JPH03234749A - Vinyl chloride resin film resistant to electron beam, and steel plate coated therewith - Google Patents

Abstract

PURPOSE:To improve the resistance to electron beam and weathing properties after irradiation with electron beams by compounding a vinyl chloride resin with two specific plasticizers, dialkyltin mercaptide stabilizer, and fine inorg. particles. CONSTITUTION:100 pts.wt. vinyl chloride resin is compounded with 10-40 pts.wt. plasticizer comprising 5-40 pts.wt. at least one plasticizer selected from the group consisting of phthalate plasticizers (e.g. di-2-ethylhexyl phthalate), sebacate plasticizers (e.g. dioctyl sebacate), and trimellitate plasticizers (e.g. trioctyl trimellitate) and 1-15 pts.wt. epoxy plasticizer (e.g. an epoxidized fatty acid ester), 1-5 pts.wt. dialkyltin mercaptide stabilizer, and inorg. fine particles having a mean particle diameter of 10mum or lower and comprising 2-30 pts.wt. aluminum hydroxide and/or hydrated magnesium silicate or 0.2-5 pts.wt. hydrotalcite compd. The resulting compsn. is formed into a film.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a vinyl chloride film having good electron beam resistance and a vinyl-coated steel plate using this film. More specifically, the present invention relates to a vinyl chloride film and a vinyl-coated steel sheet that have good electron beam resistance and weather resistance and are suitable for manufacturing vinyl-coated steel sheets that are subjected to electron beam irradiation.

<Conventional technology> Conventional methods for producing vinyl-coated steel sheets can be roughly divided into two methods: applying vinyl chloride resin paint to the surface of a thin metal sheet such as a galvanized steel sheet or cold-rolled steel sheet, and then heating it.

There are two methods: a baking method (hereinafter referred to as the paste coating method) and a method in which an adhesive is applied to the metal plate and a separately manufactured vinyl chloride film is laminated thereon (hereinafter referred to as the adhesive method). In recent years, a method of laminating films using an electron beam curable adhesive has been developed in the latter adhesive method (hereinafter referred to as electron beam curing method). This electron beam curing method coats a steel plate with an electron beam curable adhesive, then laminates a vinyl chloride film, and then irradiates the film with an electron beam to bond the film and steel plate. A method for manufacturing steel sheets. Unlike conventional paste coating methods and adhesive methods, this method does not require heating and has a fast curing speed, which not only saves energy and improves productivity, but also improves the quality of the film because no heat is applied to the film. It has the characteristic that the applied embossing is clearly retained.

However, the vinyl chloride film that is laminated on the surface of a steel plate for the purpose of design and surface protection has the problem of being easily degraded by the irradiated electron beams, which has prevented the spread of this method.

As a method to prevent this deterioration, Japanese Patent Application Laid-Open No. 622367
As seen in Publication No. 33, a vinyl chloride film is used in which a suspension polymerized vinyl chloride resin is blended with DOP or DOS as a plasticizer, a dialkyltin mercaptite stabilizer as a stabilizer, and an acrylic oligomer as a lubricant. It is known to do.

However, although this method does not cause much discoloration after electron beam irradiation and has some degree of weather resistance, it also lacks sufficient adhesion with adhesives and inks, and is not weather resistant enough to withstand long-term outdoor use. Since it does not have any properties, it has the drawback that its uses as a film for vinyl-coated steel sheets are limited, and improvements have been desired.

Problems to be Solved> An object of the present invention is to provide a vinyl chloride film that has 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 this background, and aims to provide a vinyl chloride film suitable for manufacturing vinyl-coated steel sheets by electron beam curing and a vinyl-coated steel sheet using the film. The method is to add (a) one or more of a phthalate ester plasticizer, a sebacate ester plasticizer, or a trimellitate ester plasticizer to 100 parts by weight of a vinyl chloride resin. 5
~40 parts by weight, (b) 1 to 15 parts by weight of an epoxy plasticizer, (c) 1 to 5 parts by weight of a dialkyltin mercaptite stabilizer, (d) an inorganic type with an average particle size of 10 μm or less It is a vinyl chloride film blended with 2 to 30 parts by weight of aluminum hydroxide or hydrated magnesium silicate or 0.2 to 5 parts by weight of hydrotalcites as fine particles, singly or in combination. An electron beam curable adhesive is applied to the surface, and the above-mentioned vinyl chloride film formed into a film by a calendar processing method or an extrusion processing method is laminated on the coated surface, and an electron beam is irradiated from the upper surface of the film. This is a vinyl-coated steel plate bonded to a metal base plate.

<Example> The vinyl chloride resin in the present invention includes not only a vinyl chloride homopolymer but also a copolymer of vinyl chloride and a monomer copolymerizable with vinyl chloride, such as vinyl acetate and ethylene.

Currently, various grades of vinyl chloride resins are manufactured and marketed by several companies.
As described in Publication No. 33, there are slight differences in electron beam resistance between brands, and when making a selection, it is necessary to confirm the electron beam resistance in advance. The reason for the difference between brands is not certain, but it is proposed that it is due to the influence of residual impurities (for example, dispersant 1 polymerization initiator, etc.) resulting from differences in manufacturing methods.

The degree of polymerization of vinyl chloride resin (PVC) used for vinyl chloride film for vinyl-coated steel sheets is selected from the viewpoint 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 the amount of plasticizer is 5 to 4 parts
If it is 0 parts, the average degree of polymerization (p) may be selected from 700 to 1300, but is not limited to this.

Also, a vinyl chloride resin copolymer may be used.

For example, a vinyl chloride-ethylene copolymer (ethylene content of about 5%) is selected because it has a low melt viscosity and is easy to process, and has good electron beam resistance.

The plasticizer used in the present invention is a phthalate ester plasticizer, a sebacate ester plasticizer, or a trimellitate ester plasticizer, and one or more of them are used in combination. The plasticizer is added in an amount of 5 to 40 parts by weight per 100 parts by weight of the vinyl chloride resin. Plasticizers other than those mentioned above, such as chlorinated paraffin plasticizers and polyester plasticizers.

Phosphate ester plasticizers cannot be used because they have poor weather resistance and change color after electron beam irradiation.

Examples of phthalate ester plasticizers include di-2-ethylhexyl tafrate (DOP) and dibutyl phthalate (DB
P), dinonyl phthalate (DNP), dinonyl phthalate (DHP), diisodecyl phthalate (DIDP)
etc. are used, and DOP is particularly suitable.

In addition, as sebate ester plasticizers, dioctyl sebacate (DO3), dibutyl sebacate (DBS),
Butylbenzyl sebacate (BBS) etc. are used,
In particular, DO8 is suitable.

Examples of trimellitic acid ester plasticizers include trioctyl tri-2-ethylhexyl trimellitate (TOTM);
Tributyl trimellitate (TBTM), triisodecyl trimellitate (TIDTM), etc. are used, and TOTM is particularly preferred.

The epoxy plasticizer in the present invention is epoxidized soybean oil,
Epoxidized fatty acid esters such as epoxidized linseed oil and epoxidized fatty acid octyl ester, and resin-type epoxy compounds include bisphenol-type or novolac-type epoxy resins.Epoxidized fatty acid esters are superior in terms of electron beam resistance; It is added in an amount of 1 to 15 parts by weight per 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-mentioned plasticizer in consideration of the intended use of the vinyl-coated steel sheet. That is, if the total amount of (a) one or more of the phthalate plasticizers, sebacate plasticizers, or trimellitic acid ester plasticizers and (b) the epoxy plasticizer is increased, the embossed This makes deep drawing embossing possible, and after laminating as a vinyl steel sheet, press forming into a predetermined shape allows for complex forming with acute angles.
Surface scratchability and printing suitability deteriorate. On the other hand, if the total amount of plasticizer is reduced, the film becomes hard, the impact strength decreases, and it also has poor elongation during press molding, making it difficult to obtain a predetermined shape. Therefore, as a vinyl coated steel sheet,
A suitable amount is 5 parts to 40 parts.

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

The present inventors investigated the suitability of hundreds of stabilizers after electron beam irradiation and the weather resistance after electron beam irradiation, and found that it is optimal to use dibutyltin mercaptite stabilizers in combination with inorganic fine particles described below. 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 resin. We obtained the knowledge that it is possible to obtain

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

This is because - When improving the weather resistance of a PVC resin composition for boat fishing, Sn-based stabilizers have good transparency and heat resistance but poor weather resistance, so they should be kept in the minimum amount required for processing or not used. Weather resistance is improved by using Zn stabilizers, Cd, and Ba-based stabilizers, and further adding ultraviolet absorbers and antioxidants. The result was that when even a small amount of Zn-based and Cd-based materials were added, the weather resistance deteriorated, whereas ultraviolet absorbers and antioxidants did not have much of an effect on the weather resistance. This difference in the effect of adding additives is thought to be due to the difference in the mechanism of PVC deterioration caused by electron beams and the mechanism of ultraviolet ray deterioration and oxidative deterioration under natural conditions.

Generally, when PvC is exposed to sunlight, its ultraviolet rays gradually generate dechlorination radicals, oxidize, and cleave the main chain, resulting in decomposition, and long-term exposure also causes crosslinking. To prevent this decomposition, UV absorbers and stabilizers are used to improve weather resistance.

On the other hand, when PVC is irradiated with an electron beam, it is said that crosslinking and decomposition occur simultaneously, and then crosslinking and decomposition occur even at room temperature, and it is natural that decomposition is accelerated by exposure to sunlight. It is. Such crosslinking 1 decomposition naturally varies depending on the electron beam irradiation dose.

In manufacturing vinyl steel sheets by electron beam curing, the electron beam irradiation dose is around 1QMrxd, and in the present invention, the irradiation conditions were tested at 1QMrxd.

The dialkyltin mercaptite stabilizer used in the present invention generally has the following structural formula.

1 1 Do\5R2COOR' R Engineering R2 = Alkyl group R' = H or Dioctyltin mercaptite using an n-octyl group as the alkyl group and diptyltin mercaptite using a butyl group are well-known, and both can be used in the present invention. Shows excellent suitability as a stabilizer.

The inorganic fine particles used in the present invention are aluminum hydroxide, hydrated magnesium silicate, or hydrotalcites having an average particle diameter of 10 μm or less, and these are used alone or in combination. Aluminum hydroxide has the chemical formula At(O
H) 3 is a well-known compounding agent as a flame retardant for polymers, but when this aluminum hydroxide is used in combination with dialkyltin mercaptide etc. as in the present invention, it improves weather resistance after electron beam irradiation. This was a surprising finding.

Aluminum hydroxide is widely available on the market with average particle sizes ranging from 0.6 μm to 60 μm, but those with an average particle size of 10 μm or less are suitable for use as films for vinyl steel plates. If it exceeds lOμ, unevenness will occur on the film surface, which will deteriorate the appearance and cause fisheye, resulting in ink splatter and uneven transfer during printing.

Hydrous magnesium silicate is chemically known as 3Mg0.4S.
iO-H2O, and from the crystal structure Mb(Si, os
)(OH) It can be represented by the chemical formula 4.

Hydrous magnesium silicate is used as a filler in polymer resins as inorganic fine particles with rich lubricity, but, like aluminum hydroxide, hydrated magnesium silicate can also be used as a dialkyltin mercaptite stabilizer as in the present invention. Hydrous magnesium silicate is effective in improving weather resistance after electron beam irradiation when used in combination. For the same reason as aluminum hydroxide, those with an average particle size of 10μ or less are suitable as films for vinyl-coated steel sheets. . These aluminum hydroxide or hydrated magnesium silicate is added in an amount of 2 to 30 parts.

Hydrotalcites are Mg1-A 1lx (OH)
2 (ca3)" ・μH20 (in the formula Okuχ<0.5
, O≦μ 1) Magnesium,
Aluminum is a basic carbonate.

This hydrotalcite is also effective in improving weather resistance to electron beam irradiation, similar to the above-mentioned aluminum hydroxide and hydrated magnesium silicate. However, since hydrotalcite tends to yellow when used in a large amount, it is preferable to use it in a range of 0.5 to 5 parts, and even if it is added in a low amount, it has the same properties as the above-mentioned aluminum hydroxide.

The hydrotalcites represented by the above formula have a refractive index of 1
．． 41 to 1.51, and the refractive index of vinyl chloride resin is 1.52.
Since it is close to , there is almost no decrease in transparency even when hydrotalcite is added to vinyl chloride resin. Hydrotalcite from such burial has high utility value as a transparent film for vinyl-coated steel sheets.

This will be explained in detail.

Vinyl-coated steel sheets are usually given a design by printing a woodgrain pattern or abstract pattern on the surface of a base film with a desired colorant added, or by embossing it to create an uneven pattern, but one color fades due to ink wear. In order to prevent this, after printing on the surface of the above-mentioned base film, a transparent film is sometimes laminated on top of the film to form a two-layer structure.

This not only protects the surface, but also creates a rich pattern and expands the range of designs. In this case, the transparent film used for the surface layer is required to have as much crystal transparency as possible.

Hydrous magnesium silicate and aluminum hydroxide each have a refractive index of 1.57. 1.56, therefore, when added to vinyl chloride resin (refractive index 1.52), transparency decreases. Therefore, a formulation containing hydrous magnesium silicate or aluminum hydroxide has no problem when used as a base layer (opaque layer) to which a colorant is added, but when used as a transparent film, the vividness of the ink color may be affected. Therefore, the desired design cannot be realized.

In the vinyl chloride film of the present invention, additives other than the above-mentioned essential components include lubricants, processing aids, ultraviolet absorbers, pigments, and the like.

Lubricants and processing aids vary depending on the molding equipment and process (calender, extruder), so they should be added in an appropriate amount depending on the processing machine.

For example, in the case of manufacturing by the calendar method, about 1 to 2 parts of a polyethylene wax-based lubricant, an acrylic oligomer-based lubricant, or a fatty acid ester-based lubricant are used as a lubricant, and processing aids are not particularly required, but a compound with a small amount of plasticizer (plasticizer) is used as a lubricant. Dosage amount 10
~20 parts), an acrylic processing aid or an ethylene vinyl acetate copolymer may be used in an amount of about 1 to 10 parts. However, when making this selection, it is necessary to check in advance as there are differences in electronic resistance depending on the brand.

As the ultraviolet absorber, approximately 0.2 to 0.5 part of a benzophenone or benzotriazole ultraviolet absorber, which is commonly used as an ultraviolet absorber for vinyl chloride, should be used.

In terms of value, ultraviolet absorbers only have the function of absorbing ultraviolet rays, not electron beams.

Ultraviolet absorbers are generally additives that greatly contribute to the weather resistance of vinyl chloride resin, but in order to improve weather resistance after electron beam irradiation, the selection of stabilizers and inorganic fine particles, which are essential components of the present invention, is essential. is far more important.

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

Next, specific embodiments of the present invention will be explained in detail using specific examples.

According to the formulations shown in Tables 1 and 2, a film with a thickness of 0.15 μm was prepared using a test roll at 175°C, and then
Kcv, 20mA) and irradiated with a 10M+ad electron beam, which was then tested using an accelerated weathering tester (Suga Test Instruments, Ultraviolet Long Life Weatherometer WEL-2 Model Black Panel 63°C) for a test time. The degree of yellowing of the test piece was examined after 1000 hours and 2000 hours. The degree of yellowing can be measured using a color difference meter (3M Color Conbeater, Suga Test Machine)
The color difference ΔE was determined and evaluated.

Evaluation Weather resistance after electron beam irradiation ◎ - Almost no change Color difference ΔE = 3 or less 〇 - Slightly yellowish ΔE = 3 to 6 △ - Yellowing
=7~15×-brown
= 15 to 36 × × - Brown discoloration (some parts are close to blackening); 36 or more The evaluation of the surface condition of the film in Table 2 was based on observing the appearance of the film prepared on a test roll with the naked eye.

Evaluation of the surface condition of the film ◎ - The film surface is completely smooth and no abnormalities O - The gloss of the film surface is slightly reduced, but it is smooth △ - The gloss of the film surface is reduced and small irregularities are visible to the naked eye × - The film surface The transparency of the film shown in Table 3, which is dotted with spots with nuclei, is 0.00 for the formulation without the addition of colorant.
A 1μ transparent film was prepared and its light transmittance was measured (Computer Hazemeter, manufactured by Suga Test Instruments).

Transparency evaluation Basic formulation (parts by weight) PVC resin door = 1000 100DOP
30 epoxidized soybean oil
5 Dibutyltin mercaptite 2 Polyethylene wax 0.5 Ultraviolet absorber 0.3 5 parts each of the various inorganic fine particles shown in Table 3 were added to the basic formulation, and the light transmittance was measured.

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

The following becomes clear from Table 1.

Formulated with added epoxy plasticizer (Examples 1 to 3)
) has good weather resistance, but the one without addition (Comparative Example 5) has significantly poor weather resistance.

Those to which hydrated magnesium silicate as inorganic fine particles were not added (Comparative Examples 1 and 2) had poor weather resistance.

All formulations using DOPSDO8 and TOTM as plasticizers showed excellent weather resistance, with TOTM being particularly good (Example 8.11). In comparison, the formulation using TCP and a polyester plasticizer (Comparative Example 3.4)'' has poor weather resistance.

Formulations using dibutyltin mercaptite and dioctyltin mercaptite as stabilizers (Examples 1-9) have good weather resistance, but formulations using zinc-based, barium-based, and cadmium-based stabilizers (Comparative Examples 6-10) have poor weather resistance. , and dibutyltin mercaptite (Comparative Example 9. Hl) also had poor weather resistance.

From Table 2, the following becomes clear.

The weather resistance of formulations (Examples 12 to 24) using hydrated magnesium silicate, aluminum hydroxide, and hydrotalcite as inorganic fine particles with an average particle size of 10 μ or less is as follows:
It is superior to the formulation without the addition of inorganic fine particles (Comparative Example 11), and the formulations containing calcium carbonate and silica (Comparative Examples 17 to 20) have poor weather resistance. Formulation using inorganic fine particles with an average particle size exceeding 10μ (Comparative Example 13.15
．． 16) has good weather resistance, but the surface condition of the film is poor. The formulation using 8 parts of hydrotalcite turned yellow (Comparative Example 21).

Table 3 *1 *2 *3 *4 *5 *6 *7 *8 *9 *10 *11 *2 *3 *4 *15 *6 *7 *8 *9 *20 *21 *22 *23 *24 Manufactured by Adeka Argus Chemical Same as above Same as above Same as above Same as above Same as above Same as above Japanese Taruri ■ Mitsui Petrochemical ■ ADEKA ARGUS CHEMICAL Ishihara Sangyo■ Japanese Taruri ■ Same as above Same as above Same as above Showa Light Metal Same as above Same as above Same as above Okutama Industry ■ Bihoku Powder Industry■ Fuji Davison Chemical■ Same as above Kyowa Chemical Industry Adekasizer-PN-23 (1 Adeka Sizer 0-13OS Adeka Sizer 0-180? Adeka Sizer 11-176 Mark 1292 Mark 465E Mark AC167 Simbong Hiwax 405MP Mark LA-32 Titanium R-820 Cyclo Ace P-4 Cyclo Ace X-1 Simbong Talc SS Hisilite H-43M Hisilite H-32 Hisilite H-31 Hisilite H-21 Tama Pearl TP-111 Whiten H Thyroid 72 Thyroid 404 Alkamizer 1

Claims (4)

[Claims] (1) For 100 parts by weight of vinyl chloride resin, (a) 5 to 40 parts by weight of one or more of a phthalate ester plasticizer, a sebacate ester plasticizer, or a trimellitate ester plasticizer as a plasticizer. (b) 1 to 15 parts by weight of an epoxy plasticizer, (c) 1 to 5 parts by weight of a dialkyltin mercaptite stabilizer as a stabilizer, (d) inorganic fine particles with an average particle size of 10 μ or less,
Good electron beam resistance characterized by containing 2 to 30 parts by weight of one or both of aluminum hydroxide or hydrated magnesium silicate, or 0.2 to 5 parts by weight of hydrotalcites alone or in combination. vinyl chloride film. (2) Applying an electron beam curable adhesive to the surface of a thin metal original plate, and applying a vinyl chloride film according to claim 1, which is processed into a film by calendering or extrusion. A vinyl-coated steel sheet characterized in that the film is laminated and irradiated with an electron beam from the top surface to adhere the film to a metal original plate. (3) the phthalate ester plasticizer is di-2-ethylhexyl phthalate (DOP), the sebacate ester plasticizer is dioctyl sebacate (DOS),
The vinyl chloride film and vinyl-coated steel sheet according to claims 1 and 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-coated steel sheet according to claims 1 and 2, wherein the blending amount of (a) + (b) is 10 to 40 parts by weight based on 100 parts by weight of the vinyl chloride resin. .