JPH0719838Y2 - Thermal transfer sheet for expanded polystyrene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a heat-sensitive transfer sheet for expanded polystyrene molding.

<Prior Art> Transfer sheets having a transfer layer on a releasable base sheet are well known and widely used for decoration of molded plastics, metals and the like.

<Problems to be Solved by the Invention> However, a heat-sensitive transfer sheet for a foamed polystyrene molded product has not been heretofore known. The softening point of expanded polystyrene is about 80 ° C, transfer is preferably performed at 80 ° C or lower, and at most 90 ° C or lower at the highest. The reason is that transfer is difficult because water droplets are usually left on the surface.

Therefore, an object of the present invention is to provide a heat-sensitive transfer sheet which can be satisfactorily transferred at a temperature of 90 ° C. or lower at the most and to the surface of a foamed polystyrene molded product containing water droplets.

<Means for Solving the Problems> In order to achieve this object, the present invention is a transfer sheet having a transfer layer on a releasable base sheet, and the transfer layer surface is mainly composed of polyacrylic acid ester or polymethacrylic acid ester. There is provided a heat-sensitive transfer sheet for expanded polystyrene, which is an adhesive layer having a thickness of 2 μm or more formed by applying twice the heat-sensitive adhesive by the gravure coating method.

<Embodiment> Hereinafter, the present invention will be described with reference to the drawings. The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view of a transfer sheet.

As shown in the figure, the transfer sheet is one in which the transfer layer (2) is laminated on the base sheet (1).

The base sheet (1) supports the transfer layer (2) and
After transfer, it is peeled off and removed. Heat-resistant peelable film such as polyester, nylon, stretched polypropylene,
Alternatively, a sheet obtained by laminating a peelable plastic such as polypropylene on paper can be used.

The transfer layer (2) remains on the surface of the expanded polystyrene molded product even after the base sheet (1) is peeled and removed after the transfer, and usually from the peeling layer (21), the functional layer (22) and the adhesive layer (23). Become. The peeling layer (21) is easily peeled from the base sheet (1) at the time of transfer and protects the surface of the molded product after the transfer, and may be made of polyacrylic acid ester or polymethacrylic acid ester.

The functional layer (22) ensures the function of the transfer sheet body, and is, for example, a pattern made of printing ink. Out of this
It may be a metal vapor deposition layer or the like.

The adhesive layer (23) is formed by applying an adhesive containing a polyacrylic acid ester or a polymethacrylic acid ester as a main component twice by a gravure coating method. The gravure coating method is a method in which cells formed between mesh banks of a gravure roll are filled with an adhesive and transferred onto a transfer sheet, which is applied inline with the ink pattern of the functional layer (22). On the other hand, it is unavoidable that uneven application of the adhesive occurs, but application unevenness can be prevented by applying twice. Further, by applying twice, the film thickness after drying can be increased to 2 to 4 μm.
As a result, the adhesive layer (23) has a high film strength and becomes a smooth film, and despite the presence of partial water droplets, good transfer can be performed without causing transfer unevenness.

Examples of the polyacrylic acid ester or polymethacrylic acid ester include polymethyl (meth) acrylate, polyethyl (meth) acrylate, polybutyl (meth) acrylate, and the mixture thereof can also be used. Further, polyvinyl chloride, polystyrene and the like may be mixed. Also,
You may mix polyvinyl chloride, polystyrene, etc. Further, the adhesives to be applied twice need not be applied twice, and different kinds of adhesives may be applied.

The transfer can be performed by a method of stacking a transfer sheet on a foamed polystyrene molded product and heating it with a hot press to transfer it, or a method of stacking a foamed polystyrene molded product and a transfer sheet on each other and transferring them between a substrate and a heat roll. . In any case, the surface of the expanded polystyrene molded product is 90 ° C or lower, preferably
It is performed below 80 ℃.

<Test Example 1> A polymethylmethacrylate-based release agent was applied onto a polyester film having a thickness of 16 μm, and a rubber-based ink was printed,
In-line, a mixture of polymethylmethacrylate and polybumethacrylate in a ratio of 6: 4 is applied twice by a gravure coating method to form an adhesive layer having a thickness of 3μ,
It was used as a transfer sheet.

Place expanded polystyrene with a foaming ratio of 30 times, 50 times, and 60 times on the substrate, stack the transfer sheets, and heat the surface of the hot platen.
90 ~ 95 ℃, expanded polystyrene surface temperature 75 ~ 80 ℃, 0.5 ~
Under the condition of 1 second, the transfer was performed with a pressure such that the expanded polystyrene was not dented, and only the base sheet was peeled off. The polystyrene foam used was one in which water droplets remained on the surface without being wiped off.

Transfer was satisfactorily performed on any of the expanded polystyrenes, there was no pinball, and the transfer pattern had good water resistance, alcohol resistance, and salt water resistance. In addition, 40 ℃, 80% R.
When the blocking property was examined under the conditions of H. and 500 g / cm ² , it was found that no blocking occurred even after 48 hours, and that the product had good resistance.

<Test Example 2> The same transfer sheet as in Test Example 1 was used.

Foamed polystyrene having a foaming ratio of 30, 50, 60 was placed on a substrate, and a transfer sheet was superposed and transferred by a heat roll. The expanded polystyrene used had water droplets attached thereto.

Heat roll surface temperature 90-95 ℃, Expanded polystyrene surface temperature
No transfer at 75-80 ℃, moving speed 10m / sec, heat roll surface temperature 100-105 ℃, expanded polystyrene surface temperature 85-90
Good transfer at ℃, 10m / sec moving speed, no pinball, water resistance, alcohol resistance, salt water resistance of the transfer pattern,
The blocking resistance was also excellent.

<Comparative Example 1> A transfer sheet was prepared in the same manner as in Test Example 1. However, the adhesive is applied once and the thickness is 1.5 μm.

The transfer was performed in the same manner as in Test Example 1. The pattern could not be transferred at all.

The same transfer was performed by raising the surface temperature of the expanded polystyrene to 95 ° C, but good transfer could not be obtained. 110 ° C
However, the surface of the expanded polystyrene changed and the transferred pattern became distorted.

The transfer was carried out by using a hot roll as in Test Example 2, but the results were the same. The transfer was not possible at a surface temperature of the expanded polystyrene of 95 ° C or lower, and could be transferred at 100 ° C, but the pattern was distorted.

<Test Example 3> A polymethylmethacrylate-based release agent was applied onto a polyester film having a thickness of 16 µ, a pattern was printed with a rubber-based ink, and an adhesive and a polymethylmethacrylate mixed with polyvinyl chloride were used in-line. An adhesive layer in which methyl methacrylate, polyethyl methacrylate and polystyrene were mixed was sequentially applied by a gravure coating method. The thickness of the adhesive layer is 1.5 μm, which is a total of 3 μm.

This transfer sheet was laid on foamed polystyrene with water drops of foaming ratio 30,50,60 and transferred under the conditions of hot platen surface temperature 90-95 ℃, expanded polystyrene surface temperature 75-80 ℃, 0.5-1 second. However, good transfer could not be performed due to a dropout.

When the surface temperature of expanded polystyrene was raised to 85 to 90 ℃ and transferred in the same manner, good transfer was achieved, and it was also excellent in water resistance, alcohol resistance, salt water resistance, and blocking resistance.

<Effects> As described above, according to the present invention, there is an effect that a transfer sheet can be obtained which can be satisfactorily transferred at a low temperature of 90 ° C. or lower without interfering with a water drop without deforming a polystyrene foam molding.

[Brief description of drawings]

The drawing shows an embodiment of the present invention, and FIG. 1 is a sectional view of a transfer sheet. (1) ... Base sheet, (2) ... Transfer layer (21) ... Release layer, (22) ... Functional layer (23) ... Adhesive layer

Claims (1)

[Scope of utility model registration request] 1. A transfer sheet having a transfer layer on a releasable base sheet, wherein the surface of the transfer layer is coated twice with a heat-sensitive adhesive whose main component is polyacrylic acid ester or polymethacrylic acid ester by a gravure coating method. 2μ thick
A heat-sensitive transfer sheet for expanded polystyrene, which is the above adhesive layer.