Book cloth

Abstract

To provide a book cloth using an environmentally friendly material, which simultaneously maintains excellent qualities such as surface strength, non-whitening property, curl resistance, heat sealability, blocking resistance, and bending resistance.SOLUTION: The book cloth is a laminate having a colored layer, which contains at least a biomass polyolefin resin, a hydrogenated styrene-based thermoplastic elastomer, and a colorant, laminated on a substrate, and is characterized in that the biomass polyolefin resin is mixed at 1 to 50 parts by weight and the hydrogenated styrene-based thermoplastic elastomer is mixed at 30 to 70 parts by weight.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a book cloth used for binding books, files, binders, diaries, notebooks, etc., as well as for covering the surfaces of stationery cases, and jewelry cases for cosmetics, precious metals, etc. [Technical field]

[0002] Conventionally, vinyl paper, which is made by laminating polyvinyl chloride (PVC) resin and paper, has been widely used as book cloth for binding books, files, binders, diaries, notebooks, etc., and for covering the surfaces of stationery cases, and jewelry cases for cosmetics and precious metals, etc.

[0003] Moreover, as bookcloth that does not use polyvinyl chloride, which has environmental pollution problems due to the toxic gases that are generated when burned, a type of paper called olefin paper is used, which is made by pasting a film mainly made of polypropylene (PP) resin onto paper.

[0004] The qualities required for bookcloth for bookbinding, case lamination, etc. include surface strength, non-whitening resistance, curl resistance, heat sealability, blocking resistance, stiffness, etc. As a bookcloth technology that maintains excellent qualities such as surface strength, non-whitening resistance, curl resistance, heat sealability, blocking resistance, stiffness, etc., Patent Document 1, for example, discloses a technology that uses a laminate in which a colored layer containing at least a polypropylene resin, a hydrogenated styrene-based thermoplastic elastomer, and a colorant is laminated on a substrate. [Prior art documents]

[0005] [Patent Document 1] JP 2009-18557 A Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional book cloths, the resin used is mainly a petroleum-derived plastic resin.

[0007] However, due to the recent rapid rise in environmental awareness, attempts are being made to replace petroleum-derived plastic resins with plant-derived materials. Among these, plant-derived plastics, known as biomass plastics, are attracting attention as environmentally friendly plastic materials, and their applications are expanding.

[0008] Therefore, a primary object of the present invention is to provide a book cloth which uses an environmentally friendly material and at the same time maintains excellent qualities such as surface strength, anti-whitening properties, curl resistance, heat sealability, blocking resistance, and bending resistance. [Means for solving the problem]

[0009] As a result of extensive research into the problems of the prior art, the inventors have discovered that the above object can be achieved by using a book cloth made of a specific material, thereby completing the present invention.

[0010] That is, the present invention relates to the following book cloth. 1. A book cloth, which is a laminate having a colored layer containing at least a biomass polyolefin resin, a hydrogenated styrene-based thermoplastic elastomer, and a colorant laminated on a substrate, characterized in that the biomass polyolefin resin is mixed at 1 to 50 parts by weight and the hydrogenated styrene-based thermoplastic elastomer is mixed at 30 to 70 parts by weight. 2. The book cloth according to item 1, wherein the colored layer contains an α-olefin copolymer. 3. The book cloth according to item 2, wherein the colored layer is a mixture of 1 to 50 parts by weight of a biomass polyolefin resin, 30 to 70 parts by weight of a hydrogenated styrene thermoplastic elastomer, and 1 to 40 parts by weight of an α-olefin copolymer. Effect of the Invention

[0011] In the book cloth according to the present invention, it is possible to provide a book cloth using an environmentally friendly material and at the same time to provide a book cloth that maintains excellent qualities such as surface strength, non-whitening properties, curl resistance, heat sealability, blocking resistance, bending resistance, etc. In particular, when a heat sealing process is performed between the colored layer and the polypropylene film to provide a pocket portion on the colored layer surface, it is possible to exhibit high heat sealability equal to or higher than that of conventional book cloths that used petroleum-derived polypropylene resin, which was an essential raw material for maintaining excellent heat sealability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The book cloth of the present invention is characterized in that it is a laminate in which a colored layer containing at least a biomass polyolefin resin, a hydrogenated styrene thermoplastic elastomer, and a colorant is laminated on a substrate.

[0013] Biomass polyolefin resins are so-called carbon-neutral materials that, when burned, do not increase or decrease the CO2 concentration in the atmosphere, as compared to petroleum-derived polyolefin resins, and are therefore environmentally friendly materials, making it possible to create bookcloths that are even more environmentally friendly.

[0014] The MFR of the biomass polyolefin resin can be appropriately selected, but it is preferably 1.0 to 8.0 g / 10 min. If the MFR is less than 1.0 g / 10 min, problems arise in processability.

[0015] The hydrogenated styrene-based thermoplastic elastomer is essential for maintaining surface strength, prevention of whitening and curling, and improved processability. If a hydrogenated styrene-based thermoplastic elastomer is not used, problems such as a decrease in surface strength will occur, and curling and processability will be impaired, making it impossible to maintain sufficient quality as a book cloth.

[0016] The α-olefin copolymer can be appropriately blended and used in order to maintain heat sealability.

[0017] The melting point of the α-olefin copolymer can be appropriately selected, but is desirably 45 to 160° C. It is preferably 60° C. or higher, and more preferably 70° C. or higher. If the melting point is lower than 45° C., problems will arise in terms of blocking resistance, and if the melting point is higher than 160° C., problems will arise in terms of heat sealability.

[0018] As colorants, various organic pigments such as (poly)azo, phthalocyanine, threne, dye lake, quinacridone, and dioxazine, and various inorganic pigments such as oxides such as titanium oxide, sulfides / selenides, ferrocyanides, calcium carbonate, and carbon black can be appropriately used, and it is important to maintain the appearance quality of the colored layer.

[0019] The blending ratio of the biomass polyolefin resin, hydrogenated styrene thermoplastic elastomer, and α-olefin copolymer can be appropriately selected to maintain curl resistance, heat sealability, and blocking resistance, but it is desirable for the biomass polyolefin resin to be 1 to 50 parts by weight, the hydrogenated styrene thermoplastic elastomer to be 30 to 70 parts by weight, and the α-olefin copolymer to be 0 to 40 parts by weight. If the blending ratio of the biomass polyolefin resin is more than 50 parts by weight, curling problems will occur and processability will be impaired, and if the blending ratio of the hydrogenated styrene thermoplastic elastomer is more than 70 parts by weight, problems with heat sealability will occur.

[0020] It is preferable to add an acrylic-silicone copolymer resin to the colored layer. The acrylic-silicone copolymer resin exerts an excellent effect in improving the surface strength of the colored layer surface, and the blending ratio can be appropriately selected, but it is preferable that the blending ratio is in the range of 1-5 PHR based on the total weight of the biomass polyolefin resin, hydrogenated styrene thermoplastic elastomer, and α-olefin copolymer. If the blending ratio is less than 1 PHR, the effect of improving the surface strength is not sufficient, and if the blending ratio is more than 5 PHR, problems occur in the heat sealability and printability on the surface.

[0021] The colored layer may contain additives such as fillers such as silica, talc, calcium carbonate, titanium oxide, clay, mica, barium sulfate, magnesium hydroxide, glass fiber, and carbon fiber; antioxidants such as phenols, phosphorus-based, amine-based, and sulfur-based; lubricants and stabilizers such as saturated fatty acid amides such as lauric acid amide and stearic acid amide, unsaturated fatty acid amides such as erucic acid amide and oleic acid amide, and phosphorus-based lubricants and stabilizers, within the range that does not impair the physical properties of the colored layer.

[0022] Antistatic agents can be selected from polyethylene glycol esters, amino derivatives, such as tetraalkylammonium ethyl sulfate, and the preferred mixing ratio is about 0.3% relative to the resin. Adding too much will hinder printing on the surface and heat sealing of pocket films, and not using it will attract dust and dirt due to static electricity, causing problems in appearance.

[0023] The surface of the colored layer can be embossed with various patterns, which gives it an appearance with excellent design. Furthermore, by subjecting the surface of the colored layer to corona treatment, it is possible to improve the printability of the surface and obtain adhesion between the surface and the inside paper when wrapped, and it is more preferable that the wet tension according to JIS-K6768 is 30 or more.

[0024] The substrate on which the colored layer is laminated may be appropriately selected from cloth, nonwoven fabric, paper, etc., but it is preferable to use paper in terms of cost, workability, etc. The paper to be used may be selected from pulp fiber alone or mixed paper made of pulp fiber and various fibers such as vinylon fiber, nylon fiber, polyester fiber, rayon fiber, and cotton fiber. There is no particular specification for the thickness of the substrate, but a basis weight of 120 g / m2 is recommended to prevent bouncing when wrapped. 2 It is preferable that:

[0025] The method for preparing the colored layer and laminating it to the substrate can be a known processing method such as T-die extrusion processing, calendar processing, or inflation processing, but calendar processing is preferred in terms of productivity and small-lot compatibility.

[0026] The lamination of the colored layer and the substrate is performed by calendar topping, but in order to maintain the adhesion between the colored layer and the substrate for a long period of time and to strengthen the adhesive force between the colored layer and the substrate, an adhesive layer may be provided between the colored layer and the substrate. In this case, a urethane-based resin, an acrylic-based resin, a polyolefin-based resin, a vinyl acetate-based resin, or the like is used for the adhesive layer.

[0027] A thickness of 50-200 μm is ideal for the colored layer. If the thickness is less than 50 μm, problems will arise in terms of surface strength, heat sealability, whitening of folded parts, and suitability for embossing. If the thickness is more than 200 μm, the layer will be too hard, making secondary processing such as bookbinding and case lamination difficult, and will be costly.

[0028] To be used as book cloth, it is important that the paper does not curl, and that the measured curl height is 15 mm or less. If the curl height exceeds 15 mm, problems will arise such as the difficulty of secondary processing such as bookbinding and laminating cases.

[0029] It is necessary to prevent whitening of book cloth at folded parts or wrapped corners, and therefore it is desirable that the colored layer does not whiten when folded in accordance with JIS-A6909. If whitening is observed on the surface of the colored layer, it will not only result in a poor appearance, but also make the area more susceptible to cracking.

[0030] It is expected that bookcloths will be used for a long time, and that the surface of the cover and the folded corners will be repeatedly rubbed against bookshelves and other covers. The surface strength of the colored layer should be at least grade 4 in terms of color fastness measured with a Gakushin type friction tester according to JIS-L0849, meaning that even when the dry cloth and the colored layer are rubbed together, there is almost no discoloration of the dry cloth or the colored layer surface.

[0031] The Gurley stiffness according to JIS-L1096 is preferably in the range of 0.5-10.0 mN. If the stiffness is less than 0.5 mN, the stiffness will be weak and the material will not run smoothly in a bookbinding machine, whereas if the stiffness is more than 10.0 mN, the laminate will have too much rebound and will not be able to be processed in a bookbinding machine, which is a fatal problem for a bookcloth.

[0032] It is important that sufficient heat sealability is maintained between the colored layer and the polypropylene film when heat sealing is performed between them, because if the heat sealability is weak, peeling will occur due to insufficient heat sealability when attempting to provide a pocket portion on the surface of the colored layer by heat sealing. EXAMPLES

[0033] The features of the present invention will be described in more detail below with reference to examples and comparative examples, although the scope of the present invention is not limited to the examples.

[0034] Example 1 To obtain the composition shown in Table 1, biomass polyolefin resin, hydrogenated styrene thermoplastic elastomer, and α-olefin copolymer were mixed in a weight ratio of 50 / 40 / 10, and 3 parts by weight of acrylic-silicone copolymer resin, 0.36 parts by weight of antistatic agent, 0.1 parts by weight of antioxidant, and 0.8 parts by weight of carbon black pigment were kneaded with a mixing roll to form a colored layer with a thickness of 110 μm and a basis weight of 80 g / m. 2 The surface of the colored layer was embossed with a leather pattern and further subjected to a corona treatment to make a book cloth.

[0035] Examples 2 to 7 A book cloth was produced in the same manner as in Example 1, except that the composition was changed as shown in Table 1.

[0036] Comparative Examples 1-2 A book cloth was produced in the same manner as in Example 1, except that the composition was changed as shown in Table 1.

[0037] Reference example 1 A book cloth was prepared in the same manner as in Example 1, except that the blending ratio by weight of the polypropylene resin and the hydrogenated styrene-based thermoplastic elastomer was changed to 50 / 50 to obtain the composition shown in Table 1.

[0038] [Table 1]

[0039] The components of each colored layer were obtained from the following products. (1) Biomass polyolefin resin: Ethylene-butene copolymer MFR=1.0g / 10min, density 0.916g / cm at 190℃ 3 Biomass content: 87% (2) Hydrogenated styrene-based thermoplastic elastomer: Hydrogenated styrene-butadiene copolymer MFR=5g / 10min, 230℃ Density 1.0g / cm 3 (3) α-Olefin copolymer: Propylene-α-olefin copolymer MFR=3.0g / 10min, 190℃ Melting point 75℃ Density 0.85-0.92g / cm 3 (4) Polypropylene resin (petroleum-derived): propylene-ethylene copolymer MFR=9.3g / 10min, density 0.9g / cm at 230℃ 3

[0040] The book cloths obtained in each of the Examples and Comparative Examples were examined for curl height, anti-whitening property upon folding, surface strength, Gurley stiffness, blocking resistance and heat sealability. The results are shown in Table 1. Each physical property was measured as follows.

[0041] (Curl height) A laminate sample measuring 20 cm lengthwise and 20 cm widthwise is prepared with the colored layer on top, and crosscuts are made at 45 degree angles from both the lengthwise and widthwise directions over a length of 15 cm with the intersection of the crosscuts being approximately in the center of the sample. The intersection of the crosscuts is at 7.5 cm, the center of the 15 cm length, and the crosscut angle is 90 degrees. The sample is left for 24 hours in an atmosphere of 23°C and 50% RH, and the length from the stand surface on which it was left to the maximum height of curl with the colored layer facing inward is measured, and this is the curl height, which is used as a measure of curl resistance. ○ Curl height is 15 mm or less × Curl height is greater than 15 mm

[0042] (No whitening due to bending) The base surface of the laminate is attached to a piece of cardboard 2 mm thick with adhesive, with the colored layer facing outward, and bent 90 degrees in accordance with a method conforming to JIS-A6909 by placing a rigid rod 10 mm in diameter against the cardboard surface, and visually evaluating the condition of cracks and whitening of the surface layer after bending. ○ No whitening or cracking is observed × Whitening or cracks are observed

[0043] (Surface strength (color fastness)) In a Gakushin type friction tester conforming to JIS-L0849, a dry white cotton cloth was used as the abrasion cloth and the laminate of the present invention was used as the test piece. The colored layer was rubbed back and forth 100 times with a load of 200 g, and the appearance of the abrasion cloth and the test piece surface was visually confirmed using a gray scale.

[0044] (Gurley stiffness) The Gurley stiffness was measured by the Gurley stiffness (bending resilience method A) in accordance with JIS-L1096.

[0045] (Blocking resistance) The colored layers of a 5 cm x 5 cm square laminate are brought into close contact with each other, sandwiched between glass plates of the same dimensions, and left at 60°C for 24 hours under a 3 kg load. After returning to room temperature, the state of blocking on the colored layer surface is visually evaluated. ○ The colored layers can be easily peeled off without blocking each other. × The colored layers are blocked together and do not peel off.

[0046] (Heat sealability) The colored layer surface of the laminate is placed on a polypropylene film (random copolymer, melting point 130 to 170°C, thickness 140μm) and heat sealed with a flat heat sealer at a heat seal pressure of 0.2MPa for 2 seconds. After heat sealing, the state of adhesion between the heat sealed surfaces is observed. ◎ Even if you try to peel the laminate and polypropylene film by hand, there is no peeling at the heat seal area, but if you try to peel them off forcefully, the base material will break. ○ If you peel the laminate and polypropylene film by hand and pull hard, they will break at the heat-sealed interface. × When the laminate and polypropylene film are peeled off by hand, the heat-sealed interface is easily destroyed.

[0047] (comprehensive evaluation) A comprehensive evaluation was carried out on the samples that gave excellent evaluation results in the evaluation of the present invention. ○... All evaluation results show excellent quality ×: Insufficient content in any of the evaluation items

[0048] As shown in Table 1, the blending ratio of biomass polyolefin resin to hydrogenated styrene-based thermoplastic elastomer has a significant effect on the important qualities of the bookcloth, and it was confirmed that a well-balanced, excellent quality bookcloth can be obtained when the biomass polyolefin resin is 1 to 50 parts by weight and the hydrogenated styrene-based thermoplastic elastomer is 30 to 70 parts by weight.

Claims

1. A book cloth comprising a laminate having a colored layer, which contains at least a biomass polyolefin resin, a hydrogenated styrene-based thermoplastic elastomer, and a colorant, laminated on a substrate, the book cloth being characterized in that the biomass polyolefin resin is mixed at 1 to 50 parts by weight and the hydrogenated styrene-based thermoplastic elastomer is mixed at 30 to 70 parts by weight.

2. 2. The book cloth of claim 1, wherein the colored layer comprises an α-olefin copolymer.

3. 3. The book cloth according to claim 2, wherein the colored layer is a mixture of 1 to 50 parts by weight of a biomass polyolefin resin, 30 to 70 parts by weight of a hydrogenated styrene thermoplastic elastomer, and 1 to 40 parts by weight of an α-olefin copolymer.

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