JP5664260B2 - Original decorative plate, decorative steel plate, and method for producing the same - Google Patents

Description

  The present invention relates to a decorative original plate, a decorative steel plate using the same, and a method for producing them. More specifically, the present invention provides a decorative steel sheet used for home appliances, building materials that require corrosion resistance, and the like, in which a biaxially stretched polyethylene terephthalate resin film is laminated with good adhesion on one side of the steel sheet. The present invention relates to an original plate, a decorative steel plate (pre-coated steel plate) obtained by using the original plate, and a method for producing them.

  Conventionally, as a decorative steel plate, a steel plate coated with an organic material is often used, and among them, the ratio of so-called pre-coated steel plates tends to increase. This pre-coated steel sheet has a coating type in which paint is applied to the steel sheet, a laminate type in which a color or pattern is applied to a pre-filmed film, and a transparent or translucent film coated and printed on the steel sheet. There are things that can be called composite types to be pasted.

Of these, paint types include polyester, acrylic, and urethane in addition to polyvinyl chloride, but for applications that require high corrosion resistance, a large thickness of polyvinyl chloride is often used. Yes. In particular, in applications that require high corrosion resistance, it is possible to improve the corrosion resistance of the original plate by using stainless steel plate, aluminum plate, thick galvanized steel plate, etc. as the original plate. It is not popular because it is expensive.
In the laminate type and the composite type, a film made of a single polyvinyl chloride or a film obtained by bonding polyvinyl chloride and polyethylene terephthalate (hereinafter sometimes referred to as PET) is generally used.

  By the way, in recent years, it has been pointed out that resins containing chlorine may become a cause of environmental pollution when incinerated as waste, and movement to stop the use of polyvinyl chloride has become active. ing.

  Against this background, the coating type pre-coated steel sheet has a limited coating thickness when a coating other than polyvinyl chloride is used. For applications that require high corrosion resistance, laminate type polyvinyl chloride is used. Attempts have been made to use a film made of a single polyolefin resin such as polypropylene, or a laminate of a polyolefin film and a PET film.

  However, due to the recrystallization behavior of the polyolefin resin and the lack of hardness of the resin layer, there are practically difficulties in workability and scratch resistance, and the actual situation is that satisfactory products are not supplied. . Furthermore, the method of simply laminating a film with a design is limited in the expression of the three-dimensional surface, etc., so it is possible to change the type of paint or to add a three-dimensional surface with an additive to the paint. There is also a problem that it does not reach the various design expressive powers of pre-coated steel sheets of paint / print type.

  As a pre-coated steel sheet that has excellent corrosion resistance, adhesion, workability and scratch resistance, and also has a beautiful appearance without using polyvinyl chloride, Patent Document 1 is made of a resin mainly composed of polyethylene terephthalate. A biaxially stretched film with a thickness in the range of 20 μm to 150 μm is laminated on one side of the steel sheet via an adhesive layer, and an adhesive is applied to the surface as necessary, followed by painting with a synthetic resin paint. A decorative steel sheet is disclosed in which printing is performed any number of times and in any order.

JP 2000-309067 A

The decorative steel sheet described in Patent Document 1 is excellent in corrosion resistance, adhesion, workability and scratch resistance without using polyvinyl chloride, and also has a beautiful appearance. However, there is no provision for an adhesive that forms an adhesive layer that intervenes in order to laminate a PET film on a steel sheet, and in the examples, an adhesive mainly composed of a polyester urethane polyol is used, and this polyester urethane polyol is used. According to the study by the present inventors, it has been found that the adhesive having the main component cannot sufficiently cope with harsh required physical properties such as boiling test and heat resistance at a high temperature of about 180 to 230 ° C. .
The present invention has been made under such circumstances, and is excellent in corrosion resistance, adhesion, workability and scratch resistance without using polyvinyl chloride, and also has a beautiful appearance. An object of the present invention is to provide a decorative base plate that provides a decorative steel sheet that can sufficiently cope with harsh required physical properties such as heat resistance at a high temperature of about 0 ° C. and a boiling test, and a decorative steel sheet having the above properties.

As a result of intensive studies to achieve the above object, the present inventors have obtained the following knowledge.
It has a specific thickness on one side of a steel plate via an adhesive layer formed by using an adhesive in which (1) a polyester resin having no urethane bond as a main agent and a polyisocyanate compound as a curing agent is combined. By laminating a biaxially stretched polyethylene terephthalate resin film, a cosmetic base plate is obtained that gives a decorative steel sheet that can sufficiently cope with the desired properties, that is, the severely required physical properties such as heat resistance at high temperature and boiling test. (2) In obtaining the polyester resin, particularly desired properties can be obtained by using azelaic acid as a specific aliphatic dicarboxylic acid, (3) In this cosmetic base plate, on the resin film, Desired properties by laminating at least one of an undercoat layer, a picture layer and a topcoat layer made of a synthetic resin paint That cosmetic steel sheet having is obtained, it was found.
The present invention has been completed based on such findings.

That is, the present invention
[1] A cosmetic base plate in which a biaxially stretched polyethylene terephthalate resin film is laminated on one side of a steel plate via an adhesive layer A, and the adhesive layer A has a urethane bond as a main agent. a resin, Ri Na is formed by using an adhesive comprising a polyisocyanate compound as a curing agent, the polyester resin is obtained from a polyhydric alcohol and a polybasic acid, polybasic acids and aliphatic dicarboxylic acids and aromatic cosmetic plate precursor, wherein at least one Tanedea Rukoto selected from group dicarboxylic acids,
[2] In the cosmetic original plate according to [1], at least one of an undercoat layer forming step, a picture layer forming step, and an overcoat layer forming step with a synthetic resin coating is laminated on a biaxially stretched polyethylene terephthalate resin film. Decorative steel sheet, characterized in that
[3] (a) a step of forming a semi-cured layer of the adhesive layer A on one side of a steel plate or a biaxially stretched polyethylene terephthalate resin film, (b) a semi-cured of the adhesive layer A formed in the step (a) A method for producing a cosmetic base plate comprising a step of laminating a biaxially stretched polyethylene terephthalate resin film or a steel plate on a layer under heating and pressure, wherein the semi-cured layer of the adhesive layer A in the step (a) The polyester resin is formed from a polyhydric alcohol and a polybasic acid, and is formed using an adhesive that combines a polyester resin having no urethane bond as a main component and a polyisocyanate compound as a curing agent. the method of manufacturing a cosmetic original plate base acid, wherein at least one Tanedea Rukoto selected from aliphatic dicarboxylic acids and aromatic dicarboxylic acids, and [4] above [3 On the biaxially stretched film laminated in the step (b), the undercoating layer forming step with the synthetic resin paint, the pattern layer forming step and A method for producing a decorative steel sheet, characterized by performing at least one of the topcoat layer forming steps;
Is to provide.

  According to the present invention, without using polyvinyl chloride, it has excellent corrosion resistance, adhesion, workability and scratch resistance, and also has a beautiful appearance, heat resistance and boiling at a high temperature of about 180 to 230 ° C. It is possible to provide a decorative original sheet that provides a decorative steel sheet that can sufficiently cope with harsh required physical properties such as tests, a decorative steel sheet having the above properties, and a method for producing them.

It is a cross-sectional schematic diagram which shows an example of a structure of the cosmetics original plate of this invention. It is a cross-sectional schematic diagram which shows an example of a structure of the decorative steel plate of this invention.

First, the cosmetic original plate of the present invention will be described.
[Dry plate]
The cosmetic original plate of the present invention is a cosmetic original plate obtained by laminating a biaxially stretched PET resin film on one side of a steel plate via an adhesive layer A, and the adhesive layer A is a urethane as a main ingredient. It is formed using the adhesive which combined the polyester resin which does not have a coupling | bonding, and the polyisocyanate compound as a hardening | curing agent.

(steel sheet)
The steel plate used for the decorative original plate of the present invention is not particularly limited. For example, a hot-rolled steel plate or a cold-rolled steel plate, those subjected to various metal plating or further surface treatment such as chromate treatment, stainless steel plate However, a cold rolled steel sheet plated with zinc or an alloy thereof and further subjected to surface treatment is most recommended from an economical point of view.
In the cosmetic original plate of the present invention, the back surface of the steel plate can be coated with a synthetic resin paint or other known methods as required, depending on the application or use environment.

(PET resin film)
In the cosmetic base plate of the present invention, as the PET resin film laminated on one side of the steel plate via the adhesive layer A, a biaxially stretched one is used, and from the economical viewpoint, it is inexpensive and colorless. A transparent one is preferred.
The PET resin that is the material of the PET resin film is not limited to the generally pure polymer of terephthalic acid and ethylene glycol, which is generally said, but is a partial copolymer or mixture with other monomers. A body etc. can also be included in the range which does not lose the characteristic as PET resin remarkably. Moreover, as long as the biaxial stretching generally performed industrially is performed, the film forming method and the degree of stretching are not limited. This is because the reason why PET was selected as the type of resin is that it has both hardness and corrosion resistance preferable as a surface coating of a decorative steel sheet described later, among those that do not contain chlorine and are available as inexpensive industrial products. The reason for using it in the form of a biaxially stretched film is that it has the desired smoothness of the surface, and the resin does not recrystallize due to the high melting point of the PET resin film even if it is subjected to some heating later. This is because the decline in sex is difficult to occur.

The thickness of the PET resin film is preferably selected in the range of 20 to 150 μm. When this thickness is 20 μm or more, it becomes easy to obtain a smooth appearance after painting / printing, it is possible to ensure good corrosion resistance, and it is not necessary to finish the coating / printing layer thick, which is economical. . On the other hand, when the thickness is 150 μm or less, the laminating operation does not become unstable due to the rigidity of the film, and the film follows the processing of the decorative steel sheet as a product, so that peeling does not easily occur. Moreover, when it becomes too thick, a film will become expensive and possibility that peeling will arise in a process part by internal stress will become large.
From such a viewpoint, the thickness of the PET resin film is preferably 50 to 150 μm, more preferably 75 to 100 μm.

For the purpose of improving the adhesion between the adhesive layer A and the layer provided on the surface side of the PET resin film, a physical or chemical surface treatment such as an oxidation method or an unevenness method on one or both sides is desired. Can be applied.
Examples of the oxidation method include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment method, and examples of the unevenness method include a sand blast method and a solvent treatment method. For these surface treatments, the corona discharge treatment method is generally preferably used from the viewpoints of effects and operability.
In addition, the PET resin film may be subjected to a treatment such as forming an easy-adhesion layer for the purpose of enhancing interlayer adhesion between the resin film and a layer provided thereon. However, the easy-adhesion layer is required to have adhesion even with heat resistance at a high temperature or a boiling test in terms of adhesion to the PET resin film. In addition, when using a commercially available thing as a PET resin film, the thing by which surface treatment as mentioned above was given previously, and the thing provided with the easily bonding layer can also be used for this commercial item.

(Adhesive layer A)
In the cosmetic base plate of the present invention, the adhesive layer A interposed between the steel plate and the PET resin film described above includes an adhesive containing a polyester resin having no urethane bond as a main agent and a polyisocyanate compound as a curing agent. It is formed using.

<Polyester resin>
The polyester resin which is the main component constituting the adhesive used to form the adhesive layer A does not have a urethane bond. In the present invention, having no urethane bond means that the polyester resin intentionally does not have a urethane bond, and is included in, for example, polyhydric alcohols and polybasic acids used in producing the polyester resin described below. In the case of having a urethane bond due to impurities, it is a concept including an embodiment having a urethane bond. However, even in such a case, the content contained in the urethane-bonded polyester resin is 3% by mass or less.

  Moreover, the adhesive agent used by this invention may contain other resin in the range which does not inhibit the hardening of this invention other than the polyester resin which does not have a urethane bond as a main ingredient. In the present invention, the main component of the adhesive preferably contains 60% by mass or more of a polyester resin having no urethane bond, more preferably 80% by mass or more, and most preferably 100% by mass, that is, the main agent is urethane. Only a polyester resin having no bond.

The polyester resin used in the present invention is preferably obtained from a polyhydric alcohol and a polybasic acid, more specifically, obtained by polycondensation of a polyhydric alcohol and a polybasic acid.
Polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, polyethylene glycol, poly Preferred examples include dihydric alcohols such as tetramethylene glycol and 1,4-cyclohexanediol; and trihydric alcohols such as glycerin and trimethylolpropane. Among these, ethylene glycol and neopentyl glycol are preferable. Polyhydric alcohols may be used alone or in combination.

Polybasic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecane Aliphatic dicarboxylic acids such as diacid, hexadecanedioic acid and docosanedioic acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, and biphenyldicarboxylic acid; fats such as cyclohexanedicarboxylic acid and cyclohexylsuccinic acid Preferred examples include cyclic dicarboxylic acids; aliphatic tricarboxylic acids such as citric acid and isocitric acid. Among these, aliphatic dicarboxylic acids are preferred, those having carboxyl groups at both ends are preferred, those having 5 to 20 carbon atoms in the carbon chain between the carboxyl groups are preferred, and those having 5 to 15 carbon atoms Is more preferable. Polybasic acids may be used alone or in combination.
As the aliphatic dicarboxylic acid, azelaic acid is particularly preferable. By adopting azelaic acid, in addition to the flexibility of the adhesive, boiling adhesion and long-term water resistance are improved.

In the present invention, the polyester resin preferably has a glass transition point Tg of −5 ° C. or lower. When the glass transition point Tg is −5 ° C. or lower, good results are obtained in terms of heat resistance at high temperatures, peel strength, and boiling adhesion. In the present invention, the glass transition point Tg is a value measured using a DSC apparatus under a temperature increase rate of 8 ° C./min.
In addition, the polyester resin preferably has a weight average molecular weight Mw of 20,000 or more, more preferably 25,000 or more, from the viewpoint of adhesive performance. Furthermore, the hydroxyl value is preferably 1 to 20 mgKOH / g, more preferably 4 to 20 mgKOH / g, and the acid value is preferably 10 mgKOH / g or less, more preferably 6 mgKOH / g or less.
In addition, the said weight average molecular weight Mw is a value of standard polystyrene conversion by the gel permeation chromatography method (GPC method).

<Polyisocyanate compound>
Examples of the polyisocyanate compound contained as a curing agent in the adhesive used to form the adhesive layer A include methylene bis (4,1-phenylene) = diisocyanate (MDI), tolylene diisocyanate (TDI), and xylylene diisocyanate. (XDI), aromatic polyisocyanates such as naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate; 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate (IPDI), hydrogenated tri Aliphatic (or alicyclic) polyisocyanates such as range isocyanate and hydrogenated diphenylmethane diisocyanate can be used. Among these, aromatic polyisocyanates are preferable from the viewpoint of corrosion resistance, adhesion, workability, and scratch resistance, and 4,4′-diphenylmethane diisocyanate and tolylene diisocyanate (TDI) are particularly preferable.

In addition, so-called modified polyisocyanates such as adduct-modified products, burette-modified products, isocyanurate-modified products, uretonimine-modified products, uretdione-modified products, carbodiimide-modified products, and elastic-modified polyisocyanates can also be used.
Here, the adduct modified product is a reaction product of a low molecular active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, and the various polyisocyanate compounds.
The elastically modified polyisocyanate is a polyisocyanate compound such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate as a monomer, and an active hydrogen-containing compound having elasticity in this is subjected to a urethane reaction. NCO-terminated prepolymer.
Examples of the active hydrogen-containing compound having elasticity used for elastically modifying the polyisocyanate compound include polyester polyols, polycarbonate polyols, polyether polyols, polyolefin polyols, animal and plant polyols, and copolyols thereof.
In this invention, the said polyisocyanate compound may be used individually by 1 type as a hardening | curing agent, and may be used in combination of 2 or more type.

In the present invention, the use ratio of the polyester resin as the main agent and the polyisocyanate compound as the curing agent is usually selected in the range of 100: 2 to 100: 15 by mass ratio, From the viewpoint of performance, the molar ratio [NCO] / [OH] between the NCO group in the polyisocyanate compound and the OH group in the polyester resin is preferably in the range of 0.5 to 1.5, 0.8 More preferably, it is in the range of -1.2.
In the present invention, the adhesive forming the adhesive layer A is preferably a two-component curable type. If it is a two-component curable type, excellent initial adhesion, heat resistance at high temperature, boiling adhesion and the like can be obtained.

In the cosmetic base plate of the present invention, in order to laminate a PET resin film on a steel plate, an adhesive comprising a combination of the polyester resin having the properties described above as the main agent and the polyisocyanate compound described above as the curing agent, preferably two liquids By using a curable adhesive, the resulting cosmetic base plate is excellent in corrosion resistance, adhesion, workability and scratch resistance, and also has a beautiful appearance without using polyvinyl chloride. It is possible to provide a decorative steel sheet that can sufficiently cope with harsh required physical properties such as heat resistance and boiling test.
On the other hand, an adhesive comprising a combination of a polyester urethane polyol as a main agent and a polyisocyanate compound as a curing agent is a severe requirement such as heat resistance at high temperatures and boiling adhesion as shown in Comparative Examples described later. It cannot cope with physical properties.

Next, the manufacturing method of the cosmetic original board of this invention is demonstrated.
[Manufacturing method of cosmetic base plate]
The manufacturing method of the cosmetic base plate of the present invention includes (a) a step of forming a semi-cured layer of the adhesive layer A on one side of a steel plate, (b) semi-cured of the adhesive layer A formed in the step (a). A method for producing a cosmetic base plate comprising a step of laminating a biaxially stretched polyethylene terephthalate resin film on a layer under heating and pressure, wherein the semi-cured layer of the adhesive layer A in the step (a) is a main agent. As described above, it is characterized by being formed using an adhesive that combines a polyester resin having a glass transition point Tg of −5 ° C. or lower and a polyisocyanate compound as a curing agent.

(Step (a))
In the method for producing a cosmetic base plate of the present invention, in the step (a), a semi-cured layer of the adhesive layer A is formed on one side of the steel plate or the biaxially stretched polyethylene terephthalate resin film (biaxially stretched PET resin film) described above. It is a process.
The semi-cured layer of the adhesive layer A has the above-mentioned adhesive, preferably a two-component curable adhesive, on one side of the steel plate, so that the dry film thickness is preferably 5 to 30 μm, more preferably 12 to 20 μm. Further, it can be formed by applying and heating and drying using a roll coater, a flow coater or the like.
In addition, about the said adhesive agent and its component, it is as having shown in description of the cosmetics original board of this invention mentioned above.

((B) Process)
In the method for producing a cosmetic base plate of the present invention, in the step (b), the biaxially stretched PET resin film or the steel plate is heated on the semi-cured layer of the adhesive layer A formed in the step (a). It is a step of laminating under pressure. Here, as a matter of course, when the adhesive layer A is provided on the steel plate in the step (a), a biaxially stretched PET resin film is laminated, and the adhesive layer A is biaxially stretched in the step (a). When it is provided on the PET resin film, steel plates are laminated.
Although there is no restriction | limiting in particular about lamination | stacking under the heating and pressurization in this (b) process, Usually, the method of laminating | stacking this PET resin film on about 120-250 degreeC temperature conditions is used. After lamination, the semi-cured layer of the adhesive layer A is cured by storing for a certain time under a predetermined temperature environment (usually about 30 ° C. to 60 ° C.), whereby the adhesive layer A is formed, and the PET resin film Is laminated on a steel plate with good adhesion, and the cosmetic base plate of the present invention is obtained.

In the cosmetic base plate of the present invention thus obtained, the biaxially stretched PET resin film laminated on one side of the steel plate via the adhesive layer A has a versatile and colorless property without requiring design properties. Since it can be made transparent and a design that meets the requirements of the customer can be applied by painting and printing immediately before shipment, the decorative steel sheet of the ordered design can be supplied in a short delivery time. The thickness of the biaxially stretched PET resin film is preferably in the range of 20 to 150 μm.
FIG. 1 is a schematic cross-sectional view showing the structure of an example of a cosmetic base plate according to the present invention. A cosmetic base plate 10 has a biaxially stretched PET resin film on one side of a steel plate 1 via an adhesive layer A2. 3 has a laminated structure.

Next, the decorative steel sheet of the present invention will be described.
[Decorative steel plate]
The decorative steel sheet of the present invention is such that in the cosmetic base plate of the present invention described above, at least one of an undercoat layer, a pattern layer and a topcoat layer made of a synthetic resin paint is laminated on a biaxially stretched PET resin film. Features. Here, the undercoat layer is a so-called solid layer, and the overcoat layer is a layer laminated for the purpose of protecting the surface of the steel sheet.
In the decorative steel sheet of the present invention, an adhesive layer B is provided on the biaxially stretched PET resin film as necessary, and at least one of an undercoat layer, a pattern layer, and an overcoat layer made of a synthetic resin paint is provided thereon. One may be laminated.
The adhesive for forming the adhesive layer B is not particularly limited as long as it can laminate an undercoat layer and a picture layer on a biaxially stretched PET resin film with good adhesion, and various adhesives. Can be used.

  In the decorative steel sheet of the present invention, it is preferable that an undercoat layer, a pattern layer, and an overcoat layer made of a synthetic resin paint are sequentially laminated on the biaxially stretched PET resin film. Also in this case, as described above, an adhesive layer B is provided on the biaxially stretched PET resin film as necessary, and an undercoat layer, a picture layer, and an overcoat layer are sequentially laminated thereon. May be.

  There are no particular restrictions on the types of the synthetic resin paint and ink other than selecting a type other than polyvinyl chloride in accordance with the spirit of the present invention. Polyester-based paints and inks are most suitable for the present invention in that various properties such as processability, hardness and resistance to scratches, corrosion resistance, and weather resistance of the coating film are balanced.

  As a method of painting and printing, any method employed in ordinary decorative steel sheets can be applied. In addition, as for painting and printing, the same method or different methods may be used repeatedly, and a method of sandwiching painting between printing and printing is also included in the scope of the present invention as one method of design expression. Since the PET resin film is laminated in advance, the coating thickness may be thinner than that of a normal decorative steel sheet, but it is not necessary to dare to make it thinner.

  Painting and printing may be performed within the process of laminating the PET resin film, but stocks of the above-mentioned cosmetic base plate or semi-finished products that have been subjected to primer coating on the PET resin film of the cosmetic base plate In addition, if a design according to the order is given in another process, it can contribute to production in a short delivery time.

  In addition, the adhesive layer B, the undercoat layer, the pattern layer, and the topcoat layer are preferably cured by heating at a temperature of about 200 to 240 ° C. after applying the coating material as described above.

  For decoration, that is, to give design, the principle is to print, but instead or additionally, beads such as resin are added to the paint, or the repelling phenomenon or the creaking phenomenon of the paint or ink is used. It is also effective to adopt a technique for obtaining surface irregularities. By using this technology, practical design can be secured even if any of the undercoat layer, pattern layer, and overcoat layer is omitted. It is.

Next, the manufacturing method of the decorative steel sheet of the present invention will be described.
[Method of manufacturing decorative steel sheet]
The method for producing a decorative steel sheet according to the present invention includes a cosmetic base plate obtained by the above-described method for producing a cosmetic base plate, and further, as a step (c), on a biaxially stretched PET resin film laminated in the step (b). In addition, at least one of an undercoat layer forming step, a pattern layer forming step, and an overcoat layer forming step with a synthetic resin paint, and heat drying are performed.
In this method for manufacturing a decorative steel sheet, a step (b ′) for forming the adhesive layer B can be further provided between the steps (b) and (c) as necessary.
Moreover, in the manufacturing method of the decorative steel sheet of the present invention, instead of the step (c), as the step (d), an undercoat layer made of a synthetic resin paint on the biaxially stretched PET resin film laminated in the step (b) It is preferable to sequentially perform a forming step, a pattern layer forming step, and an overcoat layer forming step. Also in this case, a step (b ′) for forming the adhesive layer B can be further provided between the step (b) and the step (d) as necessary.

The decorative steel sheet of the present invention thus obtained has excellent corrosion resistance, adhesion, workability and scratch resistance without using polyvinyl chloride, and also has a beautiful appearance, and also has heat resistance at high temperatures. It can fully cope with the severe physical properties such as boiling test and boiling.
FIG. 2 is a schematic cross-sectional view showing an example of the configuration of the decorative steel sheet of the present invention.
The decorative steel plate 20 is an adhesive provided as necessary on the resin film 3 in the decorative original plate 10 in which the biaxially stretched PET resin film 3 is laminated on the steel plate 1 via the adhesive layer A2. It has a structure in which the layer B4, the undercoat layer 5, the printing layer 6, and the topcoat layer 7 are laminated in this order.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, the various characteristics in each example were calculated | required according to the method shown below.

<About the main agent constituting the adhesive forming the adhesive layer A>
(1) Glass transition point Tg
Using a DSC apparatus, the temperature was measured under the temperature condition of 8 ° C./min.
(2) Weight average molecular weight Mw
The weight average molecular weight Mw in terms of standard polystyrene was measured by GPC method.
(3) Hydroxyl value According to the standard method, the number of mg of KOH per 1 g of the sample was determined.
(4) Acid value According to the standard method, the mg number of KOH per 1g of samples was calculated | required.

<About decorative master plate>
(5) Heat resistance at 200 ° C. The presence or absence of softening of the adhesive layer and the shrinkage value of the PET film when heated at 200 ° C. for 2 minutes and 30 seconds were determined. Moreover, the state of peeling was confirmed.
A shrinkage value of 1 mm or more is rejected. Moreover, if it has peeled, it is disqualified.
(6) Peel strength Peel strength was measured under the conditions of 30 mm / min using a peel strength measuring device. A peel strength of 30 N / 25.4 mm or more is acceptable.
(7) Workability At 20 ° C., the state of cracks in the PET film in the V-shaped bent part having no inner radius R = 0 mm was visually observed, and the workability was evaluated according to the following criteria.
X: Cracks occurred on the entire surface.
Δ: Many cracks are generated.
○: No cracks are generated.
(8) Boiling adhesion (a) Processing part About what was formed by the process of the 4mm bending allowance part (inside R = 2 (arc with a radius of 2 mm)) when a sample was immersed in 100 degreeC boiling water for 7 days. The peeling condition of the bending allowance was visually observed, and the boiling adhesion was evaluated according to the following criteria.
X: Floating occurred on the entire 4 mm bent part.
(Triangle | delta): A float generate | occur | produces partially (3 mm or more).
□: Partially floating (1 mm to less than 3 mm).
○: There is no occurrence of floating.
(B) DuPont concave part The peeling state of the PET resin film in the concave part (DuPont impact tester (1 kg / 50 cm, 1 / 2Φ)) when the sample was immersed in 100 ° C. boiling water for 2 hours was visually observed. The boiling adhesion was evaluated according to the criteria.
X: Floating occurred on the entire surface.
(Triangle | delta): A float generate | occur | produces partially (3 mm or more).
□: Partially floating (1 mm).
○: No floating occurred.
(9) Total evaluation Total evaluation was performed according to the following criteria.
×: Unusable.
□: There is a possibility of applicability by use.
○: Can be used.
A: Can be used without problems.

Example 1
(1) Production of decorative original plate As a steel plate, a cold-rolled steel plate having a thickness of 0.45 mm is subjected to continuous hot-dip galvanization (plating amount 120 g / m ² per side) and further subjected to chromate treatment. Using.
In addition, as an adhesive, polyester resin (polyester polyol, urethane bond content) obtained by polycondensation of polybasic acid (terephthalic acid, isophthalic acid and azelaic acid) and polyhydric alcohol (ethylene glycol and neopentyl glycol) : 0% by mass, glass transition point Tg: −15 ° C., Mw: 28,000, hydroxyl value: 4 mg KOH / g, acid value: 4 mg KOH / g), a polyisocyanate compound (diphenylmethane) as the main agent and a curing agent Diisocyanate) was used in combination with a mass ratio of 100: 9.

Next, the two-part curable adhesive was applied to one side of the plated steel sheet using a roll coater so that the dry film thickness was about 15 μm, and dried by heating to form a semi-cured coating film layer. . Next, on this semi-cured coating layer, a 75 μm thick biaxially stretched colorless and transparent PET film (“S-75 (trade name)”, manufactured by Unitika Ltd.) having a corona discharge treatment on the surface, By laminating using a roll under a temperature condition of about 200 ° C. and storing in a 40 ° C. environment for 24 hours, the semi-cured coating layer is cured to form an adhesive layer A, and a cosmetic base plate And various properties were evaluated.
The properties of the adhesive are shown in Table 1, and the evaluation results of various properties are shown in Table 2.
(2) Production of decorative steel sheet Next, a polyester resin adhesive (manufactured by Dainippon Paint Co., Ltd.) is roughly dried on the biaxially stretched PET film in the cosmetic base plate obtained in (1) above. After applying and heat-drying to a thickness of 2 μm, the polyester-based thermosetting primer is applied and heat-dried to a dry film thickness of approximately 20 μm, and a pattern is printed with a polyester-based ink. A decorative steel sheet having the structure shown in FIG. 2 was prepared by applying an overcoating with a transparent and colorless paint of the system to a dry film thickness of about 20 μm and baking and drying.

Examples 2-7
(1) Production of cosmetic base plate In Example 1 (1), the mass ratio of the main agent and the curing agent is 2 at the lamination temperature shown in Table 1 using a two-component curable adhesive shown in Table 1. Except having laminated the axial stretch PET film, it carried out similarly to Example 1 (1), produced six types of cosmetics original plates, and evaluated various characteristics.
The properties of the adhesive are shown in Table 1, and the evaluation results of various properties are shown in Table 2.
(2) Production of decorative steel plate Using the six types of decorative original plates obtained in (1) above, the same operation as in Example 1 (2) was performed to prepare six types of decorative steel plates.

Comparative Examples 1-8
(1) Production of a cosmetic base plate A polyester urethane polyol having a urethane bond having the properties shown in Table 1 is used as a main agent, and an adhesive obtained by adding an isocyanate curing agent at a mass ratio shown in Table 1 is used. Except that the biaxially stretched PET film was laminated at the lamination temperature shown in Table 1, a cosmetic original plate was prepared and various properties were evaluated in the same manner as in Example 1 (1). The evaluation results of various characteristics are shown in Table 2.
(2) Production of decorative steel plate Using the decorative original plate obtained in (1) above, the same operation as in Example 1 (2) was performed to produce a decorative steel plate.

[note]
Polyester urethane polyol (a): "Takelac A543 (trade name)", Takeda Pharmaceutical Co., Ltd. Polyester urethane polyol (b): "Takelac A515 (trade name)", Takeda Pharmaceutical Co., Ltd. polyester urethane polyol ( c): “Takelac A610 (trade name)”, polyester urethane polyol (d) manufactured by Takeda Pharmaceutical Co., Ltd. (d): “Takelac A310 (trade name)”, Takeda Pharmaceutical Co., Ltd. Isocyanate (a): diphenylmethane diisocyanate Isocyanate type (b): Tolylene diisocyanate (TDI)
Isocyanate type (c): cross-linked product of isophorone diisocyanate (IPDI) and xylylene diisocyanate (XDI) (mixing ratio = 3: 1)

  As can be seen from Table 2, it was confirmed that the cosmetic base plates of the examples exhibited excellent performances with respect to all of 200 ° C. heat resistance, peel strength, processability and boiling adhesion. On the other hand, the cosmetic base plate of the comparative example did not have sufficient performance for at least one of heat resistance at high temperatures (heat resistance at 200 ° C.), peel strength, workability, and boiling adhesion.

  The decorative steel sheet of the present invention obtained by using the decorative base sheet of the present invention is excellent in corrosion resistance, adhesion, workability and scratch resistance, and also has a beautiful appearance without using polyvinyl chloride. In addition, it can sufficiently cope with severe required physical properties such as heat resistance at high temperature and boiling test.

1 Steel plate 2 Adhesive layer A
3 Biaxially stretched PET resin film 4 Adhesive layer B
5 Undercoat layer 6 Print layer 7 Overcoat layer 10 Original sheet for makeup 20 Decorated steel sheet

Claims (16)

A base plate for makeup formed by laminating a biaxially stretched polyethylene terephthalate resin film on one side of a steel plate via an adhesive layer A, and the adhesive layer A has a polyester resin having no urethane bond as a main agent, Ri Na is formed by using an adhesive comprising a polyisocyanate compound as a curing agent, the polyester resin is obtained from a polyhydric alcohol and a polybasic acid, polybasic acids and aliphatic dicarboxylic acids and aromatic dicarboxylic acids cosmetic plate precursor, wherein at least one Tanedea Rukoto selected from.   The cosmetic base plate according to claim 1, wherein the polyester resin is obtained from a polyhydric alcohol and a polybasic acid, and the polybasic acid is an aliphatic dicarboxylic acid. The cosmetic base plate according to claim 1 or 2 , wherein the aliphatic dicarboxylic acid has a carboxyl group at both ends, and the carbon chain between the carboxyl groups has 5 to 20 carbon atoms. The cosmetic original plate according to any one of claims 1 to 3 , wherein the aliphatic dicarboxylic acid contains azelaic acid.   The cosmetic base plate according to any one of claims 1 to 4, wherein the polyester resin has a weight average molecular weight of 20,000 or more.   The cosmetic base plate according to any one of claims 1 to 5, wherein a use ratio of the main agent and the curing agent is 100: 2 to 100: 15 by mass ratio.   The cosmetic base plate according to any one of claims 1 to 6, wherein at least one of an undercoat layer, a pattern layer, and an overcoat layer made of a synthetic resin paint is laminated on a biaxially stretched polyethylene terephthalate resin film. A decorative steel sheet.   The adhesive layer B is further provided on the biaxially stretched polyethylene terephthalate resin film, and at least one of an undercoat layer, a pattern layer, and an overcoat layer made of a synthetic resin paint is applied thereon. Decorative steel plate. (A) a step of forming a semi-cured layer of the adhesive layer A on one surface of a steel plate or a biaxially stretched polyethylene terephthalate resin film; (b) on the semi-cured layer of the adhesive layer A formed in the step (a); A method for producing a cosmetic base plate comprising a step of laminating a biaxially stretched polyethylene terephthalate resin film or a steel plate under heating and pressure, wherein the semi-cured layer of the adhesive layer A in the step (a) is a main agent. It is formed by using an adhesive that combines a polyester resin not having a urethane bond and a polyisocyanate compound as a curing agent , and the polyester resin is obtained from a polyhydric alcohol and a polybasic acid. At least Tanedea cosmetic original sheet manufacturing method according to claim Rukoto selected from aliphatic dicarboxylic acids and aromatic dicarboxylic acids.   The method for producing a cosmetic base plate according to claim 9, wherein the polyester resin is obtained from a polyhydric alcohol and a polybasic acid, and the polybasic acid is an aliphatic dicarboxylic acid.   The method for producing a cosmetic base plate according to claim 9 or 10, wherein the aliphatic dicarboxylic acid has carboxyl groups at both ends, and the carbon chain between the carboxyl groups has 5 to 20 carbon atoms.   The method for producing a cosmetic base plate according to any one of claims 9 to 11, wherein the aliphatic dicarboxylic acid contains azelaic acid.   The method for producing a cosmetic base plate according to any one of claims 9 to 12, wherein the polyester resin has a weight average molecular weight of 20,000 or more.   The method for producing a cosmetic base plate according to any one of claims 9 to 13, wherein a use ratio of the main agent and the curing agent is 100: 2 to 100: 15 by mass ratio.   An undercoat layer made of a synthetic resin paint on the biaxially stretched film laminated in the step (b) as the step (c) on the cosmetic base plate obtained by the production method according to any one of claims 9 to 14. A method for producing a decorative steel sheet, comprising performing at least one of a forming step, a pattern layer forming step, and an overcoat layer forming step.   The method for producing a decorative steel sheet according to claim 15, further comprising (b ′) a step of forming an adhesive layer B between the step (b) and the step (c).

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