JPH0657920B2 - Synthetic fiber paper manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to chemical resistance, weather resistance, heat resistance, nonflammability, electrical insulation, non-adhesion of synthetic fibers themselves by selecting the characteristics of the fibers. It is a method for producing a synthetic fiber paper, which can take advantage of excellent properties such as water resistance, air permeability, and liquid permeability as it is as a paper-like material.

<Prior Art> In recent years, with the remarkable development of synthetic resins, various synthetic fiber papers containing these synthetic resins as main components have been developed and widely used in industrial fields. These synthetic fiber papers have chemical resistance, heat resistance, and
Since the weather resistance, electric insulation, non-adhesiveness, breathability, liquid permeability, etc. can be freely selected according to the application, the demand for the thin sheet has been recently increased. However, synthetic resin sheets that have been studied so far are films, felts, cloths, sheet-like processed products such as non-woven fabrics, of which the film lacks air permeability and liquid permeability, and the felt is unlikely to be thin.
Since the cloth has drawbacks such as too large a hole diameter,
There was a great limitation in the application of synthetic fiber as a thin sheet. In order to solve such a problem, a synthetic fiber paper-like material is desired. The paper-like material of synthetic fibers is, in reality, a paper-like material that is difficult to form because the interfacial binding force between fibers is insufficient due to the small interfacial energy of the fibers, which is a characteristic of synthetic fibers.

<Problems to be Solved by the Invention> The present invention has been made in view of the above-mentioned circumstances, and 100% of the composition is obtained by using a synthetic fiber having no self-adhesive function other than heat fusion. Relates to a method for producing thin and uniform paper made of synthetic fiber.

<Means for Solving Problems> The present inventors have conducted various studies to obtain a paper-like material composed only of synthetic fibers having no self-adhesive function other than heat fusion, and as a result, the wet papermaking method was used. By combining the synthetic fiber layer and the fiber layer having a self-adhesive property into two or more layers so that each is a separate layer, the interfiber bond strength, which is the greatest drawback of synthetic fibers, is self-adhesive. After creating a synthetic fiber sizing paper by assisting with a fiber layer, after the synthetic fiber sizing paper is thermocompression-bonded at a softening point of the synthetic fibers or higher to heat bond between the fibers of the synthetic fibers, It has been found that a uniform synthetic fiber paper can be obtained by peeling off the layer of fibers having a self-adhesive function.

The synthetic fiber used in the present invention is a thermoplastic synthetic resin, and the main components are fluorine resin, polyester resin, polyamide resin, polypropylene resin,
Examples thereof include polyacrylic resins, polyethylene resins, and polyvinyl resins, and these may be used alone or as two or more types of fibers. Fiber length is usually 1
20 mm is preferred. The fiber diameter varies depending on the characteristics of the target synthetic fiber and paper-like material, but is usually preferably 50 μm φ or less. Normally, if the fiber length is short, a uniform formation is obtained, but
If the strength becomes weak and the fiber length is long, the formation becomes poor, but the strength becomes strong. Further, if the fiber diameter is small, it tends to be bundled into lumps, and if the fiber diameter is large, defects such as rough texture of the sheet occur.

Examples of the fibers having a self-adhesive function include papermaking pulp made of wood, hemp, cotton, straw and the like which are usually used for papermaking. These are 50% thermoplastic synthetic polymers
You may contain in the following ratios. In the present invention, the solubility coefficient (S
It is preferable that P) differ by 1 or more from the viewpoint of peelability.

In carrying out the present invention, first of all, according to a wet papermaking method, for example, as shown in FIG. 1, a two-layer synthetic fiber paper-making paper [a synthetic fiber layer 1 and a fiber layer 2 having a self-adhesive function] [first Figure (a)] or 3 layers of synthetic fiber paper [Figure 1]
(b)] is created. In this case, the synthetic fiber paper-making paper can be produced by using, for example, a cylinder paper machine shown in FIG. That is, in FIG. 2, synthetic fibers are dispersed in the tank in which the cylinder cylinder 3-2 is installed, and fibers having a self-adhesive function are dispersed in water in the tanks corresponding to the cylinder cylinders 3-1 and 3-3, respectively. Then, a fiber layer having a self-adhesive function, a synthetic fiber, and a fiber having a self-adhesive function are laminated in this order on the felt 4 traveling on the cylinder cylinder, and dried with a dryer 5, and then a synthetic fiber-combined paper 6
Is wound up as.

As a method for producing the synthetic fiber paper, there is a method in which, in addition to the above-mentioned cylinder type, a fourdrinier type paper machine is used, and different kinds of papermaking raw materials are separately taken out from the head and laminated. In this case, the paper machine needs a paper machine capable of making two or more layers. Any model can be used as long as it is a multi-layer paper machine. Since the wet papermaking method uses water as a medium, some synthetic fibers have hydrophobicity, and a surfactant, a sticky agent, or the like may be added as an auxiliary agent.

The thus obtained synthetic fiber paper is applied to the thermocompression bonding apparatus shown in FIG. 3 and is passed through a heating roll 7 to heat-bond the fibers constituting the synthetic fiber paper. After that, the peeling layer 9 of fibers having a self-adhesive function with respect to the synthetic fiber paper 8 is peeled and removed. In this case, a known method such as an ordinary drying roll, a hot press, or a heat roll can be applied as the means for the heat compression bonding or the heat fusion, and it is applied to the heating roll. The treatment temperature must be set above the softening point of the synthetic fiber and is selected according to the type of synthetic fiber.The conditions for the nip pressure and pressurizing time at that time are the type of synthetic fiber, the softening point and the fiber Depending on hardness, fiber diameter, etc.,
It may be set appropriately. The thermocompression bonding process at such a temperature setting causes a bond between the synthetic fibers by heat fusion. Usually, it is preferable to perform thermocompression bonding at a softening point or a temperature about 30 ° C. higher than the softening point.

In order to remove the release layer of the fiber having the self-adhesive function from the thermocompression-bonded synthetic paper, a method of removing the layer by delamination is used. In this case, the synthetic fiber and the fiber having the self-adhesive function are used. It is preferable that the difference in SP between and is 1 or more from the viewpoint of peelability. When wood pulp is used as the fiber having a self-adhesive function, peeling can be easily performed.

<Examples> Next, the present invention will be further described with reference to Examples. All blending ratios are expressed on a weight basis.

Example 1 Wood pulp as a fiber having a self-adhesive function (mixing ratio N
50 parts of BKP and 50 parts of LBKP) were mechanically processed to a beating degree of 40 ° SR, 100 parts of pulp was put into water to make the pulp concentration 0.5%, and the mixture was stirred and dispersed to form a sheet with a TAPPI standard sheet machine (A). Got Next, as a synthetic fiber, 100 parts of polyvinylidene fluoride fiber having a length of about 6 mm and a thickness of about 20 μm was dispersed in water to obtain a dispersion having a concentration of 0.5% and an acrylic synthetic sticky agent (manufactured by Diafloc Co.). Acrypers PMP) is added to fiber 1%, and T
A wet paper web (B) was obtained by sheeting with an APPI standard sheet machine. At that time, the wet paper (B) had a thickness after drying of 20.8 μm (Sample No. 1) and 5
Conditions were set so as to obtain 8.1 μm (Sample No. 2) to form two types of wet paper (B), and wet paper (A) was laminated on each of them as described later.

Next, the wet paper (A) which was first formed into a sheet was stacked on the wet paper (B) to form a two-layer sheet, which was pressed and then dried to prepare a synthetic fiber paper. The obtained laminated paper is thermocompressed at 160 ° C. and 2 kg / cm ² , and then the pulp layer (A) and the PVDF fiber layer (B) are peeled off to remove the pulp layer (A) from the fluorine fiber. I made a synthetic fiber paper. As shown in Table 1, the synthetic fiber paper is a thin sheet which has become conventional and has practically sufficient strength characteristics.

Example 2 Wood pulp (compounding ratio N
50 parts of BKP and 50 parts of LBKP) were mechanically processed to a beating degree of 40 ° SR, 100 parts of pulp was put into water to make the pulp concentration 0.5%, and the mixture was stirred and dispersed to form a sheet with a TAPPI standard sheet machine (A). Got Next, 100 parts of polyester (PET) fiber having a length of about 6 mm and a thickness of about 20 μm as a synthetic fiber was dispersed in water to obtain a concentration of 0.5.
1% synthetic fiber (Acrypers PMP manufactured by Diafloc Co., Ltd.) in a dispersion liquid of 1%, and a wet paper (B) is formed by a TAPPI standard sheet machine.
Got At that time, the wet paper (B) had a thickness of 16.2 after being dried in advance.
μm (Sample No. 3) and 32.8 μm (Sample No. 3)
4), the conditions were set so as to form two types of wet paper (B), and wet paper (A) was laminated on each of them as described later. Next, stack the wet paper (A) first formed into a sheet on the wet paper (B) 2
The laminated sheet made into a layered sheet was pressed and then dried to prepare a synthetic fiber laminated paper. 2 pieces of the obtained laminated paper
Pulp layer (A) after thermocompression bonding at 25 ° C and 10 kg / cm ²
Then, the polyester (PET) fiber layer (B) was peeled off to obtain a porous synthetic fiber paper made of 100% polyester (PET). The characteristics of this synthetic fiber paper are, as shown in Table 2, a thin sheet having a practically sufficient strength that has never been obtained.

Example 3 Wood pulp (mixing ratio N
50 parts of BKP and 50 parts of LBKP) were mechanically processed to a beating degree of 40 ° SR, 100 parts of pulp was put into water to make the pulp concentration 0.5%, and the mixture was stirred and dispersed to form a sheet with a TAPPI standard sheet machine (A). Got Next, 100 parts of polyester (PET) fiber having a length of about 6 mm and a thickness of about 20 μm as a synthetic fiber was dispersed in water to obtain a concentration of 0.5.
% Synthetic dispersion (Acrypers PMP made by Diafloc Co., Ltd.) in a dispersion liquid of 1% with respect to the fiber and TAPP
A wet paper (B) was obtained by forming a sheet with an I standard sheet machine. At this time, the wet paper web (B) was preliminarily set to have a thickness of 20.5 μm (Sample No. 5) and 35 μm (Sample No. 6) after being dried, so that two types of wet paper web (B) were obtained The wet paper (A) was laminated on each as described below. Next, the same pulp as wet paper (A) 100 parts concentration 0.5
% Liquid was stirred and dispersed, and a wet paper (C) was obtained by forming a sheet with a TAPPI standard sheet machine. Next, a two-layer sheet obtained by stacking the wet paper (A) and the wet paper (B) was placed on the wet paper (C) to obtain a three-layer paper making sheet. At this time, the condition is that the layers (B) and (C) are laminated so that they are in contact with each other.

The thus obtained three-layered laminated sheet was pressed and then dried to prepare a synthetic fiber laminated sheet. The obtained synthetic fiber fiber-laminated paper was thermocompression bonded at 225 ° C. and 10 kg / cm ² , and then the pulp layers (A) and (C) were mixed with polyester (P).
The ET) fiber layer (B) was peeled off to obtain a porous synthetic fiber paper made of 100% polyester (PET). The characteristics of this synthetic fiber paper are, as shown in Table 3, a thin sheet having practically sufficient strength characteristics that have never been obtained.

<Effects of the Present Invention> Since the synthetic fiber paper thus produced is obtained by the wet papermaking method, it is a thin sheet and has a uniform texture compared with the synthetic fiber sheet made by the conventional dry non-woven fabric method. It is expected that the application will be expanded.

[Brief description of drawings]

FIG. 1 (a) shows a constitutional example of a synthetic fiber laminated paper when two layers are laminated by the wet papermaking method according to the present invention, in which 1 is a layer of synthetic fibers and 2 is a layer of fibers having a self-adhesive function. Indicates. FIG. 1 (b) shows a constitutional example of a synthetic fiber paper-making paper when three layers are laminated by the wet paper-making method according to the present invention.
Is a layer of fibers having a self-adhesive function, and 1 is a layer of synthetic fibers. FIG. 2 shows an example of a multi-layer paper making apparatus by the cylinder type wet paper making method. 3-1, 3-2 and 3-3 are cylinder cylinders, 4 are felts, 5 are dryers, 6 is a primary sheet. Indicates. FIG. 3 shows an outline of a thermocompression bonding apparatus, 7 is a heating roll, 8 is a synthetic fiber paper, and 9 is a release layer of fibers having a self-adhesive function.

Claims (1)

[Claims] 1. Synthetic fiber and a fiber having a self-adhesive function are combined into two or more layers by a wet paper-making method so that each layer is a separate layer, and a synthetic fiber-combined paper obtained by drying is made of synthetic fiber. A method for producing a synthetic fiber paper, comprising thermocompression bonding at a softening point or higher to thermally bond the fibers of the synthetic fiber, and then peeling and removing the fiber layer having a self-adhesive function.