Bookcloth

Abstract

The present invention provides a bookcloth made from safe and environmentally friendly materials, while simultaneously maintaining excellent quality in terms of surface strength, cold resistance, non-stick properties, rigidity, suitability for foil stamping, printability, and lightfastness. [Solution] The present invention relates to a bookcloth which is a laminate having a colored layer on a base material that contains at least a vinyl chloride resin, a biomass plasticizer, a stabilizer, and a coloring agent.

Description

Technical Field

[0001] The present invention relates to bookcloth used for covering bindings such as books, files, binders, diaries, notebooks, albums, menu cards, etc., stationery cases, and jewelry cases for cosmetics, precious metals, etc.

Background Art

[0002] Conventionally, as bookcloth used for covering bindings such as books, files, binders, diaries, notebooks, albums, menu cards, etc., stationery cases, and jewelry cases for cosmetics, precious metals, etc., what is called vinyl paper, which is obtained by laminating a polyvinyl chloride (PVC) resin and paper, has been widely used.

[0003] The quality of vinyl paper required for bookbinding, case lamination, etc. includes surface strength, cold resistance, non-stickiness, stiffness and flexibility, suitability for foil stamping, printability, light resistance, etc.

[0004] To the polyvinyl chloride resin, a plasticizer is added to impart flexibility and facilitate molding. Representative plasticizers include phthalic acid diester-based plasticizers. Among them, bis(2-ethylhexyl) phthalate (DOP) is widely used because it has an excellent balance of various physical properties such as plasticization efficiency and cold resistance.

[0005] However, recently, particularly in fields such as toys, food wraps, medical instruments, and agricultural films, substitution with non-phthalate ester-based plasticizers has been progressing with a view to ensuring safety. As a technique for substitution with non-phthalate ester-based plasticizers, for example, Patent Document 1 discloses a technique for a Japanese paper-like composite sheet capable of stably exhibiting anti-inflammatory properties for a long period in a mode including a soft vinyl chloride resin containing dialkyl cyclohexanedicarboxylate as a constituent element.

[0006] Furthermore, in recent years, efforts have been made to build a carbon-neutral circular society that reduces environmental burden by increasing the utilization of plants and plant-derived biomass resources. As a technology for converting plasticizers to biomass plasticizers, for example, Patent Document 2 discloses a technology for a flexible vinyl chloride resin film that includes at least a biomass plasticizer containing a plasticizer molecule having C-14 in part of its molecular structure, and / or a biomass vinyl chloride resin containing vinyl chloride units having C-14 in part of its molecular structure. [Prior art documents]

[0007] [Patent Document 1] Patent No. 6368903 [Patent Document 2] Japanese Patent Publication No. 2023-56760 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] In conventional bookcloths, materials containing phthalate esters are commonly used.

[0009] However, in recent years, with a growing awareness of the need to ensure safety, attempts are being made to replace phthalate ester-containing materials with non-phthalate materials that are not designated as restricted substances under legal regulations.

[0010] Furthermore, in response to the rapidly growing environmental awareness in recent years, attempts are being made to replace petroleum-derived materials with plant-derived materials. Among these, plant-derived plasticizers are attracting attention as environmentally friendly materials, particularly as biomass plasticizers, and their applications are expanding.

[0011] Therefore, the main object of the present invention is to provide a bookcloth made of safe and environmentally friendly materials, which at the same time maintains excellent quality in terms of surface strength, cold resistance, non-stick properties, rigidity, suitability for foil stamping, suitability for printing, and lightfastness. [Means for solving the problem]

[0012] In light of the problems of the prior art, the inventors conducted extensive research and, as a result, discovered that the above objective can be achieved by using a bookcloth made of a specific material, thus completing the present invention.

[0013] In other words, the present invention relates to the following bookcloth. 1. A bookcloth that is a laminate having a colored layer on a base material containing at least a vinyl chloride resin, a biomass plasticizer, a stabilizer, and a coloring agent. 2. The bookcloth according to item 1, wherein the colored layer contains a vinyl chloride resin and, per 100 parts by weight of the vinyl chloride resin, 40 to 80 parts by weight of a biomass plasticizer and 1 to 10 parts by weight of a stabilizer. 3. The bookcloth according to item 2, wherein the biomass plasticizer is a non-phthalate biomass plasticizer. 4. The bookcloth according to item 3, wherein the biomass plasticizer is a glycerol acetate fatty acid ester. 5. The bookcloth according to item 3 or 4, wherein the stabilizer is a non-phthalate stabilizer. 6. The bookcloth according to item 5, wherein the coloring agent is a non-phthalate coloring agent. [Effects of the Invention]

[0014] The bookcloth according to the present invention makes it possible to provide a bookcloth that uses safe and environmentally friendly materials while simultaneously maintaining excellent quality in terms of surface strength, cold resistance, non-stick properties, rigidity, flexibility, foil stamping suitability, printability, and lightfastness. In particular, when using biomass plasticizers, it is possible to suppress the increase in carbon dioxide emissions compared to conventional bookcloths that used DOP, which was an essential plasticizer for maintaining a balance of various physical properties such as excellent plasticization efficiency and cold resistance, and is expected to contribute to the realization of a low-environmental-impact and low-carbon society. Moreover, the bookcloth of the present invention can exhibit high non-stick properties even with the same or greater amount of plasticizer added compared to conventional bookcloths. Furthermore, it exhibits less yellowing due to aging compared to conventional bookcloths and can exhibit the same or greater lightfastness. [Modes for carrying out the invention]

[0015] The bookcloth of the present invention is a laminate comprising a base material on which a colored layer containing at least a vinyl chloride resin, a biomass plasticizer, a stabilizer, and a coloring agent is provided.

[0016] Examples of vinyl chloride resins include homopolymers of vinyl chloride monomer, copolymers or graft polymers of vinyl chloride monomer with other monomers that can copolymerize with vinyl chloride monomer, copolymers of vinyl chloride monomer with higher vinyl ethers, or mixtures thereof. Examples of copolymerization components include α-olefins having 2 to 30 carbon atoms, acrylic acid and its esters, methacrylic acid and its esters, maleic acid and its esters, vinyl acetate, vinyl propionate, alkyl vinyl ethers, and other vinyl compounds.

[0017] The degree of polymerization of the above-mentioned vinyl chloride resin is preferably 800 to 2500, and more preferably 800 to 1200. If the degree of polymerization is lower than 800, the resin is too soft and difficult to process, and if the degree of polymerization is higher than 2500, the resin is too hard and impairs processability.

[0018] Biomass plasticizers are so-called carbon-neutral materials that are environmentally friendly because the raw materials are derived from carbon dioxide absorbed by plants, and the products naturally return to carbon dioxide upon combustion and are absorbed by plants again, thus substantially neither increasing nor decreasing the carbon dioxide concentration in the atmosphere. Also, since plant-derived raw materials are used in the production of biomass plasticizers themselves, the carbon dioxide emissions during plasticizer production can be reduced, and a book cloth with a higher environmental compatibility than petroleum-derived plasticizers can be realized.

[0019] As the biomass plasticizer, glycerin acetate fatty acid ester, which is non-phthalic acid-based, is most preferable in order to ensure complete safety, but non-phthalic acid-based biomass plasticizers such as polyester-based ones may also be used.

[0020] The stabilizer is essential for maintaining the thermal stability during production and improving the processability in calendar processing. If no stabilizer is used, it will be inconvenient for the calendar molding suitability.

[0021] As the stabilizer, calcium zinc composite systems, barium zinc composite systems, organotin laurate, organotin mercaptide, epoxy systems, etc. can be appropriately used, but it is preferably a non-phthalic acid-based stabilizer in order to ensure complete safety.

[0022] The colorant is important for maintaining the appearance quality of the colored layer and can be appropriately blended and used.

[0023] As the colorant, various organic pigments such as (poly)azo-based, phthalocyanine-based, perylene-based, dye lake-based, quinacridone-based, dioxazine-based, etc., oxide-based such as titanium oxide, sulfide / selenide-based, ferrocyanide-based, various inorganic pigments such as calcium carbonate, carbon black, etc., and general organic and inorganic pigments can be appropriately used, but it is preferably a non-phthalic acid-based colorant in order to ensure complete safety.

[0024] The mixing ratio of vinyl chloride resin, biomass plasticizer, and stabilizer can be appropriately selected to maintain non-stick properties, but it is desirable that the amount of biomass plasticizer be 40 to 80 parts by weight and the amount of stabilizer be 1 to 10 parts by weight per 100 parts by weight of vinyl chloride resin. If the mixing ratio of biomass plasticizer is less than 40 parts by weight, the resin becomes hard, causing problems with processability, and if the mixing ratio of biomass plasticizer is more than 80 parts by weight, problems with non-stick properties will occur.

[0025] The colored layer may be appropriately formulated with fillers such as silica, talc, calcium carbonate, titanium dioxide, clay, mica, barium sulfate, magnesium hydroxide, glass fiber, carbon fiber, and antimony trioxide, as well as antioxidants such as phenolic, phosphorus-based, amine-based, and sulfur-based agents, 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, lubricants such as phosphorus-based agents, and additives such as ultraviolet absorbers and light stabilizers, within limits that do not impair its physical properties.

[0026] The surface of the colored layer can be embossed with various patterns, and this process results in an appearance with superior design appeal.

[0027] As the substrate for laminating the colored layer, various materials such as cloth, nonwoven fabric, and paper can be selected and used as appropriate, but paper is preferred in terms of cost and processability. The paper used can be either pulp fiber alone or a blend of pulp fiber and various fibers such as vinylon fiber, nylon fiber, polyester fiber, rayon fiber, and cotton fiber. There are no specific requirements for the thickness of the substrate, but a basis weight of 300 g / m² is preferred. 2 The following is preferable:

[0028] Bookcloths can be broadly categorized into two types: trimmed covers and perfect-cover covers. Trimmed covers are attached to the backing board with dimensions equal to the backing board, and then trimmed together as needed to bind the book. Perfect-cover covers, on the other hand, are slightly larger than the backing board and are attached to cover the surface of the backing board, wrapping around the edges and part of the back. The thickness of the base material on which the colored layer is laminated can be appropriately selected and used within a range that does not impair the physical properties of the trimmed cover or perfect-cover cover.

[0029] As a method for creating a colored layer and laminating it with the substrate, known processing methods such as T-die extrusion, calendering, and inflation can be used, but calendering is preferred due to its productivity and suitability for small-lot production.

[0030] Lamination of the colored layer and the substrate is performed by calendering, but an adhesive layer may be provided between the colored layer and the substrate to maintain long-term adhesion between the colored layer and the substrate and to strengthen the adhesive force between them. In that case, urethane resin, acrylic resin, polyolefin resin, vinyl acetate resin, vinyl chloride-vinyl acetate resin, etc., can be used for the adhesive layer.

[0031] The ideal thickness for the colored layer is 50-500 μm. If it is smaller than 50 μm, problems arise with surface strength, cold resistance, and embossing suitability. If it is larger than 500 μm, it becomes too hard, making secondary processing such as bookbinding and case lamination difficult, and also increasing costs.

[0032] Bookcloths are used over long periods, and the surface of the cover and the wrapped corners are expected to be repeatedly subjected to friction with bookshelves and other covers. The surface strength of the colored layer should preferably be such that, according to the Japan Society for the Promotion of Science (JSPS) friction tester, the colorfastness is grade 3 or higher, meaning that no partial color fading is observed on the surface of the dry cloth or the colored layer even when rubbed against it.

[0033] The rigidity of the laminate used for bookcloth for perfect binding is preferably in the range of 0.5 to 10.0 mN, and more preferably 0.5 to 2.0 mN, as measured by a Gahl flexibility tester. If the rigidity is less than 0.5 mN, the material is too weak, causing problems with running in the bookbinding machine. If the rigidity is greater than 10.0 mN, the laminate has too much rebound, making perfect binding impossible in the bookbinding machine, which is a fatal problem for bookcloth for perfect binding.

[0034] For use as a bookcloth, it is crucial that the colored layer surface of the laminate maintains sufficient non-stick properties. If the non-stick properties are weak, problems such as the cover surface blocking out from other covers and becoming difficult to separate may occur after prolonged use.

[0035] Bookcloth is used over a long period of time, and the surface of the cover is expected to be exposed to light. The lightfastness of the colored layer should preferably be grade 3 or higher, as measured by a fade meter, meaning no partial fading is observed on the surface of the colored layer. [Examples]

[0036] Examples and comparative examples are shown below to give a more detailed explanation of the features of the present invention. However, the scope of the present invention is not limited to the examples.

[0037] Example 1 As shown in Table 1, vinyl chloride resin, biomass plasticizer, and stabilizer were blended in a weight ratio of 100 / 45 / 2.9. Furthermore, 25 parts by weight of filler and 2 parts by weight of non-phthalate carbon black pigment were mixed using a mixing roll to form a colored layer with a thickness of 110 μm and a basis weight of 65 g / m². 2 It was laminated onto glossy kraft paper. The surface of the colored layer was embossed with a leather pattern to create a bookcloth.

[0038] Examples 2-5 Bookcloth was prepared in the same manner as in Example 1, except that the composition was changed as shown in Table 1.

[0039] Comparative Examples 1-2 Bookcloth was prepared in the same manner as in Example 1, except that the composition was changed as shown in Table 1.

[0040] Reference example 1 A bookcloth was prepared in the same manner as in Example 1, except that the composition shown in Table 1 was achieved by blending vinyl chloride resin, plasticizer, and stabilizer in a weight ratio of 100 / 50 / 2.9, and by changing the weight ratio to 1.2 parts by weight of phthalate ester-containing carbon black pigment.

[0041] [Table 1]

[0042] Furthermore, the components of each colored layer were obtained from the following raw materials. (1) Vinyl chloride resin: Polyvinyl chloride, degree of polymerization 1000 (2) Plasticizer 1 (Biomass Plasticizer): Glycerin acetate fatty acid ester Density 946 kg / m³ 3 Biomass content 70% (3) Plasticizer 2 (Petroleum-derived): Bis(2-ethylhexyl) phthalate (DOP) (4) Stabilizer 1: Zinc barium organic complex, non-phthalate powder stabilizer (5) Stabilizer 2: A mixture of barium fatty acid salt, zinc higher fatty acid salt, and mineral oil. Non-phthalate liquid stabilizer. Density 1.04 g / cm³ 3 (6) Stabilizer 3: Zinc stearate mixture, phthalate ester-containing powder stabilizer (7) Stabilizer 4: Mixture of barium aromatic acid salt and zinc fatty acid salt. Non-phthalate liquid stabilizer. Density 1.10 g / cm³ 3

[0043] For each example and comparative example, the bookcloth obtained was measured for surface strength, cold resistance, Gure stiffness, non-stick properties, foil stamping suitability, printability, and lightfastness. The processability of the colored layer was also evaluated. The results are shown in Table 1. Each physical property was measured as follows.

[0044] (cold resistance) A 10cm x 2cm laminate is placed in a freezer at -35°C for 1 hour. With the colored layer facing outwards, it is folded 180 degrees along its length in the freezer using a manual folding method, and the state of cracking in the surface layer after folding is visually evaluated. ○...No cracks were observed at all, and there was no change in texture. △···No cracks were observed, but there was a change in texture. ×...Cracks were observed, and the texture had changed.

[0045] (Surface strength (color fastness)) In a friction testing machine of the Japan Society for the Promotion of Science (JSPS) type, a dry white cotton cloth was used as the abrasion cloth, and the laminate of the present invention was used as the test specimen. The colored layer was rubbed back and forth 100 times with a load of 200g, and the appearance of the abrasion cloth and the surface of the test specimen was visually confirmed using a grayscale.

[0046] (Gale stiffness / softness) The Gahl stiffness was measured using the Gahl method (bending rebound method A) with a Gahl-type flexibility measuring machine.

[0047] (non-adhesive) The colored layers of a 10cm x 12cm rectangular laminate are placed in close contact with each other, sandwiched between 10cm x 10cm rectangular glass plates, and left at 70°C for 24 hours under a 4kg load. After returning to room temperature, the blocking state of the colored layer surface is visually determined. ◎...It peels off easily without blocking and leaves no transfer of shine. ○...There was some blocking, but it peeled off easily, and there was almost no transfer of shine. △...There was some blocking, but it peeled off with a slight pull, and there was some gloss transfer in some areas. ×...There was blocking, but it peeled off when pulled hard, and there was a lot of gloss transfer.

[0048] (Suitability for foil stamping) The adhesion between gold foil and vinyl chloride was evaluated. The colored layer surface of the laminate was hot-stamped at a temperature of 180°C for 1 second. After 24 hours, a cellophane test was performed to observe the state of foil peeling. ○...The foil won't peel off. △···Some foil peeling off ×...The foil is peeling off.

[0049] (Printability) The adhesion to silk screen printing ink for vinyl chloride was evaluated. After silk screen printing was performed on the colored layer surface of the laminate using a screen printing plate, a cellophane test was conducted and the state of ink peeling was observed. ○...The ink won't peel off. △···Some ink peels off ×...Ink peels off

[0050] (Lightfastness) In a fade meter, the colored layer surface was irradiated at 63°C for 200 hours, and the surface appearance was determined using color difference.

[0051] (processability) The calculability of the colored layers prepared in each example and comparative example was measured at a calender temperature of 175-180°C. ○...It can be processed and has excellent productivity. △···Processing is possible, but productivity is lower than that of a rated ○. ×...Cannot be processed

[0052] (comprehensive evaluation) A comprehensive evaluation was conducted on those that obtained excellent evaluation results in the evaluation of the present invention. ○...Those that maintain excellent quality in all evaluation results. △···Some evaluation items have insufficient content. ×...Items with insufficient content in any of the evaluation items.

[0053] As shown in Table 1, the mixing ratio of vinyl chloride resin and biomass plasticizer significantly affects the important quality of the bookcloth. It was confirmed that a well-balanced and excellent quality of bookcloth can be obtained when the biomass plasticizer is 40 parts by weight or more and 80 parts by weight or less per 100 parts by weight of vinyl chloride resin.

Claims

1. A bookcloth that is a laminate having a colored layer on a base material containing at least a vinyl chloride resin, a biomass plasticizer, a stabilizer, and a coloring agent.

2. The bookcloth according to claim 1, wherein the colored layer contains a vinyl chloride resin and, with respect to 100 parts by weight of the vinyl chloride resin, a biomass plasticizer in an amount of 40 parts by weight to 80 parts by weight and a stabilizer in an amount of 1 part by weight to 10 parts by weight.

3. The bookcloth according to claim 2, wherein the biomass plasticizer is a non-phthalate biomass plasticizer.

4. The bookcloth according to claim 3, wherein the biomass plasticizer is a glycerol acetate fatty acid ester.

5. The bookcloth according to claim 3 or 4, wherein the stabilizer is a non-phthalate stabilizer.

6. The bookcloth according to claim 5, wherein the coloring agent is a non-phthalate coloring agent.

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