JPS62106931A - Polyethylene terephthalate solution and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyethylene terephthalate solution and a method for producing the same. More specifically, polyethylene terephthalate and methylene chloride/1,1°2-trichloro-1,2 useful for producing ultrafine polyethylene terephthalate fibers.
, 2-trifluoroethane (hereinafter simply referred to as "trichlorotrifluoroethane") and a mixed solvent, and a method for producing the same.

[Conventional technology]

A method of forming fibers using a melt of a polymer and a low boiling point solvent is generally known as a dry spinning method. Among these, the so-called flash spinning method, in which a solution consisting of a low boiling point solvent and a polymer is extruded from a spinning nozzle and the solvent is instantly vaporized to form the entire fiber, is described in Japanese Patent Publications No. 40-28125 and No. 41-6215. The preparation of polyethylene terephthalate solutions is also described.

[Problem that the invention seeks to solve]

Ultra-fine, high-strength polyethylene terephthalate fibers are prepared from the polyethylene terephthalate solution described in Japanese Patent Publication No. 40-28125 and Japanese Patent Publication No. 41-6215? However, when the fibers are produced using the above methods, the strength of the obtained fibers is low and, in some cases, the fibers are not sufficiently thin. At present, a polyethylene terephthalate solution suitable for producing ultrafine polyethylene terephthalate fibers with satisfactory strength by the flood-spinning method and a method for producing the same have not been sufficiently established.

An object of the present invention is, in particular, to provide a polyethylene terephthalate solution and a method for producing the same, which are suitable for producing fine, high-strength polyethylene terephthalate fibers by the all-furanosee spinning method.

[Means for solving problems]

The present inventors have continued to conduct intensive research on a polyethylene terephthalate solution suitable for obtaining ultrafine, high-strength polyethylene terephthalate fibers by the fludge-spinning method. As a result, they discovered that solutions prepared using specific common metals are extremely useful, and that the baths can only be prepared under certain limited conditions.

The polyethylene terephthalate solution of the present invention is characterized by comprising polyethylene terephthalate and a methylene chloride/trichlorotrifluoroethane mixed bath medium.

The polyethylene terephthalate used in the present invention is a mixed solvent of 60/40% by weight of phenol/1,1.2.2-tetrachloroethane, and has an ηsp/c of 0 when measured at 35°C and a concentration of 1%. They range from fiber grades of about .6 to 4.5 to high viscosity resins made by solid phase polymerization. Other copolymerized components are added to the main chain, such as acid components such as isophthalic acid, phthalic acid, geltaric acid, azobic acid, etc., and glycol components such as diethylene glycol, phlopylene gellicol, 1,4-butanediol, 2,2
-Bis(4-hydroxyethoxyphenyl) Delono J?
Those containing up to 'e15 molt.

The concentration of polyethylene terephthalate in the solution of the present invention varies depending on the degree of polymerization of the polymer, the composition of the mixed solvent, etc., and is generally preferably 5 to 20 times the concentration, although it is not generally limited. The reason for this is that when this melt is used as a stock solution for fludge spinning, if it is less than 5% by weight, it becomes difficult to produce continuous filaments;

This is because if it exceeds 20% by weight, the filaments become spongy or foamed, not ultrafine fibers, and the strength becomes extremely weak.

Methylene chloride, which is the solvent used to prepare the solution of the present invention/
The composition of the trichlorotrifluoroethane mixed solvent is not necessarily limited depending on the degree of polymerization of the polymer, the concentration of the solution, the temperature of the solution when used for spinning, etc., but it is usually a composition of methylene chloride/trichlorotrifluoroethane in a weight ratio of 4: 6～
Preferably, the ratio is 9:1. If the composition of trichlorotrifluoroethane exceeds 60% by weight, it will be difficult to dissolve polyethylene terephthalate and a uniform solution will not be formed. Moreover, if it is less than 10% by weight, the fiber obtained by fludge-spinning using this solution will not be sufficiently drawn, probably because the vaporized gas temperature of the mixed solvent will become too low, and it will be difficult to obtain a high-strength fiber.

The above-mentioned polyethylene terephthalate solution has a specific volume of a mixture of polyethylene terephthalate and a methylene chloride/trichlorotrifluoroethane mixed solvent (+1" 1.
It is produced by a method characterized by heating to a temperature of at least 220° C., preferably 250° C. or higher to form a solution.

In the production method of the present invention, the specific volume of the mixture of polyethylene terephthalate and methylene chloride/trichlorotrifluoroethane mixed solvent is 1.2 CC/El or less.

However, when the specific volume is below 0.9 CC1g Ia, although a solution is formed, the system pressure increases significantly and equipment problems occur, so care must be taken when using it.

In addition, if the specific volume exceeds 1.2 CC71, the total temperature of the system will decrease by 2
Unless the temperature is raised to 80° C. or higher, a solution will not be formed and thermal decomposition of the polyethylene terephthalate or solvent will occur, which is not preferable.

In the production method of the present invention, a mixture of polyethylene terephthalate and a methylene chloride/trichlorotrifluoroethane mixed solvent is heated to at least 220°C or higher, preferably at 220°C or higher.
The bath liquid is completely formed by heating to 50° C. or higher, but if the heating temperature is lower than 220° C., a very long time is required to form the solution, and if the specific volume is large, it may not dissolve. At around 220℃, even if the specific volume is large, it will dissolve if it takes a long time,
Preferably 2 close to the melting point of polyethylene terephthalate
By heating to 50° C. or higher, it can be easily dissolved in a short time.

In the production method of the present invention, a pre-melted polymer and a heated solvent may be combined and dissolved. This method is effective for solution formation.

Particularly, such a method is effective in a spinning method that involves continuous steps from melting to spinning.

When a solution is formed from a mixture of polyethylene terephthalate and a methylene chloride/trichlorotrifluoroethane mixed solvent, it is unclear how the specific volume of the mixture and the heating temperature interact, but as the temperature increases, the system The pressure change is larger as the specific volume of the mixture is smaller, and the pressure itself indicated by the temperature is also higher.It is assumed that the balance between the pressure and temperature of the system causes the mixture to dissolve and not dissolve. . The relationship between pressure and temperature is unknown, but the total specific volume of the mixture is 1.2ee/fi' or less, and the temperature is 220°C.
As mentioned above, when heating preferably to 250° C. or higher, dissolution occurs under the pressure exhibited by the mixture of each specific volume and a solution is formed.

〔Effect of the invention〕

The solution of the present invention is suitable as a spinning stock solution when producing polyethylene terephthalate fibers by the fludge-spinning method, and it is possible to obtain continuous filaments composed of extremely thin fibrils and having satisfactory strength from this solution. I can do it.

Next, examples will be shown, but the examples do not limit the present invention in any way.

Blank space below [Example] Example 1 6 of phenol/1,1,2.2-tetrachloroethane
19 g of polyethylene terephthalate with a viscosity number (ηs p7c ) of 1.28 measured at 1% concentration at 35° C. using a 0/40% by weight mixed solvent and methyl chloride V7/1.1.2-
Mixed solvent of trichloro-1,2,2-trifluoroethane (weight ratio = 50750% by weight) 192. P? It was placed in a window autoclave with an internal volume of 200 d and a pressure resistance of 300 m. At this time, the polymer concentration was 9% by weight and the specific volume was 0.
．． It was 948cc/J. While rotating the Globera type stirrer, the temperature of the contents was raised from room temperature to 250℃ in about 30 minutes.
and maintained at that temperature to proceed with dissolution. Observation through the window attached to the autoclave revealed that a uniform solution was formed in about 8 minutes after reaching 250°C. At this time, the autoclave internal temperature and pressure were 251℃ and 216℃, respectively.
Examples 2 to 6, Comparative Example 1 Using the same polyethylene terephthalate, mixed solvent, and equipment as in Example 1, the polymer concentration was 9 times F[H] and the various specific volumes were the same as in Example 1. The results shown in the table (■) for the operation were obtained.

The following margins are Examples 7 to 9 and Comparative Examples 2.3 Using the same polyethylene terephthalate and equipment as in Example 1, the polyethylene terephthalate concentration was 9% by weight and the specific volume was 1. The same operation as in Example 1 was carried out by changing the mixed solvent composition using OCC/11, and the results shown in Table n> were obtained.

Example 10 The same polyethylene terephthalate and mixed solvent as in Example 1 were placed in an autoclave with an internal volume of 550 d.
Ii, 501.9 was prepared. (Polymer concentration is 8.9
% by weight, specific volume is 1.0 cc/II) Heat the autoclave while rotating the Grobetsu type stirrer, and
A solution of 97 cm"G was prepared at 192°C at 55°C.

The internal pressure of the autoclave was increased to 200 to 9/ciG with nitrogen gas, and the solution was heated to 0.9■φ* while maintaining that pressure.
8wφ through the 5w5L orifice.

Lead to 40+a+φ conduit, 1.0φ(I,/D-1)
It was released all at once into the atmosphere through a spinneret. As a result, a continuous filament with a fineness of 710 d consisting of extremely fine fibrils with a diameter of 1 to 4 μm was obtained.

The strength of this filament is 1.1.9/d and the elongation is 4
It was 8%.

Examples 11 to 16 Using the same polyethylene terephthalate and mixed solvent as in Example 1, the same operations as in Example 10 were carried out in the same apparatus as in Example 10 with various concentrations.
The results shown are obtained.

The following margin Examples 17 to 19, Comparative Example 4.5 Using the same polyethylene terephthalate as in Example 1,
By varying the mixed solvent composition, the polymer concentration was 9% by weight,
Specific volume 1. OCC/, P was charged into the same apparatus as in Example 10, and immediately before spinning, the autoclave internal pressure was adjusted to t 22 with nitrogen gas.
0kl? The same operation as in Example 1O was carried out except that the pressure was applied and maintained at /crn''G.The results shown in Table 1 were obtained.

Margin below

Claims (1)

[Claims] 1. Polyethylene terephthalate and methylene chloride/1.
A polyethylene terephthalate solution comprising a mixed solvent of 1,2-trichloro-1,2,2-trifluoroethane. 2. The concentration of polyethylene terephthalate in the solution is 5 to 2.
The polyethylene terephthalate solution according to claim 1, wherein the polyethylene terephthalate solution is 0% by weight. 3, methylene chloride/1,1,2-trichloro-1,2,
The composition of the 2-trifluoroethane mixed solvent is 4:
A polyethylene terephthalate solution according to claim 1 having a ratio of 6 to 9:1. 4, polyethylene terephthalate and methylene chloride/1,
The specific volume of the mixture with 1,2-trichloro-1,2,2-trifluoroethane mixed solvent is 1.2 cc/g or less,
A method for producing a polyethylene terephthalate solution, which comprises heating to at least 220°C or higher to form a solution. 5. The concentration of polyethylene terephthalate in the solution is 5~
The manufacturing method according to claim 4, wherein the content is 20% by weight. 6, methylene chloride/1,1,2-trichloro-1,2,
The composition of the 2-trifluoroethane mixed solvent is 4:
The manufacturing method according to claim 4, wherein the ratio is 6 to 9:1.