JPH0776676A - Protective film for PVC steel sheet - Google Patents

Abstract

(57) [Summary] [Structure] A vinyl chloride steel sheet comprising (A) a vinylidene fluoride resin layer and (B) a copolymer resin layer obtained by grafting an amino group onto a methyl methacrylate / butyl methacrylate copolymer. A protective film for use in the layer (B), having the following formula (1): [Wherein, n is an integer of 9 to 22], and the polyethylene glycol-modified epoxy compound is blended in an amount of 6 to 20 parts by weight per 100 parts by weight of the copolymer resin. . [Effect] It is possible to improve the bending resistance of the protective film without impairing the excellent properties of the vinylidene fluoride resin, such as weather resistance and chemical resistance, and without impairing the adhesion to the vinyl chloride steel plate. It was

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective film used by being laminated on a vinyl chloride steel plate, that is, a vinyl chloride resin steel plate.

[0002]

2. Description of the Related Art Although vinyl chloride steel sheets are widely used for indoor and outdoor building materials, vinyl chloride resin lacks resistance to chemicals such as ultraviolet rays, acids, alkalis, etc.
There is a problem that the characteristics are deteriorated. Therefore, in a vinyl chloride steel sheet, a vinylidene fluoride resin film such as polyvinylidene fluoride is laminated in order to improve the resistance of the vinyl chloride resin. This film is generally
Polymethacrylic acid is used as an adhesive and is laminated on the surface of a vinyl chloride steel plate by heat fusion.

[0003]

However, in the case of the protective film as described above, when this laminated PVC steel sheet is subjected to a bending process, there is a problem that the adhesive film is cracked and the protective film is peeled off. It was Therefore, an object of the present invention is to provide a protective film for a vinyl chloride steel sheet in which cracking of the adhesive layer is effectively suppressed even during such bending processing.

[0004]

According to the present invention, (A)
A vinylidene fluoride resin layer and (B) a graft copolymer resin layer obtained by grafting an organic amine onto a copolymer composed of at least two (meth) acrylic acid ester constitutional units. The following formula (1):

[Chemical 2] [Wherein, n is an integer of 9 to 22], and a polyethylene glycol-modified epoxy compound represented by the formula is blended in an amount of 6 to 20 parts by weight per 100 parts by weight of the copolymer resin. Will be provided.

[0005]

In the present invention, the layer (B) functions as an adhesive layer, and the protective film is laminated by heat-sealing this layer to a vinyl chloride steel plate.
According to the present invention, by forming the layer (B) with the graft copolymer resin and the polyethylene glycol-modified epoxy compound, it is possible to impart appropriate flexibility without impairing its adhesiveness, It becomes possible to effectively prevent cracks during the bending process described above.

(A) Vinylidene Fluoride Resin Layer This layer substantially functions as a surface protective layer, is composed of a vinylidene fluoride homopolymer, and generally has a weight average molecular weight of 300,000 to 500,000. Those in the range of are preferably used. Further, as long as the excellent properties of the vinylidene fluoride resin are not impaired, it may be a copolymer of vinylidene fluoride and another monomer such as chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, vinyl fluoride, etc. Good. Further, the vinylidene fluoride resin may be blended with other fluorine-based resin, acrylic resin, or the like, and an additive such as an ultraviolet absorber or an antistatic agent may be blended as necessary, but the amount of the vinylidene fluoride resin The range should be such that excellent properties can be maintained, and it is particularly desirable that the compounding amount of other than the fluororesin be 3% by weight or less.

The vinylidene fluoride resin layer is obtained by using a vinylidene fluoride resin pellet, for example, and extruding it into a film using a T die. If necessary, the strength can be increased by further performing an operation such as biaxial stretching. The thickness of the vinylidene fluoride resin layer is 10 in terms of weather resistance and physical strength.
It is preferable that the thickness is not less than μm, especially 15 to 30 μm.

(B) Graft Copolymer Resin Layer This layer is basically composed of at least two (meth)
It is formed from a graft copolymer resin in which an organic amine is graft copolymerized to a copolymer obtained from an acrylate ester. That is, as an example of this graft chain, the following formula: R—COO — (— R ¹ —NH) _m —H In the formula, R represents a (meth) acrylic acid ester copolymer chain, and R ¹ represents , Is an organic amine residue, and m is a positive integer.

Examples of the (meth) acrylic acid ester which is a constitutional unit of the copolymer to be grafted with the organic amine include methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and the like. It is possible to use at least two of these. In the present invention, the most preferable copolymer contains 20 to 50% by weight of a structural unit derived from at least one of methyl methacrylate and ethyl methacrylate, and methacrylic acid other than methyl methacrylate and ethyl methacrylate. A copolymer containing 50 to 80% by weight of a structural unit derived from at least one of ester and acrylic ester is used. When the constituent unit derived from methyl methacrylate or ethyl methacrylate is less than 20% by weight, the compatibility with the vinylidene fluoride resin layer is impaired, and the peel strength when the protective film is laminated on the vinyl chloride steel plate is not actual. If it exceeds 50% by weight, the resin becomes hard, cracks occur in the laminate, and the protective film tends to peel off.

The organic amine to be graft-copolymerized with the above-mentioned copolymer, that is, the grafting monomer, is the first or second
Amine is used. Examples of the primary amine include propylamine, isopropylamine, butylamine, t-
Butylamine, sec-butylamine, amylamine,
Hexylamine, 2-ethylhexylamine and other alkylamines having 3 to 8 carbon atoms, 3-diethylaminopropylamine, dibutylaminopropylamine, tetramethylenediamine, hexamethylenediamine, ethylenediamine, allylamine and other various aliphatic amines, benzyl Aromatic amines such as amine, metaphenylenediamine and diaminodiphenylmethane can be mentioned. Examples of the secondary amine include diamines having 2 to 6 carbon atoms such as diethylamine, dipropylamine, diisopropylamine, dibutylamine, and diamylamine; aliphatic amines such as diallylamine and ethyleneimine; pyrrolidine, piperidine, and hexa. Examples thereof include alicyclic amines such as methyleneimine. Of these, secondary amines are preferred in the present invention.

Further, the above-mentioned organic amine is added to the copolymer.
It is desirable to set it in the range of 0.3 to 1.0% by weight. If the graft ratio is less than 0.3% by weight, the bending resistance becomes insufficient and it becomes difficult to effectively prevent cracks during bending, and if it is higher than 1.0% by weight,
The amount of the polyethylene glycol-modified epoxy compound to be crosslinked with the amino group described below increases, and the peel strength tends to decrease.

The graft copolymer resin may have a molecular weight capable of forming a film, but in general,
It is preferred to have an average molecular weight of 50,000 to 150,000. Further, at least two kinds of (meth) acrylic acid ester are used as constitutional units, and as long as the characteristics of the copolymer are not impaired, a small amount of other constitutional units, for example, olefin units such as ethylene and styrene and vinyl chloride and the like. It may contain a vinyl unit.

In the present invention, the polyethylene glycol-modified epoxy compound represented by the above formula (1) is blended in the above graft copolymer layer. This epoxy compound acts as a cross-linking agent, and forms a three-dimensional cured product by using the amino group in the graft copolymer as a cross-linking point, thereby exhibiting flexibility.

In the above formula (1), it is important that n is an integer of 9 to 22. For example, when a modified epoxy compound in which n is smaller than 9 is used, good flexibility is imparted. Therefore, the bending resistance becomes insufficient. Further, when a modified epoxy compound having n larger than 22 is used, the adhesiveness with a vinyl chloride steel plate becomes unsatisfactory.

It is also important to use the modified epoxy compound in an amount of 6 to 20 parts by weight per 100 parts by weight of the graft copolymer. That is, when the amount is less than 6 parts by weight, good flexibility is not imparted and the flex resistance is unsatisfactory, and when the amount is more than 20 parts by weight, the adhesiveness to the vinyl chloride steel plate is unsatisfactory. Will be things.

In the present invention, the layer (B) comprising the above-mentioned graft copolymer resin and the modified epoxy compound is prepared by dissolving the blended mixture of the graft copolymer resin and the modified epoxy compound in a suitable solvent, The layer (A)
Applied to one side of the vinylidene fluoride resin film of
It can be formed by curing at a temperature of 0 to 120 ° C. The curing time is not particularly limited, but generally about 5 to 10 minutes is sufficient. As the solvent, an organic solvent containing at least one of benzene, toluene and xylene in an amount of 60 to 90% by weight and at least one of acetone, methyl ethyl ketone, ethyl acetate and isopropyl alcohol in an amount of 40 to 10% by weight is most preferable. Generally, the thickness of the layer (B) is preferably about 10 to 20 μm.

The thus-obtained film of the present invention is obtained by subjecting the layer (B) side to an adhesive surface to a soft or hard PVC steel plate by heating and pressure bonding under the conditions of 200 to 240 ° C. and 15 to 35 kgf / cm ^2. Used as a protective film.

[0018]

【Example】

Example 1 Methyl methacrylate and butyl methacrylate 36.
8: 63.2 (weight ratio) 100 wt% of graft copolymer resin (Nippon Shokubai Co., Ltd. adhesive NK350, solid content 35% toluene / isopropanol = 70/30) in which ethylene imine was grafted to the copolymer at 0.6 wt%. In the section, the above formula (1)
In the above, 6 parts by weight of a modified epoxy compound having an n of 9 (Denacol EX-832 manufactured by Nagase Kasei Co., Ltd.) was added. This was coated on a polyvinylidene fluoride film (thickness: 20 μm) so that the dry thickness would be 20 μm.
A laminated film was prepared by curing at 0 ° C. for 5 minutes. still,
The polyvinylidene fluoride film is made by passing polyvinylidene fluoride resin (Solvey 1010, manufactured by Solvay) through an extruder (inlet 140 ° C, outlet 180 ° C) and T-die (200 ° C).
It was obtained by forming a film with. Then JIS G 3302
JIS K 6744 PVC steel sheet (steel sheet thickness: 0.4 mm, PVC thickness: 0.2 mm) in which vinyl chloride resin (PVC) is laminated on the hot-dip galvanized steel sheet of A vinyl chloride laminated steel sheet was produced by laminating at a linear pressure of 25 kgf / cm and a speed of 1 m / min. With respect to this laminated steel sheet, the bending resistance by a 180-degree bending test with a radius of curvature of 0.5 mm, the weather resistance by an accelerated exposure test (1000 hours), and the adhesiveness between a vinyl chloride steel sheet and a laminated film were evaluated. The results are shown in Table 1.

Example 2 A laminated film and a vinyl chloride laminated steel sheet were prepared and evaluated in the same manner as in Example 1 except that the amount of the modified epoxy compound blended was changed to 20 parts by weight. The results are shown in Table 1.

Comparative Example 1 A laminated film and a vinyl chloride laminated steel sheet were prepared and evaluated in the same manner as in Example 1 except that the amount of the modified epoxy compound was changed to 4 parts by weight. The results are shown in Table 1.

Comparative Example 2 A laminated film and a vinyl chloride laminated steel sheet were prepared and evaluated in the same manner as in Example 1 except that the compounding amount of the modified epoxy compound was changed to 24 parts by weight. The results are shown in Table 1.

Comparative Example 3 A laminated film and a vinyl chloride laminated steel sheet were prepared and evaluated in the same manner as in Example 1 except that the modified epoxy compound was not used at all. The results are shown in Table 1.

Comparative Example 4 A polyvinylidene fluoride film (thickness: 20 μm) was coated with polymethylmethacrylate in a thickness of 20 μm, and heat-treated under the same conditions as in Example 1 to prepare a laminated film, and a vinyl chloride laminate was similarly formed. A steel plate was created. This laminated steel sheet was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0024]

[Table 1] The evaluation criteria in each test in the above table are as follows. Flex resistance; JIS G 3312 ◯: No crack occurs at all. X: Cracks occur. Weather resistance; JIS A 1415 ◯: No yellowing. Δ: slightly yellowed. X: Yellowing. Adhesiveness; JIS K 6854 ⊚: Very good. (7 kgf / 2.5 cm or more) O: Adhesive strength sufficient for lamination was shown. (7-5kgf / 2.5cm
) X: Peeled off easily. (Less than 5kgf / 2.5cm)

[0025]

According to the present invention, the excellent properties of vinylidene fluoride resin, such as weather resistance and chemical resistance, are not impaired, and the adhesion to vinyl chloride steel sheet is not impaired.
It has become possible to improve flex resistance. The film of the present invention is used as a protective film by adhering it to a vinyl chloride steel plate, and cracks in the adhesive layer during bending are effectively suppressed.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area C09J 163/00 JFM

Claims (2)

[Claims] 1. A vinylidene fluoride resin layer (A),
(B) a graft copolymer resin layer in which an organic amine is grafted to a copolymer composed of at least two (meth) acrylic acid ester constitutional units, and the layer (B) includes
Formula (1) below: [Wherein, n is an integer of 9 to 22], and a polyethylene glycol-modified epoxy compound represented by the formula is blended in an amount of 6 to 20 parts by weight per 100 parts by weight of the copolymer resin. . 2. A copolymer comprising at least two (meth) acrylic acid ester constitutional units contains 20 to 50% by weight of constitutional units derived from at least one of methyl methacrylate and ethyl methacrylate, and A copolymer containing 50 to 80% by weight of a structural unit derived from at least one of a methacrylic acid ester and an acrylic acid ester other than methyl methacrylate and ethyl methacrylate.
Protective film for PVC steel sheet according to.