JP3613517B2 - Process paper for manufacturing flexible polyurethane sheets - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a process paper for producing a flexible polyurethane sheet used as a support for forming a flexible polyurethane into a sheet in the production of a flexible polyurethane sheet.
[0002]
[Prior art]
As a method for producing a flexible polyurethane sheet, a method of coating a soft polyurethane resin prepolymer on the surface of a process sheet for producing a flexible polyurethane sheet used as a support (mounting paper), and peeling the flexible polyurethane sheet from the process sheet after molding. Is generally adopted.
[0003]
Conventionally, craft paper having a predetermined strength has been generally used as a process sheet for producing a flexible polyurethane sheet used in the production of the above-mentioned flexible polyurethane sheet. In consideration of ease of peeling of the flexible polyurethane sheet, kraft paper is used. A laminate of a synthetic resin on the surface and a coating with a release agent are also used.
[0004]
[Problems to be solved by the invention]
According to the method for producing a flexible polyurethane sheet using the above-described conventional process sheet for producing a flexible polyurethane sheet, it is possible to produce a flexible polyurethane sheet as described above, but the molded flexible polyurethane sheet is literally a soft material. It is practically impossible to print on the surface of the flexible polyurethane sheet after peeling from the process paper or in the manufacturing process. Moreover, since a flexible polyurethane sheet is soft as mentioned above, the handling and secondary processing after manufacture are difficult.
[0005]
The present invention has been made in view of these disadvantages, and can produce a flexible polyurethane sheet that can be easily and reliably printed on the surface of the flexible polyurethane sheet, and can be easily handled and subjected to secondary processing after molding. The purpose is to provide process paper.
[0006]
[Means for Solving the Problems]
The invention made in order to solve the above problems is a process sheet for producing a flexible polyurethane sheet used as a support for forming a flexible polyurethane resin into a sheet in the production of a flexible polyurethane sheet. A synthetic resin laminate layer laminated on the surface side of the base paper and a printed layer laminated on the surface side of the laminate layer, and a pseudo-adhesion state is formed between the base paper and the laminate layer It is characterized by this.
[0007]
According to the process paper for producing a flexible polyurethane sheet, the base paper provides the necessary strength as a support for forming the flexible polyurethane sheet, and the flexible polyurethane sheet formed on the surface side by the laminate layer can be easily and reliably peeled off. become. Furthermore, the printed layer laminated on the surface side of the laminate layer is peeled off from the laminate layer together with the soft polyurethane sheet when the soft polyurethane sheet formed on the surface side is peeled off, and transferred to the soft polyurethane sheet side. As a result, the flexible polyurethane sheet can be completely printed.
[0008]
A printing ink containing a release agent may be used for forming the printing layer. According to this means, the release agent contained in the printing ink facilitates the peeling of the printing layer from the laminate layer, and promotes the completeness of the transfer of the printing layer to the soft polyurethane sheet when the soft polyurethane sheet is peeled off. it can.
[0009]
Also, by applying a release agent to the surface of the laminate layer, it is possible to promote the completeness of the transfer of the printing layer to the flexible polyurethane sheet as in the above-described means.
[0010]
In the process paper for producing a flexible polyurethane sheet, the base paper and the laminate layer may be in a pseudo-adhesive state. Here, the “pseudo-adhesion state” means that both layers are bonded in a normal use state, but when both layers are peeled off, they are easily peeled off by simply pulling them manually without using a tool, etc. It means a state in which re-adhesion cannot be achieved only by overlapping and pressing. The pseudo-adhesion state is different from the normal lamination with the pressure-sensitive adhesive in that it is “a state in which re-adhesion is not possible simply by overlapping and pressing”.
[0011]
According to the means, since the base paper and the laminate layer are in a pseudo-adhesive state, after the flexible polyurethane sheet is molded on the surface of the process sheet for manufacturing the flexible polyurethane sheet, and before the release of the flexible polyurethane sheet Moreover, only the base paper can be easily peeled from the process paper for producing the flexible polyurethane sheet. The laminate with the base paper peeled off, that is, the laminate of the laminate layer, the printing layer, and the flexible polyurethane sheet has a predetermined strength due to the laminate layer made of synthetic resin, and the back side of the laminate layer from which the base paper has been peeled is Since it is not sticky, it can be stored and transported in the state of such a laminate, and can be easily subjected to secondary processing, etc., and then the laminate layer is peeled off from the flexible polyurethane sheet, so that the flexible polyurethane sheet The secondary processing or the like can be easily and reliably performed.
[0012]
The peel strength between the base paper and the laminate layer is preferably 0.02 N / 5 cm or more and 5 N / 5 cm or less. With this level of peel strength, the base paper and the laminate layer do not unintentionally peel off when the flexible polyurethane sheet is molded, and the base paper is easily peeled off from the laminate layer after molding. can do.
[0013]
The laminate layer may be made of a transparent synthetic resin, and the laminate layer may be transparent. According to this means, when the base paper is peeled off after the flexible polyurethane sheet is coated and molded, the printed layer can be visually recognized through the transparent laminate layer. Therefore, while confirming the position and size of the printed layer information, pattern, etc. Secondary processing is possible. Therefore, according to the process sheet for manufacturing a flexible polyurethane sheet, it is possible to reliably print appropriate information, patterns, and the like at appropriate positions on the secondary processed product of the flexible polyurethane sheet.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a schematic cross-sectional view showing a process sheet for producing a flexible polyurethane sheet according to the present invention. FIGS. 2 (a), (b) and (c) are soft sheets using the process sheet for producing a flexible polyurethane sheet of FIG. It is typical sectional drawing explaining the manufacturing method of a polyurethane sheet, the handling method of a flexible polyurethane sheet manufactured by this, and a secondary processing method.
[0015]
A process sheet 1 for producing a flexible polyurethane sheet in FIG. 1 is laminated on the back surface of a base paper 2, a synthetic resin laminate layer 3 laminated on the surface of the base paper 2, and the surface of the laminate layer 3. And a printing layer 4.
[0016]
The base paper 2 is a layer for imparting strength to the process paper 1 for producing the flexible polyurethane sheet as a support for sheet molding in the production process of the flexible polyurethane sheet. Examples of usable paper materials include: Bleached kraft paper, semi-bleached kraft paper, bleached kraft paper, fine paper, medium-quality paper, single gloss unbleached kraft paper, pure white roll, glassine paper, thermal paper, pressure sensitive paper, synthetic paper, Japanese paper, tracing paper, various coats Paper, paperboard, liner paper, etc. are mentioned.
[0017]
The weighing of the base paper 2 may be appropriately selected in consideration of the strength of the paper material itself to be used so that the base paper 2 has a predetermined strength, and is generally about 30 g / m ^{2 to} 450 g / m ^2. .
[0018]
The laminate layer 3 is formed by melting a thermoplastic resin, extruding it from a T die, and laminating it on the base paper 2. Examples of the thermoplastic resin that can be used for the laminate layer 3 include polyethylene, polypropylene, polymethylpentene, ethylene vinyl acetate resin, ethylene ethyl acrylate resin, ethylene acrylic acid resin, ethylene methacrylic acid resin, ethylene methyl acrylate resin, and ionomer resin. , Polyvinyl alcohol, polyester and the like. In addition, polyethylene, polypropylene and the like polymerized using a so-called metallocene catalyst can also be suitably used. The thickness of the laminate layer 3 is not particularly limited, but is generally about 8 μm to 100 μm.
[0019]
The laminate layer 3 facilitates peeling of the soft polyurethane sheet coated and molded on the surface of the process paper 1 for producing the flexible polyurethane sheet. Moreover, it is good to make the laminate layer 3 transparent using a transparent thermoplastic resin. Thereby, as will be described in detail later, after peeling the base paper 2 from the process paper 1 for producing the flexible polyurethane sheet, it is possible to see through the pattern of the printed layer 4 from the back side of the laminate layer 3.
[0020]
A pseudo-adhesion state is formed between the base paper 2 and the laminate layer 3. As described above, the pseudo-bonded state means that both layers are bonded in a normal use state, but when both layers are peeled off, they can be easily peeled off by simply pulling them manually without using a tool, etc. It is in a state where it cannot be re-bonded only by pressing together. Specifically, the adhesion state may be adjusted so that the peel strength is 0.02 N / 5 cm or more and 5 N / 5 cm or less, preferably 0.05 N / 5 cm or more and 1 N / 5 cm or less. If the peel strength is less than the above range, for example, the base paper 2 may cause unintentional peeling from the laminate layer 3 in a printing process for forming the printing layer 4, a molding process of a flexible polyurethane sheet, and the like. Conversely, if the peel strength exceeds the above range, it may be difficult to peel the base paper 2 and the laminate layer 3.
[0021]
Here, a method for measuring the peel strength will be described. First, the base paper 2 and the laminate layer 3 are laminated, pretreated according to JIS-P8111 regulations, and cut into a width of 50 mm and a length of 200 mm to obtain a test piece. One side of this test piece is attached to a metal plate with a double-sided tape, and the metal plate is set so that the length direction of the test piece is the vertical direction. Then, the lower part of the test piece is peeled off, and the peeling layer is wound up to some extent and chucked. The chuck portion is pulled upward at a pulling speed of 300 mm / min to proceed with peeling, and the stress during this time is measured. The average value of this stress is taken as the peel strength.
[0022]
The print layer 4 is formed by printing information such as characters, figures, symbols, and patterns on the surface of the laminate layer 3. The printing method for forming the printing layer 4 is not particularly limited, and for example, ink jet printing, letterpress printing, gravure printing, screen printing, and the like can be used. Also, so-called “solid printing” or partial printing may be used.
[0023]
As the printing ink used for forming the printing layer 4, those generally used for the printing method to be employed can be selected as appropriate. When a printing ink containing a release agent is used, the molded flexible polyurethane sheet is peeled off. Transfer of the printing layer to the flexible polyurethane sheet can be promoted.
[0024]
Examples of the release agent include (a) hydrocarbons such as paraffin and polyethylene wax, (b) fatty acids such as higher fatty acids, (c) fatty acid amides such as alkylene bis fatty acid amides, and (d) fatty acid lower alcohol esters. Ester esters such as (e) polyhydric alcohols, and the like can be used, and may be appropriately selected in consideration of the suitability of the printing ink with the vehicle. Among these, hydrocarbons such as paraffin are preferable in consideration of releasability from the laminate layer 3 and dispersibility in the printing ink.
[0025]
The blending amount of the release agent with respect to the printing ink is preferably 5% by mass or more and 30% by mass or less. This is because if the blending amount of the release agent is smaller than the above range, the improvement in peelability from the laminate layer 3 of the printing layer 4 is not sufficiently promoted, and conversely, the blending amount of the release agent is within the above range. If it exceeds, the function of the printing ink such as color developability will be hindered, and the transferred printing layer 4 will be easily peeled off from the flexible polyurethane sheet.
[0026]
Next, the manufacturing method of this process sheet 1 for flexible polyurethane sheet manufacture is demonstrated. First, the laminate layer 3 is formed by extruding the molten synthetic resin composition from a T-die into a film shape, laminating it on the surface of the base paper 2 fed between a pair of rolls, and pressing it. At this time, by setting the temperature of the molten synthetic resin composition to a relatively low temperature, the base paper 2 and the laminate layer 3 can be in a pseudo-adhesive state. Then, the process paper 1 for the said flexible polyurethane sheet manufacture is completed by laminating | stacking the printing layer 4 on the surface of the laminate layer 3 by printing.
[0027]
In the manufacturing method of the process paper 1 for manufacturing the flexible polyurethane sheet, the temperature of the molten synthetic resin is set to a relatively low temperature so that the base paper 2 and the laminate layer 3 are in a pseudo-adhesive state. For example, (1) the molten synthetic resin is once extruded on one roll and cooled, and then laminated with the base paper 2.
(2) The base paper 2 is cooled in advance.
(3) A release treatment is performed on the surface of the base paper 2 in advance.
(4) The lamination pressure between the extruded synthetic resin and the base paper 2 by a pair of rolls is made relatively small.
(5) The pseudo-adhesion state can be achieved by means such as selecting the material of the compatible base paper 2 and the melted synthetic resin in which the mutual adhesive strength is reduced.
[0028]
A method for producing a flexible polyurethane sheet using the process paper 1 for producing the flexible polyurethane sheet, a method for handling the produced flexible polyurethane sheet, and a method for secondary processing will be described with reference to FIG.
[0029]
First, the process paper 1 for producing a flexible polyurethane sheet is used as a support, and the surface (that is, the upper surface of the printing layer 4) is coated with a prepolymer of a flexible polyurethane resin and crosslinked, as shown in FIG. As described above, the flexible polyurethane sheet 5 can be formed on the surface of the process paper 1 for producing the flexible polyurethane sheet.
[0030]
Next, the base paper 2 is peeled from the process paper 1 for producing a flexible polyurethane sheet with the soft polyurethane sheet 5 laminated on the surface, and the laminate layer 3, the printing layer 4, and the flexible polyurethane as shown in FIG. Let it be a laminate 6 made of sheets 5. In the state of the laminated body 6, since the laminate layer 3 has a predetermined strength, handling and secondary processing are easy. Further, even if the base paper 2 is peeled off, there is no stickiness on the back surface of the laminate layer 3 of the laminate 6, so that it can be stored, transported and the like. Furthermore, when the laminate layer 3 is transparent, the print layer 4 can be visually recognized from the back side of the laminate layer 3, and secondary processing is possible in consideration of the position of the information, pattern, etc. of the print layer 4.
[0031]
After secondary processing into a bag or the like using the laminate 6 of FIG. 2 (b), the printed layer 4 is laminated by peeling the laminate layer 3 from the laminate 6 as shown in FIG. 2 (c). It peels from the layer 3 side, transfers to the flexible polyurethane sheet 5 side, and the secondary processed product 7 of the flexible polyurethane sheet 5 on which the printing layer 4 is laminated is completed. The transfer of the printing layer 4 to the flexible polyurethane sheet 5 side is promoted by the addition of a release agent to the printing ink constituting the printing layer 4.
[0032]
The process paper for producing a flexible polyurethane sheet of the present invention is not limited to the above embodiment. For example, instead of using a printing ink for forming the printing layer 4 containing a release agent, the laminate layer 3 The transfer of the printing layer 4 to the flexible polyurethane sheet 5 can also be promoted by applying a release agent to the surface of the resin.
[0033]
【The invention's effect】
As described above, if the process paper for producing a flexible polyurethane sheet of the present invention is used, printing on the surface of the flexible polyurethane sheet can be easily and reliably performed, and the handling and secondary processing of the molded flexible polyurethane sheet are easy. become.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a process sheet for producing a flexible polyurethane sheet according to an embodiment of the present invention.
2 (a), (b) and (c) are a method for producing a flexible polyurethane sheet using the process paper for producing the flexible polyurethane sheet of FIG. 1, and a handling method and secondary processing of the flexible polyurethane sheet produced thereby. It is typical sectional drawing explaining a method.
[Explanation of symbols]
1 Process paper for manufacturing a flexible polyurethane sheet 2 Base paper 3 Laminate layer 4 Print layer 5 Soft polyurethane sheet 6 Laminate 7 Secondary processed product

Claims (5)

A process paper for producing a flexible polyurethane sheet used as a support for forming a flexible polyurethane resin into a sheet in the production of a flexible polyurethane sheet, which is made of a synthetic resin laminated on the base paper and the surface side of the base paper And a printed layer laminated on the surface side of the laminate layer,
A process paper for producing a flexible polyurethane sheet, wherein the base paper and the laminate layer are in a pseudo-adhesive state . The process paper for producing a flexible polyurethane sheet according to claim 1, wherein the printing layer is formed of a printing ink containing a release agent. The process paper for manufacturing a flexible polyurethane sheet according to claim 1, wherein a release agent is applied to the surface of the laminate layer. The process paper for manufacturing a flexible polyurethane sheet according to any one of claims 1 to 3, wherein a peel strength between the base paper and the laminate layer is 0.02 N / 5 cm or more and 5 N / 5 cm or less. The process paper for producing a flexible polyurethane sheet according to any one of claims 1 to 4, wherein the laminate layer is transparent.

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