JPH04229243A - Decorative sheet - Google Patents

Abstract

PURPOSE:To provide a decorative sheet, which is in a mat tone and rich in voluminous feeling, prevents discoloration during manufacturing process and is provided with a foamed synthetic resin layer or a foamed patterned layer colored into white in high whiteness or a light color, at a low cost, by using a chemical foaming agent and a micro-capsule jointly. CONSTITUTION:At the time of formation of a foamed synthetic resin layer where voluminous feeling and a mat tone are revealed respectively by a chemical foaming agent and microcapsule by using the chemical foaming agent and microcapsule together, discoloration by action of both the foaming agent is prevented by a fluorescent whitening agent, especially a benzoxazole fluorescent agent.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative sheet that has a matte finish and a rich sense of volume, and that prevents discoloration that occurs during the manufacturing process and can produce a highly white or pale color.

0002

[Prior art] Traditionally, architecture (ceiling materials, wall materials, floor materials, etc.)
Decorative sheets made of synthetic resin are widely used as surface materials for furniture, vehicles, electrical products, footwear, bags, etc.

In order to give such a decorative sheet a sense of volume, for example, a synthetic resin composition mixed with a chemical blowing agent that thermally decomposes and generates a large amount of gas is coated on the base material and heated. There are those in which a foamed synthetic resin layer is formed by foaming, and those in which a thermally expandable microcapsule is used in place of the above chemical foaming agent and a foamed synthetic resin layer is formed in the same manner as above.

[0004] Furthermore, the foamed synthetic resin layer formed using the above-mentioned pyrolyzable chemical foaming agent has a voluminous feel, but is too glossy to have a matte finish. On the other hand, the foamed synthetic resin layer formed using the above-mentioned thermally expandable microcapsules has a matte finish but lacks a sense of volume.

[0005] Therefore, a technique has been developed in which a thermally decomposable chemical foaming agent and thermally expandable microcapsules are used in combination to form a foamed synthetic resin layer that is matte and has a voluminous feel.

[0006]

[Problems to be Solved by the Invention] However, a foamed synthetic resin layer formed using a combination of a thermally decomposable chemical foaming agent and a thermally expandable microcapsule may change color depending on the conditions for forming the resin layer. There is. Specifically, heat treatment is performed to decompose the above-mentioned thermally decomposable chemical foaming agent and expand the thermally expandable microcapsules.There is no problem if the temperature at this time is low, but if the temperature is high, For example, the white synthetic resin layer turns yellow. This discoloration phenomenon becomes more noticeable as the number of heat treatments increases and the temperature increases.

[0007] Therefore, when forming a pattern layer on the foamed synthetic resin layer or embossing a sharp uneven pattern with sharp edges for the purpose of enhancing decorativeness, the discoloration described above is noticeable. appears in That is, in the former case, the foamed synthetic resin layer is heated for gelation prior to the heat treatment for foaming, a pattern layer is formed on the gelled layer, and finally the foamed synthetic resin layer is heated for foaming. Perform processing. In the latter case as well, heat treatment is performed to soften the foamed synthetic resin layer immediately before embossing. As described above, both require heat treatment multiple times and also require heat treatment at a high temperature to obtain a sufficient foaming state and a sufficient softening state. As a result, a noticeable discoloration appears on the product sheet.

[0008] As a countermeasure against this problem, measures have been taken such as using a large amount of white pigment such as TiO2, or coloring the foamed synthetic resin layer in another color to hide the above-mentioned discoloration and make it less noticeable. . However, the former measure of using a large amount of white pigment not only increases cost but also does not provide a sufficient concealing effect. The latter method of coloring other colors does not have a sufficient concealing effect if it is colored in a light color, so
It has to be colored in a dark color, and it is impossible to obtain a light-colored, matte foamed synthetic resin layer.

In consideration of the above points, the present invention uses a thermally decomposable chemical foaming agent and thermally expandable microcapsules in combination to achieve not only a matte finish and a rich sense of volume, but also to prevent discoloration during the manufacturing process. To provide, at low cost, a decorative sheet provided with a foamed synthetic resin layer or a foamed pattern layer colored with high whiteness or light color while preventing the above.

0010

[Means for Solving the Problems] The decorative sheet of the present invention is
In order to achieve the above object, in a decorative sheet in which a foamed synthetic resin layer is formed by a combination of a pyrolytic chemical foaming agent and a thermally expandable microcapsule, the foamed synthetic resin layer is It is characterized in that a fluorescent whitening agent is added together with the agent and thermally expandable microcapsules.

The present invention is also characterized in that the above-mentioned fluorescent whitening agent is a benzoxazole type fluorescent agent.

The foamed synthetic resin layer in the decorative sheet of the present invention is a foamed layer made of a combination of a thermally decomposable chemical foaming agent and thermally expandable microcapsules, and the synthetic resin as the base material of the layer includes vinyl chloride resin, Examples include vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, and acrylic resin.

Examples of thermally decomposable chemical blowing agents added to these synthetic resins include dinitrosopentamethylenetetramine, N,N'-dimethyl-N,N'-dinitrosoterephthalamide, benzenesulfonylhydrazide, p
-Toluenesulfonylhydrazide, p,p'-oxybis(benzenesulfonylhydrazide), 3,3'-disulfonehydrazide diphenylsulfone, toluenedisulfonylhydrazine, p-toluenedisulfonylhydrazide, p-toluenesulfonyl semicarbazide, azobisisobutyro Nitrile, azodicarbonamide (ADCA)
), diethyl azodicarboxylate, etc.

[0014] As the thermally expandable microcapsules to be added together with these thermally decomposable chemical foaming agents, those having the property of expanding at 140°C or higher are preferably used. Examples of the thermoplastic resin constituting the shell of the thermally expandable microcapsules include homopolymers such as polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polymethyl acrylate, and polyvinyl acetate, or copolymers thereof, or copolymers with these homopolymers. If the shell thickness is too thick, it will be difficult to expand, and if the shell is too thin, uniform mixing with the synthetic resin and pyrolytic chemical blowing agent will be impossible. In general,
The thickness is preferably 15 μm or less. In addition to isobutane, which is a typical example, hydrocarbons having a low boiling point such as pentane, neopentane, and hexane are sealed in the shell of such a thermoplastic resin. If the particle size of the microcapsules is too large, uniform mixing with the above-mentioned synthetic resin becomes difficult, so it is preferable to use microcapsules with a particle size of about 5 to 50 μm or less.

[0015] The addition ratio of the above-mentioned thermally decomposable chemical blowing agent and thermally expandable microcapsules is appropriately selected depending on the desired degree of foaming of the foamed synthetic resin layer, but if the chemical blowing agent is too large, the microcapsules may If there are too many microcapsules, the amount of the chemical blowing agent will be relatively too small, and it will not be possible to obtain a sufficient volume. Therefore, in order to obtain a sufficient matting effect and a sufficient sense of volume, it is generally recommended to use about 2 to 8 parts by weight of a thermally decomposable chemical blowing agent and 4 parts by weight of thermally expandable microcapsules to 100 parts by weight of synthetic resin.
It is preferable to appropriately select from a range of about 8 parts by weight.

[0016] Various types of fluorescent brighteners such as stilbene type, benzimidazole type, benzoxazole type, naphthalimide type, etc. can be used as the optical brightener added together with the above-mentioned thermal decomposition type chemical foaming agent and thermal expansion type microcapsules. ,
It is preferable to use a benzoxazole fluorescent agent for the reasons described below. The amount of optical brightener added varies depending on the amount of pyrolytic chemical foaming agent and thermally expandable microcapsules, and cannot be determined unconditionally, but if it is too small,
The effect of inhibiting discoloration, which is assumed to be due to the synergistic effect of these chemical blowing agents and microcapsules at high temperatures, does not occur, and if too much is used, problems such as saturation of the discoloration inhibiting effect and uneconomical problems occur. , in the addition ratio of the above chemical blowing agent and microcapsules, 0.05 to 0.6
It is preferable to appropriately select from a range of about 0 parts by weight.

[0017] In addition to the above-mentioned thermally decomposable chemical foaming agent, thermally expandable microcapsules, and optical brightener, a plasticizer that is usually used when making the above-mentioned synthetic resin into a paste, and if necessary, Coloring agents, stabilizers, fillers, diluents, flame retardants, fungicides, antistatic agents, etc. can also be added.

The decorative sheet of the present invention having a foamed synthetic resin layer made of each of the above-mentioned constituent materials is manufactured, for example, as follows. A paste made by kneading each of the above constituent materials on a base material such as paper, woven fabric, non-woven fabric, knitted fabric, synthetic resin sheet, composite material of these, or a base material that has been given various properties such as flame retardancy. A synthetic resin composition is coated by an appropriate method such as a doctor knife method, a rotary screen method, a gravure method, an offset method, or a flexo method, and the coating layer is heated to gel. as needed,
On this gelled layer, a printing plastisol or organosol made of ordinary printing ink or a pasty resin composition similar to the above is applied to an appropriate printing method such as a rotary screen method, a gravure method, an offset method, or a flexo method. It is also possible to print in an appropriate pattern. After that, heat treatment is performed to decompose the thermally decomposable chemical foaming agent and expand the thermally expandable microcapsules, thereby foaming the gel layer and the printing layer, and fixing the resin composition. Form a printing layer.

[0019] If necessary, the above-mentioned foamed synthetic resin layer or foamed printing layer may be embossed after being heat-treated again.

[0020] Further, the above paste-like resin composition is coated on a release paper, heat-treated if necessary, and the above-mentioned base material and the foamed synthetic resin layer are further bonded via an adhesive if necessary. The decorative sheet of the present invention can also be produced by a method called a transfer method, which involves bonding and then peeling off a release paper.

[0021]

[Operation] In the decorative sheet of the present invention, after coating with the above paste-like synthetic resin composition, the thermally decomposable chemical foaming agent and thermally expandable microcapsules are sufficiently decomposed and expanded to form a foam with a rich sense of volume. The action of optical brighteners prevents discoloration that occurs during heat treatment. The effect of the fluorescent whitening agent in this case is presumed to be as follows.

[0022] That is, the inventor first found that when either a thermally decomposable chemical foaming agent or a thermally expandable microcapsule is used alone, there is no discoloration even when heat-treated at high temperatures; It was confirmed that discoloration occurs only when the agent and microcapsules are used together and heat treated at high temperatures. This indicates that the pyrolytic chemical blowing agent and the thermally expandable microcapsules, or compounds derived from both (for example, the decomposition products of the pyrolytic chemical foaming agent or the shells of the thermally expandable microcapsules are torn). (e.g., the vaporized liquid that leaked to the outside or the vaporized components of the liquid) may cause some kind of chemical reaction at high temperatures, and the reaction product may react with the resin and cause the resin to change color, or the reaction product itself may It was concluded that the resin had some color and that the color of this reaction product was mixed and caused the resin to discolor. Therefore, we found that if we could inhibit the above reaction, we could prevent discoloration of the resin, and in the process of searching for substances that inhibit this reaction, we unexpectedly discovered that optical brighteners, especially benzoxazole, It was confirmed that discoloration can be effectively prevented by adding a type of fluorescent agent. After further investigation, we compared the discoloration prevention effects of benzoxazole-type fluorescent agents and other optical brighteners, and found that other fluorescent agents can prevent discoloration (yellowing) of the white foam layer to some extent. However, the discoloration prevention effect of the light-colored foam layer is not very good, whereas the benzoxazole type fluorescent agent extremely effectively prevents not only the yellowing of the white foam layer but also the discoloration of the light-colored foam layer. (This tendency becomes more pronounced as the heat treatment temperature increases, so
When heat-treating at a high temperature range of about 190 to 210 degrees Celsius,
It can be said that it is preferable to use a benzoxazole-based fluorescent agent). From this, benzoxazole-type fluorescent agents, although the reason for this is not necessarily clear, indicate that the oxazole ring present in the chemical formula is a compound derived from the above-mentioned thermal decomposition type chemical foaming agent, thermal expansion type microcapsules, or both. It is presumed that these compounds have some kind of chemical effect on them, inhibiting the reactions between them. Therefore, the above-mentioned discoloration prevention effect, especially the discoloration prevention effect by the benzoxazole type fluorescent agent, is not only due to a simple whitening effect (whitening effect due to light emission which is a complementary color of yellow);
It is presumed that this is due to the effect of inhibiting the above reaction.

[0023]

[Example] Example 1, Comparative Example, Reference Examples 1 to 2 A paste-like synthetic resin composition shown as Formulation A in Table 1 was coated onto flame-retardant paper using a roll coater to a thickness of 0.16 mm. Thereafter, the sheet 1 of the present invention is heated at 150° C. for 1 minute to gel, and then heated at 200° C. for 1 minute to foam, immediately embossed, and provided with a foamed synthetic resin layer having an uneven pattern on the surface. I got it.

For comparison, a paste-like synthetic resin composition shown as Formulation B in Table 1 was coated, gelled, foamed, and embossed under the same conditions as above to obtain Comparative Sheet 1.

Furthermore, for reference, paste-like synthetic resin compositions shown as formulations C and D in Table 1 were coated, gelled, foamed, and embossed under the same conditions as above to produce reference sheets 1 to 2. I got it.

Sheet 1 of the present invention obtained from a composition in which a benzoxazole type fluorescent agent is added together with the thermally decomposable chemical foaming agent and thermally expandable microcapsules of Formulation A is a composition containing a benzoxazole type fluorescent agent in Formulation A. Compared to Comparative Sheet 1 obtained from the composition of Formulation B to which no .

Reference sheets 1 and 2 obtained from the compositions of formulations C and D in which the thermally decomposable chemical blowing agent or thermally expandable microcapsules were added alone and no benzoxazole fluorescent agent were added were as follows. However, the reference sheet 1 obtained from the composition of Formulation C, in which the chemical blowing agent was added alone, had a rich sense of volume, but had a high degree of white color with no discoloration. Reference Sheet 2, which was glossy and obtained from the composition of Formulation D in which the microcapsules were added alone, had a calm matte tone, but lacked a sense of volume.

[0028]

[Table 1]

(parts by weight)

A B C
D Polyvinyl chloride
100 100 100
100 Plasticizer (dioctyl phthalate)
60 60 60
60 Flame retardant plasticizer (chlorinated paraffin) 10
10 10 10
Filler (CaCO3)
60 60 60
60 (Turpen)
3 3
3 3 Stabilizer (Ba-Zn type)
3 3
3 3 Colorant (Ti
O2) 15
15 15 15 Pyrolytic chemical blowing agent (ADCA) 3
3 3 - Thermal expansion type microcapsule 6
6-
6 (Product name F90 manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.) Benzoxazole type fluorescent agent 0.15
- - - (Product name: UVITEXOB, manufactured by Ciba Geigy) (2,5bis(5'-tert-butylbenzoxazolyl (2)
) Thiophene)

Example 2 First, Table 1 of Example 1 was placed on the flame retardant paper used in Example 1.
Using the composition of Formulation C, a predetermined pattern was printed using a rotary screen printer and gelatinized under the same conditions as in Example 1. The composition of Formulation A in Table 1 of Example 1 was then printed in another predetermined pattern on a rotary screen printer and gelled under the same conditions as Example 1. Thereafter, the sheet was passed through a foaming furnace set at 200°C to obtain sheet 2 of the present invention. This sheet 2 has an excellent design in which a glossy, high white pattern area created by the composition of Formulation C and a white pattern area with a calm, matte tone and high whiteness created by the composition of Formulation A coexist. It was something that I had.

Example 3 Except for using a composition in which a stilbene-based, benzimidazole-based, or naphthalimide-based optical brightener was added instead of the benzoxazole-type fluorescent agent of Formulation A in Table 1 of Example 1. , Invention sheets 3 to 5 were prepared in the same manner as in Example 1.
I got it. All of these sheets 3 to 5 were colored with high whiteness.

Example 4 Except for using a composition in which the organic pigment AY-1021 Pink (trade name manufactured by Tokushu Color Co., Ltd.) was added instead of the coloring agent TiO2 in Formulation A in Table 1 of Example 1. In the same manner as in Example 1, the present invention sheet 6 was obtained. This sheet 6 was colored bright pink.

Example 5 The stilbene-based, benzimidazole-based, or naphthalimide-based fluorescent brightener of Example 3 was used in place of the benzoxazole type fluorescent agent of Formulation A in Table 1 of Example 1, and as a colorant. The same procedure as in Example 1 was carried out, except that the organic pigment AY-1021 Pink (manufactured by Tokushu Shiryo Co., Ltd.) of Example 4 was used.
Invention sheets 7 to 9 were obtained. These sheets 7 to 9 are
All had a slightly yellowish pink color.

[0033]

[Effects of the Invention] As detailed above, according to the sheet of the present invention, the thermally decomposable chemical foaming agent and thermally expandable microcapsules are sufficiently decomposed and expanded by heat treatment at high temperatures, resulting in a matte finish. Discoloration of the foam layer, which conventionally occurs when forming a foam layer with a rich sense of volume, can be effectively prevented.

[0034] Furthermore, in the sheet of the present invention, the above-mentioned discoloration is
To inhibit the chemical reaction that occurs at high temperatures between the thermally decomposable chemical blowing agent and the thermally expandable microcapsules, or between compounds derived from both, which is assumed to be the cause of the discoloration, using a specific fluorescent whitening agent. ■ Only a small amount of the fluorescent whitening agent is needed, which can significantly reduce costs compared to the conventional discoloration concealment measures that use large amounts of white pigments; ■ Creates bright light colors without discoloration. Compared to the conventional method of hiding discoloration by painting it in a dark color,
This has effects such as being able to express a variety of designs.

Claims (2)

[Claims] 1. A decorative sheet comprising a foamed synthetic resin layer formed by a combination of a pyrolytic chemical blowing agent and thermally expandable microcapsules, wherein the foamed synthetic resin layer is formed by combining the pyrolytic chemical blowing agent and thermally expandable microcapsules. A decorative sheet characterized by containing expandable microcapsules and a fluorescent whitening agent. 2. The decorative sheet according to claim 1, wherein the fluorescent whitening agent is a benzoxazole type fluorescent agent.