JPS6111188B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing foamed polyvinyl chloride decorative materials. The manufacturing method of the present invention provides a decorative material that has an embossed pattern on the surface in addition to the unevenness caused by foaming that matches the pattern, and has an extremely excellent design feel.

BACKGROUND ART Conventionally, the following techniques have been generally used to manufacture synthetic resin decorative materials that have uneven surfaces and are used primarily for interior decoration, such as flooring and wall materials.

〇 Mechanical embossing method, in which a flat sheet is embossed by mechanical means; 〇 So-called chemical embossing method, in which a sheet of foamable resin is embossed with foam accelerators or inhibitors, radical inhibitors, crosslinking agents, and penetrating agents. A method in which a pattern is printed with a printing ink containing a hardening resin, etc., and then heat-foamed to create unevenness that matches the pattern. 〇 This is called the valley printing method, in which ink is applied to the convex portions of an embossing plate and embossing is done. A method of printing a pattern at the same time as the operation, or a method of printing with foaming ink or raised ink.

In the mechanical embossing method, it is necessary to prepare an embossing plate for each pattern, and it is extremely difficult to perform embossing in perfect synchronization with the pattern. The burley printing method can only produce a single-color pattern, and it also has the problem that if the pattern has a large embossed concave area, the ink tends to adhere unevenly. Since the raised printing ink takes time to dry and the printing speed is low, it is not practical, especially for gravure printing. Therefore, the chemical embossing method is advantageous because it allows printing in multiple colors that match the pattern with relatively high productivity, and the most common products on the market today are manufactured using this technology.

However, the chemical embossing method is not completely satisfactory, and in designs where the area of the embossed recesses is small, the embossed parts and the three-dimensional effect of the convex parts are poor, and as a result, the number of patterns that can be embossed with excellent design is limited.

The present invention was completed by combining the chemical embossing method with other embossing techniques, with the intention of utilizing the advantages of the chemical embossing method and compensating for the disadvantages thereof.

The method for producing a foamed polyvinyl chloride decorative material of the present invention consists of the following steps (A) to (D).

(A) Step of applying a transparent polyvinyl chloride sol onto a release sheet with an embossed surface and semi-gelling it to obtain a smooth surface that can be printed on. (B) Printing any pattern on the above smooth surface. A step of obtaining a printed sheet by using a printing ink containing at least one of a foaming suppressor, a foaming accelerator, a radical inhibitor, a crosslinking agent, or a penetrating hardening resin for part or all of the pattern. (C) The obtained printed sheet is placed on a base sheet having a colored foamable polyvinyl chloride layer on its surface.
After laminating the printed surfaces in contact, peeling off the release sheet, and (D) heating to completely gel the transparent polyvinyl chloride layer and foaming the colored expandable polyvinyl chloride. process.

The feature of the present invention is that by gelling (semi-gelling) the sol of polyvinyl chloride (hereinafter referred to as "PVC") on the embossed surface, the emboss is copied, and the next chemical is applied to the copied unevenness. This is due to the use of a technology that overlaps the unevenness through the embossing process.

Hereinafter, the above steps will be explained with reference to the drawings.

First, a release sheet 2 having an embossed surface whose cross section is shown in FIG. 1 is prepared. The irregularities are shaped to correspond to the irregularities to be imparted to the surface of the decorative material of the final product. What can be used as sheet material:
In addition to synthetic resin films such as polyester, polyolefin, cellophane, and vinylon that are inherently releasable to PVC, extrusion coatings of polyolefin resins can be applied to paper, and silicone resins, thermosetting resins, etc. can be applied and peeled off after drying. There are things that give it gender. The thickness is
A material with a diameter of about 20 to 500μ would be easy to use. There are methods such as heat embossing and mechanical embossing to provide an embossed surface, but these methods need to be able to withstand the temperature at which the PVC becomes semi-gelled later. From this point of view, in order to obtain high emboss fastness, a sheet is sandwiched between the male and female molds and pressed from both sides.
A so-called paper embossing method is preferred.

However, the term "emboss" here refers not only to intentionally created large irregularities, but also to includes small irregularities such as the surface roughness that the sheet originally has. Therefore, the release sheet having an embossed surface prepared here may not necessarily be obtained without embossing as described above.

Release sheet 2 having such an embossed surface
A transparent PVC sol is applied on top and heated to form semi-gelled PVC3 (Step A). PVC sol is a mixture of 100 parts by weight of PVC powder and 5 to 60 parts by weight of a plasticizer such as dioctyl phthalate (DOP) or dibutyl phthalate (DBP). It goes without saying that agents, fillers, and other arbitrary additives can be used as long as they do not cause any problems. The composition of the sol and the method for semi-gelling and gelling it may be in accordance with those well known in the art. The amount of sol applied to the sheet 2 is sufficient to fill in the dents on the embossed surface, form a smooth surface, and form a coating film of the required thickness. As the coating method, a knife coater or other suitable technique for providing a thick film may be selected.

After heating and semi-gelling a transparent PVC smooth surface 31 is obtained, printing 4 of an arbitrary pattern is applied thereon to form the printed sheet 1 shown in FIG. 1 (Step B). At that time, as mentioned above, a printing ink containing at least one of a foaming accelerator, a foaming suppressor, a radical inhibitor, a crosslinking agent, or a penetrating hardening resin, for example 1 to 40%, is applied to part or all of the pattern. use. Among the above-mentioned agents, foam accelerators, as the name suggests, enhance the subsequent foaming of expandable PVC, while foam suppressants and other agents inhibit foaming. Chemical embossing that produces unevenness that is in sync with the pattern is realized by either of these effects or by a combination of promotion and suppression.

Furthermore, among the above-mentioned substances that have a foaming suppressing effect,
It is preferable to print the permeable thermosetting resin on the surface of expandable PVC rather than on the smooth surface of transparent PVC, since the effect is more reliably obtained.

Examples of foaming accelerators include zinc compounds, cadmium compounds, lead compounds, urea, borax, and ethanolamine (see Japanese Patent Publication No. 15713/1973), and specific examples of foaming inhibitors include organic acids. ,
Examples include halides and anhydrides, polyhydric alcohols, certain nitrogen compounds, ionic compounds, isocyanate compounds, polyketones, polyaldehydes, phosphates, phosphites, and positive chlorine compounds (Japanese Patent Publication No. 54-953). ), the group of radical inhibitors includes nitroso compounds, quinones, secondary amines, phosphites, etc. (see Japanese Patent Publication No. 53-7190), and crosslinking agents, especially agents that cause crosslinking reactions in PVC, include: Triazine derivatives are known (Japanese Patent Publication No. 54-42390). moreover,
Permeable thermosetting resins include formalin condensates, epoxy compounds, compounds having an aziline ring, etc. (Japanese Patent Publication No. 36299/1983).

It is desired that the printing ink vehicle has as good adhesion as possible to the PVC layer, and therefore it is recommended that it contain PVC as at least one component.

As the printing method, most commonly used methods such as letterpress, offset, gravure, silk screen, and flexo printing can be used.

Next, print sheet 1 made as above.
is colored foamed PVC as shown in Figure 2.
The release sheet 2 is pasted onto the base sheet 5A, which has a layer 51A on its surface and is lined with an appropriate base fabric 52 if desired, so that the printed surface is in contact with the base sheet 5A.
(Step C).

The foamable PVC base sheet 5A is made of, for example, the transparent PVC composition described above, a coloring agent such as titanium white, an inorganic filler such as calcium carbonate, a foaming agent such as azodicarbonamide, and, if necessary, a foaming assistant. It may be made by applying a composition containing additives and other additives onto the base fabric 52 and heating it to semi-gel, or alternatively, by applying this composition to a foaming temperature by a calendering method or the like. The material 51A made into a sheet at a temperature that is not
It can also be made by pasting it on.

The printing sheet 1 and the foamable PVC base sheet 5A can be easily bonded together by a thermal fusion method. In this step, there is no need to apply very high pressure to achieve close contact. This is because sufficient adhesion can be obtained in the subsequent foaming step.

After removing the release sheet 2, heat it to make it foamable.
Achieve chemical embossing by foaming PVC. At the same time, the transparent PVC layer is completely gelled (Step D). This process maintains the embossment on the transparent PVC surface, preserving not only the large irregularities but also the small matte surface. When trying to obtain a matte surface using conventional technology, transparent
Extender pigments are sometimes mixed into PVC sol, but this sometimes results in a lack of adhesion between the sol and the printing ink. However, in the present invention, there is no such concern.

In the above manner, foaming as shown in Figure 3 is achieved.
A PVC decorative board is obtained. This is a foamed PVC material having a foamed PVC layer 51B lined with a base fabric 52.
A transparent PVC gel 3B having an embossed pattern is closely adhered to the base sheet 5B, and in the illustrated example, the printed portion 4 of the foaming suppressant has a concave shape.

Needless to say, the combination of the embossing derived from the release sheet on the transparent PVC surface and the chemical embossing on the foamed PVC layer is arbitrary. For example, contrary to the illustrated example, the embossing can overlap the recesses of the expanded PVC, or it can extend between the recesses and the projections.

Example A release sheet paper was prepared by laminating a 40 μm polypropylene film onto a 50 g/m ² thick high-quality paper using an extrusion coating method. This was applied to a paper embossing machine to give it a textured emboss.

On the polypropylene surface of this release sheet with an embossed surface, a transparent PVC sol with the following composition was applied in an amount of 150 g/m ² by knife coating method, PVC 100 parts by weight DOP 60 parts by weight Ba-Zn stable 5 parts by weight of the agent was heated to 180° C. for 2 minutes to semi-gel.

The joints of the check pattern were printed on the smooth surface of the transparent PVC obtained in this way using a PVC vehicle printing ink containing 10% benzotriazole, which acts as a foaming inhibitor, and the other areas were printed with benzotriazole-free ink. I printed it out and completed the pattern.

Separately, glass nonwoven fabric (manufactured by Mitsubishi Paper Mills, “GS-
4000''), a colored foamable PVC sol of the following formulation was applied in an amount of 200 g/m ² and heated to semi-gel.

PVC 100 parts by weight DOP 60 parts by weight Ba-Zn stabilizer 5 parts by weight Azodicarbonamide 5 parts by weight Calcium carbonate 30 parts by weight Titanium white 10 parts by weight The above-mentioned printed sheet was brought into contact with this colored semi-gelled PVC surface, Temperature 250℃, pressure 10Kg/cm ² , speed 15
After bonding under conditions of m/min, the release sheet was peeled off.

This sheet was placed in a furnace and heated to 200℃ for 2.5 minutes to foam and completely gel.
Foaming was suppressed only at the joints, resulting in concave portions, and the other portions became convex portions. The grain embossment was well maintained, and along with the unevenness caused by foaming, it helped the three-dimensional appearance of the product decorative material.

[Brief explanation of the drawing]

The drawings are schematic cross-sectional views for step-by-step explanation of typical patterns of the manufacturing method of the decorative material of the present invention, and FIG. It shows the stage where the printed sheet has been obtained, that is, the step (B) has been completed,
Figure 2 shows the second half of step (C), where the printing sheet is laminated onto the foamable polyvinyl chloride base sheet and the release sheet is peeled off.
The figure shows the stage where complete gelation and foaming have been performed, that is, step (D) has been completed and the makeup has been completed. DESCRIPTION OF SYMBOLS 1...Printed sheet, 2...Peelable sheet, 3A...Polyvinyl chloride (semi-gel), 3B...Polyvinyl chloride (gel), 4...Printing, 51A...Foamable polyvinyl chloride, 51B...Foamed polyvinyl chloride.

Claims (1)

[Claims] 1. A method for producing a foamed polyvinyl chloride decorative material comprising the following steps. (A) A process in which a transparent polyvinyl chloride sol is applied onto a release sheet with an embossed surface and semi-gelled to obtain a smooth, printable surface. (B) A printed sheet is obtained by printing an arbitrary pattern on the smooth surface, and at that time, part or all of the pattern is
A process of using a printing ink containing at least one of a foaming suppressor, a foaming accelerator, a radical inhibitor, a crosslinking agent or a penetrating curing resin. (C) The obtained printed sheet is placed on a base sheet having a colored foamable polyvinyl chloride layer on its surface.
After bonding the printed surfaces in contact, peeling off the release sheet, and (D) heating to completely gel the transparent polyvinyl chloride and foam the colored expandable polyvinyl chloride. Process. 2. The manufacturing method according to claim 1, wherein the ink for printing the pattern uses an ink whose vehicle contains polyvinyl chloride.