JPS609054B2 - Method for preventing yoking of filler-containing vinyl chloride resin molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing chalking of vinyl chloride resin molded articles.

Vinyl chloride resins are superior to other resins in terms of physical properties, processability, price, etc., and are therefore widely used in many fields, especially in various molded products.

Since pinyl chloride resin has limited uses when used alone, it is often blended with other resins or mixed with various fillers such as calcium carbonate and titanium oxide. We are improving the quality.
However, vinyl chloride resin molded products containing fillers have low weather resistance and, in particular, cause so-called chalking on the surface, so they cannot be used outdoors. The present inventors conducted research on the choking phenomenon of filler-containing vinyl chloride resin molded articles, and as a result, they obtained the following knowledge.

That is, in a filler-containing vinyl chloride resin molded product, as shown in FIG.
A part of the molded product is fixed with resin in a partially exposed state on the surface of the molded product. When such a molded product is exposed outdoors, the surface resin layer gradually deteriorates due to the effects of light, ultraviolet rays, heat, water, etc. As shown in Figure 2, the filler on the surface of the molded product deteriorates. 1 falls off and the surface of the molded product becomes rough, and light is diffusely reflected by this rough surface, causing a chalking phenomenon (whitening phenomenon). In this way, the chalking phenomenon is caused by the deterioration of the surface resin layer due to light, ultraviolet rays, heat, water, etc.
It is assumed that the main causes are a decrease in the bonding force between fillers and the dropout of the fillers. The fall-off of the filler in such cases has been demonstrated by electron micrographs, surface roughness measurements, and infrared spectroscopy of the surface layer. Furthermore, based on the above research results, as a method to prevent chalking, the use of fillers that have excellent affinity with vinyl chloride resins, or the use of fillers that have been specially treated to increase their affinity with vinyl chloride resins. Various methods were tried, but none of them yielded satisfactory results.

However, as shown in FIG.
It has been found that by coating with a filler, it is possible to extremely effectively prevent the filler from falling off due to outdoor deterioration, etc., and the chalking caused thereby, leading to the present invention. The method for preventing chalking of a filler-containing polyvinyl chloride resin molded article of the present invention is to prevent the surface of a filler-containing pinyl chloride resin molded article from
20 to 8 parts of plasticizer per 100 parts by weight of polyvinyl chloride
This method is characterized by coating with a polyvinyl chloride plastisol containing part by weight of polyvinyl chloride and no filler. The filler-containing vinyl chloride resin molded product in the present invention refers to a molded product obtained by molding a resin composition prepared by adding a filler and, if necessary, various additives to a vinyl chloride resin using various molding methods. It is.

Examples of the vinyl chloride resin include, for example, PoIJ vinyl chloride “vinyl chloride/ethylene copolymer and vinyl chloride/ethylene copolymer”.
Examples include vinyl acetate copolymer.

Further, the polyvinyl chloride constituting the polyvinyl chloride plastisol may be a vinyl chloride copolymer containing a relatively small amount of vinyl acetate as a copolymerization component, in addition to a vinyl chloride homopolymer. Fillers added to vinyl chloride resins include inorganic fillers such as calcium carbonate, clay, diatomaceous earth, talc, powdered alumina, mica, aluminum sulfate, barium sulfate, asbestos, titanium oxide, calcium fluoride, and calcium sulfate. Fillers: organic fillers such as wood flour (cellulosin), rice husk, pulp, cellulose flour, shellac, eponite flour, and coconut flour.

The polyvinyl chloride plastisol used for coating the filler-containing vinyl chloride resin molded article in the present invention contains a plasticizer in an amount of 20 to 8 parts by weight, preferably 35 to 55 parts by weight based on 10 parts by weight of polyvinyl chloride. % and contains no filler. Examples of the plasticizer include diphenyl phthalate (DPP), tricresyl phosphate (TCP), dioctyl adipate (DOA), dimethyl phthalate (DMP), and trioctyl phosphate (TOP).
and dioctyl phthalate (DOP).
If the plasticizer content of the plastisol is less than 2 parts by weight per 10 parts by weight of vinyl chloride, the sol will lack stability and the plasticizer will easily phase separate, while if it exceeds 8 parts by weight, it will coat the surface of the molded product. Both of these methods are undesirable because the plastisol layer obtained becomes sticky and the surface hardness of the coating layer decreases. The polyJ vinyl chloride plastisol of the present invention may optionally contain various additives such as stabilizers, ultraviolet absorbers, colorants, antioxidants, lubricants, and impact modifiers. In the present invention, such polyvinyl chloride plastisol can be used as it is to coat molded products, but it can also be diluted with a water-insoluble solvent that does not dissolve the vinyl chloride resin to create a diluted polyvinyl chloride plastisol solution. It may also be used as a coating for molded products.

Examples of the non-aqueous solvent include petroleum ether, petroleum benzine, ligroin, and mineral spirits. In the present invention, various methods can be used to coat a molded article with polyvinyl chloride plastisol or a diluted solution of the plastisol.

Examples include the roll coater method, the blade coater method, the bonding method, and the spraying method. A coating thickness of at least 5 mm is usually required to completely coat the filler. There is no particular limit to the upper limit of the thickness of the coating layer, but from the viewpoint of ease of coating, necessary anti-choking effect, and economic efficiency, it is usually up to about 200 mm.
No particular benefit is usually obtained from coatings thicker than that.

Thus, the molded article coated with the plastisol or plastisol diluent may contain, for example, 130 to 200 q
The plastisol coating layer is gelled and solidified by heating three to two powders of sand at a temperature of 0°C.

When coating with a plastisol diluted solution diluted with a diluent, it is usually coated with hot air blowing, zero
If this happens, it is desirable to volatilize and remove the diluent using a method such as heating in an oven. The anti-choking method of the present invention can be applied to molded products of various shapes.

For example, it can be applied to plate-like objects, pipe-like objects, rod-like objects, and irregularly shaped objects of various shapes. For molded articles with complex shapes, such as irregularly shaped articles, spraying or immersion methods are suitable. Further, plastisol and plastisol diluted liquid are appropriately selected and used depending on the desired surface roughness of the coated article. For example, if you want to maintain the surface irregularities of the molded product in the coating, you can use a diluted plastisol solution to coat it relatively thinly, or if you want to finish it on a flat surface, you can use plastisol as it is to coat it thickly. . Since the method for preventing chalking of the present invention simply applies polyvinyl chloride plastisol to a molded article, the method itself is simple and easy, and moreover, it can very effectively prevent chalking of a molded article.

In other words, a molded product to which the chalking prevention method of the present invention is applied will not whiten even if left outdoors for a long time, and patterns applied to the surface of the molded product (for example, wood grain patterns) will not disappear. This is because the vinyl chloride resin of the base material and the polyvinyl chloride plastisol layer of the coating layer are of the same type of resin, and the adhesion between the two is extremely good, and the filler does not fall off even when left outdoors for a long time. This is thought to be because it can effectively prevent In addition, polyvinyl chloride plastisol or a diluted solution of the plastisol is stable, and there is no fear of damaging the molded product during coating. Furthermore, by selectively using plastisol and plastisol diluent, coatings of various desired thicknesses can be easily applied. In addition, the method of using a polyvinyl chloride emulsion instead of using the polyvinyl chloride blastisol of the present invention or its diluted solution is difficult because the emulsion has poor stability and the coating from the emulsion has poor heat resistance. Due to the poor performance, it is not possible to prevent chalking as easily and effectively as in the present invention.

In addition, the method of using a polyvinyl chloride solvent solution instead of using the plastisol of the present invention or its diluted solution also has the disadvantage that the base material of the molded article is attacked by the solvent during coating, and that the solvent solution does not allow thick film coating. Therefore, the excellent effects as in the present invention cannot be expected. Next, the present invention will be explained by giving examples.

Example 1 Polyvinyl chloride (degree of polymerization: 800, straight polymer) 10 parts by weight Dibutyl tin mate 2.0 Calcium stearate 1.0 Pigment (PMP-MJB162 manufactured by Dainichiseika Chemical Co., Ltd.) 0.1 Calcium carbonate 10 Thickness 10 obtained by extrusion molding from a vinyl chloride resin composition having the above composition
Apply polyvinyl chloride plastisol of the following composition to the board material of the ribs and middle 20 ribs using a roll coater to a film thickness of 50 mm, and heat it for 5 minutes at a temperature of 185°C to gel and solidify the plastisol coating. I let it happen.

Polyvinyl chloride (Nippon Zeon Co., Ltd. Zeon 121: paste resin) 10 parts by weight DOP
60 〃Calcium stearate 1 〃Zinc stearate 1 〃Next, the obtained plastisol-coated board material was subjected to standard sunshine treatment.
When an irradiation test was conducted using a Weatherometer (manufactured by Toyo Rika Kogyo Co., Ltd.), no chalking phenomenon was observed even after irradiation for 100 hours.

On the other hand, when the above molded plate was subjected to an irradiation test in the same manner as above without being coated with plastisol, 30
A chalking phenomenon appeared during the process, and the surface became white.

Example 2 Polyvinyl chloride (degree of polymerization: 1050, straight polymer) 10 parts by weight Calcium stearate 1.0 Zinc stearate 1.0 Pigment (Brown D3605 manufactured by Dainippon Ink and Chemicals)
0.1 Talc
20 A pipe with an inner diameter of 50 legs and a wall thickness of 2 obtained by extrusion molding from a vinyl chloride resin composition having the above composition was immersed in a diluted solution of plastisol having the following composition to coat it to a film thickness of 20 r, 10,000 pieces of this coated pipe
, After heat treatment for 2 minutes to volatilize and remove ligroin,
It was heated at 140 oo for 2 minutes to gel and solidify the coating film.

Vinyl chloride/vinyl acetate copolymer (Kaneka PCM-12: paste resin manufactured by Kanekabuchi Chemical Co., Ltd.) 10 parts by weight TC
P
40 〃Dibasic head lead phosphate 2
〃Ligroin 30〃
Next, the obtained plastisol-coated pipe was subjected to the same irradiation test as in Example 1, and no chalking phenomenon was observed even after 100 field hours of irradiation.

On the other hand, when a similar test was carried out on the above-mentioned extruded pipe, irradiation chalking occurred for 300 hours and the surface became white.

Example 3 Polyvinyl chloride (degree of polymerization: 1020, straight polymer) 10 parts by weight Tribasic lead sulfate 2.0
〃Stearic acid 1.0 〃Pigment (TPH-NM Red No. 4 manufactured by Toyo Ink Manufacturing Co., Ltd.)
0.1 Pulp
30 A cross section obtained by extrusion molding using a vinyl chloride resin composition having the above composition was made of a drainboard material with the following composition: A diluted polyvinyl chloride plastisol solution was applied using the spray Z method so that the film thickness was 5 mm, and the coated drainboard material was heat-treated at 40q0 for 1 minute to volatilize and remove the mineral spirit, and then heated to 185°C. The coating film was gelled and solidified by heating for 5 minutes.

Polyvinyl chloride (Kaneka PSH-ZI manufactured by Kaneka Kagaku Kogyo Co., Ltd.)
O: paste resin) 10 parts by weight D
OA
20 〃Dibutyltin malate 2 〃Mineral spirit 60 〃The obtained plastisol-coated drainboard materials were then subjected to the same irradiation test as in Example 1, and no chalking phenomenon was observed even after irradiation for 100 hours. On the other hand,
When the same irradiation test was carried out on the above extruded drainboard material, chalking occurred and the surface became white after irradiation for 250 hours and 2 hours.

Example 4 Polyvinyl chloride (degree of polymerization: 1450 straight polymer) 10 parts by weight 3 tribasic lead sulfate 20 Stearic acid 1.0 Wood powder
30 Using a Nito extruder in the same direction on the 7.5 side, 100 parts by weight of the self-composed vinyl chloride resin composition was added from a part of the hopper of the extruder, and a polyvinyl chloride color pellet 2 colored brown was added from the vent port. Parts by weight were fed to extrude a slatted wood having a grain pattern of the same shape and dimensions as described in Example 3.

The same diluted polyvinyl chloride plastisol solution used in Example 3 was applied to this drainboard material using a spray method so that the coating film was 5 cm thick, and then the drainboard material was coated with 40q0
After heat treatment for 1 minute to volatilize and remove the mineral spirit, the coating film was heated for 5 minutes at a temperature of 18,500° C. to gel and solidify the coating film. When the obtained plastisol-coated drainboard material was subjected to the same irradiation test as in Example 1, no chalking phenomenon was observed even after irradiation for 100 cycles, and the wood grain pattern on the surface did not disappear.

On the other hand, in the same irradiation test, the as-molded slat material developed a chalking phenomenon after irradiation for 25 hours, and the wood grain pattern disappeared.

[Brief explanation of the drawing]

Figure 1 is a partial vertical cross-sectional view of a filler-containing vinyl chloride resin molded product, Figure 2 is a partial vertical cross-sectional view of the same molded product that has developed chalking due to being left outdoors, etc., and Figure 3 is a partial vertical cross-sectional view of the same molded product coated with polyvinyl chloride plastisol. A partial vertical cross-sectional view of the same molded product is shown. The symbols in each drawing indicate the following. 1:
filler, 2: vinyl chloride resin, 3: irregularities on the surface of the molded product caused by falling off of the filler, 4: polyvinyl chloride plastisol coating layer. Figure 1, Curtain 2, Complete 3

Claims (1)

[Claims] 1. The surface of the filler-containing vinyl chloride resin molded product is coated with polyvinyl chloride plastisol, which contains 20 to 80 parts by weight of a plasticizer per 100 parts by weight of polyvinyl chloride and does not contain a filler. A method for preventing yoking of filler-containing vinyl chloride resin molded products.