JP5454450B2 - Paper yarn base paper - Google Patents

Description

The present invention relates to a paper thread base paper having high strength and excellent slit processing performance.

Paper cloths, which are made by cutting paper into long and narrow strips and twisting them into paper yarns and weaving the paper yarns, have long been widely used as paper clothing. The paper garments made in this way are light and breathable. However, with the decline of the textile industry after the war, the demand for paper yarn, which is a substitute for textiles such as cotton and silk, has declined, and in recent years it has been limited to small-scale production.

In general, paper yarn base paper is obtained by obtaining non-wood or wood from chemical pulp by methods such as soda cooking, sulfuric acid cooking, kraft cooking, etc., followed by bleaching and beating, and removing foreign substances in the selection process. A chemical is added and paper is made using a paper machine such as a round net, a short net, a long net, or an inclined wire.

As raw materials for general paper yarn base paper, for example, three bases, Manila hemp, sisal hemp, flax, cannabis, jute and conifer are used. These are raw materials with a relatively long fiber length. However, when pulp is made as a raw material, twisting due to entanglement or entanglement of fibers tends to occur, and operation troubles such as paper breakage occur due to defects caused by twisting. Cheap. In order to reduce the twist, it is possible to use a raw material having a relatively short fiber length such as hardwood, but since the fiber itself is short, it is difficult to obtain a high strength paper yarn base paper.

The base paper for paper yarn is cut into a slit shape for processing into paper yarn. As a method of cutting into a slit shape, a method of cutting a paper thread base paper into a uniform length in the width direction by passing the paper thread base paper through a slitter composed of rotating blades arranged at regular intervals. Is mentioned. As such an apparatus, for example, the apparatus disclosed in Patent Document 1 can be used.

A paper yarn can be obtained by twisting the slit-like paper yarn base paper obtained in this way using a paper yarn manufacturing machine as shown in Patent Document 2. As described above, the production of paper yarn is very laborious. In particular, in the process of slitting paper and the process of twisting slit paper, troubles of breaking are likely to occur due to insufficient strength and elongation of the paper.

As a method for enhancing the paper strength, a method of enhancing the paper strength by making a fine fiberized pulp in which all or most of the pulp fibers are fine fibers and adding it to the pulp slurry before papermaking (Patent Document 3, Patent Document) 4) is disclosed.

JP 2003-221149 A JP 2005-42280 A JP 58-197400 A JP 2007-231438 A

An object of the present invention is to provide a base paper for paper yarn that is reproducible, has high tensile strength and wet strength, and is excellent in slit processing performance.

The present invention has the following configuration.
(1) Paper yarn base paper containing fine fibrous cellulose having a fiber width of 20 nm to 1000 nm in an amount of 1% by mass to 100% by mass and subjected to water resistance treatment with a wet paper strength agent (2) Longitudinal direction The base paper for paper yarn according to (1), wherein the strength ratio in the transverse direction is 3 or more, and the geometric average of the strength in the longitudinal and transverse directions is 80 MPa or more.

The inventors prepared various base papers and finished them into paper threads. We examined the tensile strength and wet strength of paper yarn and the suitability of slit processing when finishing paper yarn. The base paper for paper yarn contains 1% by mass to 100% by mass of fine fibrous cellulose having a fiber width of 20 nm or more and 1000 nm or less, and has a high tensile strength and wet strength by being subjected to water resistance treatment with a wet paper strength agent. It was found that the slitting process for finishing the paper thread and the process of twisting the slit paper are less likely to cause paper breakage and have good production efficiency.

Hereinafter, the present invention will be described in detail.
The paper yarn base paper of the present invention contains 1% by mass to 100% by mass of fine fibrous cellulose having a fiber width of 20 nm to 1000 nm, and has been subjected to water resistance treatment with a wet paper strength agent. As a pulp component, general papermaking pulp can be blended except that it contains 100% by mass of fine fibrous cellulose.

(Fine fibrous cellulose)
The fine fibrous cellulose of the present invention can be obtained by refining plant fibers by a publicly known method. Although it does not specifically limit as a kind of plant fiber, Non-wood fibers, such as wood fiber, such as conifer and hardwood, and cotton, a hemp, flax, firewood, bamboo, pagas, and kenaf, are mentioned. For example, wood fibers include chemical pulp fibers obtained by digesting coniferous and broadleaf trees using the kraft method, sulfuric acid method, soda method, polysulfide method, etc., mechanical pulp fibers pulped by mechanical force such as refiners and grinders, and after pretreatment with chemicals Examples thereof include semi-chemical pulp fibers pulped by mechanical force or waste paper pulp fibers, which can be used in an unbleached (before bleaching) or bleached (after bleaching) state, respectively. As the non-wood fiber, a fiber pulped by the same method as wood pulp can be used.

As a method for producing fine fibrous cellulose from plant fibers, for example, plant fiber-containing materials such as grinders (stone mill type grinders), high-pressure homogenizers, ultrahigh-pressure homogenizers, high-pressure collision type grinders, disk type refiners, conical refiners, etc. Examples thereof include a method of thinning the cellulosic fibers by wet pulverization using a mechanical action. In addition, there is a method of miniaturization after chemical treatment such as TEMPO oxidation, ozone treatment, enzyme treatment and the like. Of course, after pulverizing wood, it is also possible to obtain it by performing a treatment such as delignification. Generally, a fine plant fiber suspension of about 0.01 to 20% by mass is obtained by the above method.

The fine fibrous cellulose used in the present invention has a fiber width of 20 nm to 1000 nm. It is preferable to contain fine fibrous cellulose having a fiber width of 20 nm to 500 nm, and most preferable to contain fine fibrous cellulose having a fiber width of 20 nm to 200 nm. When the fiber width exceeds 1000 nm, sufficient fibrillation has not been performed, which is insufficient to reinforce hydrogen bonding between fibers. In order to obtain a fine fibrous cellulose having a fiber width of less than 20 nm, the energy consumption during the refining is large, and the fine fibrous cellulose tends to fall off from the wire during paper making, which may reduce the yield during paper making. The fiber width of the present invention is observed and measured with a scanning or transmission electron microscope. In the present invention, the magnification of the microscope is changed between 2000 and 100000 times, the number of measurements is increased, and the fiber width is specified.

The fine fibrous cellulosic fiber can further strengthen the interfiber bond in the pulp having a normal size. The added amount is effectively 1% by mass or more. The range of 3 mass% or more and 75 mass% or less is more preferable, and the range of 5 mass% or more and 50 mass% or less is most preferable. When the addition amount is less than 1% by mass, it is insufficient to reinforce the bond between fibers. If the amount added is too large, fine fibrous cellulose tends to fall off from the wire during paper making, and the yield during paper making may decrease.

(General paper pulp)
As a pulp component, when it is other than 100% by mass of fine fibrous cellulose, general papermaking pulp can be blended. The type of pulp for general papermaking is not particularly limited, but for example, pulping is carried out by mechanical force such as chemical pulp, refiner, grinder, etc., which is obtained by digesting conifers and hardwoods using the craft method, sulfite method, soda method, polysulfide method, etc. Examples include mechanical pulp, wood-derived pulp such as semi-chemical pulp that has been pulped by mechanical force after chemical pretreatment, or waste paper pulp, which are unbleached (before bleaching) or bleached (after bleaching), respectively. Can be used in Examples of non-wood pulp include fibers obtained by pulping cotton, manila hemp, flax, straw, bamboo, pagas, kenaf and the like by the same method as wood pulp. Paper sheets containing wood-derived pulp and waste paper pulp are generally weak in strength and difficult to increase in strength. The addition of fine fibrous cellulose is particularly effective for increasing the strength of paper sheets containing wood pulp and waste paper pulp.

Tree species used as pulp are red pine, black pine, todo pine, spruce pine, beech pine, larch, fir, tsuga, cedar, hinoki, larch, shirabe, spruce, hiba, douglas fir, hemlock, white fur, spruce, balsam fur, cedar. Conifers such as pine, merck pine and radiata pine, broadleaf trees such as beech, hippopotamus, alder, oak, tub, shii, birch, boxwood, poplar, tamo, dry willow, eucalyptus, mangrove and lawan. It is also possible to pulp and use hemp, sanban, bamboo, and straw.

(Water resistance treatment)
Paper yarn generally requires wet strength. As a result of intensive studies by the inventors, a paper thread base paper containing fine fibrous cellulose having a fiber width of 20 nm to 1000 nm was subjected to a water resistance treatment by adding a wet paper strength agent for paper making. It was found that the wet strength of the paper yarn obtained from the paper yarn base paper was remarkably improved. Water resistance treatment by adding a wet paper strength agent is, for example, (a) a processing method in which a wet paper strength agent is added to a fine fibrous cellulose-containing suspension to make paper, and (b) a fine fibrous cellulose-containing suspension. Paper processing without adding wet paper strength agent, and impregnating or coating the obtained base paper with wet paper strength agent-containing solution, (c) Suspension containing fine fibrous cellulose in wet fiber strength agent And the like, and the resulting base paper is further impregnated with a wet paper strength agent-containing solution or coated. The coating method in the case of coating is not particularly limited, and examples thereof include a gate roll, a size press, a bar coater, a gravure coater, a blade coater, a roll coater, an air knife coater, a die coater, and a curtain coater. In addition, when impregnating and coating, it may be carried out on already slit paper.

The wet paper strength agent used in the present invention is not particularly limited, and examples thereof include urea formaldehyde resin, melamine formaldehyde resin, polyamide polyamine epichlorohydrin resin, vegetable gum, latex, and polyethyleneimine. Polyamide polyamine epichlorohydrin resin is easily adsorbed to fibers in water, and is particularly preferable because of its water resistance effect and ease of use. In combination with the wet paper strength agent, paper strength enhancers such as glyoxal, gum, mannogalactan polyethyleneimine, polyacrylamide resin, polyvinyl alcohol, starch, carboxymethyl cellulose, guar gum, urea resin, etc. may be used.

The addition amount of the wet paper strength agent is not particularly limited, but it is preferably 0.1 to 10 parts with respect to 100 parts of the total pulp amount including fine fibrous cellulose in the paper yarn base paper. . More preferably, it contains 0.5 to 5 parts. If it is less than 0.1 part, the water resistance is insufficient, and if it exceeds 10 parts, the resulting paper becomes hard, and troubles such as paper breakage are likely to occur when it is processed into a paper thread.

When making a raw pulp, which is a fine fibrous cellulose-containing suspension, a filler, a pH adjuster, an antifoaming agent, a thickener, etc. may be added externally or internally as required. Is possible.

(Manufacture of base paper)
The raw pulp, which is a suspension containing fine fibrous cellulose, can be used for continuous paper machines such as the long-mesh type, circular net type, and inclined type used in ordinary paper making, as well as the multi-layered paper making machine that combines these, It can be made into a sheet by a known paper making method such as hand making. It is possible to obtain a base paper for paper yarn by dehydrating on a wire to obtain a wet paper sheet and then pressing and drying. The basis weight of the paper yarn base paper is not particularly limited, but 10 to 30 g / m ² is preferable.

In the pressing step, it is possible to obtain a denser sheet by sufficiently pressing the wet paper sheet, and as a result, it is possible to obtain a high-strength paper thread base paper. After pressing, it is dried by general drying equipment such as Yankee dryer, cylinder dryer, through dryer and oven. Thereafter, the density can be improved by using a machine calendar or a super calendar to further increase the strength. The sheet density is preferably in the range of 1.05 to 1.40 g / cm ³ . The base paper for paper yarn obtained in this way has few paper breaks in the slit processing step and the step of twisting into a paper yarn, and has good processability.

(Tensile strength)
High strength and slitting by adjusting the aspect ratio of the tensile strength (measured according to JIS-P8113) of the paper yarn base paper to 3.0 or more and the geometric average of the strength in the longitudinal direction and the strength in the transverse direction to 80 MPa or more. It is possible to obtain a paper thread base paper excellent in processing performance. When the aspect ratio of the tensile strength is less than 3.0, or the geometric average of the tensile strength in the longitudinal direction and the tensile strength in the transverse direction is less than 80 MPa, the strength as a paper thread base paper is insufficient, and the slit processing step It is easy for paper breakage to occur. In order to efficiently produce using the general paper manufacturing method, the aspect ratio of the tensile strength is preferably 3.0 to 6.0, and particularly preferably 3.0 to 4.0. In order to increase the geometric mean value of the strength in the vertical direction and the strength in the horizontal direction, it is necessary to add fine fibrous cellulose and paper strength agent. From the viewpoint of production efficiency and cost, the strength in the vertical direction and the strength in the horizontal direction are The geometric average is preferably from 80 to 300 MPa, particularly preferably from 80 to 200 MPa.

The method for producing paper yarn using the paper yarn base paper obtained by the present invention is not particularly limited. For example, it is possible to obtain a paper thread by the method of Patent Document 1. The paper yarn obtained from the base paper of the present invention can be dyed by the same method as a normal yarn. In addition, it exhibits excellent dry strength and wet strength, particularly in the longitudinal direction. In addition, the fabric woven from this paper thread can be used as a cloth, such as wallpaper, canvas for oil paintings, tatami mats, samurai, sports clothes for karate, yukata obi, shirts, work clothes, handkerchiefs, towels, curtains, etc. It can be used for applications where general fabrics are used.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples. Moreover, unless otherwise indicated, the part and% in an example show a mass part and mass%, respectively.

(Preparation of fine fibrous cellulose)
Softwood bleached kraft pulp (manufactured by Oji Paper Co., Ltd., moisture 50%, Canadian standard freeness (CSF) measured according to JIS P8121 is 550 ml) is added with water to a concentration of 1% and disaggregated with a disintegrator. A pulp suspension was obtained. The pulp suspension was defibrated using a mass collider manufactured by Masuko Sangyo Co., Ltd. having a grinder with a major axis of 250 mm. The supernatant of the defibrated solution obtained by the following number of treatments is taken, vacuum dried, and the surface of the sample is sputtered with a sputtering current (10 mA, sputtering time: 90 seconds) using an auto fine coater (JFC-1600, JEOL). After coating, it was observed with an electrolytic emission scanning microscope (JSM-6700, JEOL). The fiber width of 100 fine cellulose fibers in the field of view was measured while changing the magnification of the microscope.
Fine fibrous cellulose 1 (number of treatments: 3 times): The fiber width was in the range of 60 to 700 nm. The average fiber width was 140 nm.
Fine fibrous cellulose 2 (number of treatments: 10 times): The fiber width was in the range of 20 to 200 nm. The average fiber width was 55 nm.

Example 1
Prepare a 2% coniferous bleached kraft pulp water dispersion for general papermaking (NBKP, Canadian Standard Freeness (CSF) 500ml measured according to JIS P8121), beaten with a double disc refiner, 120ml CSF A length-weighted average fiber length of 1.33 mm was obtained. The product thus obtained is referred to as NBKP1. While stirring NBKP1 with a three-one motor so that the whole amount was sufficiently mixed, 2 parts of fine fibrous cellulose 2 was added to 98 parts of NBKP1, and the raw material was prepared so that the concentration was 0.2%. . Furthermore, 1.5 parts of a wet paper strength enhancer (manufactured by WS-4024 Starlight PMC, polyamide polyamine epichlorohydrin resin) was added to 100 parts of the raw material. The raw material prepared in this manner is used to make an inclined wire-type paper machine with a basis weight of 15.0 g / m ² (in this case, a membrane filter with a pore size of 0.8 μm cut into a predetermined size is calendered, and then filtered. Used as a paper). At that time, while adjusting the J / W ratio (speed ratio between the paper raw material jet and the wire), the aspect ratio of the tensile strength of the obtained sheet was measured, and papermaking was performed when the aspect ratio became 3.0 or more. . Then, the calendar process was performed through the super calender set to roll temperature 105 degreeC and the pressure 1MPa.

(Example 2)
A base paper for paper yarn having a basis weight of 15.0 g / m ² was obtained in the same manner as in Example 1 except that 10 parts of fine fibrous cellulose 2 was added to 90 parts of NBKP1.

(Example 3)
A base paper for paper yarn having a basis weight of 15.0 g / m ² was obtained in the same manner as in Example 1 except that 25 parts of fine fibrous cellulose 2 was added to 75 parts of NBKP1.

Example 4
A base paper for paper yarn having a basis weight of 15.0 g / m ² was obtained in the same manner as in Example 1 except that 50 parts of fine fibrous cellulose 2 was added to 50 parts of NBKP1.

(Example 5)
A base paper for paper yarn having a basis weight of 15.0 g / m ² was obtained in the same manner as in Example 1 except that 75 parts of fine fibrous cellulose 2 was added to 25 parts of NBKP1.

(Example 6)
A base paper for paper yarn having a basis weight of 15.0 g / m ² was obtained in the same manner as in Example 1 except that 90 parts of fine fibrous cellulose 2 was added to 10 parts of NBKP1.

(Example 7)
A base paper for paper yarn having a basis weight of 15.0 g / m ² was obtained in the same manner as in Example 2 except that the fine fibrous cellulose 2 was changed to the fine fibrous cellulose 1.

(Example 8)
A base paper for paper yarn having a basis weight of 15.0 g / m ² was obtained in the same manner as in Example 2 except that the wet paper strength agent was changed to 0.4 part.

Example 9
A base paper for paper yarn having a basis weight of 15.0 g / m ² was obtained in the same manner as in Example 2 except that the wet paper strength agent was changed to 4.0 parts.

(Example 10)
A base paper for paper yarn having a basis weight of 15.0 g / m ² was obtained in the same manner as in Example 2 except that the wet paper strength agent was changed to melamine resin (manufactured by Taoka Chemical Industries, Sumirez Resin 8% AC).

(Example 11)
While adjusting the J / W ratio, the aspect ratio of the tensile strength of the obtained sheet was measured, and papermaking was performed when the aspect ratio became 2.5 to 3.0. A base paper for paper yarn having a basis weight of 15.0 g / m ² was obtained in the same manner as in Example 2 except that the J / W ratio was changed.

(Comparative Example 1)
A base paper for paper yarn having a basis weight of 15.0 g / m ² was prepared without adding the fine fibrous cellulose 2 in Example 1.

(Comparative Example 2)
A base paper for paper yarn having a basis weight of 15.0 g / m ² was produced in the same manner as in Example 1 except that the wet paper strength enhancer was not added.

(Comparative Example 3)
A base paper for paper yarn having a basis weight of 15.0 g / m ² was prepared in the same manner as in Example 3 except that the wet paper strength enhancer was not added.

[Evaluation method]
(Content of fine fibrous cellulose)
Since the present invention contains fine fibrous cellulose in the pulp slurry raw material, the fine fibrous cellulose does not stay on the surface of the filter medium when the pulp slurry is filtered on the filter medium of an inclined wire type paper machine to form a paper sheet. May fall into the filtrate. The content of fine fibrous cellulose was calculated as follows.
Fine fibrous cellulose content (%) = (mass of fine fibrous cellulose mixed in raw material−fine fibrous cellulose mass in filtrate) / total mass of paper sheet × 100

(Yield of fine fibrous cellulose)
Yield (%) of fine fibrous cellulose = (mass of fine fibrous cellulose blended in raw material−microfibrous cellulose mass in filtrate) / mass of fine fibrous cellulose blended in raw material × 100
The smaller the amount of fine fibrous cellulose in the filtrate, the better the yield and the better the drainage during papermaking.

(Tensile strength of sheet)
Measured according to JIS P 8113, and the strength per unit area was expressed in MPa. Furthermore, the geometric mean of the tensile strength in the machine direction and the transverse direction was shown.
(Aspect ratio of tensile strength of sheet)
The longitudinal tensile strength was divided by the transverse tensile strength.
(Wet tensile strength)
Based on JIS L-8135, the wet tensile strength in the longitudinal direction after being immersed in water for 10 minutes was measured.

(Slit processing aptitude)
A base paper roll (width: 300 mm, length: 300 m) of the present invention was prepared and slit to a width of 2 mm for paper yarn. The ease of slit processing was evaluated by the following method.
A: High-speed slitting was possible and there was no paper break
○: There is a paper break in the high-speed slit, but the paper break disappears if the speed is slightly reduced.
Δ: Even if the slitting speed is slightly reduced, the paper breakage is not completely lost but is greatly reduced. There is no problem in implementation.
X: Even when the slitting speed is lowered, the paper breaks frequently. Productivity is extremely inferior.

As is apparent from Table 1, the base papers of Examples 1 to 11 have high tensile strength and wet strength, and have good slit processability in the process of finishing into paper yarn.

Claims (2)

Paper yarn base paper containing fine fibrous cellulose having a fiber width of 20 nm to 1000 nm in an amount of 1% by mass to 100% by mass and subjected to a water resistance treatment with a wet paper strength agent. The paper yarn base paper according to claim 1, wherein the strength ratio between the longitudinal direction and the transverse direction is 3 or more, and the geometric average of the strengths in the longitudinal direction and the transverse direction is 80 MPa or more.