JP5822336B2 - Heat-bonded shoji paper - Google Patents

Description

  The present invention relates to a heat-bonded shoji paper that can be easily pasted with heat of iron, iron, etc., can be pasted neatly without wrinkles and slack, has excellent strength, and can maintain the texture and lighting properties of shoji paper.

  Conventionally, shoji paper used for Japanese-style building shojis is usually Japanese paper that is air permeable and lustrous. This air permeability provides a function of gradual ventilation and humidity adjustment inside and outside, and the unique chromaticity of Japanese paper provides gentle light indoors.

  However, conventional shoji paper is generally weak against impact force and has a drawback that children, pets and the like can easily make holes. For this reason, since the operation | work which changes frequently is required, the need of the shoji paper which raised intensity | strength is high.

  As for air permeability, shoji paper with high air permeability is preferable for ventilation and humidity adjustment, but in recent living environments, the use of air conditioning equipment has increased, and while energy conservation has been screamed worldwide, On the contrary, shoji paper that is not air permeable may be used because of its high airtightness and improved efficiency of air conditioning.

  In order to satisfy these needs, the applicant of the present invention previously described in Japanese Patent Application Laid-Open No. 2004-228561 was a shoji paper in which a pair of polyethylene film layers were provided on both sides of a sheet-like paper layer and a pair of polypropylene film layers were provided on the outer surface thereof. Disclosed.

  Patent Document 2 also proposes a shoji paper in which a thin paper material is bonded to both surfaces of a synthetic resin sheet to block air permeability and maintain strength while maintaining the texture of Japanese paper.

  Further, the applicant of the present application previously disclosed a thermal adhesive shoji paper in which a thermal adhesive resin is dispersed and adhered to one side of the paper in order to facilitate the replacement operation of the shoji paper in Patent Document 3. Thermally bonded shoji paper also has the ability to reinforce shoji paper.

Japanese Patent Laid-Open No. 2007-8100 Japanese Utility Model Publication No. 4-44400 Japanese Patent Laid-Open No. 7-300575

  However, each of the above-mentioned shoji papers has drawbacks in the following points.

  About patent document 1, since it affixes using a double-sided tape for the affixing construction to a shoji, it requires time for work and is troublesome. In order to improve this point, if a thermal adhesive resin layer is provided and affixed with an iron, the polypropylene film layer shrinks and deforms due to the heat of the iron, making it unsuitable as shoji paper.

  Next, regarding Patent Document 2, starch paste is used for application to shoji paper, but since there is a synthetic resin layer in the intermediate layer of paper, drying and solidification of the paste is slow and the finish takes 6 hours or more. It will take.

  Furthermore, Patent Document 3 is unsuitable for energy saving because of its air permeability, and has a problem in strength.

  In addition, in claim 2 and paragraphs 0020 to 0023 of Patent Document 3, “use a composite paper base material provided with a layer such as a film for preventing the transfer of the thermoadhesive resin to one side, both sides or the middle of the paper base material. For example, a layer of a resin film that does not melt at the heat bonding operating temperature is provided by laminating or coating, such as polyester, cellophane, polyolefin, etc. As the coating layer, starch and EVA emulsion alone or In this case, it is described that when there is no air permeability, there is no transfer or leaching of the thermal adhesive resin. ”According to this configuration, the air permeability can be cut off. However, this configuration has the following problems.

  Typical examples of the polyolefin resin listed as the material of the resin film in Patent Document 3 include polyethylene and polypropylene, but polyethylene is not strong compared to polypropylene or polyester, and is attached to a shoji bar. There are problems such as shrinkage deformation (wrinkles and loosening) due to heating during the process, and in the case of polypropylene, sufficient adhesive strength cannot be obtained without using an adhesive when laminating paper and polypropylene film. Will be caused. As for cellophane, sufficient adhesive strength cannot be obtained without using an adhesive when laminating with paper, and delamination occurs due to heating when sticking a shoji to a crosspiece. Furthermore, there are problems such as shrinkage deformation (wrinkle and slack generation) due to heating, which is not as strong as polypropylene or polyester. Even with polyester, when adhesive is not used when laminating with paper, sufficient adhesive strength cannot be obtained, and delamination occurs due to heating such as an iron when sticking the shoji to the crosspiece, causing wrinkles and slack Occurs and detracts from aesthetics. Moreover, the adhesive force of the shoji to the crosspiece is weak, so it cannot be satisfactorily pasted.

  The problem to be solved in the present invention is that it is resistant to impact force while maintaining the unique chromaticity of conventional shoji paper, and furthermore, can maintain energy saving from the air conditioning surface, An object of the present invention is to provide a shoji paper that has sufficient thermal adhesiveness to the crosspieces and that has little shrinkage deformation (wrinkle and slack) due to heating.

The present invention relates to a thermal adhesive shoji paper in which a thermal adhesive resin layer (hot melt layer) is provided on one side of a paper sheet base material in which paper is bonded to both sides of the plastic film via an adhesive layer. The heat distortion temperature is 160 ° C. or more , the basis weight of the paper is 40 to 120 g / m ^{2 in} total, and the basis weight of the paper on one side of the paper sheet substrate on which the thermal adhesive resin layer is provided is 10 to 50 g / m ² . characterized in that it is a m ^2.

(1) By sticking paper on both sides of a plastic film, it becomes a shoji paper having strength and taking advantage of the texture of paper and having excellent airtightness. In addition, since the heat deformation temperature of the plastic film is 160 ° C. or higher, shrinkage deformation (generation of wrinkles and slack) due to heating such as household iron heating when sticking the shoji paper to the shoji can be suppressed. And since paper and a plastic film are bonded together via the adhesive bond layer which consists of polyethylene etc., the problem of delamination can also be eliminated.

(2) Since both sides of the paper are pasted together, some slacks that occur during pasting can be eliminated by a spraying operation similar to normal shoji paper, and the finish can be made beautiful.

(3) Due to the presence of the plastic film between the paper layers, when the bonding operation is performed at a medium temperature (about 140 to 160 ° C.) of a general household iron, the adhesive resin penetrates into the back side of the bonding surface. This is a shoji paper that can be suppressed and can provide the same adhesive strength with a smaller amount of thermal adhesive resin than in the past. Further, by reducing the basis weight of the paper on the side where the thermal adhesive resin layer is provided, it is possible to further suppress the penetration.

It is a disassembled perspective view which shows one Example of the shoji paper based on this invention.

  In the present invention, the plastic film is used for blocking air permeability, improving strength, and preventing back-through of the thermal adhesive resin. This plastic film is required to have a heat deformation temperature of 160 ° C. or higher from the viewpoint of suppressing shrinkage deformation (wrinkle and slack generation) due to partial heating in a household iron when sticking shoji paper to the shoji. From this point, polyethylene terephthalate having a heat distortion temperature of 240 to 245 ° C. (“Polymer Dictionary” and “Nippon Chemical Handbook”) can be suitably used. On the other hand, polyolefins such as polyethylene and polypropylene having a heat distortion temperature of about 43 to 64 ° C. are unsuitable. In addition, although the said ester polyethylene terephthalate is 1 type of polyester of the said patent document 3, a polyester has saturated polyester with a heat deformation temperature of 50-85 degreeC, and unsaturated polyester with a heat deformation temperature of 80-180 degreeC. ("Plastic Reader 9th Edition: Edited by Plastics Technology Association, Issued by: Plastics Age Co., Ltd."), the thermal deformation temperature is below 160 ° C. In the present invention, as described above, the heat distortion temperature of the plastic film needs to be 160 ° C. or higher, and not all polyesters satisfy this.

Here, "thermal deformation temperature" is synonymous with "load deflection temperature" based on JIS K 7191 "Plastic load deflection temperature test method". While applying a predetermined bending stress (1.82 MPa (18.6 kgf / cm ² )) to the test piece, the temperature of the heating medium was increased at a rate of 2 ° C./min, and the deflection of the test piece reached a predetermined amount. The temperature of the heating medium at that time is defined as the heat distortion temperature of the material.

  The thickness of the plastic film is preferably 12 to 100 μm, and more preferably 12 to 50 μm, from the viewpoints of film forming properties in bonding processing (laminating processing) with paper and workability in product processing (small winding processing).

  In addition, as paper to be bonded to both sides of plastic film, natural bast fibers such as kouzo, mitsumata, husk, hemp, etc., single or composite of cellulosic fibers such as wood pulp, cotton linter pulp, rayon, etc. Paper can be used as a raw material, but in order to reduce the shrinkage of the paper due to the moisture release (drying) of the paper, which causes peeling after pasting, the fibers that make up the paper are hydrophilic fibers. It is preferable to reduce the amount of hydrophobic fiber as much as possible and improve the dimensional stability against temperature change and humidity change by blending 5 to 100% by weight of hydrophobic fiber.

  As the hydrophobic fiber, for example, any one selected from “hydrophobic heat-sensitive shrinkable fiber”, “inorganic fiber”, “acrylic fiber”, “vinylon fiber” and the like disclosed in JP-B-5-77800 is used. it can.

  In order to improve the adhesiveness between the paper sheet base material and the thermal adhesive resin, 5 to 100% by mass of synthetic fiber having high affinity for the thermal adhesive resin is blended in the paper constituting the outer surface of the paper sheet base material. It is preferable. For example, when the thermal adhesive resin is polyethylene, EVA, modified EVA, or ionomer, a polyolefin resin fiber or the like is suitable. When the heat-bonding resin is a polyester resin, a polyester fiber or the like is suitable, and when it is a polyamide resin, a nylon fiber or the like is suitable. Furthermore, it is preferable to mix 10 to 90% by mass of cellulose fiber such as pulp, rayon, bast fiber, or polyester fiber, etc., as a fiber having good thermal dimensional stability at 200 ° C. or less. It is more preferable to mix.

In addition, the basis weight of the paper is preferably 40 to 120 g / m ^{2 in} total for the two sheets of paper to be bonded to both sides of the plastic film, from the viewpoint of the properties of the shoji paper that maintains the translucency. Use in 2 minutes. The ratio is from 9: 1 to 1: from the point that the heating condition to the thermal adhesive resin changes depending on the processing order, so that the thermal adhesive resin maintains a substantially hemispherical shape and secures the adhesive force of the shoji to the crosspiece. A range of 9 is appropriate. More specifically, for example, when a thermal adhesive resin is applied to paper by the powder scatter method described later, it is necessary to heat both the resin and the paper from both sides at a temperature of 100 to 150 ° C. Also, in the paper laminating process, the processing temperature varies depending on the processing method, but when the extrusion method is used, the lamination is performed while forming an adhesive layer with a polyethylene melt film heated and melted at about 300 degrees. It is necessary to control the temperature transmitted to the thermoadhesive resin in order to maintain the thermoadhesive resin layer that maintains a hemispherical shape in the order of the application of the thermoadhesive resin and the laminating process. The control of the heat transfer temperature is adjusted by the paper thickness (basis weight). For example, if the total basis weight of two sheets of paper is 50 g / m ² , one paper is distributed to an arbitrary basis weight such as 40 g / m ² and the other is 10 g / m ² , and is bonded to a plastic film. Depending on the processing method and order, the surface of the thermal adhesive resin to be applied to the paper is selected. Specifically, when the laminating process is performed later, it is preferable that the paper on which the heat-adhesive resin layer is formed be thick (basis weight is large). When the laminating process is in front, it is preferable to be thin (basis weight is small).

  As a method of laminating (laminating) a plastic film and paper, there are an extrusion laminate, a hot melt laminate, a dry laminate, a wet laminate, and the like, and any method may be used.

  The extrusion laminate is a method in which a molten film is extruded as an adhesive from the narrow slit of the T-die of the extruder, and the plastic film and paper sent from the front are laminated and cooled and solidified. As the adhesive, polyethylene, polypropylene , Ionomers, ethylene copolymers and the like can be used. An anchor coating agent may be used as an adhesion aid. As the anchor coating agent, tetraalkyl titanate polymer, polyethyleneimine, imine compound and the like can be used. Further, as a method for increasing the adhesive force, a surface-treated plastic film may be used. As the surface treatment method, there are corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone irradiation, ultraviolet irradiation and the like which oxidize the plastic film surface. In addition, there are also sandblasting, solvent treatment, etc. that make the plastic film surface uneven.

  Hot melt laminating is a method in which a heat-melted adhesive is applied onto a substrate (paper or plastic film), and the plastic film or paper is immediately bonded and cooled. Paraffin wax and microcrystalline wax are used as the adhesive. Or a low molecular weight ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, or the like.

  Dry laminating is performed by coating a plastic film (or paper) with an adhesive in which an organic solvent soluble vinyl resin, cellulose resin, epoxy resin, rubber resin, etc. are dissolved in an organic solvent, and then drying. This is a method of drying in a zone, and then laminating by pressure bonding with paper (or plastic film) with a heating roll. Specific adhesives include vinyl resins such as vinyl acetate, vinyl chloride, vinylidene chloride resins, and cellulose. Examples of the resin include nitrocellulose, ethyl cellulose, and cellulose acetate. Moreover, an epoxy resin, a copolymer of synthetic rubber and acrylic resin is also used. Examples of the coating method include gravure coating, reverse roll coating, dip coating, doctor blade, and air knife coating.

  Wet laminating is a method of laminating paper (or plastic film) in a wet state immediately after the adhesive is coated on the plastic film (or paper) with an applicator, and then drying. As the adhesive, polyvinyl chloride, There are polyvinyl acetate, polyvinylidene chloride, vinyl butyral, emulsion of vinyl acetate and acrylate copolymer, latex of synthetic rubber, and the like. Coating is performed by the same method as the above dry lamination.

  In the method of laminating the above plastic film and paper, it is preferable to use polyethylene, polypropylene, ionomer, ethylene copolymer, etc. as the adhesive from the viewpoint of affinity for both the plastic film and paper. Most preferably, is used.

  A thermoadhesive resin layer is formed on one side of the paper sheet base material in which paper is bonded to both sides of the plastic film as described above. At this time, by forming the heat-adhesive resin layer on the side having a small paper basis weight, it is possible to suppress the penetration of the heat-adhesive resin into the paper layer when the sheet is attached with heat such as an iron or a trowel.

  As the resin material for forming the heat-adhesive resin layer, the “heat-sensitive adhesive” disclosed in JP-B-5-77800 can be used. However, when a water-soluble modified PVA system is used, its adhesive strength and wind Is not preferred because it is affected by changes in moisture. Therefore, hydrophobic LDPE system, EVA system, modified EVA system, polyester system, polyamide system, modified PE system, ionomer system and the like having properties that do not affect the adhesive force due to moisture change and do not impair the texture are suitable. is there. What is necessary is just to select a kind and melting | fusing point from a thing of 60 to 150 degreeC according to a use.

  For the formation of the thermal adhesive resin layer, “island or linear formation of thermal adhesive resin” disclosed in Patent Document 3 can be used. That is, the island-like or linear formation of the heat-adhesive resin is sprayed or applied by a powder scatter method or a powder dot method as a powder obtained by pulverizing a heat-adhesive resin material such as the “heat-sensitive adhesive”. Alternatively, the powder can be put in a solvent by a paste dot method to form a paste, transferred from a screen roll to a paper sheet substrate, and then hot-melt bonded to the paper sheet substrate through a heating device. Alternatively, the powder may be melted by heating, transferred from a screen roll to a paper sheet substrate, and then cooled. Alternatively, the resin material emulsion may be sprayed onto a paper sheet base material by spraying, or applied to a gravure plate, transferred to a paper sheet base material, heated, and the solvent may be blown off. Furthermore, not only the method described above but also a composite process can be used to perform dot processing by superposing two or three types of resins having different substitution or compatibility in a double or triple manner.

The thermal adhesive resin layer may be formed only in the state of paper before being laminated (laminated) to the plastic film. In particular, when the temperature at the time of forming the heat bonding resin layer becomes higher than the heat deformation temperature of the plastic film to be laminated, it is preferable to form the heat bonding resin layer before the lamination. In this case, since powder processing or the like is performed using only paper, a paper thickness that can withstand the tension during the processing is required. Therefore, 10-50 g / m < ² > is suitable for the basis weight of the paper on the side on which the thermal adhesive resin layer is formed, and more preferably 15-40 g / m < ² >.

  FIG. 1 is an exploded perspective view showing an embodiment of a shoji paper according to the present invention.

  The shoji paper A shown in the figure is a paper sheet in which papers 3a and 3b are bonded to the upper and lower surfaces of a polyethylene terephthalate (PET) film 1 as a plastic film via a polyethylene (PE) layer 2 as an adhesive layer. The thermal adhesive resin layer 4 is provided on one side (the paper 3a side) of the substrate A1. Specific examples will be described below.

Example 1
On one side of a paper 3a having a basis weight of 25 g / m ² blended with 87% by mass of pulp, 10% by mass of rayon and 3% by mass of binder, Water-soluble EVA (for example, saponified ethylene vinyl acetate copolymer resin manufactured by Tosoh Corporation) is dispersed by heating and melting after spraying 6 g / m ² by a powder scatter method, and is scattered in a spherical or hemispherical island shape. The heat bonding resin layer 4 was formed.

Next, a paper 3b having a basis weight of 25 g / m ² in which 87% by mass of pulp, 10% by mass of rayon, and 3% by mass of binder are blended on one side of the PET film 1 having a double-sided corona treatment having a thickness of 16 μm is extracted. Laminated by lamination. At this time, the polyethylene resin heated and melted by the extruder was extruded from the slit of the T die at 18 μm and sandwiched between the PET film 1 and the paper 3b. Thereafter, similarly, the paper 3a on which the heat-adhesive resin layer 4 was formed was laminated on the other surface of the other surface through polyethylene resin by extrusion lamination to produce shoji paper A.

(Example 2)
The shoji paper A was prepared in the same manner as in Example 1 except that the basis weight of the paper 3a on the side on which the thermal adhesive resin layer 4 was formed was 40 g / m ² and the basis weight of the opposite paper 3b was 10 g / m ^2. Produced.

(Example 3)
The shoji paper A was prepared in the same manner as in Example 1 except that the basis weight of the paper 3a on the side on which the thermal adhesive resin layer 4 was formed was 10 g / m ² and the basis weight of the paper 3b on the opposite side was 40 g / m ^2. Produced.

  For the shoji paper of Examples 1 to 3, the burst strength and adhesive strength were measured, and the appearance (“paper texture” and “no wrinkles or slack”) was examined. Judged. Further, as a comparative example, the same evaluation was performed on the shoji paper having the configuration according to Patent Documents 1 to 3 to determine whether or not the paper was successful.

  The burst strength was measured according to JIS P8112. The burst strength was set to 400 kPa as a reference value, and more than this was regarded as acceptable. This reference value was set from 5 times (392 kPa) or more of the burst strength of shoji paper JIS S3102: 78.45 kPa.

The adhesive strength was measured in the following manner according to the conditions at the time of applying the shoji paper iron.
[Measurement procedure for adhesive strength]
(1) Sample preparation • The shoji paper of each example is cut out, and a test piece having a size of 100 mm in the vertical direction and 50 mm in the horizontal direction is collected.
-The collected test piece was applied to a test plate (length: width: thickness = 100 mm: 50 mm: 9 mm, material: spruce), heat sealing machine (linear pressure: 0.16 MPa (1.6 kgf / cm ² ), temperature: Heat bonding (seal width: 10 mm × 50 mm) at 133.8 ° C., time: 2 seconds) is used as a test sample.
(2) Peel test ・ Put the test sample prepared in (1) between jigs, set it on a tensile testing machine (Yasuda Seiki Seisakusho LLOYD LRX), and pull it up and down as per JIS P 8113. The strength at the time of peeling between the (test piece) and the test plate is defined as the adhesive strength.

The adhesive strength was 49 N (5 kgf) / 50 mm as a reference value, and more than that was acceptable. This reference value was set from a value obtained by measuring the breaking strength of paper by a tensile test of a horizontal (width) 50 mm of standard shoji paper (25% long fiber content, basis weight 48 g / m ² ).

  Table 1 summarizes the results and configuration of the shoji paper according to the above examples and comparative examples.

  As shown in Table 1, Examples 1 to 3 of the present invention all satisfy the standard values of bursting strength and adhesive strength, and even in the appearance before and after construction, both sides are paper, so the texture is not impaired. Even if slack sometimes occurred, it was possible to eliminate the slack by performing the spraying operation in the same manner as normal shoji paper.

  In the comparison of Examples 1 to 3, the adhesive strength was 153N (15.56 kgf) in Example 1, 96N (9.74 kgf) in Example 2, and 189N (19.24 kgf) in Example 3, and the paper basis weight. There is a difference in adhesive strength. This is because, when the basis weight of the paper to which the thermal adhesive resin is attached is large, the thermal adhesive resin penetrates more into the paper, and the amount of resin that contributes to adhesion to the test plate (actually the shoji paper) It seems to decrease.

  On the other hand, since the comparative example 1 corresponding to the shoji paper of the said patent document 1 has bonded together the polypropylene (PP) film on both surfaces of paper, the burst strength is satisfying the reference value. However, since the adhesive strength between the PP film and the thermal adhesive resin (EVA) is insufficient, the adhesive strength does not satisfy the standard value. Moreover, since the outer surface is a PP film, the texture of the paper is impaired due to the gloss of the film itself. Furthermore, since the heat deformation temperature of PP is lower than the heating temperature of the iron at the time of applying the shoji to the crosspiece, wrinkles and slack are generated by heat at the time of application, which impairs the beauty.

  Since Comparative Example 2 corresponding to the shoji paper of Patent Document 2 does not describe specific examples in Patent Document 2, it cannot be clearly evaluated, but there is no adhesive layer between the paper and the plastic. Therefore, it is considered unsuitable as a shoji paper as in Comparative Examples 4 to 6 below because of insufficient adhesive strength.

  Since the comparative example 3 corresponding to the shoji paper of claim 1 of Patent Document 3 is not reinforced with a plastic film and has only the strength of paper, the burst strength is small. Moreover, since there is no plastic film, there is no air-permeable blocking effect.

  As for Comparative Examples 4 to 6 corresponding to the shoji paper of claim 2 of Patent Document 3, polyester, cellophane, and polyolefin are listed as examples of plastic films in Patent Document 3, but these have a heat distortion temperature. Low, wrinkles and slack occur due to heat during construction. Moreover, since there is no adhesive layer between paper and a plastic film, adhesive strength is small. Further, when a plastic film is pasted on the surface, there is a problem of gloss.

A Shoji paper A1 Paper sheet base material 1 Plastic film (PET film)
2 Adhesive layer (polyethylene)
3a, 3b Paper 4 Thermal bonding resin layer

Claims (5)

In a heat-bonded shoji paper in which a heat-bonding resin layer is provided on one side of a paper sheet base material in which paper is bonded to both surfaces of the plastic film via an adhesive layer, the heat deformation temperature of the plastic film is 160 ° C. or higher , the basis weight of the paper 40 to 120 g / ^{m 2} in total of two, the basis weight of one side of the paper of the paper sheet substrate to provide the thermal adhesive resin layer is characterized by a 10 to 50 g / ^{m 2} Heat-bonded shoji paper.   The heat-bonded shoji paper according to claim 1, wherein the plastic film is made of polyethylene terephthalate.   The heat-bonded shoji paper according to claim 1 or 2, wherein the plastic film has a thickness of 12 to 100 µm.   The thermal adhesive paper sheet according to any one of claims 1 to 3, wherein the adhesive layer is made of polyethylene, polypropylene, ionomer, or ethylene copolymer. The thermal bonding shoji according to any one of claims 1 to 4 , wherein the basis weight of the paper on one side of the paper sheet substrate on which the thermal adhesive resin layer is provided is smaller than the basis weight of the paper on the opposite side of the paper sheet substrate. paper.