JPH0717803B2 - Vinyl chloride film having good electron beam resistance and vinyl-coated steel sheet using the film - Google Patents

Description

The present invention relates to a vinyl chloride film having good electron beam resistance and a vinyl-coated steel sheet using this film. More specifically, the present invention relates to a vinyl chloride film and a vinyl-coated steel sheet having good electron beam resistance and weather resistance suitable for producing a vinyl-coated steel sheet that is subjected to electron beam irradiation.

<Prior Art> A conventional method for producing a vinyl-coated steel sheet is roughly classified into a method in which a vinyl chloride resin coating material is applied to the surface of a thin metal plate such as a galvanized steel sheet or a cold-rolled steel sheet, and the product is heated and baked ( Hereinafter, it is divided into a paste application method) and a method of applying an adhesive to the metal plate and laminating a separately manufactured vinyl chloride film (hereinafter referred to as an adhesive method). Recently, in the latter adhesive method, a method of laminating films using an electron beam curable adhesive has been developed (hereinafter referred to as electron beam curing method). In this electron beam curing method, an electron beam curable adhesive is applied to a steel sheet and then a vinyl chloride film is laminated, and then,
A method of producing vinyl-coated steel sheet by irradiating electron beam from the film side to bond the film and steel sheet.This method is different from the conventional paste coating method and adhesive method in that heating is not required and the curing speed is fast. Therefore, not only energy saving and high productivity but also the feature that the embossing applied to the film is clearly retained because heat is not applied to the film.

However, there is a problem that the vinyl chloride film laminated on the surface of the steel sheet for the purpose of design and surface protection is easily deteriorated by the electron beam irradiated, which has prevented the spread of this method.

As a method of preventing this deterioration, as seen in JP-A-62-236733, DOP or DOS as a plasticizer in the suspension polymerization vinyl chloride resin, using a dialkyl tin mercaptide-based stabilizer as a stabilizer, It is known to use a vinyl chloride film containing an acrylic oligomer as a lubricant.

However, this method does not cause discoloration after electron beam irradiation and has some weather resistance, but it does not have sufficient adhesiveness with adhesives and inks, and it has weather resistance enough to withstand long-term outdoor use. Since it does not have the property, the vinyl coated steel sheet has a drawback that its use is limited, and therefore improvement has been desired.

<Problem to be Solved> An object of the present invention is to provide a vinyl chloride film having good electron beam resistance and excellent weather resistance even after electron beam irradiation, and a vinyl-coated steel sheet using the same.

<Means for Solving the Problems> The present invention has been made in view of the above background, and provides a vinyl chloride film suitable for producing a vinyl-coated steel sheet by an electron beam curing method, and a vinyl-coated steel sheet using the film. The means is to use vinyl chloride resin
To 100 parts by weight, one or more of (a) a phthalate ester-based plasticizer, a sebacate ester-based plasticizer, or a trimellitic acid ester-based plasticizer is used as a plasticizer.
40 parts by weight, (b) 1 to 15 parts by weight of an epoxy plasticizer,
(C) 1 to 5 parts by weight of a dialkyl tin mercaptide stabilizer as a stabilizer, and (d) 2 to 30 parts by weight of aluminum hydroxide or hydrous magnesium silicate as inorganic fine particles having an average particle diameter of 10 μm or less, or hydrotal. A vinyl chloride film in which 0.2 to 5 parts by weight of sites are mixed alone or in combination, and an electron beam curable adhesive is applied to the surface of a thin metal original plate, and a calendering method is applied to the applied surface. Alternatively, it is a vinyl-coated steel sheet obtained by laminating the vinyl chloride film formed into a film by an extrusion method and irradiating the film with an electron beam to adhere the film to a metal original plate.

<Examples> The vinyl chloride resin in the present invention includes, in addition to vinyl chloride homopolymer, a copolymer of vinyl chloride and a monomer copolymerizable with vinyl chloride such as vinyl acetate and ethylene.

Various grades of such vinyl chloride resin are currently manufactured and marketed by several companies, but as described in JP-A-62-236733, there is a slight difference in electron beam resistance between brands. There is a difference, and it is necessary to confirm the electron beam resistance in advance when selecting this. The reason why there is a difference between brands is
Although it is not clear, it is suggested that it may be due to residual impurities (for example, dispersants, polymerization initiators, etc.) resulting from different manufacturing methods.

The degree of polymerization of the vinyl chloride resin (PVC) used in the vinyl chloride film for vinyl-coated steel sheets is selected in terms of processability. Vinyl chloride resin can be formed into a film by calendering or extrusion, and the degree of polymerization is selected in relation to the amount of plasticizer used. Usually, if the amount of the plasticizer is 5 to 40 parts, the average degree of polymerization () of 700 to 1300 can be selected, but it is not limited thereto.

Moreover, you may use a vinyl chloride resin copolymer. For example, vinyl chloride-ethylene copolymer (ethylene content 5
%), The melt viscosity decreases and processing becomes easier,
Electron beam resistance is also good, so it can be selected.

The plasticizer used in the present invention is a phthalate ester-based plasticizer, a sebacate ester-based plasticizer, or a trimellitic acid ester-based plasticizer, and one or more of them are mixed and used. 5 to 40 parts by weight of the plasticizer is added to 100 parts by weight of the vinyl chloride resin. Plasticizers other than those mentioned above, such as chlorinated paraffin plasticizers, polyester plasticizers, and phosphoric acid ester plasticizers, have poor weather resistance after electron beam irradiation and cannot be used because they discolor.

As phthalate plasticizers, di-2-ethylhexyl taflate (DOP), dibutyl phthalate (DBP),
Dinonyl phthalate (DNP), diheptyl phthalate (D
HP), diisodecyl phthalate (DIDP) and the like are used, and DOP is particularly preferable.

As the sebacate ester plasticizer, dioctyl sebacate (DOS), dibutyl sebacate (DBS), butylbenzyl sebacate (BBS) and the like are used, and DOS is particularly preferable.

As the trimellitic acid ester plasticizer, trioctyltri-2-ethylhexyl trimellitate (TOTM), tributyl trimellitate (TBTM), triisodecyl trimellitate (TIDTM), etc. are used, and TOTM is particularly preferable. is there.

The epoxy plasticizer in the present invention is epoxidized soybean oil,
Epoxidized linseed oil, epoxidized fatty acid ester such as epoxidized fatty acid octyl ester and bisphenol type or novolac type epoxy resin as a resin type epoxy compound, epoxidized fatty acid ester is excellent in terms of electron beam resistance, chloride 1 to 15 parts by weight is added to 100 parts by weight of vinyl resin. Preferably 3-10
Parts by weight.

In the present invention, it is necessary to select an appropriate amount of the above plasticizer in consideration of the application of the vinyl-coated steel sheet. That is, when the total amount of one or more of the above-mentioned (a) phthalate ester-based plasticizer, sebacate ester-based plasticizer or trimellitic acid ester-based plasticizer, and the epoxy-based plasticizer (b) is increased, embossing Makes it possible to perform deep drawing embossing, and enables complex molding with an acute angle even when it is molded into a predetermined shape by press molding after being laminated as a vinyl steel sheet.
The scratchability and printability of the surface are inferior. On the other hand, if the total amount of the plasticizer is reduced, the film becomes harder, the impact strength is lowered, and the elongation during press molding is poor and it is difficult to obtain a predetermined shape. So as vinyl coated steel sheet,
A suitable blending amount is 5 to 40 parts.

The type of stabilizer used in the present invention is a very important factor.

As a result of examining the suitability of hundreds of kinds of stabilizers after electron beam irradiation and the weather resistance after electron beam irradiation, the present inventors have found that it is optimal to use dibutyltin mercaptide-based stabilizers and inorganic fine particles described below in combination. Yes, not only can it be used in combination, but good results can be obtained by not using other stabilizers, especially those containing Cd, Zn, Ca, Ba, etc. which are commonly used as stabilizers for vinyl chloride resins. We obtained the knowledge that

This finding was a surprising finding for the present inventors, who have long been studying PVC blending systems.

Because, in general, when improving the weather resistance of the vinyl chloride resin composition, the Sn-based stabilizer has good transparency and heat resistance but poor weather resistance, and thus is not used or limited to the minimum amount necessary for processing,
Zn stabilizer or Cd, Ba-based stabilizer is used, and further ultraviolet absorber or antioxidant is added to improve the weather resistance, but see the weather resistance after electron beam irradiation, which is a characteristic of the present invention. As a result, Zn-based and Cd-based compounds have the effect of lowering the weather resistance when added in a small amount, and the ultraviolet absorbers and the antioxidants have little effect on the weather resistance. It is considered that such a difference in the effect of addition of additives is caused by the difference between the mechanism of deterioration of PVC by electron beam and the mechanism of ultraviolet deterioration and oxidative deterioration under natural conditions.

In general, PVC is exposed to sunlight to gradually generate dechlorinated radicals, oxidize, and break the main chain by its ultraviolet rays, and decomposes, and also cross-links due to long-term exposure. To prevent this decomposition, an ultraviolet absorber or a stabilizer is used to improve weather resistance.

On the other hand, when an electron beam is applied to PVC, it is said that crosslinking and decomposition occur instantaneously at the same time, and then crosslinking and decomposition occur even at room temperature, and it is natural that exposure to sunlight accelerates decomposition. Is. Such cross-linking and decomposition depend of course on the electron beam irradiation dose.

In the production of a vinyl steel sheet by the electron beam curing method, the electron beam irradiation dose is about 10 Mrad, and in the present invention, the irradiation condition was tested at 10 Mrad.

The dialkyltin mercaptide-based stabilizer used in the present invention generally has the following structural formula.

R ₁ , R ₂ = alkyl group R ′ = H or alkyl group Dioctyltin mercaptide using an n-octyl group as R ₁ and dibutyltin mercaptide using a butyl group are prominent, and both are stabilizers used in the present invention. Shows excellent aptitude.

The inorganic fine particles used in the present invention are aluminum hydroxide or hydrous magnesium silicate having an average particle diameter of 10 μm or less, or hydrotalcites, and these are used alone or in combination. The chemical formula of aluminum hydroxide is Al (OH) ₃
It is usually a prominent compounding agent as a flame retardant for polymers, but when this aluminum hydroxide is used in combination with a dialkyltin mercaptide as in the present invention, it has an effect of improving weather resistance after electron beam irradiation. Was a surprising finding.

Aluminum hydroxide having a mean particle size of 0.6 μ to 60 μ is widely available on the market, but a film having a mean particle size of 10 μ or less is suitable as a film for vinyl steel sheet. 10μ
If it exceeds the range, unevenness is generated on the film surface, the appearance is deteriorated, and it causes fishy eyes, causing ink scattering and transfer unevenness during printing.

Hydrous magnesium silicate is chemically 3MgO ・ 4SiO ・ H ₂
It is O and can be represented by the chemical formula of Mg ₆ (Si ₈ O ₂₀ ) (OH) ₄ from the crystal structure.

Hydrous magnesium silicate is used as a filler of polymer resin as inorganic fine particles having high lubricity, and this hydrous magnesium silicate, like aluminum hydroxide, is used as a dialkyltin mercaptide-based stabilizer as in the present invention. When used together, it is effective in improving weather resistance after electron beam irradiation.

For hydrous magnesium silicate, the one having an average particle size of 10 μm or less is suitable as a film for vinyl-coated steel sheet for the same reason as aluminum hydroxide. The amount of aluminum hydroxide or hydrous magnesium silicate added is 2 to 30 parts.

Hydrotalcites are Mg _1- xAl ₁ x (OH) ₂ (Co ₃ ) x
-Magnesium, aluminum, and basic carbonate represented by μH ₂ O (wherein O <χ <0.5, 0 ≦ μ <1).

This hydrotalcite is also effective in improving the weather resistance of electron beam irradiation, like the aluminum hydroxide and hydrous magnesium silicate. However, it is desirable to use hydrotalcite in the range of 0.5 to 5 parts because it tends to yellow when used in a large amount, and even if it is added in a small amount, it has the same properties as aluminum hydroxide.

Hydrotalcites represented by the above formula have a refractive index of 1.
41 to 1.51, which is close to the refractive index of vinyl chloride resin of 1.52,
Addition of hydrotalcite to vinyl chloride resin shows almost no decrease in transparency. For these reasons, hydrotalcite is highly useful as a transparent film for vinyl coated steel sheets.

This will be described in detail.

Vinyl-coated steel sheets are usually given a design by printing the grain side or an abstract pattern on the surface of the base film with the desired colorant added, or by embossing to give a concavo-convex pattern, but the abrasion and discoloration of the ink In order to prevent this, after printing on the surface of the base film described above, a transparent film may be laminated on the film to form a two-layer structure.

This is not only to protect the surface, but also to develop a fluffy pattern to broaden the range of design. In this case, the transparent film used for the surface layer is required to have crystal transparency as much as possible. Since hydrous magnesium silicate and aluminum hydroxide have refractive indices of 1.57 and 1.56, respectively, when added to vinyl chloride resin (refractive index 1.52),
Transparency decreases. Therefore, a hydrous magnesium silicate or a compounding system containing aluminum hydroxide is not problematic when it is used as a base layer (opaque layer) to which a colorant is added, but when it is used as a transparent film, the vividness of the color of the ink is improved. It is lost and the desired design cannot be expressed.

The vinyl chloride film in the present invention may include a lubricant, a processing aid, an ultraviolet absorber, a pigment and the like as a compounding agent other than the above-mentioned essential components.

Lubricants and processing aids vary depending on the molding equipment and process (calender, extruder), so appropriate amounts should be added according to the processing machine.

For example, in the case of manufacturing by the calendar method, about 1 to 2 parts of a polyethylene wax lubricant, an acrylic oligomer lubricant, a fatty acid ester lubricant as a lubricant is used as a lubricant, a processing aid is not particularly necessary, but a compounding system having a small amount of a plasticizer (plastic Dosage 10 ~
In 20 parts), about 1 to 10 parts of an acrylic processing aid or an ethylene vinyl acetate copolymer may be used. However, in this selection, it is necessary to confirm in advance because the electronic resistance differs depending on the brand.

As the UV absorber, a benzophenone-based or benzotriazole-based UV absorber usually used as a UV absorber for vinyl chloride should be used in an amount of about 0.2 to 0.5 part.

However, the ultraviolet absorber has only a function of absorbing ultraviolet rays, and does not absorb electron beams.
UV absorbers are generally additives that greatly contribute to the weather resistance of vinyl chloride resins, but for improving the weather resistance after electron beam irradiation, the selection of stabilizers and inorganic fine particles that are essential components of the present invention Is much more important.

The type and amount of pigment should be selected from the viewpoint of design as a vinyl coated steel sheet. It is self-evident that pigments with good electron beam resistance must be selected.

Next, specific embodiments of the present invention will be described in detail with reference to specific examples.

According to the formulations shown in Tables 1 and 2, 0.1 with a test roll at 175 ° C.
After creating a film with a thickness of 5 μm, a Cuastron electron beam irradiation device (manufactured by Nisshin High Voltage Co., Ltd., 200Kcv, 2
Electron beam of 10 Mrad is irradiated using 0 mA), and then this is accelerated weather resistance tester (Suga Test Instruments Co., Ltd., UV long life weatherometer WEL-2 type black panel 63 ° C.)
Then, the degree of yellowing of the test piece after the test time of 1000 hours and 2000 hours was examined. The degree of yellowing was evaluated by obtaining a color difference ΔE using a color difference meter (SM color comb beater, manufactured by Suga Test Instruments Co., Ltd.).

Evaluation Weather resistance after electron beam irradiation ◎ -Almost no change Color difference ΔE = 3 or less ○ -Slightly yellowish ΔE = 3 to 6 △ -Yellowness = 7 to 15 × -Brown color = 15 to 36 ×× -Brown color (Some parts are close to blackening) = 36 or more The surface condition of the film in Table 2 was evaluated by observing the appearance of the film prepared with the test roll with the naked eye.

Evaluation of film surface condition ◎ -Film surface is completely smooth and normal. ○ -Film surface gloss is slightly reduced but smooth. △ -Film surface gloss is reduced and fine irregularities are visible to the naked eye. × -Film surface Regarding the transparency of the film in Table 3 in which spots having nuclei are scattered, 0.1 μm transparent film was prepared with a composition containing no coloring agent, and the light transmittance was measured (manufactured by Suga Test Instruments Co., Ltd.). , Computer haze meter).

Evaluation of transparency Basic composition (parts by weight) Vinyl chloride resin = 1000 100 DOP 30 Epoxidized soybean oil 5 Dibutyltin mercaptide 2 Polyethylene wax 0.5 UV absorber 0.3 Add 5 parts each of the various inorganic fine particles shown in Table 3 to the basic composition. The light transmittance was measured.

As can be seen from the results in Table 3, the light transmittance decreases when hydrous magnesium silicate and aluminum hydroxide are added, but the light transmittance slightly decreases even when hydrotalcite is added.

The following is clear from Table 1.

Compounds containing an epoxy plasticizer (Examples 1 to 1)
3) has good weather resistance, but the one not added (Comparative Example 5) has remarkably poor weather resistance.

Those without addition of hydrous magnesium silicate as inorganic fine particles (Comparative Examples 1 and 2) have poor weather resistance.

Formulations using DOP, DOS, and TOTM as plasticizers all show excellent weather resistance, and TOTM is particularly good (Examples 8,1
1). In comparison, the formulations using TCP and polyester-based plasticizers (Comparative Examples 3 and 4) have poor weather resistance.

Formulations using dibutyltin mercaptide and dioctyltin mercaptide as stabilizers (Examples 1 to 9) have good weather resistance, but formulations using zinc-based, barium-based, and cadmium-based compounds (Comparative Examples 6 to 10) are poor. However, the weather resistance is poor even in the case where the compound is used in combination with dibutyltin mercaptide (Comparative Examples 9 and 10).

The following is clear from Table 2.

The weather resistance of the formulations (Examples 12 to 24) using hydrous magnesium silicate, aluminum hydroxide, and hydrotalcite as the inorganic fine particles having an average particle size of 10 μm or less is better than that of the formulation not adding the inorganic fine particles (Comparative Example 11). Is excellent,
Formulation with addition of calcium carbonate and silica (Comparative Examples 17-2
The weather resistance of 0) is poor. The formulations (Comparative Examples 13, 15, 16) using the inorganic fine particles having an average particle size of more than 10 μ have good weather resistance, but the surface condition of the film is poor. The composition containing 8 parts of hydrotalcite turned yellow (Comparative Example 21).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08K 5/12 KGZ 5/15 KHC 5/58 KJC // (C08L 27/06 63:00) ( 72) Inventor Kenichi Masuhara 7-1 Takatani Shinmachi, Ichikawa City, Chiba Prefecture Nisshin Steel Co., Ltd. New Materials Research Laboratory Polymer Applied Technology Laboratory (72) Inventor Kenji Koshiishi 7-1 Takatani Shinmachi, Ichikawa City, Chiba Prefecture (72) Inventor, Tomao Susumu, Takara Shinmachi, Ichikawa City, Chiba, Niishin Steel Co., Ltd. 72) Inventor Koji Mori 7-1 Takatani Shinmachi, Ichikawa City, Chiba Prefecture Nisshin Steel Co., Ltd. New Material Research Laboratory, Polymer Applied Technology Laboratory (56) Reference JP-A-2-70740 (JP, A) JP flat 1-182351 (JP, A) JP-A 1-210447 (JP, A) JP-A-59-140247 (JP, A)

Claims (4)

[Claims] 1. One or more of (a) a phthalate ester-based plasticizer, a sebacate ester-based plasticizer or a trimellitic acid ester-based plasticizer as a plasticizer is added to 100 parts by weight of a vinyl chloride resin. 40 parts by weight, (b) 1 to 15 parts by weight of an epoxy-based plasticizer, (c) 1 to 5 parts by weight of a dialkyl tin mercaptide-based stabilizer as a stabilizer, and (d) an inorganic fine particle having an average particle size of 10 μm or less. As for the electron beam resistance, it is characterized in that one or both of aluminum hydroxide and hydrous magnesium silicate is blended in an amount of 2 to 30 parts by weight, or 0.2 to 5 parts by weight of hydrotalcites, alone or in combination. Vinyl chloride film. 2. The vinyl chloride according to claim 1, wherein an electron beam curable adhesive is applied to the surface of the thin plate metal original plate, and the applied surface is film processed by a calendering method or an extrusion method. A vinyl-coated steel sheet, characterized in that a film is laminated, and an electron beam is irradiated from the upper surface of the film to bond the film to a metal original plate. 3. A phthalate ester plasticizer is di-2-ethylhexyl phthalate (DOP), and a sebacate ester plasticizer is dioctyl sebacate (DOS).
The vinyl chloride film and vinyl-coated steel sheet according to claim 1 or 2, wherein the trimellitic acid ester plasticizer is trioctyl trimellitate (TOTM), and the epoxy plasticizer is an epoxidized fatty acid ester. 4. The vinyl chloride film and vinyl according to claim 1, wherein the compounding amount of (a) + (b) is 10 to 40 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. Coated steel sheet.