JP2007168284A - Paper-fiber structured laminate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper-fiber structured laminate which is simple in process, keeps paper functions and physical characteristics even if a paper layer is low in mass and strong in opacifying properties to a base material layer, and its manufacturing method. <P>SOLUTION: The paper-fiber structured laminate which is strong in opacifying properties even if the paper layer is low in mass and excellent in functions and physical properties is obtained by spraying a slurry prepared by dispersing extremely highly fibrillated organic fiber pulp in a solvent such as water on a variety of base materials to coat thinly and evenly, and the surface is dried and pressure-bonded. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper-fiber structure laminate and a method for producing the same, in which the paper layer portion containing the organic fiber pulp sufficiently maintains the function and physical properties of the paper even when the basis weight is low. More specifically, a paper-fiber structure obtained by thinly and uniformly laminating a slurry prepared by dispersing organic pulp in a dispersion medium on a base fiber structure such as a nonwoven fabric or a woven / knitted fabric by spray coating, followed by heat pressing. The present invention relates to a product laminate and a manufacturing method thereof.

  In general, non-woven fabrics are widely used for industrial materials, sanitary products, civil engineering materials and the like because fabrics with low weight and high strength can be obtained. However, these have drawbacks that surface properties such as water absorption, water repellency, heat sealability, heat resistance and the like are not sufficient depending on applications, or that uniformity is low at low basis weight and concealment is low.

  On the other hand, paper made by wet papermaking is made by a method in which a slurry in which pulp or shortcut fibers are dispersed in a solvent such as water is pulverized using a wire mesh for papermaking to form a dense and uniform layer, and has excellent concealment properties. However, there were problems in terms of strength and rigidity.

  Therefore, in order to take advantage of the characteristics of the nonwoven fabric and paper and to compensate for the defects, a nonwoven fabric-paper bonded composite has been devised. For example, JP-A-5-279997 and JP-A-10-53950 disclose a method for producing a composite paper in which a wet papermaking paper layer is laminated on a spunbonded nonwoven fabric. Certainly, the surface functionality and concealability are improved to some extent by appropriately selecting the fibers of the wet papermaking layer by this method. However, if the wet papermaking layer has a low basis weight, the wet strength at the time of wet papermaking is insufficient, so there is a production limit, and a considerable amount of weight is required to sufficiently conceal the underlying spunbond nonwoven fabric. There is a problem that the weight increases due to the basis weight, the cost increases, and the rigidity increases. Japanese Laid-Open Patent Publication No. 4-91299 discloses a method in which a stock containing synthetic pulp is dispersed in an aqueous medium, paper is made directly on a reinforcing layer such as a non-woven fabric, and a dry heat treatment is performed. According to this method, a wet papermaking layer can be formed even with a low basis weight, but in this case as well, the concealability with a low basis weight of the surface was not sufficient. Therefore, there is a demand for a processing method that has a concealability as well as a surface function even with a low basis weight.

JP-A-5-279997 JP 10-53950 A Japanese Unexamined Patent Publication No. 4-91299

  Paper-fiber structure laminate having a paper layer with a simple process and sufficiently maintaining the functions and physical properties of the paper even when the paper layer portion has a low basis weight and having a strong concealability of the base material layer, and its production Provide a method.

  The concealability of the lower base fiber structure layer depends greatly on the specific surface area of the fibers and pulp used in the upper wet papermaking layer, and the formation of a paper layer that does not depend on the wet strength during wet papermaking. The present invention was completed by intensively studying the method.

  That is, the present inventors applied a slurry obtained by dispersing a highly highly fibrillated organic fiber pulp in a solvent such as water onto a variety of substrates by spraying thinly and uniformly, and adding a surface after drying. It has been found that a paper-fiber structure laminate can be obtained by pressure bonding, even if the paper layer portion has a low basis weight, and the base layer is highly concealed and has excellent functions and physical properties.

  According to the present invention, after the organic fiber pulp slurry is spray-coated on the base fiber structure, it is pressed and dried by hot pressing, so that a laminate of a thin and uniform paper layer and the base fiber structure can be easily obtained. This paper-fiber structure laminate reflects the paper properties and characteristics sufficiently even if the paper layer is thin, and is useful for reducing the manufacturing cost of paper-fiber structure laminates suitable for various applications. It is.

The present invention will be described in detail below.
The highly fibrillated organic fiber pulp as used in the present invention refers to a highly fibrillated organic fiber having a rigid molecular structure by means of a refiner, beater, mill, high-pressure homogenizer, grinding device or the like. The higher the degree of fibrillation, the higher the effect of imparting functionality and the effect of concealing the base by fibrils, and a denser surface can be formed.

The degree of fibrillation that has an effect on concealability and the like needs to have a specific surface area of 1 to 24 m ² / g. More preferably, it is 5-20 m < ² > / g. When it is 1 m ² / g or less, there are few fibrils and sufficient concealability cannot be obtained. Moreover, the adhesive strength with the base fiber structure cannot be obtained. When it is 24 m ² / g or more, not only the productivity of the organic fiber pulp is significantly lowered, but the organic pulp is entangled with each other during disaggregation and becomes a lump, so that the effective fibrils are reduced and the concealability is also reversed. To drop. Moreover, it becomes easy to cause clogging of the spray nozzle.

  Furthermore, the fiber length of the organic fiber is preferably 1 mm or less. More preferably, it is the range of 0.5-1.0 mm. The reason for this is that when the thickness is 1 mm or more, the organic pulp is easily entangled with each other in the slurry and becomes agglomerated, so that the effective fibrils are insufficient and the base cannot be covered, and the concealability is also lowered. Furthermore, since it becomes a lump, it becomes easy to cause clogging of the spray nozzle. On the other hand, when the thickness is 0.5 mm or less, the fibers are not entangled and the strength cannot be obtained.

  The organic fiber in the present invention is preferably a liquid crystalline polymer fiber having a high degree of molecular orientation composed of an organic polymer having a thermal decomposition starting temperature of 350 ° C. or higher. Particularly, an aromatic polyamide fiber, an aromatic polyester fiber, a poly Benzazole fibers are suitable in terms of strength, heat resistance, and ease of fibrillation.

  As aromatic polyamide fibers, poly-p-phenylene terephthalamide, poly-p-benzamide, poly-p-amide hydrazide, poly-p-phenylene terephthalamide-3,4-diphenyl ether terephthalamide, etc. are spun into fibers. Although not limited to these, poly-p-phenylene terephthalamide is more preferable.

  Aromatic polyesters are synthesized by combining monomers such as aromatic diol, aromatic dicarboxylic acid, and aromatic hydroxycarboxylic acid and changing the composition ratio. For example, a copolymer of p-hydroxybenzoic acid and 2-hydroxy-6-naphthoic acid can be mentioned, but it is not limited to this. The aromatic polyester fiber is a fiber obtained by spinning such a polymer.

  Polybenzazole fiber is a fiber prepared by spinning a poly-p-phenylenebenzobisoxazole (PBO) homopolymer and a random, sequential or block copolymer with polybenzazole containing substantially 85% or more PBO component. It has become.

  In addition to the organic fiber pulp, it is preferable to use an organic pulp-like material called fibrid. The fibril referred to in the present invention is a general term for thin leaf-like, scaly small pieces having fine fibrils having binder performance in the wet papermaking process, or fine short fibers randomly fibrillated, for example, WO2004 / 099476A1. The organic polymer solution is converted into a system in which a precipitant of the polymer solution and shear force exist by the methods described in Japanese Patent Publication No. 35-11851, Japanese Patent Publication No. 37-5732, and the like. Or a molded product having molecular orientation formed from a polymer solution exhibiting optical anisotropy by a fibrid produced by mixing in the above or a method described in Japanese Patent Publication No. 59-603. It is preferable to use a fibril that is randomly fibrillated by applying mechanical shearing force such as beating. Shall is optimal. Fibrid is distinguished from the organic fiber in that it can be obtained without going through a spinning process. The use of this fibrid is preferable because the adhesion between the paper layers or between the paper layer and the base fiber layer is improved.

  Furthermore, cellulose fibers such as linter pulp and wood pulp, organic fibers such as meta-type aramid fibers, acrylic fibers, polyimide fibers, polyamide fibers, glass fibers, rock wool, potassium titanate fibers, silica fibers, alumina fibers, metal fibers Inorganic fibers such as can also be used as a fibrous material.

  The base fiber structure used for the lower layer in the present invention may be a nonwoven fabric, a woven or knitted fabric, or paper. Examples of fibers constituting the base fiber structure include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyamides such as nylon 6 and nylon 66, aromatic polyamides such as meta-type polyamide and para-type polyamide, glass fibers, carbon fibers, Examples thereof include fibers mainly composed of metal fibers. Of these, aromatic polyamide, glass fiber, carbon fiber, and metal fiber are preferable from the viewpoint of heat resistance during hot pressing.

  Next, in the present invention, it is necessary to perform the spray coating method to form the paper layer. In general, the spray coating method is used for the purpose of spray-coating a fluid obtained by dispersing fine particles and the like in a solvent to give a new function, making it easy to produce continuously, and a substrate having an uneven surface. In contrast, it is an excellent industrial technique that enables uniform and thin coating. Specifically, in order to prevent the collapse of exposed ground such as tunnel excavation, a rapid setting concrete spraying method in which a quick setting agent is mixed with concrete is performed (Japanese Patent Publication No. 60-4149). It is widely used industrially, such as spraying various paints on a base material to impart a photocatalytic function to the base material, or for coloring purposes.

  In order to obtain an upper paper layer by the spray coating method of the present invention, first, a slurry is prepared in which a paper layer part-constituting material containing organic fiber pulp is dispersed in a dispersion medium such as water. By sufficiently disaggregating using a known stirrer such as a disaggregator, a slurry in which each component is uniformly dispersed can be obtained. Next, this slurry is sprayed on the base fiber structure using a known spray device. Under the present circumstances, a binder component can also be added to a slurry in order to improve the adhesiveness of a paper layer part and a base fiber structure. Examples of the binder component include organic binders such as epoxy resins, phenol resins, polyurethane resins, melamine resins, formaldehyde resins, fluoropolymer resins, and inorganic binders such as alumina, zirconia, and silica. It will not be limited to these as long as it improves the adhesion to the base fiber structure.

  The obtained laminate needs to be pressure-bonded and dried by a hot press after drying. As the heating press, commonly used ones such as a heating drum press and a calender press can be used, and the heating press conditions are preferably 120 to 300 ° C. surface pressure and 0.49 to 3.9 kPa. .

Thus, according to the present invention, a paper-fiber structure laminate in which a paper layer containing at least an organic fiber pulp obtained by fibrillating organic fibers is laminated on a base fiber structure layer on at least one side, A paper-fiber structure laminate characterized in that the organic fiber pulp constituting the paper layer is a highly fibrillated organic fiber pulp having a specific surface area of 1 to 24 m ² / g, and the organic fiber pulp is dispersed. There is provided a method for producing a paper-fiber structure laminate, characterized by being dispersed in a medium to form a slurry, spray-coated on a base fiber structure, and then pressure-bonded and dried by a hot press.
The present invention will be specifically described below based on examples. The present invention is not limited to these.

Various physical properties were measured according to the measurement methods described below.
1 Breaking length Evaluation of the breaking length of the paper-fiber structure laminate was performed according to JIS P8113.
Testing machine: INSTRON 5565 type (manufactured by INSTRON)
Temperature: Distance between room temperature gauges: 100mm
Tensile speed: 10 mm / min N number: 5
In addition, it sampled so that the tensile direction and the longitudinal direction of a nonwoven fabric might become parallel.
Two-paper layer thickness measurement The cross section of the obtained paper-fiber structure laminate was observed with a scanning electron microscope 1000 times, and the thickness was measured.
3 Gurley Air Permeability In order to evaluate the air permeability of the obtained paper-fiber structure laminate, evaluation by Gurley air permeability was performed. Evaluation was performed according to JIS P8117.
Adhesiveness between the four paper layers and the underlying fiber structure (hereinafter abbreviated as adhesive strength)
The obtained paper-fiber structure laminate was cut to a width of 1 cm and a length of 10 cm, and the same width of cello tape (registered trademark) was applied to the surface of the paper layer. (Trademark) was simply expressed by the resistance when peeled off.
○: Peeled at the interface between the paper layer and the substrate, but strong adhesion.
×: Peeled easily at the interface between the paper layer and the base, and the adhesive strength was poor.
It was observed whether the spots of the underlying non-woven fabric layer were seen through from above.
○: The base is concealed and good. ×: The base is not concealed and is transparent.
Preparation of 6 fibrids Fibrids of para-type aromatic polyamides (hereinafter abbreviated as aramid fibrids) were prepared by the technique of WO2004 / 099476A1.

[Example 1]
5 parts by weight of para-aromatic polyamide fibrid as an organic fiber pulp (specific surface area = 2.0, fiber length = 1.0 mm WL, made by Teijin Techno Products Aramid Pulp 1) at 3000 rpm for 3 minutes using a JIS standard disintegrator Disaggregation gave a slurry. The obtained slurry was put into a commercially available sprayer (nozzle diameter: 1 mm), sprayed onto a meta-type polyamide nonwoven fabric (30 parts by weight) with a weight of 60 g / m ² at a pressure of 5 kPa, press dehydrated, and a temperature of 140 ° C. Then, a paper-fiber structure laminate was obtained by heat-press drying for 5 minutes at a surface pressure of 0.5 kPa. The basis weight of the paper layer portion was 25 g / m ² . Compared to Comparative Example 3, it can be seen that the spray spraying method is more effective for forming the low weight paper layer. This material had good concealability and adhesive strength, strong paper strength, and excellent heat resistance, smoothness and tactile feel as well as air permeability on the surface.

[Example 2]
In Example 1, the fibrous material constituting the slurry is a highly fibrillated pulp (trade name “Twaron 1094”, specific surface area = 14 m ² / g, fiber length as an organic fiber pulp. = 1.1 to 1.7 mm WL, made of Teijin Techno Products Aramid Pulp 2) was used to prepare a paper-fiber structure laminate in the same manner as in Example 1 except that 5 parts by weight was used.
This material had very good concealability and adhesive strength, and was excellent in heat resistance, smoothness and tactile properties as well as air permeability on the surface.

[Example 3]
In Example 1, the fibrous material constituting the slurry was a paper-like example 1 except that 2.5 parts by weight of aramid pulp 1 and 2.5 parts by weight of aramid pulp 2 were used as organic fiber pulp. A fiber structure laminate was prepared.
This material had very good concealability and adhesive strength, was excellent in heat resistance, smoothness, and tactile feel as well as air permeability on the surface, and also had strong paper strength due to the addition of aramid fibrids.

[Comparative Example 1]
5 parts by weight of para-type aromatic polyamide short fiber (trade name “Twaron 1081”, specific surface area = 0.1 m ² / g, fiber length = 5.0 mm WL, aramid pulp 3 manufactured by Teijin Techno Products) as organic fiber A paper-fiber structure laminate was prepared in the same manner as in Example 1 except that it was used. This product had no fibrils, had a poor base concealment property, and a weak paper strength.

[Comparative Example 2]
5 parts by weight of a highly fibrillated pulp of para-type aromatic polyamide fibers as organic fiber pulp, specific surface area = 30 m ² / g, fiber length = 5.0 mm WL, made by Teijin Techno Products Aramid Pulp 4) A paper-fiber structure laminate was prepared in the same manner as in Example 1 except that. In this slurry, fibrils were entangled in the slurry to form a lump, and the surface design was poor, and it was easily clogged with spray. Therefore, even if the specific surface area is high, it cannot be utilized effectively, so that the concealability and adhesion are poor.

[Comparative Example 3]
5 parts by weight of aramid fibrid (aramid pulp 1) was disaggregated with a JIS standard disaggregator at 3000 rpm for 3 minutes to obtain a slurry. Thereafter, this slurry was made with a TAPPI square paper machine but could not be rolled up.

[Comparative Example 4]
Water containing no organic fiber pulp was sprayed onto a 60 g / m ² meta-type polyamide nonwoven fabric (30 parts by weight), press dehydrated, and then heated and dried by heating at 140 ° C. and a surface pressure of 0.5 kPa for 5 minutes.

  The present invention provides a paper-fiber structure laminate that has high concealability even when the paper layer is low in weight and is excellent in heat resistance, strength, air permeability, sealing properties, and the like.

Claims (9)

An organic fiber pulp comprising a paper-fiber structure laminate in which a paper layer containing an organic fiber pulp obtained by fibrillating organic fibers is laminated on a base fiber structure layer on at least one side, and constituting the paper layer A paper-fiber structure laminate, which is a highly fibrillated organic fiber pulp having a specific surface area of 1 to 24 m ² / g. The paper-fiber structure laminate according to claim 1, which is a highly fibrillated organic fiber pulp in which the specific surface area of the organic fiber pulp constituting the paper layer is 5 to ²⁰ m ² / g.   The paper-fiber structure laminate according to any one of claims 1 and 2, wherein the organic fiber pulp is a fiber pulp made of an organic polymer having a thermal decomposition start temperature of 350 ° C or higher.   The organic fiber pulp includes a fiber pulp made of an organic polymer having a thermal decomposition start temperature of 350 ° C or higher and / or a fibrid made of an organic polymer having a thermal decomposition start temperature of 350 ° C or higher. The paper-fiber structure laminate according to any one of claims 1 and 2.   The fiber pulp comprising an organic polymer having a thermal decomposition start temperature of 350 ° C or higher is a para-type aromatic polyamide fiber pulp and / or a meta-type aromatic polyamide fiber pulp. Paper-fiber structure laminate.   The paper according to any one of claims 4 and 5, wherein the fibrid composed of an organic polymer having a thermal decomposition starting temperature of 350 ° C or higher is a fibrid composed of a para-type aromatic polyamide and / or a meta-type aromatic polyamide. Fiber structure laminate.   The thickness of a paper layer is 5-100 micrometers, The paper-fiber structure laminated body as described in any one of Claims 1-6.   The paper according to any one of claims 1 to 7, which is obtained by dispersing organic fiber pulp in a dispersion medium to obtain a slurry, spray-applying onto a base fiber structure, and then pressing and drying with a heating press. -Manufacturing method of fiber structure laminated body.   A paper-fiber comprising a paper-fiber structure laminate unit composed of the paper layer according to any one of claims 1 to 7 and a base fiber structure layer, wherein at least two units are stacked. Structure laminate.