JP3261393B2 - Polyester monofilament, method for producing the same, and industrial fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester monofilament excellent in hydrolysis resistance, a method for producing the same, and an industrial fabric using the polyester monofilament.

[0002]

2. Description of the Related Art Polyester monofilaments have excellent tensile strength, acid resistance, and dimensional stability. Therefore, industrial fabrics such as paper dryer canvases, papermaking wires, filters, conveyor belts, screen gauze, and various brushes, brushes, It has been widely used for applications such as fishing line.

However, when polyester monofilaments are used under conditions that are easily hydrolyzed, such as at high temperature and high humidity, for example, when used as a constituent material of a papermaking dryer canvas, the monofilaments in use decrease in strength due to hydrolysis degradation. Therefore, it was difficult to withstand long-term use.

Therefore, various proposals have been made in the past to improve the hydrolysis resistance of polyester monofilaments, for example, polyolefins such as polyethylene, polypropylene, polybutene, poly-4-methylpentene 1 and polystyrene. Monofilament to which a specific amount of is added (JP-A-51-1
No. 36923) is known, but polyester monofilaments obtained by this technique, for example, polyethylene terephthalate monofilaments to which polyethylene is added, have low strength and a small effect of improving hydrolysis resistance, and thus lack practical performance. was there.

[0005] Also, a method for improving the hydrolysis resistance of polyester by adding a carbodiimide compound is known. For example, a mono- or bis-carbodiimide compound is added and kneaded and spun in a short time. A method of forming a polyester filament containing no reactive carbodiimide (JP-A-50-95517) and a method of adding a polycarbodiimide compound having three or more carbodiimide groups in a molecule to a polyester (Japanese Patent Publication No. 38-15220). ), And the carboxyl end group is capped by reaction with the carbodiimide,
Free mono- and / or biscarbodiimide compound 3
Polyester fibers and filaments containing 0 to 200 ppm and at least 0.02% by weight of a free polycarbodiimide or a reaction product containing a still reactive polycarbodiimide group (JP-A-4-289221) have been proposed. I have.

The applicant of the present application also discloses a polyester monofilament for a papermaking canvas in which a specific amount of a specific carbodiimide compound is left unreacted (Japanese Patent Application Laid-Open No. 58-1983).
No. 23916) and a method for producing an industrial polyester filament comprising adding a specific carbodiimide compound to a polyester containing a specific amount of phosphorus (JP-A-57-205518). Improvement of hydrolyzability has been attempted.

[0007]

However, in recent years, the use conditions of polyester monofilaments used for papermaking dryer canvas and the like tend to be more severe than in the past, and are more resistant than the above-mentioned prior art. There is a demand for a polyester monofilament having excellent hydrolyzability.

The present invention has been made as a result of studying to solve the above-mentioned problems in the prior art.
A polyester monofilament having even more excellent hydrolysis resistance than conventional ones, and useful as an industrial fabric, particularly a papermaking dryer canvas, and a method for producing the same, and an industrial fabric using the polyester monofilament. Is what you do.

[0009]

To achieve the above objects resolving means for the ## polyester monofilament of the present invention, terminal carboxyl group concentration of 10 eq / polyester 10 ⁶ g
The unreacted monocarbodiimide compound (A) is contained in an amount of 230 ppm or more and 1.5% by weight or less,
The polycarbodiimide compound (B) which partially reacts with the unreacted polycarbodiimide compound and / or the carboxyl terminal group of the polyester and has an unreacted carbodiimide group contains from 0.05% by weight to 1.5% by weight. It is characterized by.

The polyester monofilament of the present invention is obtained by adding a liquid composition obtained by melt-mixing a monocarbodiimide compound (A) and a polycarbodiimide compound (B) at 80 to 150 ° C. to the polyester at the entrance of a melt spinning machine. After melt-mixing with polyester, the mixture is spun. The concentration of the terminal carboxyl group is 10 equivalents / 106 g or less of polyester, and the unreacted monocarbodiimide compound (A) is 230 ppm or more and 1.5% by weight.
Hereafter, particularly preferably, a polycarbodiimide compound (B) containing 300 ppm or more and 1.3% by weight or less, partially reacting with the unreacted polycarbodiimide compound and / or the carboxyl terminal group of the polyester and having an unreacted carbodiimide group (B ) Is contained in an amount of 0.05% by weight or more and 1.5% by weight or less, particularly preferably 0.1% by weight or more and 1.2% by weight or less.

Further, the industrial woven fabric of the present invention is characterized in that the polyester monofilament having the above characteristics is used for at least a part of a weft and / or a warp.

Hereinafter, the present invention will be described in detail. The polyester used in the present invention is mainly composed of polyethylene terephthalate (hereinafter referred to as PET) and polybutylene terephthalate. A part of the dicarboxylic acid component is isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4 -Cyclohexanedicarboxylic acid, adipic acid, sebacic acid, dimer acid, sulfonic acid metal salt-substituted isophthalic acid, etc., and part of the glycol component may be diethylene glycol, neopentyl glycol, 1,4-cyclohexanediol, , 4
-Cyclohexanedimethanol, polyalkylene glycol, or the like. Further, a small amount of a chain branching agent such as pentaerythritol, trimethylolpropane, trimellitic acid, trimesic acid, and boric acid can be used in combination.

The polyester used in the present invention includes:
Various inorganic particles such as titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin, and zirconate, and particles such as cross-linked polymer particles and various metal particles, as well as conventionally known antioxidants , Sequestering agents, ion exchange agents, anti-coloring agents, light-fast agents, inclusion compounds, antistatic agents, various coloring agents, waxes, silicone oils, various fluorine-based surfactants, and various reinforcing fibers It may be.

Further, the polyester used in the present invention includes:
It contains two or more blended polymers of the above-mentioned polyesters, and further includes resins other than the above-mentioned polyesters, such as polyamides, polyesteramides, polyolefins, epoxy resins, silicone resins, polycarbonates, polyurethane resins, polyacrylates, and fluorine. What blended resin etc. as needed may be sufficient.

The polyester monofilament of the present invention must have a terminal carboxyl group concentration of 10 equivalents / 10 ⁶ g or less. Here, the term “terminal carboxyl group concentration” refers to ANALYTICAL CHEMISTRY,
Vol., Page 1614.
When the terminal carboxyl group concentration exceeds 10 equivalents / 10 ⁶ g, even if the following conditions are satisfied, only monofilaments having a low hydrolysis resistance level are obtained, which is not preferable.

In order to obtain a polyester monofilament having a terminal carboxyl group concentration of 10 equivalents / 10 ⁶ g or less according to the present invention, the terminal carboxyl group concentration is 10 equivalents / 10 ⁶ g.
For more polyesters, in the molten state of the polyester, a known epoxy compound or oxazoline such as phenyl glycidyl ether, N-glycidyl phthalimide, o-phenyl phenyl glycidyl ether, ethylene oxide, and propylene oxide, or the carbodiimide compound described above. Can be obtained by reacting a suitable amount of the compound of formula (I), but the polyester monofilament of the present invention is obtained by converting unreacted monocarbodiimide compound to 23
Since it contains 0 ppm or more and 1.5% by weight or less, it is most advantageous to use a monocarbodiimide compound.

That is, the amount of the monocarbodiimide compound remaining unreacted in the polyester after the reaction becomes 230 ppm or more and 1.5% by weight or less in the polyester after the reaction, depending on the terminal carboxyl group concentration of the polyester as a raw material and the reaction conditions. It is advantageous to add and react the monocarbodiimide compound of the formula (1) to the polyester.

The limiting viscosity of the polyester monofilament of the present invention is usually 0.6 or more. here,
The intrinsic viscosity is the intrinsic viscosity obtained from the viscosity measured at 25 ° C. in an orthochlorophenol solution, and is represented by [η].

In order to efficiently exhibit the effects of the present invention, a phosphorus compound can be contained in the polyester in an amount of 50 ppm or less as a phosphorus atom and within the range of the following general formula.

5 × 10 ⁻³ ≦ P ≦ M + 8 × 10 ⁻³ (where P is mol% of phosphorus atom with respect to the dibasic acid constituting the polyester, M is a metal in the polyester resin, and Group II, VII, VIII and one or two or more metal atoms selected from the third and fourth cycles are mol% with respect to the dibasic acid constituting the polyester, where M = 0. May be).

The monocarbodiimide compound (A) contained in the polyester monofilament of the present invention includes:
Any compound may be used as long as it has one carbodiimide group in one molecule. For example, N, N'-di-o-
Triylcarbodiimide, N, N'-diphenylcarbodiimide, N, N'-dioctyldecylcarbodiimide, N, N'-di-2,6-dimethylphenylcarbodiimide, N-triyl-N'-cyclohexylcarbodiimide, N, N ' -Di-2,6-diisopropylphenylcarbodiimide, N, N'-di-2,6-di-tert.
-Butylphenylcarbodiimide, N-triyl-N '
-Phenylcarbodiimide, N, N'-di-p-nitrophenylcarbodiimide, N, N'-di-p-aminophenylcarbodiimide, N, N'-di-p-hydroxyphenylcarbodiimide, N, N'-di- Cyclohexylcarbodiimide, N, N'-di-p-triylcarbodiimide and the like.

These monocarbodiimide compounds (A)
Arbitrarily select one or more compounds from
The compound having an aromatic skeleton tends to be advantageous from the viewpoint of stability after being added to the polyester. Among them, N, N′-di-2,6-diisopropylphenylcarbodiimide, N, N'-di-2,
6-di-tert.-butylphenylcarbodiimide, N,
N'-di-2,6-dimethylphenylcarbodiimide,
And N, N'-di-o-triylcarbodiimide tend to be advantageous. In particular, N, N'-di-2,6-diisopropylphenylcarbodiimide is most advantageously used because of its excellent reactivity. You.

The unreacted monocarbodiimide compound (A) contained in the polyester monofilament of the present invention must be in the range of 230 ppm to 1.5% by weight, and the unreacted monocarbodiimide compound The content of (A) is in the range of 300 ppm or more and 1.3% by weight or less, but is more preferable. When the content of the unreacted monocarbodiimide compound (A) contained in the polyester monofilament is less than 230 ppm, the effect of improving hydrolysis resistance is insufficient, and
When the amount is more than the weight%, the physical properties of the monofilament are impaired, and the monocarbodiimide compound (A) is more contained in the polymer.
It is not preferable because bleed-out becomes easy.

Here, the content of the carbodiimide compound (A) having an unreacted monocarbodiimide group in the polyester monofilament according to the present invention is measured by the following method. (1) About 200 mg of a sample is weighed into a 100 ml measuring flask. (2) Add 2 ml of hexafluoroisopropanol / chloroform (volume ratio 1/1) to dissolve the sample. (3) When the sample is dissolved, add 8 ml of chloroform. (4) Acetonitrile / chloroform (volume ratio 9/1)
Is gradually added to make 100 ml while precipitating the polymer. (5) The sample solution is filtered through a 0.45 μm disk filter and quantitatively analyzed by HPLC. HPLC analysis conditions are as follows. Column: Inertsil ODS-2 4.6 mm
× 250 mm Different phase: acetonitrile / water (volume ratio 94/6) Flow rate: 1.5 ml / min Sample quantity: 20 μl Detector: UV (280 nm).

The mixing and reaction between the monocarbodiimide compound (A) and the polyester are carried out by adding the monocarbodiimide compound (A) to the molten polyester immediately after the completion of the polycondensation reaction and stirring and reacting the mixture. After adding and mixing the carbodiimide compound (A), kneading in a reaction vessel or extruder.
The reaction can be carried out, or a method in which a liquid monocarbodiimide compound (A) is continuously added to the polyester with an extruder, and kneaded and reacted.

The polycarbodiimide compound (B) contained in the polyester monofilament of the present invention includes an aromatic polycarbodiimide represented by the following general formula. Among them, R in the following general formula is an isopropyl group. Certain polycarbodiimide compounds are particularly preferred.

[0027]

Embedded image (However, R in the formula represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n represents an integer of 2 to 30.) The above-mentioned polycarbodiimide compound (B) is at least a part of carbodiimide in a polyester monofilament. The group is present in an unreacted state. The carbodiimide group of the polycarbodiimide compound (B) has lower reactivity of the carbodiimide group than the carbodiimide group of the monocarbodiimide compound (A), and therefore, when used in combination with an excess of the monocarbodiimide compound (A) as in the present invention. In the polyester monofilament, a polycarbodiimide compound which partially reacts with an unreacted polycarbodiimide compound and / or a carboxyl terminal group of polyester together with an unreacted monocarbodiimide compound and has an unreacted carbodiimide group is contained in the polyester monofilament. Will be.

The polyester monofilament of the present invention is a polycarbodiimide compound which partially reacts with an unreacted polycarbodiimide compound and / or a carboxyl terminal group of a polyester and has an unreacted carbodiimide group [hereinafter simply referred to as a polycarbodiimide compound (B )) Is required to be contained in an amount of 0.05% by weight or more and 1.5% by weight or less, preferably 0.1% by weight or more and 1.2% by weight or less. The above polycarbodiimide compound (B) contained in the polyester monofilament of the present invention
However, if it is less than 0.05% by weight, the effect of improving the hydrolysis resistance is insufficient, and if it is more than 1.5% by weight, the polyester tends to thicken or gel, making it difficult to melt-spin, which is not preferred. .

The mixing and reaction of the polycarbodiimide compound (B) and the polyester are carried out by adding the polycarbodiimide compound (B) to the molten polyester immediately after the completion of the polycondensation reaction and stirring and reacting the mixture. After adding and mixing the carbodiimide compound (B), the mixture is kneaded and reacted in a reaction vessel or an extruder, or by a method in which the liquid polycarbodiimide compound (B) is continuously added to the polyester with an extruder and kneaded and reacted. be able to.

The polyester monofilament of the present invention is obtained by melt-mixing a predetermined amount of a monocarbodiimide compound (A) and a polycarbodiimide compound (B) at 80 to 150 ° C. into a polyester at the entrance of a melt spinning machine. It is spun after addition and melt-mixing with polyester, and the terminal carboxyl group concentration is 10 equivalents /
Not more than 106 g of polyester, and 230 ppm or more of unreacted monocarbodiimide compound (A)
Wt% or less, particularly preferably 300 ppm or more.
3% by weight or less, a polycarbodiimide compound (B) which partially reacts with an unreacted polycarbodiimide compound and / or a carboxyl terminal group of polyester and has an unreacted carbodiimide group, at least 0.05% by weight,
The content is 1.5% by weight or less, particularly preferably 0.1% by weight or more and 1.2% by weight or less. The polyester monofilament is industrially advantageous in that it has an excellent effect of improving hydrolysis resistance and requires only one device for adding the monocarbodiimide compound (A) and the polycarbodiimide compound (B).

In a method in which the monocarbodiimide compound (A) and the polycarbodiimide compound (B) are separately added to the polyester at the entrance of the melt spinning machine, melt-mixed with the polyester, and then spun, two adding devices are required. ,
Operation becomes complicated. In addition, when a master pellet obtained by adding the polycarbodiimide compound (B) to the polyester in advance to the polyester is mixed with the monofilament raw material pellets, the monocarbodiimide compound (A) is added thereto, and the mixture is melt-spun, the polycarbodiimide compound (B) is used. Since the polyester-containing polyester master pellets must be exposed to the high temperature of the melt molding of the polyester twice during the production of the master batch and during the melt spinning, the modification of the polycarbodiimide compound (B) proceeds, and the resulting polyester monofilament Is not preferred, because the effect of improving the hydrolysis resistance of the polymer becomes low.

In the above, when the melting and mixing temperature of the monocarbodiimide compound (A) and the polycarbodiimide compound (B) is lower than 80 ° C., the dissolution and mixing of the monocarbodiimide compound (A) and the polycarbodiimide compound (B) become uneven. Becomes On the other hand, if the melting and mixing temperature is higher than 150 ° C., the effect of improving the hydrolysis resistance of the polyester monofilament obtained by adding a mixture of these compounds is not preferable.

The melt mixing time of the monocarbodiimide compound (A) and the polycarbodiimide compound (B) is preferably from 30 minutes to 3 hours. If the dissolution time is shorter than 30 minutes,
It is not preferable because the dissolution and mixing of the monocarbodiimide compound (A) and the polycarbodiimide compound (B) become uneven. On the other hand, if the melt mixing time is longer than 3 hours, the carbodiimide compound tends to deteriorate, which is not preferable.

In the production of the polyester monofilament of the present invention, a polyester containing a monocarbodiimide compound (A) and a polycarbodiimide compound (B) is prepared by:
For example, it is extruded from the spinneret through a polymer streamliner installed at the extruder tip, a filtration layer, etc.
It can be manufactured by a known method such as stretching and heat setting.

The polyester monofilament of the present invention is a continuous yarn composed of one single yarn, and may have any shape such as a cross-sectional shape such as a circle, a triangle, a square, and a regular polygon. The diameter of the cross section can be appropriately selected depending on the application, but the range of 0.05 to 3 mm is most often used. Further, although the required strength of the yarn varies depending on the application, it is preferably about 3.0 g / denier or more.

The polyester monofilament of the present invention thus obtained is superior in hydrolysis resistance to the conventional one, and is extremely useful as a constituent thread of industrial fabrics, especially dryer canvas for papermaking.

The industrial fabric of the present invention is obtained by weaving at least a part of the weft and / or warp constituting the fabric by using the above-mentioned polyester monofilament of the present invention.

The weaving method of this industrial woven fabric can be appropriately selected depending on the application, for example, plain weave, twill weave,
Known weaving methods such as heavy weaving and triple weaving can be employed.

Specific examples of the industrial woven fabric referred to in the present invention include a papermaking drier canvas, a papermaking wire, a filter, a conveyor belt, and a screen gauze. Can be obtained.

The industrial fabric of the present invention, in particular, the papermaking dryer canvas, is much more excellent in hydrolysis resistance than the conventional one, and is more excellent than the conventional papermaking dryer canvas using polyester monofilament. This is also very useful because deterioration during use is reduced and long-term use is possible.

[0041]

EXAMPLES The structure and effects of the present invention will be described in more detail with reference to the following examples.

[Examples 1 to 10, Comparative Examples 1 to 8] Intrinsic viscosity 0.93, terminal carboxyl group concentration 20 equivalents / 1
0 300Pp the ⁶ g of polyethylene terephthalate dried chips [antimony compound as a catalyst in an antimony atom
m, the manganese compound contains 60 ppm of manganese atoms (0.021 mol% of manganese atoms to terephthalic acid), and the phosphorus compound contains 30 ppm of phosphorus atoms (0.019 mol% of phosphorus atoms to terephthalic acid)] (hereinafter PET) Chips).

On the other hand, N, N'-di-2,6-diisopropylphenylcarbodiimide (hereinafter, referred to as TIC) is used as the monocarbodiimide compound (A), and the above-mentioned general formula (where R is a polycarbodiimide compound (B)). An isopropyl group) compound “Stavaxol P (registered trademark), a product of Bayer AG” (hereinafter, referred to as PCD) was prepared at a weight ratio corresponding to the addition amount shown in Table 1.

Next, the TIC was placed in a heating dissolution tank equipped with a stirrer and melted at 135 ° C.
The above PCD was added thereto with stirring, and a mixture (hereinafter, referred to as a TIC / PCD mixture) obtained by dissolving and mixing at 135 ° C. for 2 hours was obtained.

Subsequently, the above-mentioned TIC / PCD mixture was supplied to 100 parts by weight of the above-mentioned PET chips at the addition amount shown in Table 1 at the inlet of the extruder.

Then, the molten polymer kneaded at 285 ° C., which was kneaded for about 3 minutes, was spun from a spinneret through a filtration layer in a spinning pack and a streamline exchanger (“Static Mixer” manufactured by Chemis, USA) via a gear pump. .

Next, the spun filament was cooled in a hot water bath at 80 ° C., then stretched and heat-set by a total of 6 times according to a conventional method to obtain a polyester monofilament having a diameter of 0.4 mm.

The content of terminal carboxyl groups, the content of unreacted TIC, and the strength of the obtained polyester monofilament, and the strength retention when the monofilament was continuously treated in saturated steam at 121 ° C. for 12 days and 15 days were evaluated. The results are shown in Table 1.

[0049]

[Table 1] Comparative Example 9 The evaluation results of polyester monofilaments obtained in the same manner as in Example 1 except that the melting and mixing temperatures of TIC and PCD in Example 1 were changed to 160 ° C., are shown in Table 9 as Comparative Example 9. Also described in 1.

[Comparative Example 10] TI in Example 1
When the dissolution / mixing temperature of C and PCD was changed to 70 ° C., the dissolution of PCD was insufficient, and undissolved PCD was present in the TIC / PCD mixture and could not be added to the PET chip. Was.

[Comparative Example 11] TI in Example 1
When the dissolution / mixing time of C and PCD was changed to 20 minutes, the dissolution of PCD was insufficient, and undissolved PCD was present in the TIC / PCD mixture and could not be added to the PET chip. Was.

Example 11 and Comparative Example 12 Example 1
The polyester monofilament obtained in the above was used for warp and weft to prepare a twill woven canvas for a papermaking dryer. The canvas was mounted on a dryer of a neutral paper machine, and used at 140 ° C. for 4 months for drying the paper. Then, the canvas was removed. The residual strength of the warp of this canvas was 86%. In addition, a twill woven canvas for a papermaking dryer was prepared using the monofilament obtained in Comparative Example 2 for warp and weft. The canvas was mounted on a dryer of a neutral paper machine, and used at 140 ° C. for 4 months for drying the paper. Then, the canvas was removed.
The residual strength of the warp of this canvas was 70%.

[0053]

Industrial Applicability The polyester monofilament of the present invention and the polyester monofilament obtained industrially advantageously by the method of the present invention have excellent hydrolysis resistance as compared with conventional polyester monofilaments. It is useful as a constituent material for various industrial fabrics.

In particular, the papermaking dryer canvas using the polyester monofilament of the present invention has less decrease in strength at the time of use than the conventional papermaking dryer canvas using the polyester monofilament.
This is preferable because the use period can be extended.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI D21F 7/08 D21F 7/08 A (72) Inventor Tadanori Iwama 1 Kawara, Showa-cho, Okazaki-shi, Aichi Prefecture Toray Monofilament Co., Ltd. (56) References JP-A-3-104919 (JP, A) JP-A-4-289221 (JP, A) JP-A-58-163717 (JP, A) JP-A-6-220718 (JP, A) JP-A-58-23915 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D01F 6/62 D01F 6/92

Claims (6)

(57) [Claims] 1. An unreacted polycarbodiimide compound having a terminal carboxyl group concentration of 10 equivalents / 106 g or less of polyester and containing an unreacted monocarbodiimide compound (A) of not less than 230 ppm and not more than 1.5% by weight. And / or 0.05% by weight or more of a polycarbodiimide compound (B) partially reacting with a carboxyl terminal group of the polyester and having an unreacted carbodiimide group.
Polyester monofilament characterized by containing not more than weight%. 2. The polyester monofilament according to claim 1, wherein the content of the unreacted monocarbodiimide compound (A) is 300 ppm or more and 1.3% by weight or less. 3. The content of the unreacted polycarbodiimide compound and / or the polycarbodiimide compound (B) partially reacting with the carboxyl terminal group of the polyester and having an unreacted carbodiimide group is 0.1% by weight or more,
The polyester monofilament according to claim 1 or 2, wherein the content is 1.2% by weight or less. 4. A liquid composition obtained by melt-mixing a monocarbodiimide compound (A) and a polycarbodiimide compound (B) at 80 to 150 ° C. is added to polyester at the entrance of a melt spinning machine, and then melt-mixed with the polyester. The method for producing a polyester monofilament according to any one of claims 1 to 3, wherein the spinning is performed. 5. An industrial fabric, wherein the polyester monofilament according to claim 1, 2 or 3 obtained by the production method according to claim 4 is used for at least a part of a weft and / or a warp. 6. The industrial fabric according to claim 5, which is used as a papermaking dryer canvas.