JP4066940B2 - Laminated sheet suitable for electrophotographic recording - Google Patents

Description

  The present invention relates to a laminated sheet in which a layer made of a thermoplastic resin is laminated on at least one surface of a paper substrate, and particularly to a laminated sheet suitable for recording by an electrophotographic method.

  At present, recording by an electrophotographic method is generally performed. This method copies characters, images, etc. of a copy onto a recording sheet by transferring charged latent image toner. Plain paper copy machines (PPC machines), laser beam printers (LBP), etc. Used as a recording device. One of the main uses of such an electrophotographic recording sheet is POP (Point Of Purchase) of goods at convenience stores and supermarkets. In this use, beauty is also regarded as important.

  In general, paper is used for an electrophotographic recording sheet, but so-called synthetic paper or laminated paper can be used when high aesthetics such as gloss and water resistance are required. Among these, the laminated paper is obtained by laminating a thermoplastic resin on a paper base material. For example, as disclosed in Patent Document 1, thermoplasticity is obtained by an extrusion lamination method or a coextrusion lamination method on one or both sides of a paper base material. Manufactured by laminating resins.

Patent 2763011

  In the electrophotographic system, the latent image toner is transferred to a recording sheet and fixed by thermal fusion. Since the recording sheet is passed between hot rolls at about 200 ° C., when laminated paper is used, laminated paper is used. Is softened as it passes between the hot rolls, and the surface condition of the hot rolls is transferred to the softened resin, and the surface properties of the laminated paper are deteriorated and the beauty is impaired. When a paper-feed jam occurs in the contact state, the resin layer may be fused to the heat roll, causing a problem.

  Further, when a paper-based recording sheet is used, moisture in the paper evaporates due to heating at this time. However, when laminated paper with a thermoplastic resin laminated on both sides of a paper substrate is used, the beauty of the thermoplastic resin is sufficient, but there is no escape for moisture evaporated by the thermoplastic resin layer. Since they are blocked, they push up the thermoplastic resin laminated on the surface of the paper substrate, and between the paper substrate and the thermoplastic resin layer, which must originally be adhered to the entire surface so as not to be peeled off. In some cases, partial voids (non-adhered portions) called blisters were produced, and the sheet was uneven and the appearance deteriorated.

  Further, if the adhesiveness inside the laminated paper is insufficient, it becomes easy to peel off when the thermoplastic resin is fused to the hot roll, or the blister resistance is lowered.

  Based on the above, the present invention uses a laminated paper in which a thermoplastic resin is laminated on a paper base material, and there is no trouble that the surface is damaged by a heat roll or a fusing to the heat roll during recording, and an electron having excellent beauty. The object of the present invention is to provide a laminated sheet suitable for a photographic recording system.

  As a result of intensive studies, the present inventors have determined that at least one layer of the laminated paper is a layer made of a soft thermoplastic resin having a relatively low melting point, and the outermost layer has a high melting point and a hard heat. The present invention has been completed by finding that the above-mentioned problems can be solved by the layer made of a plastic resin.

That is, the present invention is a laminated sheet in which two or more layers of thermoplastic resin are laminated on at least one side of a paper substrate, and at least one of the layers excluding the outermost layer has a melting point of 80 ° C. or higher and 130 ° C. smaller thermal and thermoplastic resin are laminated, and is Homoporipuropire on to the outermost layer a laminated sheet characterized by being stacked.

  In the present invention, a polyethylene resin is selected as the thermoplastic resin having a melting point of 80 ° C. or higher and lower than 130 ° C., and the thermoplastic resin having a melting point of 80 ° C. or higher and lower than 130 ° C. is in contact with the paper substrate. By laminating, it is possible to better achieve the problem.

Furthermore, in particular, when a thermoplastic resin is laminated on both sides of a paper substrate, the moisture permeability measured by the moisture permeability test method described in JIS Z0208 is 15 g / m ² · 24 hrs or more, and at least the paper substrate It is effective to contain a porous filler in the thermoplastic resin layer laminated on one surface.

  The laminated sheet of the present invention is highly glossy, and when recorded with an electrophotographic method, the surface is not damaged by the fusing with a hot roll and running trouble does not occur, and a thermoplastic resin layer is laminated on both sides. Blisters that are likely to occur can also be prevented. Therefore, according to the present invention, it is possible to obtain a recording sheet that is excellent in beauty and suitable for an electrophotographic system. Moreover, since the laminated sheet of the present invention has high water resistance, it can be used for various purposes and has extremely high practical value.

  In the present invention, the paper base refers to a product produced by intertwining and sticking plant fibers or plant fibers and other fibers. Any substrate such as this can be used in the present invention, but smooth paper, for example, high-quality paper, coated paper, etc., is more clearly recorded when recorded on the finished laminated sheet by electrophotography. Give a stamp.

  In the present invention, a thermoplastic resin having a relatively low melting point is used for at least one of the thermoplastic resin layers laminated on one side of the paper base, excluding the outermost layer. “Relatively low” means a melting point of 80 ° C. or higher and lower than 130 ° C. It is considered that adhesion within the laminated sheet is improved by being in this range. When the thermoplastic resin is laminated on both surfaces, such a resin is used at least on the surface in contact with the heat roll.

  Examples of the thermoplastic resin having a melting point of 80 ° C. or higher and lower than 130 ° C. include ethylene resins, propylene resins, and copolymer resins thereof. Among these, polyethylene resins are preferable, for example, high density polyethylene (HDPE) , Low density polyethylene (LDPE), linear low density polyethylene (LLDPE), linear low density polyethylene (SS-LLDPE) synthesized using a single site catalyst, and the like. It is not something. These resins may be used alone or in combination of two or more, and in the case of two or more, the melting point of the mixture is adjusted to be in the above range.

  In particular, SS-LLDPE is preferably used because it has high adhesion to a paper base material and other thermoplastic resin layers. SS-LLDPE shows a sharp molecular weight distribution because it is synthesized by a single-site catalyst having a uniform active site. A typical example of the single site catalyst is a metallocene catalyst. This is a catalyst having a structure in which transition metal atoms such as titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten are sandwiched between two cyclopentadiene rings. In addition, you may perform the synthesis | combination of LLDPE using a single site type | system | group catalyst by any method of a vapor phase method, a high pressure method, and a solution method.

  In addition, since the adhesiveness in the laminated sheet tends to be the weakest between the paper substrate and the thermoplastic resin, in the present invention, a layer made of a thermoplastic resin having a melting point of 80 ° C. or higher and lower than 130 ° C. It is desirable that the adhesion can be enhanced by being laminated so as to be in contact with the paper substrate.

  Next, as a thermoplastic resin to be laminated other than a thermoplastic resin having a melting point of 80 ° C. or higher and lower than 130 ° C., if the resin has good adhesion to the surface to be laminated, the density, MFR It can be used without limitation. Such a resin is not particularly limited. For example, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), SS-LLDPE, random polypropylene (random PP). In addition, polyolefin resins such as homopolypropylene (homo PP), polystyrene, polyester, polyamide and the like can be mentioned. These resins may be used alone or in admixture of two or more.

However, since the laminated sheet of the present invention is exposed to a high temperature for thermal fusion of toner during recording by electrophotography, the outermost layer (surface layer) on the side in contact with the heat roll has a melting point. It is necessary to use a high thermoplastic resin. From this point of view, polypropylene having a relatively high melting point and being inexpensive is suitable as a thermoplastic resin used for the outermost layer of the present invention. Among them, since homopolypropylene has a high melting point and a hard resin, if it is formed mainly of this homopropylene, it is possible to obtain a laminated sheet in which the surface is hardly scratched and the fusion to the hot roll is suppressed. When the thermoplastic resin is laminated on both sides, homopolypropylene is used for at least the outermost layer on the side in contact with the heat roll.

In the laminated sheet of the present invention, the outermost layer of layers and homo poly pyromellitic pyrene melting point consists of 130 ° C. less than the thermoplastic resin at 80 ° C. or more, may be laminated only on one surface of the paper substrate, both surfaces May be laminated. When a layer made of a thermoplastic resin is provided on the other surface of the paper base as required, the number of layers made of the thermoplastic resin and the type of resin forming the layer are not particularly limited. For example, polyolefin resins such as HDPE, LDPE, LLDPE, SS-LLDPE, random PP, and homo PP can be used in the same manner as the thermoplastic resin laminated in addition to the thermoplastic resin having a melting point of 80 ° C. or higher and lower than 130 ° C. First, as long as the adhesiveness with the surface on which these are laminated, such as a mixture of one or more of polystyrene, polyester, and polyamide, can be used without limitation of density, MFR, and the like. The layer laminated on the other surface can also have the same laminated structure as the surface in contact with the heat roll.

  Also, between the paper substrate and a layer made of a thermoplastic resin having a melting point of 80 ° C. or more and less than 130 ° C., or between a layer made of a thermoplastic resin having a melting point of 80 ° C. or more and less than 130 ° C. Can be laminated with the same or different types of thermoplastic resin layers, but the layers of thermoplastic resin with a melting point of 80 ° C. or higher and lower than 130 ° C. are in contact with the paper substrate. The desired effect is sufficient if the outermost layer is provided and the outermost layer is laminated thereon, that is, the laminated structure of the paper base material / melting layer having a melting point of 80 ° C. or higher and smaller than 130 ° C./outermost layer. However, it is industrially advantageous because the manufacturing cost can be reduced.

  In the present invention, the layer in contact with the paper substrate or the layer made of a thermoplastic resin having a melting point of 80 ° C. or higher and lower than 130 ° C. preferably has a thickness of 3 to 40 μm. When the thickness is less than 3 μm, the adhesiveness to the paper substrate is deteriorated, and when it exceeds 40 μm, static electricity is likely to be generated, and the entire laminated sheet including this layer is weakened. When used in LBP, there is a risk of causing problems such as paper jams.

  Moreover, it is preferable that the thickness as a whole of the thermoplastic resin layer (in the case where the thermoplastic resin layers are laminated on both surfaces) is in the range of 10 to 40 μm, particularly 15 to 30 μm. If the thickness of the entire resin layer is too thin, the thickness of each layer is inevitably further reduced, so that it is difficult to stack the layers by the extrusion lamination method or the coextrusion lamination method. Moreover, if this thickness is too thick, the manufacturing cost increases, and static electricity is likely to be generated. The thickness of the resin layer is too thick relative to the thickness of the paper base material, so that the waist becomes weak, and a PPC machine or LBP When used in the above, there is a risk of causing the same trouble as above.

  The method for laminating the thermoplastic resin is not particularly limited, and a known method such as an extrusion laminating method or a coextrusion laminating method can be used alone or in combination.

  In the present invention, a paper base material, a layer made of a thermoplastic resin having a melting point of 80 ° C. or higher and lower than 130 ° C., an outermost layer, and a thermoplastic resin layer or a paper base laminated as necessary In addition to the above, various additives may be added to the layer made of the thermoplastic resin laminated on the other side of the material, as long as the object of the present invention is not impaired, or the coating layer may be applied to the surface of the outermost layer. Can be provided.

  For example, as these additives and coating layers, a sizing agent can be added to the paper substrate, an antistatic agent, acrylic beads, glass beads, silica and other anti-blocking agents can be added to each resin layer, A layer for improving the adhesion of the toner can be coated on the outermost surface of these layers.

Next, when the laminated sheet of the present invention is measured by a moisture permeability test method described in JIS Z 0208, it is desirable that the moisture permeability is 15 g / m ² · 24 hrs or more. When the water vapor transmission rate is 15 g / m ² · 24 hrs or more, it is possible to provide blister resistance when recording by electrophotography.

  Blister is not a problem when a layer made of a thermoplastic resin is laminated on only one side of a paper substrate, but when laminated on both sides, it is heated by a hot roll and evaporated from the paper substrate. It is easy to generate because there is no escape place for moisture. On the other hand, in this invention, a blister can be improved by containing a porous filler in the layer which consists of a thermoplastic resin laminated | stacked on one side of a paper base material. When layers made of a thermoplastic resin are laminated on both sides of the paper substrate, at least all of the thermoplastic resin layers laminated on one side of the paper substrate contain a porous filler. Of course, when one or more thermoplastic resin layers are laminated on the other surface, a part or all of the thermoplastic resin layer may similarly contain a porous filler. Even if the thermoplastic resin layer is not provided on the other side of the paper substrate, a part or all of the thermoplastic resin layer laminated on one side may contain a porous filler.

  The term “porous filler” as used herein means a material having a large number of fine pores on the surface. The particle size is preferably 0.1 to 20 μm. If the particle size is too small, it is difficult to control the particle size during production. If the particle size is too large, the filler protrudes from these layers in relation to the thickness of the thermoplastic resin layer in which it is blended. The surface may be roughened, which may adversely affect the adhesion of each layer and the recording property on the surface of the laminated sheet by the electrophotographic method.

  As such a porous filler, either an inorganic filler or an organic filler can be used. Examples of inorganic fillers include calcium carbonate (for example, “Calsees P” manufactured by Kamishima Chemical Co., Ltd.), titanium oxide (for example, “Taibak” manufactured by Ishihara Sangyo Co., Ltd.), and silica (for example, “Silo Hovic 456 manufactured by Fuji Silysia Chemical Ltd.). ), Talc (for example, “ACE Series” manufactured by Nippon Talc Co., Ltd.), mica (for example, “HC-1069” manufactured by Yamaguchi Mica Co., Ltd.), etc., as an organic filler, acrylic, polystyrene, styrene acrylic, A filler made of a resin such as malon indene or modified melamine can be used having a large number of microvoid structures, but is not limited thereto. Among these, calcium carbonate is preferable because it is easy to control the shape during production. In addition, these porous fillers may use only 1 type, or may use 2 or more types together.

  The blending amount of the porous filler is preferably 15 to 65% by weight, particularly preferably 20 to 50% by weight, based on the entire thermoplastic resin layer. If the amount is too small, it will be difficult to prevent blisters sufficiently. On the other hand, if the amount is too large, the processability of the resin deteriorates, and the surface of these resin layers becomes rough, which may adversely affect the adhesion of each layer.

  The porous filler may be mixed with the thermoplastic resin layer immediately before the lamination of these resin layers, but a master batch in which these resins and the porous filler are mixed at an appropriate ratio is prepared in advance. In addition, this may be used as a laminated material. In any case, the porous filler has a melting point of 10 ° C. or more higher than that of a thermoplastic resin layer having a melting point of 80 ° C. or higher and lower than 130 ° C., or a thermoplastic resin having a melting point of 80 ° C. or higher and lower than 130 ° C. It is desirable that the resin is uniformly dispersed in an outermost layer made of resin and, if necessary, a layer made of a thermoplastic resin laminated on the same side or the other side of the paper substrate. Any known method can be used for this purpose.

  The porous filler may be mixed in a considerable amount in the layer in contact with the paper substrate. However, if the filler is added to the thermoplastic resin layer laminated in contact with the paper substrate, the adhesion to the paper substrate will be improved. A decline is inevitable. Therefore, it is preferable to select the above-described SS-LLDPE as the resin that forms a layer that is laminated in contact with the paper base material containing the porous filler. This is because SS-LLDPE exhibits good adhesion to the paper substrate even when a high amount of porous filler is blended.

[Action]
As an electrophotographic recording sheet, a laminated sheet made of a thermoplastic resin on at least one side of a paper base is more glossy and beautiful than ordinary paper, but it has a thermoplastic resin layer. Therefore, when fixing the toner, the surface is damaged by softening with a heat roll, or when the adhesion between the paper substrate and the thermoplastic resin or the thermoplastic resin layer is poor, coupled with the thermal melting of the resin, It is considered that the resistance when fused to the hot roll is reduced and the film is easily peeled off, causing a running trouble. The lower the melting point of the thermoplastic resin, the easier it is to obtain the adhesiveness. However, when the melting point is low, there is a concern about fusion when passing between the hot rolls and deterioration of the beauty.

  On the other hand, according to the present invention, among the layers made of two or more thermoplastic resins laminated on one side, the melting point of at least one thermoplastic resin is 80 ° C. or higher and smaller than 130 ° C. Since the inner adhesiveness is good and the melting point of the outermost thermoplastic resin is as high as 130 ° C. or more, a recording sheet suitable for an electrophotographic recording method and having excellent beauty can be obtained.

  In addition, the present inventors have a blister that occurs when a laminated sheet in which a thermoplastic resin is laminated on both sides of a paper base material is used for recording by a PPC machine or LBP, when the laminated sheet is heated. It has been found that the evaporating moisture in the paper base material occurs because the escape place is blocked by the thermoplastic resin layer laminated on the paper base material.

Therefore, in the present invention, when the thermoplastic resin is laminated on both sides, at least the layer made of the thermoplastic resin laminated on one side of the paper base material contains a porous filler. , Preventing the occurrence of blisters. Since the porous filler has a large number of fine pores on its surface, when it is blended in a layer made of a thermoplastic resin, there are fine voids between the thermoplastic resin and the surface of the porous filler. It is considered that the voids are appropriately connected in the layer made of the thermoplastic resin to form cracks and form an escape route for the evaporated water.
Furthermore, since the laminated sheet of the present invention has excellent internal adhesion and is difficult to peel off, it is considered that blisters are efficiently prevented.

  Hereinafter, the present invention will be described based on examples, but the present invention is not limited thereto. In the obtained Examples and Comparative Examples, the glossiness, adhesion with a hot roll, adhesion to a paper substrate, moisture permeability, and the state of occurrence of blisters were evaluated as follows.

<Glossiness>
The 75 ° glossiness of the printed surface was measured according to JIS P-8142.

<Fusibility with hot roll>
Color laser beam printer manufactured by Fuji Xerox Co., Ltd. A3 size sample is printed using Docu Print C3530, paper jam is forcibly generated, contacted with the hot roll for 5 minutes, and whether there is resin fusion to the hot roll Visual evaluation was performed.
○… No fusing is seen ×… Fusing is seen

<Adhesion with paper substrate>
A sample cut to 25 mm × 100 mm was manually peeled between a paper substrate and a layer laminated in contact with the paper substrate, and the degree of ease of peeling at that time was evaluated according to the following criteria: did.
◎… The paper substrate and the layer laminated in contact with the paper substrate are in very close contact with each other, and cannot be peeled or the paper substrate is destroyed when trying to peel. The layer laminated in contact with the material is strongly adhered and difficult to peel ×: The paper substrate and the layer laminated in contact with the paper substrate are weakly adhered or not adhered Easy to peel

<Moisture permeability>
The measurement was performed according to the moisture permeability test method for moisture-proof packaging materials described in JIS Z0208.

<Blister outbreak status>
Ten samples were printed continuously with a Canon LBP printer “LBP-740e”, and the blister occurrence of the sample after printing was observed with the naked eye and evaluated according to the following criteria.
○… Blisters are not generated ×… Blisters are generated

[Example 1]
A low-density polyethylene (hereinafter LDPE: melting point 122 ° C., density 0.907 g / cm ³ ) melt and a homopropylene (hereinafter homo-PP: melting point 160 ° C., density 0.91 g / cm ³ ) melt have a basis weight of 155 g. A laminated sheet was produced by coextrusion lamination at an extrusion temperature of 300 ° C. using a T-die so that the LDPE melt was laminated on one side of the high quality paper / m ^{2 on} the fine paper side.
That is, this laminated sheet has a laminated structure of homo PP layer / LDPE layer / quality paper. At this time, the thicknesses of the homo PP layer and the LDPE layer were both 10 μm.
Table 2 shows the results of evaluating the obtained laminated sheet for glossiness, adhesion with a hot roll, and adhesion with a paper substrate. As is clear from Table 2, this laminated sheet was excellent in glossiness, was not observed to be fused with a hot roll, and was strongly adhered to the paper substrate.

[Example 2]
SS-LLDPE (melting point: 120 ° C., density: 0.908 g / cm ³ ) melt and homo PP (melting point: 160 ° C., density: 0.91 g / cm ³ ) melt of high-quality paper having a basis weight of 155 g / m ² A laminated sheet was produced by performing coextrusion lamination at an extrusion temperature of 300 ° C. using a T die so that the LDPE melt was laminated on one side of the fine paper.
That is, this laminated sheet has a laminated structure of homo PP layer / SS-LLDPE layer / quality paper. At this time, the thicknesses of the homo PP layer and the LDPE layer were both 10 μm.
Table 2 shows the results of evaluating the obtained laminated sheet for glossiness, adhesion with a hot roll, and adhesion with a paper substrate. As is clear from Table 2, this laminated sheet was excellent in glossiness, did not show any fusion with a hot roll, and was in very strong contact with the paper substrate.

[Example 3]
An LDPE (melting point: 122 ° C., density: 0.907 g / cm ³ ) melt and a homo PP (melting point: 160 ° C., density: 0.91 g / cm ³ ) 80 wt% and calcium carbonate: 20 wt% melt basis weight Laminated sheet by co-extrusion lamination at an extrusion temperature of 300 ° C. using a T-die so that the melt of SS-LLDPE is laminated on one side of the fine paper of 155 g / m ^{2 on} the fine paper side Manufactured.
That is, this laminated sheet has a laminated structure of calcium carbonate-containing homo PP layer (a layer made of a thermoplastic resin containing a porous filler) / LDPE layer / quality paper. At this time, the thicknesses of the calcium carbonate-containing homo PP layer and the LDPE layer were both 10 μm.
Table 2 shows the evaluation results of the obtained laminated sheet with respect to glossiness, fusing property with a heat roll, adhesion to a paper base material and moisture permeability, and occurrence of blisters. As is clear from Table 2, this laminated sheet was excellent in glossiness, was not observed to be fused with a hot roll, and was in very close contact with the paper substrate.

[Example 4]
A molten mixture of SS-LLDPE (melting point 120 ° C., density 0.908 g / cm ³ ) 65 wt% and calcium carbonate 35 wt% and homo PP (melting point 160 ° C., density 0.91 g / cm ³ ) A laminated sheet is produced in the same manner as in Example 1 except that co-extrusion lamination is performed so that a molten mixture of SS-LLDPE and calcium carbonate is laminated on one side of the fine paper so as to be laminated on the fine paper side. did.
That is, this laminated sheet has a laminated structure of homo PP layer / calcium carbonate-containing SS-LLDPE layer (a layer made of SS-LLDPE containing a porous filler) / quality paper.
Table 2 shows the results of evaluating the obtained laminated sheet for glossiness, adhesion with a hot roll, and adhesion with a paper substrate. As is clear from Table 2, this laminated sheet was excellent in glossiness, was not observed to be fused with a hot roll, and was in very close contact with the paper substrate.

[Example 5]
LDPE (melting point 122 ° C., density 0.907 g / cm ³ ) 65 wt% and calcium carbonate 35 wt% molten mixture, homo PP (melting point 160 ° C., density 0.91 g / cm ³ ) 80 wt% and calcium carbonate 20 Using a T-die so that the molten mixture of weight% is laminated on both sides of the high-quality paper having a basis weight of 155 g / m ² and the molten mixture of SS-LLDPE and calcium carbonate is positioned on the high-quality paper side. Co-extrusion lamination was performed at an extrusion temperature of 300 ° C. to produce a laminated sheet.
That is, this laminated sheet has a calcium carbonate-containing homo PP layer (a layer made of a thermoplastic resin containing a porous filler) / a calcium carbonate-containing LDPE layer (a layer made of an LDPE containing a porous filler) / fine paper / carbonic acid. It has a laminated structure of a calcium-containing LDPE layer (a layer made of LDPE containing a porous filler) / a calcium carbonate-containing homo PP layer (a layer made of a thermoplastic resin containing a porous filler). At this time, the thicknesses of the calcium carbonate-containing homo PP layer and the calcium carbonate-containing SS-LLDPE layer were both 10 μm.
Tables 2 and 3 show the evaluation results of the obtained laminated sheet with respect to glossiness, adhesion with a heat roll, adhesion to a paper base material, moisture permeability, and occurrence of blisters. As is apparent from the table, this laminated sheet is excellent in glossiness, does not show any fusion with the heat roll, is very closely adhered to the paper substrate, and further has a moisture permeability of 15 g / m ² · 24 hrs. Thus, no blistering was observed at all.

[Example 6]
SS-LLDPE (melting point 120 ° C., density 0.908 g / cm ³ ) 65 wt% and calcium carbonate 35 wt% molten mixture, homo PP (melting point 160 ° C., density 0.91 g / cm ³ ) 80 wt% and carbonic acid A T-die is used so that a molten mixture of 20% by weight of calcium is laminated on both sides of a high-quality paper having a basis weight of 155 g / m ² with the molten mixture of SS-LLDPE and calcium carbonate positioned on the high-quality paper. The laminated sheet was manufactured by performing coextrusion lamination at an extrusion temperature of 300 ° C.
That is, this laminated sheet has a calcium carbonate-containing homo PP layer (a layer made of a thermoplastic resin containing a porous filler) / a calcium carbonate-containing SS-LLDPE layer (a layer made of SS-LLDPE containing a porous filler) / It has a laminated structure of fine paper / calcium carbonate-containing SS-LLDPE layer (a layer made of SS-LLDPE containing a porous filler) / calcium carbonate-containing homo PP layer (a layer made of a thermoplastic resin containing a porous filler). . At this time, the thicknesses of the calcium carbonate-containing homo PP layer and the calcium carbonate-containing SS-LLDPE layer were both 10 μm.
Tables 2 and 3 show the results of evaluating the obtained laminated sheet for glossiness, adhesion to a hot roll, adhesion to a paper base material, moisture permeability, and the state of occurrence of blisters. As is apparent from the table, this laminated sheet is excellent in glossiness, does not show any fusion with the hot roll, is in very close contact with the paper substrate, and further has a moisture permeability of 15 g / m ² · 24 hrs. Thus, no blistering was observed at all.

[Example 7]
A laminated sheet was produced in the same manner as in Example 6 except that the thickness of the calcium carbonate-containing homo PP layer was 15 μm and the thickness of the calcium carbonate-containing SS-LLDPE layer was 5 μm on both sides.
Tables 2 and 3 show the results of evaluation of the obtained laminated sheet with respect to glossiness, fusing property with a heat roll, adhesion to a paper base material, moisture permeability, and occurrence of blisters. As is apparent from the table, this laminated sheet is excellent in glossiness, does not show any fusion with the heat roll, is very closely adhered to the paper substrate, and further has a moisture permeability of 15 g / m ² · 24 hrs. Thus, no blistering was observed at all.

[Example 8]
As a layer made of SS-LLDPE containing porous fillers on both sides, SS-LLDPE (melting point: 120 ° C., density: 0.908 g / cm ³ ) was used except that 50% by weight of calcium carbonate was blended. A laminated sheet was produced in the same manner as in Example 6.
Tables 2 and 3 show the results of evaluation of the obtained laminated sheet with respect to glossiness, fusing property with a heat roll, adhesion to a paper base material, moisture permeability, and occurrence of blisters. As is apparent from the table, this laminated sheet is excellent in glossiness, does not show any fusion with the heat roll, is very closely adhered to the paper substrate, and further has a moisture permeability of 15 g / m ² · 24 hrs. Thus, no blistering was observed at all.

[Example 9]
As a layer made of SS-LLDPE containing a porous filler on both sides, SS-LLDPE (melting point 120 ° C., density 0.908 g / cm ³ ) 40% by weight and calcium carbonate 60% by weight were used. Except for using a layer composed of a thermoplastic resin containing a porous filler, 50% by weight of homo carbonate (melting point: 160 ° C., density: 0.91 g / cm ³ ) and 50% by weight of calcium carbonate were used. A laminated sheet was produced in the same manner as in No. 6.
Tables 2 and 3 show the results of evaluation of the obtained laminated sheet with respect to glossiness, fusing property with a heat roll, adhesion to a paper base material, moisture permeability, and occurrence of blisters. As is apparent from the table, this laminated sheet is excellent in glossiness, does not show any fusion with the heat roll, is very closely adhered to the paper substrate, and further has a moisture permeability of 15 g / m ² · 24 hrs. Thus, no blistering was observed at all.

[Example 10]
As a layer made of SS-LLDPE containing a porous filler on both sides, SS-LLDPE (melting point 120 ° C., density 0.908 g / cm ³ ) 30% by weight and calcium carbonate 70% by weight were used. Except that a layer composed of a thermoplastic resin containing a porous filler was used, except that 80% by weight of homo PP (melting point: 160 ° C., density: 0.91 g / cm ³ ) was mixed with 20% by weight of calcium carbonate. A laminated sheet was produced in the same manner as in No. 6.
Tables 2 and 3 show the results of evaluating the moisture permeability, the occurrence of blisters, and the adhesion to the paper substrate for the obtained laminated sheet. As is apparent from the table, this laminated sheet is excellent in glossiness, does not show any fusion with the heat roll, has good adhesion to the paper base material, and has a moisture permeability of 15 g / m ² · 24 hrs or more. No blistering was observed.

[Comparative Example 1]
A melt of random polypropylene (hereinafter, random PP: melting point 159 ° C., density 0.91 g / cm ³ ) and a homo PP (melting point 160 ° C., density 0.91 g / cm ³ ) melt on one side of the fine paper, A laminated sheet was produced in the same manner as in Example 6 except that co-extrusion lamination was performed so that the melt of random PP was laminated on the fine paper side.
That is, this laminated sheet has a laminated structure of homo PP layer / random PP / quality paper / random PP / homo PP layer.
Table 2 shows the results of evaluating the obtained laminated sheet for glossiness, adhesion with a hot roll, and adhesion with a paper substrate. As is clear from Table 2, this laminated sheet is excellent in gloss and does not adhere to the heat roll, but does not adhere to the paper base material and has a moisture permeability of less than 15 g / m ² · 24 hrs. As a result, blistering occurred and it was difficult to use as a recording paper for electrophotography.

[Comparative Example 2]
LDPE (melting point 122 ° C., a density 0.907 g / cm ³⁾ melt and the SS-LLDPE (melting point 120 ° C., a density 0.908 g / cm ³⁾ and the melt is, on one side of fine paper having a basis weight of 155 g / ^{m 2} A laminated sheet was produced by performing coextrusion lamination at an extrusion temperature of 300 ° C. using a T die so that the LDPE was laminated on the fine paper side.
That is, this laminated sheet has a laminated structure of SS-LLDPE layer / LDPE layer / quality paper / LDPE layer / SS-LLDPE layer. At this time, the thicknesses of the LDPE layer and the SS-LLDPE layer were both 10 μm.
Table 2 shows the results of evaluating the obtained laminated sheet for glossiness, adhesion with a hot roll, and adhesion with a paper substrate. As is clear from Table 2, this laminated sheet has excellent gloss and good adhesion to the paper substrate, but it is difficult to use as a recording paper for electrophotography because it is fused with a hot roll. there were.

[Comparative Example 3]
LDPE (melting point 122 ° C., density 0.907 g / cm ³ ) melt and homo PP (melting point 160 ° C., density 0.91 g / cm ³ ) melt are homo PP on one side of 155 g / m ² fine paper. A laminated sheet was manufactured by performing coextrusion lamination at an extrusion temperature of 300 ° C. using a T die so as to be laminated on the fine paper side.
That is, this laminated sheet has a laminated structure of LDPE layer / homo PP layer / quality paper / homo PP layer / LDPE layer. At this time, the thicknesses of the LDPE layer and the homo PP layer were both 10 μm.
Table 2 shows the results of evaluating the obtained laminated sheet for glossiness, adhesion with a hot roll, and adhesion with a paper substrate. As can be seen from Table 2, this laminated sheet is excellent in glossiness, but it can be fused with a hot roll and has poor adhesion to a paper substrate, making it difficult to use as an electrophotographic recording paper. there were.

[Comparative Example 4]
Nothing was laminated on the high-quality paper having a basis weight of 155 g / m ² . Table 2 shows the results of evaluating the glossiness and the fusing property with a hot roll. As is apparent from Table 2, this high-quality paper has low gloss and insufficient beauty. Moreover, since it is normal paper, it is inferior also in terms of water resistance.

注）最外層および下層に用いられた熱可塑性樹脂と融点
ホモＰＰ：１６０℃、ＬＤＰＥ：１２２℃、ＳＳ−ＬＬＤＰＥ：１２０℃、ランダムＰＰ：１５９℃

Note) Thermoplastic resin and melting point used for outermost layer and lower layer Homo PP: 160 ° C, LDPE: 122 ° C, SS-LLDPE: 120 ° C, Random PP: 159 ° C

Claims (5)

A laminated sheet in which layers of two or more thermoplastic resins are laminated on at least one side of a paper substrate, and a thermoplastic resin having a melting point of 80 ° C. or higher and lower than 130 ° C. is present in at least one layer excluding the outermost layer. A laminated sheet for an electrophotographic system , characterized in that it is laminated and homopolypropylene is laminated on the outermost layer. The laminated sheet for an electrophotographic system according to claim 1, wherein the thermoplastic resin having a melting point of 80 ° C or higher and lower than 130 ° C is a polyethylene resin. The laminated sheet for an electrophotographic system according to claim 1 or 2, wherein a layer made of a thermoplastic resin having a melting point of 80 ° C or higher and lower than 130 ° C is laminated so as to be in contact with the paper substrate. 4. The electrophotographic laminate sheet according to claim 1, wherein the moisture permeability measured by the moisture permeability test method described in JIS Z 0208 is 15 g / m ² · 24 hrs or more. The laminate sheet for an electrophotographic system according to claim 4, wherein at least one of the thermoplastic resin layers laminated on one side of the paper base material contains a porous filler.