular weight isocyanate include hexamethylene diisocyanate, phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, diphenylmethane-4,4-diisocyanate, 3,3-dimethyl-4,4-biphenylene diisocyanate, Examples include dicyclohexylmethane-4,4-diisocyanate, isophorone diisocyanate, xylylene diisocyanate and mixtures thereof.

Examples of the polyhydric alcohol include those described above as the raw material for producing the polyester resin (b1) used in the present invention, and among them, trimethylolpropane is preferably used.

As the blocked isocyanate compound (b3) of the present invention, the above polyfunctional isocyanate is used as an alcohol type blocking agent, a phenol type blocking agent, an oxime type blocking agent, a lactam type blocking agent, a mercaptan type blocking agent, an acid amide type blocking agent. Obtained by reacting with a blocking agent (also referred to as a masking agent) such as a blocking agent, an imide blocking agent, an amine blocking agent, an imidazole blocking agent, a urea blocking agent, a carbamic acid blocking agent, or an imine blocking agent. Some of them are listed.

In the present invention, the linear polyester resin (b1) having a hydroxyl group at the terminal and having a glass transition point of 60 ° C. or higher, the polyfunctional isocyanate compound (b2) or the blocked isocyanate compound (b3) means the ratio of NCO / OH. Is added to 1.0 to 5.0. The ratio of NCO / OH is 1.
When it is 0 or less, the performance as a laminated laminate is insufficient. Since it is a moisture-curing adhesive, the NCO / OH ratio may be somewhat high, but if the NCO / OH ratio is 5.0 or more, the isocyanate tends to remain.

An epoxy resin or a filler may be used alone or in a mixture in the adhesive composition (B) comprising the polyester resin (b1), the polyfunctional isocyanate compound (b2) or the blocked isocyanate compound (b3). You may add.

The amount of the epoxy resin added is preferably 0 to 30 parts by weight with respect to 100 parts by weight of the adhesive composition. As the epoxy resin, a bisphenol type epoxy resin, for example, Epicoheat 828, 1001, 100
2, 1004 (produced by Yuka Shell Epoxy Co., Ltd.).

Examples of the filler include calcium carbonate, ultrafine particle silica and talc. Other, colorants,
A catalyst and an anti-aging agent may also be added if necessary.

To produce a laminated laminate using the composition for forming the adhesive layer of the present invention, first, a solution of an aminosilane coupling agent is applied to a base metal plate,
Form a primer layer by drying at 40-50 ° C for 2-3 minutes,
Immediately thereafter, an adhesive composition (B) comprising the polyester resin (b1), a polyfunctional isocyanate compound (b2) or a blocked isocyanate compound (b3)
It is desirable to apply the above, and after drying at 150 to 160 ° C. for 60 seconds, laminate a synthetic resin film such as a vinyl chloride film. The coating amount of the adhesive composition when dried is 1 to 10
a g / m ² approximately, 2 to 4 g / m ² is preferred.

A steel plate is particularly suitable as the metal plate.

[0026]

EXAMPLES Examples will be described below. In the example,
“Parts” means “parts by weight”.

(1) Preparation of Primer 1 N-β (aminoethyl) γ-aminopropyltrimethoxysilane is dissolved in isopropyl alcohol from which water is sufficiently removed in an amount of 0.1% by weight.

(2) Preparation of Primer 2 γ-aminopropyltriethoxysilane is dissolved in toluene, from which water is sufficiently removed, in an amount of 0.1 wt%.

(3) Production of Primer 3 (Comparative Example) 0.1-wt% of 3-glycidoxypropyltrimethoxysilane is dissolved in toluene from which water is sufficiently removed.

(4) Production of Adhesive Composition 1 Dimethyl terephthalate (679 parts), ethylene glycol (248 parts), neopentyl glycol (156 parts) and zinc acetate (0.1 parts) were charged into a reaction kettle and stirred under a nitrogen stream at 160 to 160 parts. The mixture is heated to 220 ° C., the transesterification reaction is carried out for 4 hours, and when 95% of the theoretical amount of methanol is distilled off, 249 parts of isophthalic acid are charged and gradually heated to 240 ° C. to react. Further, the reaction vessel was gradually depressurized to 5 mmHg and the depressurization reaction was continued until the acid value became 2 or less to obtain a linear polyester resin. The obtained linear polyester resin has a glass transition point of about 65 ° C. and a molecular weight of 20,000.
Met. 100 parts of this resin is mixed with toluene / methyl ethyl ketone (hereinafter abbreviated as MEK) = 1/1 mixed solution 500
Dissolved in parts. To this resin solution, 30 parts of an adduct body (solid content 50%) obtained by reacting diphenylmethane-4,4-diisocyanate with trimethylolpropane was added and dissolved. An adhesive composition 1 was obtained from the obtained solution having a solid content of 18%.

(5) Production of Adhesive Composition 2 In Adhesive Composition 1 above, dimethyl terephthalate was changed to 485 parts, ethylene glycol to 248 parts, neopentyl glycol to 208 parts, and isophthalic acid to 249 parts. A linear polyester resin was synthesized in the same manner except that 216 parts of 6-naphthalenedicarboxylic acid was added. The linear polyester resin thus obtained had a glass transition point of about 73 ° C. and a molecular weight of 18,000. This resin 10
0 part was dissolved in 500 parts of a toluene / MEK = 1/1 mixed solution. To this resin solution, 35 parts of an adduct body (solid content 50%) obtained by reacting xylylene diisocyanate and trimethylolpropane was added and dissolved. Further, a toluene / MEK = 1/1 mixed solution was added to obtain an adhesive composition 2 having a solid content of 18%.

(6) Production of adhesive composition 3 An adhesive composition having a solid content of 18% was prepared in the same manner as in the adhesive composition 2 except that methylketoxime was used as a blocking agent instead of trimethylolpropane. Got 3.

(7) Production of Adhesive Composition 4 (Comparative Example) In Adhesive Composition 1, 338 parts of dimethyl terephthalate, 186 parts of ethylene glycol, 312 parts of neopentyl glycol and 230 parts of isophthalic acid were prepared. A linear polyester resin was synthesized in the same manner except that the modification was added and 219 parts of adipic acid was added. The obtained linear polyester resin had a glass transition point of about 40 ° C. and a molecular weight of 12,000. 100 parts of this resin is dissolved in 500 parts of a toluene / MEK = 1/1 mixed solution. To this, 30 parts of an adduct body (solid content 50%) obtained by reacting diphenylmethane-4,4-diisocyanate with trimethylolpropane was added and dissolved. An adhesive composition 4 was obtained using the obtained solution having a solid content of 18% as a comparative example.

Example 1 The primer 1 was applied to an electrogalvanized steel plate (0.5 mm) and dried at 40 to 50 ° C. for 2 to 3 minutes. The dry coating amount was 0.02 g / m ² . Immediately, the adhesive composition 1 was applied onto the dried primer coating film, and 150 to 1
It was dried at 60 ° C. for 60 seconds. Coating amount when dried is 2.5 g /
It was m ² . Immediately while keeping the steel plate temperature at 150 to 160 ° C., a vinyl chloride film (200 μm) having an embossed pattern was laminated to produce a laminate.

Examples 2 to 5 and Comparative Examples 1 to 3 As shown in Table 1, various combinations of a primer and an adhesive composition were used, and a laminate was obtained in the same manner as in Example 1.

Comparative Example 4 A laminate was obtained in the same manner as in Example 1 except that Primer 1 was not used.

Comparative Example 5 The temperature during lamination was 200 ° C. without using Primer 1.
A laminate was obtained in the same manner as in Example 1 except that

[0038]

[Table 1]

The laminates obtained were subjected to the tests described in (1) and (2) to evaluate the adhesive performance. Also, the change in appearance was evaluated. The results are shown in Table 2.

(1) Normal state Erichsen test According to JIS K6744. Using a cutter, create a test piece with two scratches at a distance of 5 mm in the center of the vinyl chloride surface of the laminate so as to be orthogonal to the vertical and horizontal directions. Using this test piece, an Erichsen test was performed, and the state of scratches after the test was visually evaluated. ◯: There is no peeling at all. Δ: The intersection of scratches slightly floats from the steel plate. X: Peeled.

(2) Boil-resistant Erichsen test A laminated body boiled in pure water for 2 hours was subjected to the same test as the (1) normal-state Erichsen test.

(3) Appearance evaluation Compared with the embossed pattern of the PVC film before lamination,
The change in the embossed pattern on the PVC surface of the laminate was visually evaluated. ◯: The embossed pattern did not change at all. Δ: The embossed pattern became slightly thin. X: The embossed pattern disappeared and an odd pattern was generated.

[0043]

[Table 2]

As is clear from Table 2, when the primer of the present invention and the adhesive composition were combined, the results of the normal state and boiling Erichsen test were excellent.
On the other hand, when a linear polyester having a glass transition point of less than 60 ° C. is used in the adhesive composition, when a coupling agent other than the aminosilane coupling agent is used as a primer, or when no primer is used at all. Was inferior in the results of the normal state and boiling Erichsen test, and was not put to practical use. Also, when laminated at a high temperature without using any primer, the results of normal state and boiling Erichsen test were satisfactory, but the embossed pattern of the vinyl chloride film disappeared, and a strange pattern was generated, making it practical. Did not serve.

[0045]

The composition for forming the adhesive layer of the present invention has a glass transition point of 60 ° C. or higher in the linear polyester resin (b1) because the aminosilane coupling agent acts as an anchor agent on the metal plate as the base material. Succeeded in laminating a synthetic resin film (sheet) to a composition (B) containing a polyfunctional isocyanate compound (b2) or a blocked isocyanate compound (b3) at a low temperature, and as a result, a synthetic resin film (sheet). It has become possible to obtain a synthetic resin film (sheet) -metal plate laminate having sufficient adhesion performance without damaging the pre-formed embossed pattern or the like.

Claims (3)

[Claims] 1. Aminosilane coupling agent layer (A)
And a linear polyester resin (b1) having a glass transition point of 60 ° C. or higher, a polyfunctional isocyanate compound (b2) or a compound (b3) in which the isocyanate of the polyfunctional isocyanate compound is blocked (B) An adhesive structure comprising: 2. A linear polyester resin (b) having a glass transition point of 60 ° C. or higher, which is obtained by coating an aminosilane coupling agent (A) as a primer on a metal plate and immediately after drying.
1), a composition (B) containing a polyfunctional isocyanate compound (b2) or a compound (b3) in which the isocyanate of the polyfunctional isocyanate compound is blocked
On the dried aminosilane coupling agent.
A metal laminate, which is dried and laminated with a synthetic resin film or a synthetic resin sheet. 3. The laminate according to claim 2, wherein the synthetic resin film or synthetic resin sheet is vinyl chloride.