JPH03138143A - Composite coated steel sheet of vinyl chloride resin with excellent weatherability and surface smoothness and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve the weatherability and surface smoothness by providing a primer layer for sticking vinyl chloride, a coating of a specified plastisol and a synthetic resin layer on a steel sheet. CONSTITUTION:On a steel sheet, a primer layer for sticking vinyl chloride, a plastisol coating of a soft vinyl chloride resin contg. 0.001-0.5 pt.wt. liq. silicone terpolymer soluble in a phthalate based on 100 pts.wt. resin and with a film thickness after drying of 50-100mum thereon and a synthetic resin layer of polyacrylate with a film thickness of 20-75mum furthermore thereon are provided. A composite coated steel sheet of vinyl chloride resin with excellent weatherability and surface smoothness can be obtd. thereby.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is used for building materials, electrical equipment, vehicles, etc., and is particularly useful for products that are used outdoors for a long period of time. This invention relates to a vinyl chloride resin-based composite coated steel sheet with excellent smoothness and a method for manufacturing the same.

<Conventional Technology> Conventionally, vinyl chloride resin-coated steel sheets have been widely used for building materials, electrical equipment, vehicles, etc. due to their excellent performance. However, when PVC resin-coated steel sheets are used continuously outdoors for a long period of time, the plasticizer in the PVC resin layer on the surface evaporates, and the PVC resin itself undergoes chemical changes and deterioration, resulting in a significant decrease in surface properties. At the same time,
It had the disadvantage of exhibiting severe discoloration.

As described above, vinyl chloride resin-coated steel sheets have poor weather resistance, and to improve this, a technique has been developed in which a polyacrylate synthetic resin layer is laminated on top of the vinyl chloride resin layer (for example, Japanese Patent Laid-Open No. 17876/1983) ) is known.

<Problems to be Solved by the Invention> As mentioned above, it is a known fact that polyacrylate synthetic resin layers are laminated in order to improve the weather resistance of vinyl chloride resin coated steel sheets. However, using only these conventional techniques, it is not possible to obtain a composite coated steel sheet with excellent surface properties as the object of the present invention.

That is, for soft vinyl chloride resin plastisol used for boat fishing, there is a literature [Journal of vinyltechn.
ology, Vol. 9. No, 4. P.17
9-182 (1987), etc., the occurrence of craters due to the adverse effects of silicone oil mixed as an impurity on the surface of the resulting coating film or film is unavoidable, and therefore Even if a polyacrylate-based synthetic resin layer is laminated on top of the coated steel plate, crater marks remain and only a composite coated steel sheet with poor surface properties is obtained.

An object of the present invention is to provide a composite wave 'N9!4 board made of vinyl chloride resin and having excellent weather resistance and surface smoothness.

<Means for Solving the Problems> The present inventors have developed a vinyl chloride resin liquid containing a plasticizer. ! In order to prevent the steel plate from being adversely affected by ultraviolet rays, heat, moisture, etc., we focused on a technology that covers the surface with a layer of polyacrylate-based synthetic resin, while at the same time maintaining the steel plate's excellent workability and surface smoothness. In order to achieve this goal, we discovered that only a composition containing a liquid silicone-based terpolymer soluble in phthalate ester could be used as the plastisol used to form the vinyl chloride resin layer. The invention was completed.

That is, in order to achieve the above object, according to the present invention, a vinyl chloride adhesion primer layer is formed on a steel plate, and a liquid silicone-based terpolymer that is soluble in phthalate ester is applied on the primer layer by weight of 100% resin. A soft vinyl chloride resin plastisol coating containing 0.001 to 0.5 parts by weight per part and having a film thickness of 50 to 100 μm after drying, and a coating film of polyacrylate resin having a film thickness of 20 to 75 μm on top of that. A vinyl chloride resin-based composite coated steel sheet having a synthetic resin layer and having excellent weather resistance and surface smoothness is provided.

Further, according to the present invention, on the surface of the steel plate coated with a primer, 0.001 to 0.001 to 100 parts of a liquid silicone-based ternary copolymer that is soluble in phthalate is added to 100 parts by weight of the soft vinyl chloride resin. The film thickness after drying the plastisol of soft vinyl chloride resin containing 0.51 parts by weight is 50 to 10
A vinyl chloride resin composite coating with excellent weather resistance and surface smoothness, which is coated to a thickness of 0 μm, dried and baked, and then laminated with a polyacrylate synthetic resin layer with a film thickness of 20 to 75 μm. A method of manufacturing a steel plate is provided.

It is preferable that the silicon-based terpolymer is polyether-modified silicon oxide.

The present invention will be explained in more detail below.

The steel plate serving as the substrate used in the present invention has a structure of 1. Suitable materials include, but are not limited to, cold-rolled steel sheets, various galvanized steel sheets, chrome-plated steel sheets, tin-plated steel sheets, nickel-plated steel sheets, lead-plated steel sheets, aluminized steel sheets, alloy-plated steel sheets, or Examples include composite coated steel sheets and multilayer plated steel sheets.

Further, these steel plates may be subjected to pretreatment, such as degreasing, phosphate treatment, chromic acid treatment, etc., as necessary, and then subjected to the above-mentioned plating.

The soft vinyl chloride resin in the present invention may be formed using known raw materials and methods, but preferably has an average degree of polymerization of 500 to 2,500, and has a chlorinated vinyl resin for plastisol produced by an emulsion polymerization method or a microsuspension method. It is preferable that the material contains vinyl resin as a main component.

That is, homopolymers of vinyl chloride or polymers copolymerizable with vinyl chloride, such as ethylene, propylene, vinyl acetate, vinyl propionate, vinyl stearate,
The vinyl chloride copolymer resin contains 20% by weight or less of alkyl vinyl ether, vinylidene chloride, diethyl fumarate, acrylic ester, methacrylic ester, etc., and is preferably in powder form.

The soft vinyl chloride resin plastisol of the present invention contains a plasticizer, which is an essential component to fluidize the resin component, and a heat stabilizer, which is an essential component to obtain a coating film of vinyl chloride resin. Further, as other components, pigments, fillers, etc. can also be contained as necessary.

As the plasticizer, all plasticizers commonly used for plastisol can be used, including dibutyl phthalate,
Cyamyl phthalate, dimethoxyethyl phthalate, dibutoxyethyl phthalate, dicyclohexyl phthalate, dihexyl phthalate, diheptyl phthalate, butyloctyl phthalate, di(n-octyl) phthalate, di(n-octyl) phthalate
2-ethylhexyl), diisooctyl phthalate, didecyl phthalate, didodecyl phthalate, butylbenzyl phthalate, and other phthalic acid esters; alkyldiphenyl phosphate, tricresyl phosphate, and other phosphates; or adipic acid, succinic acid, and azelaic acid. ,
Examples include esters such as cicapril, didecyl, and di-2-ethylhexyl such as sebacic acid, but also polyester plasticizers for vinyl chloride, epoxy plasticizers,
It is possible to use chlorinated paraffin etc. in combination.

Furthermore, it is also possible to replace a part of the plasticizer with a diluent such as mineral spirit or Tsurpez.

As the heat stabilizer, all the heat stabilizers used for plastisol made of vinyl chloride resin in boat fishing can be applied, but specifically organic tin compounds (loughric acid ester of diptyltin, mercapto) are applicable. etc.) Metal soaps (lead, cadmium, barium, zinc, calcium salts such as stearic acid, lauric acid, naphthenic acid, 2-ethylhexoate acid, etc.), lead salts (basic lead carbonate, tribasic lead sulfate, dibasic lead phthalate, tribasic lead maleate, lead silicate, etc.).

Furthermore, the other ingredients include - calcium carbonate, which is used in plastisol made of vinyl chloride resin for boat fishing;
Examples include barium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, silica, clay titanium oxide, carbon black, red iron oxide, and the like.

A preferred example of a method for coating the steel plate with plastisol of soft vinyl chloride resin is as follows.

First, the steel plate is treated with brimer. Specifically, vinyl chloride resin adhesives such as nitrile rubber, acrylic-modified epoxy resin, or a mixture of epoxy resin and phenolic resin, which exhibit adhesive properties to both the steel plate and the soft vinyl chloride resin layer, are used. Use a brimer and apply the coating under the conditions used for boat fishing.

To be more specific, it is preferable to apply the primer so that the primer layer thickness after baking and drying is 4 to 10 μm, set the steel plate temperature to 200 to 260°C, and perform baking and drying for 30 to 90 seconds. .

A plastisol is coated on the steel plate treated with the primer in this way and baked to obtain a vinyl chloride resin-coated steel plate.In the present invention, a liquid silicone-based ternary element that is soluble in phthalate ester is added to the plastisol. By containing 0.001 to 0.5 parts by weight of the polymer (based on 100 parts by weight of the resin), it is possible to obtain a vinyl chloride resin-based composite coated steel sheet with excellent surface smoothness, which has never been seen before.

This silicon-based ternary copolymer is specifically a polyether-modified silicon oxide, which is a silicon-based ternary copolymer in which a portion of dimethylpolysiloxane is a hydrophobic group and a portion of polyether is a parent wood group. , ethylene oxide, and propylene oxide are preferred.

If the amount of the silicone-based ternary copolymer added is less than 0.001 part by weight, no effect of improving surface smoothness by the addition of the silicone-based ternary copolymer is observed; on the other hand, if it exceeds 0.5 part by weight, This method is unsuitable because it has drawbacks such as reduced adhesion to the polyacrylate synthetic resin layer forming the uppermost layer.

As described above, the soft vinyl chloride resin plastisol containing the silicone-based terpolymer is preferably applied so that the layer thickness after drying is 50 to 100 μm. This is because if the layer thickness is less than 50 μm, it is difficult to control the layer thickness uniformly during coating, whereas if it exceeds 100 μm, it will only increase the cost and no further improvement in performance can be expected. be. After coating the steel plate with soft vinyl chloride resin plastisol,
Baking is performed at 150-230°C for 60-120 seconds,
It is preferred to complete the vinyl chloride resin layer.

Lamination of polyacrylate-based synthetic resin layers contributes to improving the weather resistance of the vinyl chloride resin-coated steel sheet, but in the present invention, polyacrylate-based synthetic resins having a limited composition as described below are applied.

That is, it contains 70% by weight or more of methacrylic acid and methacrylic acid ester monomers, and also contains monomers that can be copolymerized with acrylic acid and acrylic ester monomers.

Specifically, the methacrylic monomers include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, n-lauryl methacrylate, ethoxydiethyl methacrylate, methacrylic acid, ethylene glycol dimethacrylate, glycidyl methacrylate, 2-
Examples include hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, etc. Examples of acrylic monomers include methyl acrylate, ethyl acrylate, n-butyl acrylate, n-hebutyl acrylate, 2-ethylhexyl acrylate, ethoxy Examples include ethyl acrylate, acrylic acid, glycidyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, acrylamide, diacetone acrylamide, and other copolymerizable monomers include styrene, vinyl acetate, and the like.

In order to obtain the polyacrylate synthetic resin of the present invention, polymerization of these acrylic, methacrylic, and copolymerizable polymers is carried out, and in this case, bulk polymerization, solution polymerization, emulsion polymerization, Polymerization methods such as suspension polymerization and granular polymerization can be used. In order to further create a film from the synthetic resin obtained by such a polymerization method, extrusion molding, rolling processing, etc. are commonly used.

When laminating the polyacrylate-based synthetic resin layer on the vinyl chloride resin-coated steel plate, it may be carried out by a known method, that is, the laminating roll method, and the temperature of the steel plate is 150 to 2
At 30℃, roll pressure is 0.5 to 5,0 kg/c
It may be done at about m'.

<Examples> The present invention will be specifically described below based on Examples. The performance evaluation of vinyl chloride resin-based composite coated steel sheets is based on J.
The following evaluation method based on IS standards was followed.

(1) Eriksen test (JIS K-6744) 5m
m width cut, Erichsen 6mm Extrusion 5 points (no abnormality) to 1 point (full peeling) 5-point evaluation (2) Bending test (-5400 to JIS) Vise tightening (OT) 5 points (no abnormality) to 1 point ( 5-level evaluation (3) Impact test (JIS G-3312) φ1 /
2 x 50 cm x 500 g 5-point evaluation from 5 points (no abnormality) to 1 point (full surface peeling 1li) (4) Due cycle accelerated weather resistance test (JIS G-
3312) The color difference (ΔE) after 500 hours of irradiation was measured with Hitachi Color Analyzer Model 607 and calculated using the CIE (1976) color difference calculation formula.

(5) Surface smoothness The glossiness (G, R, %) of the surface of the vinyl chloride resin coated steel plate was measured by the 60 degree specular reflectance method using a variable angle gloss meter tJGV-5K manufactured by Suga Test Instruments.

(6) Secondary adhesion The vinyl chloride resin composite steel plate to be subjected to N is immersed in boiling water for 1 hour, taken out, cooled, and subjected to the Erichsen test in the same manner as in (1).

Five-point evaluation (Example 1): 5 points (no abnormality) to 1 point (full surface peeling 11!) Acrylic-modified epoxy resin-based brimer was applied to steel plates with different pretreatment conditions shown in Table 1, and 245°C 45
Baking was performed at a temperature of 1.5 seconds to form a brimer layer having a thickness of 5 μm after drying.

Next, to plastisol of soft vinyl chloride resin having the composition shown in Table 2, various silicone-based ternary copolymers having properties shown in Table 3 were added at 0.01 parts by weight per 100 parts by weight of vinyl chloride resin.
After blending parts by weight, it was coated and baked at a temperature of 210° C. for 90 seconds to form a vinyl chloride resin layer with a thickness of 1004 m after drying. The surface smoothness of the vinyl chloride resin coated steel sheet thus prepared was measured.

Next, as a polyacrylate synthetic resin layer, X;
Acrylic resin film (Sunduren 003, wall thickness 75
Lamination was carried out using a steel plate temperature of 200° C. and a roll linear pressure of 1 and 0 kg/cm 2 using the following conditions.

Various performance evaluations were performed using the vinyl chloride resin composite coated steel sheet manufactured in this way, and as shown in Table 1, all the results were satisfactory (Inventive Examples 1 to 4).
In particular, the workability (Erichsen test, bending test, impact test) and secondary adhesion were at the same level as a steel plate provided with only a normal vinyl chloride resin layer (see Comparative Example 3 below).

table 1 (Parts by weight based on 100 parts by weight of resin) Surface smoothness (G, R, %) Types of polyacrylate resin film erichsen test bending test ffTs test Secondary adhesion test Due cycle test (ΔE) Table 2 table The explanation is as follows.

I ; 11 ・ Type of vinyl chloride resin coated steel sheet Test results; Type of steel sheet; Thickness of steel sheet (mm); Pretreatment; Type of silicone-based terpolymer; Addition amount of silicone-based terpolymer 1 ) OP: ictyt Phthlate (Representative example of phthalate ester) *1) Confirmation of silicone-based ternary copolymer; Containment of the three components was confirmed by NMR (nuclear magnetic resonance) method. In addition,
All ANFs are manufactured by Shin-Etsu Silicon Hook, and their product names are as follows.

A; KF351 (A) B, KF352 (A) C, KF354 (A) D; KF355 (A) E, KF353 (A) FIX-22-6008 *2) Viscosity (C5); According to JIS K-7117 .

*3) Specific gravity (25°C), according to JIS-7112.

Umbrella 4) Solubility in DOP In a test tube DOP: Silicone terpolymer = 9:
After shaking for 3 minutes, the mixture was determined to be dissolved (S) if it became homogeneous, and not dissolved (I) if it became non-uniform.

(Example 2) A hot-dip Zn-plated steel plate was coated with Brimer plastisol and baked in the same manner as in Example 1, and then a polyacrylate synthetic resin layer was formed: Acrylic resin film 2A.

Wall thickness 50 μm coloring) (Sandyu Lamination of Application examples 5 to 8) obtained vinyl chloride resin composite coated steel sheets (final completion Regarding these, We conducted various performance evaluations, but As shown in Table 4, all the results were satisfactory.

In particular, the secondary adhesion was at the same level as that of the steel sheet provided with only a normal vinyl chloride resin layer (see Comparative Example 3 below), similar to Example 1 described above.

PVC resin-based composite coated steel sheets were manufactured under the same manufacturing conditions as in Example 1 using hot-dip Zn-plated steel sheets with different silicon-based ternary copolymer contents (Comparative Examples 1 to 3). We conducted an evaluation.

The results are shown in Table 5, and silicon-based terpolymer E, F
are insoluble in phthalate esters, Comparative Examples 1 and 2 of vinyl chloride resin composite coated steel sheets were created by blending these silicone ternary copolymers and laminating a polyacrylate synthetic resin layer. A decrease in surface smoothness and secondary adhesion was observed, giving unsatisfactory results. In addition, Comparative Example 3, which did not have a polyacrylate synthetic resin layer laminated, gave unsatisfactory results in the weather resistance due cycle test.

Table (Comparative Examples 4 to 6) Using stainless steel sheets, vinyl chloride resin composite coated steel sheets with different amounts of silicone ternary copolymer added were manufactured under the same manufacturing conditions as in Example 2. We conducted an evaluation.

The results are shown in Table 6, and Comparative Example 4, in which the amount of silicone-based ternary copolymer was not added, and Comparative Example 5, in which the amount of silicone-based ternary copolymer added was too small, had poor surface smoothness. On the other hand, in Comparative Example 6, in which an excessive amount of the silicone-based terpolymer was added, the secondary adhesion was poor, and all results were unsatisfactory.

Table <Effects of the Invention> Since the present invention is constructed as described above, it is possible to provide a vinyl chloride resin composite coated steel sheet having excellent weather resistance, surface smoothness, and economical efficiency. Therefore, the use of the vinyl chloride resin composite coated steel sheet can be expanded to include products that are used outdoors for a long period of time.

Claims (4)

[Claims] (1) A primer layer for adhesion of vinyl chloride on a steel plate, and on top of that, 0.001 to 0.001 parts by weight of a liquid silicone-based ternary copolymer that is soluble in phthalate ester per 100 parts by weight of resin.
A soft vinyl chloride resin plastisol coating containing 0.5 parts by weight and having a thickness of 50 to 100 μm after drying, and a polyacrylate synthetic resin layer having a thickness of 20 to 75 μm thereon. A vinyl chloride resin-based composite coated steel sheet with excellent weather resistance and surface smoothness. (2) The vinyl chloride resin-based composite coated steel sheet with excellent weather resistance and surface smoothness according to claim 1, wherein the silicon-based ternary copolymer is polyether-modified silicon oxide. (3) Apply 0.0% of a liquid silicone-based ternary copolymer that is soluble in phthalate esters to 100 parts by weight of soft vinyl chloride-based resin on the surface of the steel plate that has been baked and painted with a primer.
A plastisol of soft vinyl chloride resin containing 01 to 0.5 parts by weight is coated so that the film thickness after drying is 50 to 100 μm, and after drying and baking, the film thickness is 20 to 75 μm.
A method for manufacturing a vinyl chloride resin-based composite coated steel sheet with excellent weather resistance and surface smoothness, which comprises laminating polyacrylate-based synthetic resin layers. (4) The method for producing a vinyl chloride resin-based composite coated steel sheet with excellent weather resistance and surface smoothness according to claim 3, wherein the silicon-based ternary copolymer is polyether-modified silicon oxide.