JPS6026843B2 - Method for producing polyalkylene terephthalate pulp-like material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a pulp-like material comprising polyalkylene terephthalate.

More specifically, it is a method for producing a pulp-like material that has excellent electrical insulation properties, mechanical properties, heat resistance, moisture absorption resistance, and is useful for producing a uniform sheet-like structure with good texture and good paper-making properties. be.

Conventionally, polyalkylene terephthalate has been widely used for applications such as fibers, films, and molding plastics.
For example, the polyethylene phthalate used in the fibers, films, and molding plastics mentioned above is not produced in pulp-like form, but in granular form for convenience in melt extrusion or compression processes; It is impossible to make paper into sheets. In order to eliminate such drawbacks, the present inventor has conducted intensive research and found that polyalkylene terephthalate can be dissolved in a specific solvent, introduced into a precipitant that satisfies specific conditions, and precipitated as fine particles. Furthermore, the pulp-like material has good paper-making properties, and even when mixed with short fibers and continuously made into paper using a remesh-type paper machine, for example, there are no problems such as paper breakage. There are almost no problems; after drying the sheet thus obtained, the paper obtained by heating under pressure has a good quality and uniform texture, and has good electrical insulation, mechanical properties, heat resistance, moisture absorption resistance, and resistance. They discovered that it has excellent chemical properties, etc., and completed the present invention. That is, the present invention provides a method for producing a pulp-like material by introducing a polyalkylene terephthalate solution into a precipitant, including: a
A solution of polyalkylene terephthalate dissolved in a phenolic solvent was used as a precipitant, and the alcohol concentration was 40%.
Production of a pulp-like material, characterized in that the polyalkylene terephthalate is precipitated as fine particles by introducing the polyalkylene terephthalate into an alcohol or an aqueous solution containing 1 to 3 carbon water at a concentration of 1 to 10% by weight. It is the law.

The present invention will be explained.

Polyalkylene terephthalate The polyalkylene terephthalate referred to in the present invention is commercially available for use in industrial materials and clothing.

Although ordinary polyethylene terephthalate, polybutylene terephthalate, etc. can be used, polyethylene terephthalate is particularly preferably used in the present invention. Phenolic Solvent The phenolic solvent used in the present invention is a general term for so-called phenolic solvents such as phenol, 0-1, m- or P-cresol, mixed cresol, and 0-chlorophenol.

In the present invention, a solvent containing phenol as a main component is preferably used.

When dissolving polyalkylene terephthalate with phenol, it is easier to make a homogeneous solution by dissolving it under humid conditions of 6 pi or more, and since phenol solidifies at 4 pi or less, phenol solutions of polyalkylene terephthalate are usually
It is desirable to keep it above 0:00. These phenolic solvents can be used alone or in combination with water.

In this case, the concentration of the phenolic solvent is preferably 6% by weight or more, and the temperature of the solution must be 66°C or more. Polymer solution When producing a pulp-like material by the method of the present invention, a solution of polyalkylene terephthalate dissolved in a phenolic solvent is introduced into a precipitant consisting of an alcohol with 1 to 3 carbon atoms or an aqueous solution thereof, and fine particles are prepared. A method is applied to precipitate it as a pulp-like material.

The concentration of polyalkylene terephthalate in a solution of polyalkylene terephthalate dissolved in a phenolic solvent varies depending on the degree of polymerization of the polyalkylene terephthalate, but is generally 5 to 25% by weight, preferably 8 to 2% by weight, particularly preferably is 10 to 15% by weight.

If the concentration of polyalkylene terephthalate in the solution is less than 5% by weight, the size of the resulting pulp-like material will be extremely small, which is undesirable because it will cause a lot of leakage from the wire mesh during paper making.

Conversely, if the concentration of polyalkylene terephthalate in the solution is 2
If it is more than 5% by weight, the shape of the pulp-like substance obtained will be coarse and have few tentacles, and the entanglement of pulp-like substances with each other and the entanglement of pulp-like substances with short fibers will be reduced.
Paper-making properties deteriorate and the mechanical properties of the resulting paper also deteriorate. Also, the temperature of the solution when subjected to precipitation is 4 to 0 to 12
The temperature is preferably 60°C to 8pm. Precipitating agent In the present invention, the precipitating agent is one having an alcohol concentration of 40 to 10
% by weight of alcohol or its aqueous solution.

When the alcohol concentration is less than 4% by weight, solvent removal from the solution is poor, and the pulp-like substances produced often coagulate and weld together, resulting in the resulting pulp-like substance having a coarse, spherical or twilled shape. , the entanglement of the pulp-like substances and the entanglement of the pulp-like substances and the short fibers become small, resulting in poor paper-making properties. The temperature of the precipitant is also one of the important factors for obtaining a pulp-like material with good paper-making properties and a good shape. , in the present invention, generally 10 to 60°C
is employed, preferably 20 to 40.

It is preferable that the precipitant be operated at high speed so as to remove the solvent from the introduced solution and at the same time to produce a refining or beating action. The flow rate ratio of precipitant/polymer solution is 5/
Desirably 1 to 100/1, particularly preferably 8/1 to 3
It is 0/1. Furthermore, the term "alcohol" used in the present invention refers to alcohols having 1 to 3 carbon atoms such as methanol, ethanol, n-propanol, isopropanol, etc., and methanol is preferably used in the present invention.

Paper Making The pulp-like material produced according to the present invention is mixed with short fibers and made into paper to form an excellent sheet.

At this time, the weight of the pulp-like substance in the sheet is 10 to 9,
Particularly preferred is from 40 to 8% by weight. A sheet in which the amount of pulp-like material is less than the amount of blood charge (%) is not preferable because the mechanical properties and dielectric breakdown voltage are lowered. If the amount of pulp-like material is more than 9% by weight, both impregnating properties and mechanical properties will deteriorate, which is not preferable. Paper made from pulp-like substances and short fibers is preferably made by a wet process using a Fourdrinier or cylinder paper machine, as in the case of conventional paper making from natural pulp. At this time, a surfactant, a dispersing agent such as root juice of A. japonica, and a thickening agent may be added as necessary. The monofilament weave of the short fibers used in the present invention is 0.5 to 10.0 deniers, preferably 1 to 3 deniers.

In addition, the short fibers have a fiber length of 1 to 2 yen, preferably 2 to 15 yen.
The fence is particularly preferably 3 to 1 inch long.

Various types of short fibers can be used, but
Examples include the following: 1 Polypropylene fiber 2 Polyethylene fiber 3 Polycarbonate fiber 4 Polyamide fiber (including aromatic polyamide) 5
Polyester fibers (including aromatic polyester fibers)
6 Polyacrylonitrile fiber 7 Polyvinyl alcohol fiber 8 Aromatic polyamideimide fiber 9 Polyvinyl chloride fiber 10 Polyvinylidene chloride fiber 11 Inorganic fiber such as glass fiber, Shiho fiber, asbestos, etc. 12
Cellulose-based regenerated fibers (pisco-laceion, cupra, etc.) 13 Protein-based regenerated fibers 14 Cellulose-based semi-synthetic fibers (acetate, triacetate, acetate acetate, etc.) After drying, the sheet obtained as described above is heated, Excellent performance can be imparted by heating under pressure using a means such as a hot roll.

The temperature at which pressure is applied varies depending on the type of short fibers and the amount of pulp-like material in the sheet, but a suitable temperature is 70 to 240°C. The pressure, as well as the temperature, varies depending on the type of short fibers, the content of the pulp-like material in the sheet, etc., but it is preferably 400 k9/min or less. Hereinafter, the measurement method for the main measurement values in the present invention will be explained.

Tensile strength: Performed according to the method of JISP8118, k
9/ Expressed in numbers.

Elongation: Measured according to the method of JISP8132 and expressed in %.

Dielectric breakdown voltage: Measured using AC voltage according to the method of JISC2111.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Preparation of polymer solution 20 parts by weight of polyester chips [manufactured by Teijin Co., Ltd.] 0.60 were poured into 8 parts by weight of phenol, and then overflowed to about 120 qo to completely dissolve the polymer. Dissolved.

Then, the temperature of the solution was cooled to 50°C to prepare a solution for producing a pulp-like material. Preparation of Precipitating Agent 5 parts by weight of methyl alcohol and 5 parts by weight of water were mixed to prepare a precipitating agent.

Production of pulp-like substances A conduit-type continuous sedimentation machine consisting of a combination of a stator with a full-throttle and a turbine blade-shaped rotor, and equipped with a supply port for a precipitant polymer solution and a discharge port for the pulp-like material slurry after precipitation. 0.5 kg/mi of the polymer
The precipitant was fed at the same time at a flow rate of 5 k9/h, and the pulpy material slurry was taken out from the outlet.

At this time, the temperature of the precipitant was 39qo, and the temperature of the polymer solution was 5
The temperature was adjusted to 0°C. Also, the rotation speed of the rotor is 7.10. p. It was set as m. The resulting pulpy substance slurry was
The mixture was placed in a Nutsche type vacuum furnace equipped with a 00 mesh stainless steel wire mesh, and most of the precipitant was separated as a furnace liquid. Then, without removing the pulp-like material from the filtration machine,
A large amount of ion-exchanged water was supplied and washed under reduced pressure.
From an aqueous dispersion containing 1.5 denier of the pulp-like material (solid content) obtained in the above papermaking process and 1.0 denier of polyester fibers (trade name: Tetron, manufactured by Teijin) with a monofilament weave of 2 denier and a fiber length of 5. When paper was made using a Tatsupi standard sheet machine, a sheet with good paper-making properties and good texture was obtained, with good water drainage from the paper-making wire mesh.

After drying this sheet, it was hot pressed under the conditions of 200 qo and 150 k9 to obtain paper with a thickness of about 120 mm.

The tensile strength of this paper was 4.5 kg/square, the elongation was 12%, and the dielectric breakdown voltage was 1 V/barrel. Example 2 In Example 1, the concentrations of methanol and acetone in the precipitant were determined according to the following Table 1. A pulp-like material was obtained using the same machine except that the concentrations shown in 1 to 5 were used, and paper was then produced from it.

The measurement results for these are shown in Table 1. Table 1 *(
Weight ※) ※※ (KVihada) Ship. 1, 2, and 4 are examples in which the concentration of methanol in the precipitating agent is lower than the range of the present invention. In case of M.1, it becomes lumpy instead of pulpy. In both cases No. 2 and No. 4, the shape of the pulp-like material obtained was coarse.

Also, the gunwale. The surface of the paper obtained in Examples 2 and 4 was significantly uneven, and the dielectric breakdown pressure and tensile strength were also low. Also, the gunwale. 3 is a case where acetone is used as a precipitant, but the concentration of acetone in the precipitant is too low; A pulpy substance similar to 2 and 4 was bound. M. No. 5 is a case in which the concentration of methanol in the precipitant is within the range of the present invention, and when the obtained pulp-like material was made into paper, water drained from the paper-making wire mesh, and the paper-making properties were good and the texture was good, as in the example. Got a sheet. Example 3 A pulp-like material and paper were produced therefrom under exactly the same conditions as in Example 1, except that the concentration of the polyethylene terephthalate solution was changed.

The measurement results for these are shown in Table 2. Table 2 M. 1 is an example where the solution concentration is too low, and the shape of the pulp-like material obtained is small in particle size and has short bulb-like tentacles, which makes it difficult to drain water during paper making, resulting in a sheet with poor alignment. Ta.

M. 2 and 3 are within the scope of the present invention, have good pulp shape,
The pulp-like tentacles were long and water drained well during paper making, and a sheet with good texture was obtained. M. No. 4 is outside the scope of the present invention; the viscosity of the polyethylene terephthalate solution was high, the solvent removal was poor, and a coarse pulp-like material was obtained, which was used to make paper, but the surface was often uneven. Ikeai's defective product was obtained.

The paper obtained by processing the pulp-like material obtained by the present invention is not only effectively used as electrical insulating paper by taking advantage of its excellent heat resistance and black-green property, but also has flame retardant and mechanical properties. It is also applied to building materials, structural materials, packaging materials, etc.

Example 4 In Example 1, the precipitant was used as M. in Table 3 below. 1-4
A pulp-like material was obtained under exactly the same conditions except for the concentration shown in , and paper was then produced from it.

The measurement results for these are shown in Table 3. It can be seen that, regardless of the type of alcohol, if the concentration is appropriate, pulp that can be used to make good paper can be obtained.

Claims (1)

[Claims] 1. In a method for producing a pulp-like material by introducing a polyalkylene terephthalate solution into a precipitant: a) a solution of polyalkylene terephthalate dissolved in a phenolic solvent;
1. A method for producing a pulp-like material, which comprises introducing the polyalkylene terephthalate into a 00% by weight alcohol having 1 to 3 carbon atoms or an aqueous solution thereof under stirring to precipitate the polyalkylene terephthalate as fine particles.