JPH0236382B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a mechanically foamed embossed sheet that is lightweight, has a sharp uneven pattern, and has a three-dimensional effect. The production of foam by mechanically foaming plastisol or latex (mechanical foaming) and then heating and melting is a well-known technique that has been effectively employed in the production of packing materials for carpets, flooring, trunk mats, etc. be. For example, it is known that a mechanically foamed polyvinyl chloride plastisol foam is processed into a sheet and heated with hot air to be used as a backing material, but there is almost no technology for deeply embossing the resulting foam sheet. It's unknown. Specifically, in order to impart deep, sharp embossability to polyvinyl chloride foam, it is necessary to appropriately increase the melt viscosity of plastisol. Separately, if the melt adhesion of the material to be embossed to, for example, the base material is insufficient, a phenomenon occurs in which the material to be embossed is taken by the embossing roll. The appropriate heating temperature for mechanical foaming is in the range of 160 to 190°C; heating at temperatures higher than this will cause the melt viscosity to drop dramatically, and the holding power of the foam to decrease, resulting in the phenomenon of stagnation. , it is not possible to apply sufficient heating,
Naturally, the physical properties of the obtained foam are low. Therefore, the range of processing conditions that satisfy embossing suitability is currently extremely narrow. As a means of improving so-called embossing suitability to obtain a sharp pattern with unevenness, for example, a method of adding an inorganic filler such as calcium carbonate, a method of embossing by making the coating thickness much thicker than the desired thickness, and a method of foaming. One possible method is to dramatically increase the magnification. However, in method (2), it is necessary to add a large amount of filler, which may cause the foam to become brittle and get caught in the embossing roll, or reduce the stability of the foam during the heating process, resulting in a decrease in foaming ratio. It is difficult to obtain a product with satisfactory physical properties, and the product is heavy. In the method, the thermal conductivity of plastisol containing air bubbles is
It is extremely poor compared to normal plastisol, and when heated, there is a difference in meltability in the thickness direction, and good physical properties cannot be obtained. Also, bubbles are destroyed due to roll removal, and at low magnification. It has the disadvantage that only heavy products can be obtained. This method is impractical because the coating method of the sol containing bubbles is extremely poor, the physical properties of the resulting foam are poor, and a substantially sharp uneven pattern cannot be obtained. The present inventors investigated various methods for manufacturing embossed sheets by mechanical foaming that have a sharp three-dimensional effect with an uneven pattern, and found that a part or all of the inorganic filler should be an inorganic filler consisting of a hollow body. As a result, the inventors discovered that a machine-foamed embossed sheet with an extremely sharp uneven pattern and a three-dimensional effect, which is lightweight, could be obtained, and the present invention was completed. That is, an object of the present invention is to provide a method for manufacturing a lightweight mechanically foamed embossed sheet with a sharp uneven pattern and a three-dimensional effect. A method for producing a mechanically foamed embossed sheet, which comprises mechanically foaming latex, heating and melting the latex to produce a foam, and then mechanically applying an uneven pattern using an embossed roll or an embossed press plate. exists in To explain the method of the present invention in detail, the plastisol used in the present invention is a polyvinyl chloride dispersion prepared by blending an inorganic filler, a plasticizer, and a foam stabilizer into a paste resin mainly composed of polyvinyl chloride. Alternatively, it may be an organosol with some diluent added. Further, the latex used in the present invention includes latexes such as polyvinyl chloride, polyvinyl acetate, and SBR, and the latexes may be blended with inorganic fillers, foam stabilizers, and if necessary, plasticizers and other additives. ing. Therefore, it is essential for plastisols and latexes that at least a portion of the inorganic filler is hollow. An inorganic filler consisting of a hollow body is not particularly limited as long as it is inorganic and hollow, but it has a true specific gravity.
It is preferable to use granules with a value in the range of 0.18 to 0.21 and a particle size in the range of 10 to 200 microns, such as white hollow bodies made of silicic acid, alumina, and various other metal conjugates. Therefore, the amount of the hollow inorganic filler used is, for example, 1 to 15 parts by weight, preferably 3 to 10 parts by weight, per 100 parts by weight of the resin component such as polyvinyl chloride. If the blending ratio is in the range of 10 to 15 parts by weight, the texture of the resulting mechanically foamed embossed sheet will be very dry and hard, and if it exceeds 15 parts by weight, the texture will be similar to that of plastisol or latex. The viscosity increases markedly, making foaming difficult, and the cells of the mechanically foamed foam become rough, making them more likely to burst during heating and melting. By using the amount of filler in the range of 3 to 10 parts by weight, even if the mechanically foamed plastisol or latex foam is placed on the substrate to a thickness of about 2 to 4 mm, the foaming ratio can be increased to 2. Even if it is increased by about 3 times, it becomes a mechanically foamed embossed sheet with a particularly sharp three-dimensional effect with an uneven pattern. To carry out the method of the present invention, plastisol or latex containing the above-mentioned hollow inorganic filler is mechanically whipped using a high-speed stirrer, Mondo mixer, etc. to form a foamed foam. After coating the base material to a specified thickness with a knife coater, etc., heat and melt it in a hot air drying oven to produce a mechanically foamed sheet, and then mechanically emboss it using an embossed roll or an embossed press plate. I do. In order to perform embossing, it is preferable to heat the mechanically foamed sheet with far infrared rays to melt the surface of the foamed sheet beforehand. If a mechanically foamed embossed sheet is produced by the method of the present invention, a lightweight product with an uneven pattern and a sharp three-dimensional effect can be obtained.In particular, 3 to 10 parts by weight of an inorganic filler made of hollow bodies can be added to 100 parts by weight of the resin component. By using a mechanically foamed foam, an embossed sheet with a sharp three-dimensional effect with an uneven pattern can be obtained even if it is thinly coated on a substrate to a thickness of about 2 to 4 mm. This is a unique effect that cannot be obtained from a composition containing a filler made of hollow bodies using a pyrolytic foaming agent. Hereinafter, the method of the present invention will be explained in detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Example 1 70 parts by weight of vinyl chloride paste resin with an average degree of polymerization () of about 1500, 30 parts by weight of vinyl chloride blending resin with a moderate degree of polymerization of about 1200, 65 parts by weight of dioctyl phthalate (DOP), 5 parts by weight of dodecylbenzene,
2 parts by weight of epoxidized soybean oil, 3 parts by weight of calcium-zinc (Ca-Zn) stabilizer, 3 parts by weight of silicone foam stabilizer, hollow body filler mainly composed of silicic acid (product name Q-Cel200, Asahi A plastisol having a specific gravity of 1.045 was prepared by uniformly kneading 5 parts by weight (manufactured by Glass Co., Ltd.) and 1 part by weight of a pigment. The plastisol was passed through a Mondo mixer B-25M (mechanical foaming device manufactured by Mondo Mix).
After mixing with compressed air to form a plastisol foam (specific gravity 0.348) using
Coated with a thickness of 160 mm and dried in a hot air drying oven.
The foam was heated and held at ℃ for 2 minutes to gel and melt the expanded foam. The obtained foam was irradiated with far infrared rays to heat the foam surface (irradiation conditions: irradiation voltage 150 volts,
Embossing was then applied using a mechanical embossing roll (irradiation height 7 cm, irradiation time 25 seconds). The resulting mechanically foamed embossed sheet has a foaming ratio of
At 2.9x magnification, the product had a sharp three-dimensional effect with an uneven pattern and had excellent surface strength. The composition, physical properties of the sol, physical properties of the embossed sheet, etc. are summarized in a table. Examples 2 to 4, Comparative Examples 1 to 2 Mechanically foamed embossed sheets were produced in the same manner as in Example 1 using the formulations shown in the table. The results are also listed in Table 1.

[Table] Examples 5 and 6, Comparative Example 3 In Examples 2 and 3, embossed sheets were produced in the same manner as in Examples 2 and 3 without irradiating the foam with far infrared rays, and the physical properties of the sheets were measured. It is shown in Table 2. Further, in Comparative Example 2, an embossed sheet was manufactured in the same manner as in Comparative Example 2 without irradiating far infrared rays, and the physical properties of the sheet were measured and are also listed in Table 2.

[Table] As can be seen from Table 2, without far-infrared irradiation, the tensile strength was lower than in Examples 2 and 3.
In addition, the embossing properties are slightly inferior and are not as good as those of Examples 2 and 3 in terms of physical properties, but are better than those of Comparative Examples 2 and 3. Comparative examples show that it is necessary to add a large amount of filler to improve embossing properties, and in this case the tensile strength is extremely reduced.

Claims (1)

[Claims] 1. Plastisol or latex containing an inorganic filler made of hollow bodies is mechanically foamed and then heated and melted to produce a foam, and then an embossed roll or an embossed press plate is used to create irregularities. A method for producing a mechanically foamed embossed sheet, which is characterized by mechanically applying a pattern. 2. The method for producing a mechanically foamed embossed sheet according to claim 1, wherein the foam is heated by far infrared rays before mechanically applying the uneven pattern.