KR930007829B1 - Producing process of polyester monofilament for drafting paper - Google Patents

Abstract

blending 50-99.9 wt.% of polyester polymer and 0.1-50 wt.% of ethylene-tetrafluoroethylene copolymer; or blending 40-99.8 wt.% of polyester polymer, 0.1-50 wt.% of ethylene-tetrafluoroethylene copolymer and 0.1-10 wt.% of polycarbodiimide; and melt-spinning the mixture. The purpose of this method is to impart durable anti-soiling property to the convas during the paper-making process, as well as to prevent hydrolysis of the monofilament by reducing the end-released carboxylic group.

Description

Manufacturing method of polyester monofilament for papermaking

The present invention relates to a method for producing a polyester monofilament for papermaking, and more particularly, melt-spun a polyester polymer and an ethylene-tetrafluoroethylene polymer, which is a thermoplastic polymer, or further mixes a plicabodiimide. The present invention relates to a method for producing a monofilament having a fouling resistance and hydrolysis resistance by fusion spinning.

In general, papermaking equipment can be classified into Forming Fabrics, Press Felts, and Dry Canvas.

Among them, dry canvas is installed in a rotating drying cylinder while making paper in the form of a cloth, and serves to transport the wetland in an undried state. The complex is usually composed of three groups, and each group has a dry canvas as a belt, and the upper and lower parts are connected to each other to dry the wetlands.

Problems that may occur include a decrease in productivity due to contamination of the grass paper due to contamination of the canvas and a decrease in air permeability, and hydrolysis of the monofilament due to high temperature hot air for drying the paper, and thus a decrease in mechanical properties.

On the other hand, as the pollutants generated during the papermaking process at the paper mill, the printing inks are produced by using the short fibers and rosin of the pulp, the raw material of the paper, dust generated by the working environment, and waste paper. Attached to the surface of the paper, and the fall of lubrication material generated by the paper machine's rotation. These pollutants contaminate the paper surface during the paper drying process, producing poor paper products. To lower the papermaking drying effect.

In addition, due to the high temperature hot air for paper drying, the inside of the workplace is easily heated to high temperature and humidity, thereby causing hydrolysis of the monofilament, thereby facilitating the mechanical properties of the canvas.

In the conventional general papermaking process, the canvas must be frequently replaced for the same reason as described above, which causes a decrease in the productivity of the paper due to the interruption of the process.

Therefore, as a solution to the above problems, a known technique for improving fouling resistance in order to extend the canvas replacement time is a method using a low molecular fluorine compound (US Pat. No. 4,388,372), using a polyglycol containing a monoether group. (US Pat. No. 4,754,142) and the like, but these methods are simply a method of applying a low-molecular compound having a fouling resistance imparting function to the surface of the fiber or fabric, the contamination resistance effect by these methods It is pointed out that such a lack of durability is obtained because only a temporary effect can be obtained and the wear effect of the compound applied to the canvas disappears easily in actual use.

In addition, as a method of imparting hydrolysis resistance, Japanese Patent Laid-Open Publication No. 50-59,525 (1975) adds a polyester and a phenylene bioxazorine compound to reduce terminal free carboxyl groups to suppress hydrolysis of monofilaments. Although the method has been introduced, there is a disadvantage in that the polyester is decomposed in the melting process to lower the molecular weight as well as the terminal free carboxyl groups are not sufficiently reduced.

Accordingly, an object of the present invention is a method for reducing the contamination of the canvas during the papermaking process, the melt processing by mixing the thermoplastic polyester polymer, ethylene-tetrafluoroethylene copolymer, and polycarbodiimide during the manufacture of monofilament for papermaking Accordingly, to provide a paper-drying morofilament that prevents hydrolysis by permanently imparting pollution resistance to improve durability and at the same time reduce the terminal free carboxyl group.

Hereinafter, the present invention will be described in detail.

The present invention is to prepare a papermaking drying monofilament using a polyester polymer, it is characterized in that the melt polymer is prepared by mixing the ethylene-tetrafluoroethylene copolymer 0.1-50% by weight to 50 ~ 99.9% by weight of the polyester polymer It is done.

In another aspect, the present invention is characterized in that the polyester polymer 40 to 99.9% by weight, ethylene-tetrafluoroethylene copolymer 0.1 to 50% by weight, and polycarbodiimide by mixing 0.1 to 10% by weight of the melt spinning prepared.

As described above, the present invention will be described in more detail.

The present invention is a polyester polymer 0.1 to 50 ethylene-tetrafluoroethylene copolymer to polyethylene terephthalate having an intrinsic viscosity of 0.6 to 1.2 dl / g or 50 to 99.9 wt% of polybutylene terephthalate having an intrinsic viscosity of 0.9 to 1.2 dl / g. By mixing the weight percent and melt spinning to produce monofilament having stain resistance during paper drying.

At this time, if the amount of the ethylene-tetrafluoroethylene copolymer used is less than 0.1% by weight, the effect of addition may not be improved, and thus, the stain resistance may not be improved. If the amount of the ethylene-tetrafluoroethylene copolymer is more than 50% by weight, the strength of the monofilament decreases.

In addition, the present invention is a polyester polymer 40 to 99.9% by weight of polyethylene terephthalate or polybutylene terephthalate and 0.1 to 50% by weight of ethylene-tetrafluoroethylene copolymer, and in addition to the above components 0.1 to 10 polycarbodiimide It includes mixing the melt by weight in the same manner.

At this time, the ethylene-tetrafluoroethylene copolymer has the advantage that the pollutant is easily removed because the surface tension is large when the contact angle is measured. It is difficult to expect the improvement of and exceeds 50% by weight, a phenomenon that the strength of the monofilament is lowered.

In addition, when the amount of polycarbodiimide is less than 0.01% by weight, there is no effect of disintegrating or linking the polyester terminal free carboxyl group, and when the amount of the polycarbodiimide exceeds 10% by weight, the color of the monofilament is changed by thermal decomposition of the polycarbodiimide, but rather the terminal glass There is a problem that the content of the carboxyl group is increased.

As such, the present invention adjusts the content of the free carboxyl group to 10 meq / kg or less by hydrolyzing the polyester by disintegrating or quenching the terminal free carboxyl group which catalyzes the decomposition of the polyester by adding polycarbodiimide as an additive. It is to prevent shortening of life. In other words, even when the polyester is used under high temperature and high humidity conditions, it exhibits an effect of delaying hydrolysis and stabilizes it.

In addition, in the present invention, ethylene-tetrafluoroethylene is used as an essential component to impart pollution resistance, and both monofilaments mixed with two or three components as described above may be used, and additionally polycarbodiimide is added. If the case is excellent in the effect of reducing the content of the free carboxyl group compared to the case without addition.

Therefore, the polyester monofilament obtained by the present invention has excellent stain resistance as it permanently works by improving the surface properties of the monofilament, and also has hydrolysis resistance at the same time for long-term use at high temperature and high humidity conditions. Surface properties that can prevent the adhesion of contaminants, which are a problem in the process of use, are affected by the paper industry, and the water repellency of the paper is excellent. It has the effect of guaranteeing the life of the instrument.

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

[Production example]

(Method of mixing polymer and additive)

The polymer and the additive were melt mixed using a compounder according to the composition ratio of Table 1 below, and then mixed by metering using a dosing machine. At this time, the cylinder temperature was set at 260 to 320 ° C. and mixed, and the mixture was cut and used in a pellet state by passing through a cooling bath.

The polymer used in this process is a polyethylene-terephthalate polymer having a intrinsic viscosity of 0.6 to 1.2 dl / g and a terminal free carboxyl group having a content of 20 to 35 meq / kg, and a melting point of 250 to 270 ° C. And a copolymer having a copolymerization ratio of ethylene and tetrafluoroethylene of 1: 1 was used, and an additive was used as a compounding pellet to which a polycarbodiimide compound having a melting point of 130 to 160 ° C was added.

In this process, various colors of pigments were used to impart a specific color, and this coloration method was performed in a conventional manner.

(Method of manufacturing monofilament)

The pellets obtained by the compounding operation are crystallized at a temperature of about 100 to 140 ° C., and then dried in a dehumidifying dryer at 160 to 180 ° C. for 5 to 10 hours to have a moisture content of 0.003% or less, and then used for melt spinning. It was.

The melt spinning operation was carried out in a 280 to 320 ℃ range of the dried pellets transferred to the hopper of the melt spinning apparatus, the spinneret used was a circular mold having a diameter of 2.2mm and 45 holes. The molten monofilament injected through the spinneret passes through a cooling tank maintained at 60 to 90 ° C to obtain a sufficiently hardened monofilament.

The unstretched monofilament is stretched and heat-treated step by step to wind up the finished polyester monofilament to produce a product. At this time, the stretching ratio is performed to about 3 to 6 and the heat treatment temperature is carried out step by step from 80 to 200 ℃.

The polyester monofilament obtained in this way has a circular cross sectional shape with a diameter of 0.7 mm, a fineness of about 4780 denier and a roundness of 98% or more.

EXAMPLES 1-4

A polyethylene terephthalate having an intrinsic viscosity of 0.64 dl / g and a terminal free carboxyl group having a content of 30 meq / kg and an ethylene-tetrafluoroethylene copolymer having a melting temperature of 270 ° C. were mixed according to the ratio of Table 1 below. To evaluate the physical properties and stain resistance of the monofilament obtained using the results are shown in Table 1 below.

EXAMPLES 5-13

Polycarbodiimide having a melting point of 145 ° C was mixed according to the ratio of the following Table 2, and then the compounding pellet was dried in a drying process and then evaluated for physical properties, fouling resistance and hydrolysis resistance of the monofilament obtained through the melt spinning process. The results are shown in Table 1 below.

Example 14

Polyethylene terephthalate having an intrinsic viscosity of 0.64 dl / g and a content of terminal free carboxyl group of 30 meq / kg and an ethylene-tetrafluoroethylene copolymer having a melting temperature of 270 ° C. were mixed at a predetermined ratio as shown in Table 1 below. 0.3 wt% of blue pigment was added in the compounding process to prepare pellets, and the colored compounding pellets were used to evaluate the physical properties, fouling resistance and hydrolysis resistance of the monofilament obtained by the melt spinning process. It is shown in Table 1 below.

Example 15

Polycarbodiimide having a melting point of 145 ° C. was mixed according to the ratio of Table 3, and 0.3 wt% of cyanine blue pigment was added to prepare a pellet by compounding, followed by drying in a drying step to obtain a melt spinning step. The physical properties, fouling resistance and hydrolysis resistance of the monofilament were evaluated and shown in Table 1 below.

Example 16

Compounding a polybutylene terephthalate having an intrinsic viscosity of 1.01 dl / g and a content of terminal free carboxyl group of 35 meq / kg and an ethylene-tetrafluoroethylene copolymer having a melting temperature of 270 ° C. according to the ratio of Table 1 below. The physical properties, fouling resistance and hydrolysis resistance of the monofilament obtained using the pellets were evaluated and shown in Table 1 below.

Example 17

In order to enhance hydrolysis resistance, polycarbodiimide having a melting point of 145 ° C was mixed according to the ratio of the following Table 1, and then the compounding pellet was dried in a drying process and then subjected to melt spinning process. The contamination and hydrolysis resistance were evaluated and shown in Table 1 below.

Comparative Example 1

The physical properties and fouling resistance of the monofilament obtained using the polyethylene terephthalate having the intrinsic viscosity of 0.64 dl / kg and the content of the terminal free carboxyl group of 30 meq / kg are shown in Table 1 below.

[Comparative Examples 2-4]

The polyethylene terephthalate of Comparative Example 1 and polycarbodiimide having a melting point of 145 ° C. were mixed according to the ratio of the following Table 2, and then the physical properties, fouling resistance and hydrolysis resistance of the monofilament obtained through the melt spinning process were evaluated. Is shown in Table 1 below.

[Comparative Example 5]

45% by weight of polyethylene terephthalate, 40% by weight of ethylene-tetrafluoroethylene copolymer, and 15% by weight of polycarbodiimide were mixed, and 0.3% by weight of cyanine blue pigment was added during compounding to prepare a pellet. Using the colored compounding pellets, the properties of the monofilament obtained through the drying process and the melt spinning process were evaluated. The results are shown in Table 1 below.

Comparative Example 6

The physical properties, fouling resistance and hydrolysis resistance of the monofilament obtained by using polybutylene terephthalate having an intrinsic viscosity of 1.01 dl / g and a content of terminal free carboxyl group of 35 meq / kg are shown in Table 1 below. .

TABLE 1

A: polyester polymer

B: ethylene-tetrafluoroethylene copolymer

C: polycarbodiimide resin

D: Cyanine Blue (pigment)

The physical property measurement method of the monofilament manufactured by the above method is as follows.

(Evaluation method for pollution resistance)

After 5 minutes of monofilament was immersed in lubricating oil, which is a kind of contaminant, the contact angle of the lubricating oil was evaluated by using the contact angle measuring device.

(Hydrolysis resistance evaluation method)

The monofilament was collected for 5 days under high pressure steam at 130 ° C. using an accelerated life measuring apparatus, which is a hydrolysis measuring apparatus, and then evaluated by measuring the change in the terminal glass carboxyl group of fiber properties and intrinsic viscosity.

(Measurement of Intrinsic Viscosity)

The polymer was prepared at a solubility of 0.5 dl / g using a 1: 1 mixed solvent of phenol and tetrachloroethane, and then the time for the solution to pass through the capillary using an Ubbelohde Viscometer in a 20 ° C thermostat. It was obtained by measuring the intrinsic viscosity.

(Measuring method of terminal free carboxyl group)

Grind the polymer finely into a grinder, put 0.1-0.2 g into a test tube, add benzyl alcohol, and dissolve by stirring for about 2 minutes at a temperature of 215 ℃. The lysate is quenched in water at room temperature and then added to a beaker with 10 ml of chloroform. Phenolphthalein is added to this solution and titrated using 0.1N caustic soda solution dissolved in benzyl alcohol. And it calculated by performing the blank test which titrates the mixed solution of the same amount of benzyl alcohol and chloroform.

Claims (2)

In preparing the papermaking monofilament by melt spinning using a polyester polymer, 50 to 99.9 wt% of the polyester polymer and 0.1 to 50 wt% of the ethylene-tetrafluoroethylene copolymer are mixed and melt spun. Method for producing a polyester monofilament for papermaking drying. In preparing a papermaking monofilament using a polyester polymer, 40 to 99.9% by weight of polyester polymer, 0.1 to 50% by weight of ethylene-tetrafluoroethylene copolymer, and 0.1 to 10% by weight of polycarbodiimide Method for producing a polyester monofilament for papermaking drying, characterized in that the melting and spinning by mixing.