JP5142765B2 - Strong folding strength paper - Google Patents

Description

  The present invention relates to a paper that has an extremely large number of folding resistances, a high strength, and can be spread many times.

  Adds an internal additive consisting of polymer fine particles of an ethylenically unsaturated monomer or diene monomer with a cationic polyvinyl alcohol having a mercapto group as a dispersant on the paper to increase the folding resistance of the paper There is a technology (see, for example, Patent Document 1).

  Further, in order to produce an impregnated processed paper excellent in tensile strength when dried, tensile strength when wet, and folding strength, 0.1 to 10% by weight of N-methylol (meth) acrylamide (meta ) Polymerization composition for impregnation processing obtained by emulsion polymerization of a monomer mixture containing 0.1 to 30% by weight of acrylamide and 0.1 to 10% by weight of itaconic acid using a nonionic emulsifier and / or an anionic emulsifier There is a technology related to things (see, for example, Patent Document 2).

  Furthermore, it is a base material for a printer comprising a laminated film in which a polyester layer is laminated on one side or both sides of a white polyester composition layer, and the white polyester composition has a melting point of 206 to 249 ° C. and a copolymerized polyethylene terephthalate 30 to 78. % By weight, inorganic pigments 20-40% by weight and fatty acid hydrocarbon polymer incompatible with the copolymerized polyethylene terephthalate 2-30% by weight, the glossiness of the polyester layer surface is 80-110%, In addition, there is a disclosure of a technique in which the void ratio of the laminated film is 10 to 40% and the number of folding times is 2000 or more (see, for example, Patent Document 3). The base material for printers of Patent Document 3 is lightweight, highly concealed, highly glossy, and excellent in durability (particularly bending resistance).

JP-A-8-170296 JP-A-9-279085 JP 2001-341440 A

  However, the papers described in Patent Documents 1 to 3 or papers with new chemicals internally added or impregnated cannot satisfy the folding resistance of 20,000 times or more.

  Accordingly, an object of the present invention is to provide a strong folding-resistant strength paper that can satisfy the folding-resistant frequency of 20,000 times or more.

As a result of intensive studies to solve the above-mentioned problems, the present invention intends to solve the problems by the following invention. That is, strong folding endurance paper according to the present invention, 20 to 80% by weight of polyester fibers and 80 to 20% by weight of softwood bleached kraft pulp (hereinafter. Abbreviated as "N-BKP") containing a, 1 wherein the base paper layer paper making, Ri Na binder resin or rubber, or components both of which are impregnated 20 to 100 g / m ^2, wherein the polyester fiber is a mixture of main fibers and core-sheath binder fibers And In the present invention, the amount of the binder impregnated (g / m ² ) is represented by an absolute dry mass.

  In the strong folding strength paper according to the present invention, the binder is preferably styrene / butadiene rubber, acrylic resin, ethylene vinyl acetate, vinyl acetate, methyl methacrylate / butadiene rubber, acrylonitrile / butadiene rubber, or a mixture thereof. . The fibers in the base paper are firmly bonded to each other, and a sufficient strength with many folding resistances can be obtained.

In the strong folding strength paper according to the present invention, the basis weight is preferably 100 to 230 g / m ² . It is easy to fold while giving the strength of strong folding strength paper.

  In the strong folding strength paper according to the present invention, the vertical folding resistance specified in JIS P 8115: 1994 “Paper and paperboard—Folding strength test method—MIT test machine method” is 20,000 times or more. Is preferred. It is less likely to tear against extreme wrapping after printing.

The strong folding strength paper of the invention is obtained by impregnating a base paper composed of polyester fiber and N-BKP with a binder containing resin as a component at 20 to 100 g / m ^2, so that the folding resistance is 20,000 times or more. A strong folding strength paper having a remarkably high number of times can be produced. In addition, by using this as a base paper and coating liquids for various purposes, it is possible to produce various papers with high folding strength and high strength.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention should not be construed as being limited to these embodiments.

The strong folding strength paper according to the present embodiment comprises a single layer base paper containing 20 to 80% by mass of polyester fiber and 80 to 20% by mass of N-BKP, and a resin or rubber or both . Ri binder whose components Na is 20 to 100 g / m ² impregnated, the polyester fibers is a mixture of main fibers and core-sheath binder fibers. Thereby, for example, in a paper having a basis weight of 100 to 230 g / m ² , the folding endurance can be set to 20,000 times or more.

[Action]
A heat-fusable polyester fiber with paper-making properties, a main fiber (for example, polyethylene terephthalate fiber) made of polyester resin with a long fiber length, and high-strength N-BKP that is a pulp fiber are blended and heat-fused by drying. The base paper is made to make a paper and impregnated with a binder containing resin or rubber or both as a component so that the long fibers are strongly bonded to each other, so that the strength of folding can be increased to 20,000 times or more. it is conceivable that.

  The polyester fiber is classified into a main fiber made of a polyester resin having a long fiber length and a heat-fusible polyester fiber having a long fiber length and having a papermaking property, for example, a core-sheath binder fiber.

  The main fiber is polyethylene terephthalate (PET) fiber, the fiber diameter is preferably 3 to 30 μm, more preferably 5 to 20 μm, and the length is preferably 3 to 10 mm, more preferably 4 to 8 mm. When paper is made, the fibers are entangled and the number of folding times can be increased. For example, a product commercially available from Teijin Fibers Ltd. under the trade name TM04PN can be used, but the present embodiment is not limited to TM04PN.

  The core-sheath binder fiber is a heat-sealable polyester fiber, the fiber diameter is preferably 3 to 20 μm, more preferably 5 to 10 μm, and the length is preferably 3 to 10 mm, more preferably 4 to 8 mm. It is. When paper is made, the fibers are entangled, and the number of folding times can be increased. Moreover, 80-150 degreeC is preferable and, as for melting | fusing point of a core sheath binder fiber, 100-130 degreeC is more preferable, for example, it is 110 degreeC. For example, although what is marketed with the brand name of the ester 4080 from Unitika can be used, in this embodiment, it is not limited to this ester 4080.

  It is preferable that the polyester fiber is preferably 30 to 70% by mass of the main fiber made of polyester resin and 70 to 30% by mass of the core-sheath binder fiber as the blending ratio. By using this blending ratio, the strength can be obtained by the main fibers, and the fibers can be firmly bonded to each other by the core-sheath binder fibers.

  As the wood pulp used for the base paper in this embodiment, wood bleached chemical pulp typified by N-BKP (coniferous bleached kraft pulp) is mainly used. The Canadian standard freeness of N-BKP is preferably 400 to 700 ml, more preferably 500 to 600 ml. If necessary, mechanical pulp such as L-BKP (hardwood bleached kraft pulp), GP (crushed wood pulp), TMP (thermomechanical pulp), BCTMP (bleached chemithermomechanical pulp) and the like may be appropriately blended. it can.

  As a blend of raw materials, preferably 20 to 80% by mass of polyester fiber and 80 to 20% by mass of N-BKP are blended, more preferably 30 to 70% by mass of polyester fiber and 70 to 30% by mass of N-BKP. %. Here, a part of the polyester fiber may be a main fiber having a long fiber length, for example, a polyethylene terephthalate fiber having a long fiber length, and the remainder of the polyester fiber may be constituted by a core-sheath binder fiber.

  In addition to polyester fiber and N-BKP in the base paper, various yield improvers, paper strength improvers, internal sizing agents, pitch control, etc. that are generally used within the range that does not impair the object effects of the present invention. Chemicals such as agents and antifoaming agents can be used as appropriate.

  The production method of the base paper used in this embodiment is not particularly specified, and is a general paper machine such as an inclined wire paper machine, a long net paper machine, a circular net paper machine, a Yankee paper machine, and a long net and circular net combination machine. Although it can be manufactured by a machine, a method of making a paper by using an inclined wire paper machine is effective.

  A pulp slurry containing polyester fiber and N-BKP is made and dried, whereby the core-sheath binder fiber is thermally fused to the surrounding fibers. The drying temperature is, for example, 100 to 140 ° C. By this heat-sealing, the main fibers made of polyester resin having a long fiber length are strong, and a combined base paper is made. As a drying method, for example, a cylinder dryer or an air dryer at the time of papermaking is used.

In the strong folding strength paper according to the present embodiment, the base paper is impregnated with a binder containing resin or rubber or both . The binder is, for example, a simple substance such as styrene / butadiene rubber (SBR), acrylic resin, ethylene vinyl acetate, vinyl acetate, methyl methacrylate / butadiene (MBR), acrylonitrile / butadiene rubber (NBR), or any mixture thereof. It is good. The binder is used as the impregnation liquid, and the base paper is impregnated with the binder. The impregnation liquid is preferably a binder dispersion. For example, the binder is preferably an emulsion type. In the strong folding strength paper according to the present embodiment, a binder is impregnated from one side or both sides as an impregnating liquid.

The impregnation amount of the binder is 20 to 100 g / m ² , preferably 30 to 80 g / m ² . If the amount of impregnation of the binder is less than 20 g / m ² , sufficient folding resistance cannot be obtained. On the other hand, if the amount of impregnation of the binder exceeds 100 g / m ² , it may cause process contamination and cannot be impregnated uniformly. , Impregnation unevenness occurs.

  The strong folding strength paper according to the present embodiment can be coated with a coating liquid on one side and both sides according to the use, and a strong folding strength paper having specific characteristics can be produced. Examples of the coating liquid include coated paper paint and inkjet coated paper paint. In addition to the dispersant, a lubricant, an antiseptic, an antifoaming agent, a water-resistant agent, a dye, and the like may be added as appropriate to the coating liquid. it can. As a result, properties such as printability and inkjet suitability can be imparted.

  Next, the paper impregnated with the binder is dried before the following calendar treatment. Dry with an air dryer. The drying temperature is, for example, 100 to 140 ° C.

  In the production of the strong folding strength paper according to the present embodiment, it is preferable to perform a calendering treatment after impregnating the base paper with a binder. The calendar process is performed for the purpose of making the paper thickness uniform, improving the surface smoothness, and improving the glossiness. For calendar processing, machine calendars arranged on-machine, super calendars, friction calendars, gloss calendars, brush calendars, matte calendars, soft calendars, etc. can be used, and the types of calendars are not particularly limited Absent.

The strong folding strength paper according to the present embodiment preferably has a basis weight of 100 to 230 g / m ^2, and more preferably 150 to 200 g / m ² . If the basis weight is less than 100 g / m ² , the strength of the paper itself may be inferior. On the other hand, if the basis weight exceeds 230 g / m ² , bending cracks may occur.

  In the strong folding strength paper according to the present embodiment, the vertical folding resistance specified by JIS P 8115: 1994 “Paper and paperboard—Folding strength test method—MIT testing machine method” is 20,000 times. The above is preferable. If the vertical folding endurance number is 20,000 times or less, tearing is likely to occur with respect to extreme folding after printing.

  The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, unless otherwise indicated, the part or% in an example is a mass part or mass% in conversion of solid content.

Example 1
<Manufacture of base paper>
N-BKP is Canadian Standard Freeness (hereinafter abbreviated as “freeness”) 600 ml of pulp, 30% by mass, core-sheath binder fiber (Entica 4080, ester 4080), and further, as a main fiber, Fiber slurry containing 25% by mass of polyethylene terephthalate (PET) fiber (manufactured by Teijin Fibers Ltd., TM04PN), 0.5% sulfuric acid band to fiber, wet paper strength enhancer (manufactured by Seiko PMC, WS-547) 1.5% of fiber was added, 140 g / m ² of paper was made with a square hand-made paper machine, and dried at 110 ° C. with a hot air circulating dryer to make a base paper.

<Binder impregnation>
The dried base paper shown above was directly impregnated with SBR (A-7007, manufactured by Asahi Kasei Co., Ltd., 20% solids) as an impregnating liquid, and impregnated with 30 g / m ^{2 in} terms of absolute dry mass from both sides. After drying at 0 ° C., the surface was smoothed with a calendar to produce strong folding strength paper. This was designated Example 1.

  The basis weight, folding number of times, burst strength, and tensile strength in the examples were evaluated according to the following contents.

(Basis weight)
In accordance with JIS P 8124: 1998 “Paper and Paperboard—Method of Measuring Basis Weight”, the basis weight of strong folding-resistant strength paper was measured.

(Folding resistance)
According to JIS P 8115: 1994 “Paper and paperboard—Folding strength test method—MIT testing machine method”, the number of folding resistances of the strong folding strength paper was measured.

(Burst strength)
In accordance with JIS P 8131: 1995 “Paper and paperboard—Burn strength test method using Murren high-pressure tester”, the burst strength of the strong folding strength paper was measured.

(Tensile strength)
Tensile strength was measured in accordance with JIS P 8113: 2006 “Paper and paperboard—Test method for tensile properties—Part 2: Constant speed extension method”.

(Example 2)
A strong folding strength paper of Example 2 was obtained in the same manner as in Example 1 except that the impregnation liquid of Example 1 was an acrylic resin (manufactured by Gantz Kasei Co., Ltd., B400H).

(Example 3)
In the same manner as in Example 1 except that PET fiber is 35% by mass, N-BKP is 20% by mass, and core-sheath fiber is 45% as the raw material blend of Example 1, the strong folding strength paper of Example 3 is used. Obtained.

Example 4
A strong folding strength paper of Example 4 was obtained in the same manner as in Example 1 except that the impregnation amount of the impregnating solution of Example 1 was 80 g / m ² .

(Example 5)
The strong bending strength of Example 5 was the same as Example 1, except that the raw material blend of Example 1 was 20% by mass of PET fiber as the main fiber, 50% by mass of N-BKP, and 30% by mass of core-sheath fiber. I got paper.

(Example 6)
The strong bending strength of Example 6 was the same as in Example 1 except that PET fiber as the main fiber was 30% by mass, N-BKP 30% by mass, and core-sheath fiber 40% by mass. I got paper.

(Example 7)
A folding-resistant paper of Example 7 was obtained in the same manner as Example 1 except that the basis weight of the base paper was 80 g / m ² .

(Example 8)
A folding-resistant paper of Example 8 was obtained in the same manner as Example 1 except that the basis weight of the base paper was 160 g / m ² .

(Comparative Example 1)
Comparative Example as in Example 1 except that rayon fiber (2.2 dtex × 5 mm, manufactured by Accord Corp., Lyocell) was used instead of polyethylene terephthalate (PET) fiber, which is the main fiber, as the raw material composition of Example 1. 1 strong folding strength paper was obtained.

(Comparative Example 2)
A strong folding strength paper of Comparative Example 2 was obtained in the same manner as in Example 1 except that L-BKP (freeness; 600 ml) was used instead of N-BKP as the raw material formulation of Example 1.

(Comparative Example 3)
A strong folding strength paper of Comparative Example 3 was obtained in the same manner as in Example 1 except that the impregnation amount of the impregnation liquid in Example 1 was 130 g / m ² .

(Comparative Example 4)
A strong folding strength paper of Comparative Example 4 was obtained in the same manner as in Example 1 except that the impregnation amount of the impregnation liquid in Example 1 was 15 g / m ² .

  The evaluation results of Examples and Comparative Examples are shown in Table 1.

  Referring to Examples 1 to 8, the folding endurance number exceeded 20,000 times, and the burst strength value and the tensile strength value were larger than those of the comparative example. Therefore, it was confirmed that it is suitable as a paper that can be spread many times.

On the other hand, since the comparative example 1 used the rayon fiber as the main fiber, all of folding resistance, burst strength, and tensile strength were insufficient. Since the comparative example 2 mix | blended L-BKP instead of N-BKP, all of folding-resistant frequency, burst strength, and tensile strength were insufficient. In Comparative Example 3, since the impregnation amount of the binder was as large as 130 g / m ² , the impregnation unevenness was caused, and all of folding resistance, burst strength and tensile strength were insufficient. In Comparative Example 4, since the impregnation amount of the binder was as small as 15 g / m ² , all of folding resistance, burst strength, and tensile strength were insufficient.

Claims (4)

A binder containing 20 to 100 g / m ^{2 of} resin or rubber or both on a single-layer base paper containing 20 to 80% by mass of polyester fiber and 80 to 20% by mass of softwood bleached kraft pulp. Ri Na is impregnated, wherein the polyester fibers are strong folding endurance paper which is a mixture of main fibers and core-sheath binder fibers. The strong folding resistance according to claim 1 , wherein the binder is styrene-butadiene rubber, acrylic resin, ethylene vinyl acetate, vinyl acetate, methyl methacrylate-butadiene rubber, acrylonitrile-butadiene rubber, or a mixture thereof. Strength paper. Strong folding endurance paper according to claim 1 or 2, wherein the basis weight of 100~230g / ^{m 2.} JIS P 8115: 1994 "Paper and board - folding endurance test method -MIT Tester Method" according to claim 1, 2 or 3 folding number of vertical defined in is equal to or not less than 20,000 Strong folding strength paper as described in 1.