JPS6043858B2 - polyester molding - Google Patents

Description

[Detailed description of the invention] The present invention relates to polyester molded articles.

More specifically, the present invention relates to a polyester molded product having micropores inside. Polyesters containing alkylene terephthalate as the main repeating unit have excellent performance and are used in a wide range of fields in the polymer industry, particularly in fiber and film applications.

However, since such polyester is hydrophobic, for example, when polyester is molded into fiber, the resulting fiber itself has a disadvantage of poor water absorption and hygroscopicity.

Furthermore, when polyester is formed into a film, sheet, etc., it has the disadvantage of poor printability and adhesive properties. Conventionally, in order to impart water absorbency to polyester fibers, a method has been proposed in which polyalkylene glycol or polyalkylene glycol and an organic sulfonic acid metal salt are blended at a stage before spinning.

However, the polyester molded articles obtained by these methods do not have sufficient hydrophilicity, and furthermore, the hydrophilicity decreases when washed or the like. Furthermore, there is also the disadvantage that the physical properties of the resulting fibers, particularly light resistance and heat resistance, are reduced. Furthermore,
A method has been proposed in which the above-mentioned hydrophilic fibers are heated in water or an alkaline aqueous solution to form wrinkle-like micropores in the fiber axis direction on the fiber surface to improve hygroscopicity and water absorption.

However, even with this method, the fibers obtained do not have sufficient hygroscopicity and water absorption, and furthermore, other physical properties of the fibers, particularly strength, etc., have the disadvantage of being significantly reduced. The present inventors have developed a polyester molded product that does not have the above-mentioned drawbacks, has excellent durability, hygroscopicity and water absorption, and also has excellent adhesiveness and printability, and which has less deterioration in other physical properties. As a result of intensive study to provide molded products, we decided to blend specific compounds into the polyester before molding it.
By removing a part of the specific compound after molding, it is possible to obtain a new polyester molded product having uniformly micropores, and the above-mentioned object can be achieved, and the present invention has been achieved. It is something. That is, the present invention relates to a polyester mainly containing repeating units represented by the following general formula [1] (n is an integer of 2 to 6). A polyester molded product consisting of a polyester molded product, the molded product has micropores uniformly and at least partially communicating with each other, and the micropores are formed by the following general formula [■] [R is 3 to 30 carbon atoms] Alkyl group or carbon number 7-
40 is an aryl group or an alkylaryl group, M represents an alkali metal or an alkaline earth metal.

] A polyester molding having micropores formed by removing at least a portion of the organic sulfonic acid metal salt from a polyester molding compounded with the organic sulfonic acid metal salt represented by the above formula by treating with an aqueous solution of an alkaline compound. It is related to things. The polyester used in the present invention has terephthalic acid as the main acid component and has 2 to 2 carbon atoms.
The main glycol component is at least one type of alkylene glycol selected from No. 6 alkylene glycol, namely ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol and hexamethylene glycol, particularly preferably ethylene glycol and tetramethylene glycol. Targets polyester.

In such a polyester, part of its acid component terephthalic acid may be replaced with another difunctional carboxylic acid. Examples of such other carboxylic acids include isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid,
Difunctional aromatic carboxylic acids such as diphenoxyethanedicarboxylic acid, β-oxyethoxybenzoic acid, P-oxybenzoic acid, difunctional aliphatic carboxylic acids such as sebacic acid, adipic acid, oxalic acid, or 1● Examples include difunctional alicyclic carboxylic acids such as 4-cyclohexanedicarboxylic acid. Further, a part of the glycol component of the polyester may be replaced with another glycol component, and such glycol components include the above-mentioned glycols other than the main component and other diol compounds, such as cyclohexane-1,
Examples include aliphatic, alicyclic, and aromatic diol compounds such as 4-dimethanol, neopentyl glycol, bisphenol A1, and bisphenol S. Such polyesters can be obtained by any manufacturing method.

For example, to explain polyethylene terephthalate, terephthalic acid and ethylene glycol are directly esterified, a lower alkyl ester of terephthalic acid such as dimethyl terephthalate and ethylene glycol are transesterified, or terephthalic acid and ethylene glycol are transesterified. The first stage reaction is to produce a glycol ester of terephthalic acid and/or its low polymer by reacting with oxide, and then the product is heated under reduced pressure to undergo a polycondensation reaction until a desired degree of polymerization is achieved. It is easily produced by the second stage reaction. In the production of polyester, in addition to the compounds used as raw materials mentioned above, small amounts of other dicarboxylic acids or glycols as mentioned above may be used in combination. Furthermore, a polyfunctional compound having three or more ester-forming functional groups, such as trimellitic acid, pyromellitic acid, glycerin pentaerythritol, etc., may be used in combination within the range where the obtained polyester has substantially thermoplasticity. . Further, a monofunctional compound such as benzoic acid may be used in combination within the range in which a polyester having a sufficient high molecular weight can be obtained. The form of the polyester molded product is
Any material may be used, such as fibers, films, sheets, etc.

Fibers are particularly preferred; in this case, the cross-sectional shape may be round or irregular, and there is no restriction on the size of the cross-section. The polyester molded product according to the present invention is a polyester molded product such as the one described above in which fine pores are uniformly present.

Such micropores are uniformly scattered throughout the cross section of the molded article.
If the micropores are concentrated near the surface of the molded product and are not uniformly scattered over the entire cross section, the polyester molded product will have insufficient water absorption and hydrophilicity, and other physical properties will deteriorate. Further, the micropores communicate with each other, and as a result, the outside and the inside of the molded product as a whole communicate through the micropores. In this way, sufficient water absorption and hydrophilicity can be obtained for the first time. The form of the polyester molded article of the present invention will be explained below using photographs, taking the case of fiber as an example.

FIG. 1 is a cross section of the fiber according to the present invention, and FIG. 2 is a photograph showing the outer shape of the fiber.

FIGS. 3 and 4 are photographs showing the cross section and external shape of a conventional fiber having micropores (fiber obtained in Comparative Example 1, which will be described later). As shown in FIG. 1, the fibers of the present invention have micropores uniformly scattered over the entire cross section, and
It is not unevenly distributed in a part of the fiber cross section, nor is it concentrated only near the fiber surface. Further, as shown in FIG. 2, the outer shape of such fibers is not fibrillated, but maintains the shape of threads, and the micropores are arranged in the fiber axis direction. On the other hand, as shown in FIG. 3, conventional fibers with micropores have micropores only near the fiber surface, and the micropores are not uniformly present over the entire cross section. Moreover, the outer shape of such fibers becomes fibrillated as shown in FIG. 4, and the strength is significantly reduced. As mentioned above, when the polyester molded product is a fiber, micropores are uniformly present over the entire cross section.

In addition, the size of such micropores is 0.001 to 5 in diameter.
Preferably, it is in the μm range. The diameter of the micropore is 0.
If the diameter is smaller than 0.001 μm, the water absorption effect tends to decrease, and if the diameter is larger than 5 μm, the strength of the fiber itself will decrease. In particular, the size of the micropores is preferably in the range of 0.01 to 1 pL. The proportion of such micropores in the fiber cross section is preferably 0.01 to 50% of the fiber cross section. If it is less than 0.01%, the water absorption effect will be reduced, and if it is more than 50%, the strength of the fiber itself will be reduced.

Among these, the range of 0.1 to 30% is particularly preferable. Such a molded article of the present invention can be easily produced by blending an organic sulfonic acid metal salt into a polyester before completing molding, and eluting at least a portion of the sulfonic acid metal salt after molding.

The organic sulfonic acid metal salt used here has the following general formula [■
] [R is an alkyl group having 3 to 30 carbon atoms, or an alkyl group having 7 to 30 carbon atoms
40 aryl or alkylaryl groups are shown.

M represents an alkali metal or an alkaline earth metal.゛It is expressed as ゛.

In the general formula [formula], when R is an alkyl group or an alkylaryl group, it may have a linear or branched side chain. In particular, from the viewpoint of compatibility with polyester, organic sulfonic acid metal salts in which R is an alkyl group are preferred. M is N
Alkali metals such as al/KNLi, Mg. , and alkaline earth metals such as Ca. Among them, Na. K is preferred. Note that when using the organic sulfonic acid metal salt, it is not necessary to use a single compound, and a mixture of organic sulfonic acid metal salts having various alkyl groups or alkylaryl groups may be used. Preferred examples of such metal organic sulfonates include sodium stearylsulfonate, sodium octylsulfonate, sodium dodecylsulfonate, and mixtures of sodium alkylsulfonates having an average carbon number of 14. It will be done. The amount of the organic sulfonic acid metal salt added to the polyester is 0.01 parts by weight per 100 parts by weight of the polyester.
A range of ~4 saliva parts is preferred.

If the amount is less than 0.01 part by weight, the water absorption and hygroscopicity of the polyester molded product obtained after elution and removal of the organic sulfonic acid metal salt will not be sufficient as described below, and if it is more than 4 parts by weight, the mixing operation will be difficult. This is not preferable because it makes molding difficult. Such an organic sulfonic acid metal salt is added to the polyester at any stage before the completion of the molding process.

For example, even if it is added in advance to the raw materials for polyester production, the first
It can also be added during the stage reaction or during the subsequent second stage polycondensation reaction, or the polymer obtained after the polycondensation reaction and the organic sulfonic acid metal salt can be melted using, for example, a melt extruder. It is also possible to adopt a method of mixing, a method of adding to the polymer and mixing at a stage before exiting the melt molding machine, etc. When molding a polyester molded product blended with an organic sulfonic acid metal salt, there is no need to employ special conditions, and any conditions can be employed. Various methods can be used to remove the organic sulfonic acid metal salt from the polyester molded product produced in this way, but it is particularly preferable to immerse the polyester molded product in an aqueous solution of an alkaline compound. The organic sulfonic acid metal salt can be easily eluted and removed.

Examples of alkaline compounds include sodium hydroxide and potassium hydroxide. hydroxide, tetramethylene ammonium hydroxide, sodium carbonate, potassium carbonate, etc. are used. Among these, sodium hydroxide and potassium hydroxide are preferred. The concentration of such an aqueous solution of an alkaline compound depends on the type of alkaline compound, treatment. Although it varies depending on the method etc., it is usually carried out in the range of 0.01 to 40%, especially 0.1%.
A range of 30% is preferred. Processing temperature is room temperature to 100℃
The treatment time is usually within the range of 1 minute to 4 hours. When the polyester molded product is a fiber, the fiber obtained by spinning and drawing or a fabric made of the fiber may be immersed in an aqueous solution of the above-mentioned alkaline compound, and the proportion of the organic sulfonic acid metal salt to be eluted is adjusted. Although it varies depending on the amount of the organic sulfonic acid metal salt added and the required water absorption performance, it is preferable to elute at least 10% of the added amount.

The polyester molded article may contain conventionally known catalysts, color inhibitors, heat resistant agents, fluorescent agents, flame retardants, dyes, pigments, inert fine particles, and the like.

Since the polyester molded product of the present invention has uniform and continuous micropores, it exhibits excellent water absorption and hygroscopicity when used as a fiber, and has excellent printability and adhesion when made into a film or sheet. Furthermore, it can also be used as a filter membrane for sewage, wastewater, etc.

Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, parts in Examples indicate parts by weight, and the water absorbency of the obtained fibers was measured by the water absorption measuring method described below.

Water absorption measurement method A fabric is obtained from the fibers, and the fabric is washed with an anionic detergent sub (
The fabric was washed with a 0.3% aqueous solution of Kao Soap Co., Ltd. (manufactured by Kao Soap Co., Ltd.) for 3 gins at 40°C using a household electric washing machine, then dried, and the resulting sample was immersed in water for at least 3 gins. Afterwards
Dehydrate for 5 minutes using a household electric washing machine (manufactured by Fuji Electric Co., Ltd.).

It is obtained using the following formula from the weight of the dried sample before dehydration and the weight of the sample after dehydration. Example 1 197 parts of dimethyl terephthalate, 24 parts of ethylene glycono Vl, and 0.118 parts of calcium acetate were placed in a glass flask equipped with a rectifying column, and a transesterification reaction was carried out according to a conventional method. After distilling off a theoretical amount of methanol, the reaction was carried out. The product was transferred to a polycondensation flask equipped with a rectification column, and 0.11 parts of trimethyl phosphate was added as a stabilizer. 0.079 parts of antimony oxide was added as a cold polycondensation catalyst, and three powders were reacted at a temperature of 280°C and normal pressure. After reacting one powder under reduced pressure of 3-Hg,
Once returned to normal pressure, the carbon number is 8 to 20 and the average carbon number is 14.
After adding 1 part of a mixture of sodium alkylsulfonates, the pressure in the system was gradually reduced, and the 8 powders were reacted with stirring.

The final internal temperature was 280° C., the final internal pressure was 0.32 WfLHg, and the obtained polymer had an intrinsic viscosity of 0.655. After the reaction was completed, the polymer was formed into chips according to a conventional method and dried. Next, using this dried chip, 30
Make yarn of 0c1e/30fi1, 4.0ff! A multifilament of 75 de/36 fi1 was obtained. This filament was made into a knitted fabric, and after scouring and drying by a conventional method, it was treated with a 0.5% caustic soda aqueous solution at boiling temperature for 18 minutes to obtain a knitted fabric having an alkali weight loss rate as shown in Table 1. The water absorption rate of this stockinette fabric is shown in Table 1. Incidentally, FIGS. 1 and 2 are electron microscope (300@) photographs of the cross section and side surface of the constituent fibers of the knitted knitted fabric. Example 2 The same operation as in Example 1 was carried out except that the amount of the sodium alkyl sulfonate mixture added was changed to 5 parts to obtain polyethylene terephthalate chips, which were then spun and drawn to obtain 72 denier/36 A multi-filament filament was manufactured.

This filament was knitted into a knitted fabric, and after being scoured and dried by a conventional method, it was treated with a 0.5% caustic soda aqueous solution at boiling temperature to obtain a fabric made of fibers having micropores. The water absorption rate of this sample is as shown in Table 1.
Example 3 Polyethylene phthalate containing no sulfonic acid metal salt and having an intrinsic viscosity of 0.640 was obtained by performing almost the same operation as in Example 1 except that the sulfonic acid metal salt was not used. 3 parts of the alkyl sulfonic acid sorter mixture used in step 1 was heated to a maximum temperature of 290℃.
Melt mix using a screw-type melt extruder at °C;
Got a tip.

This chip was spun and drawn in the same manner as in Example 1 to produce a 73 denier/36 filament multifilament. This filament is used to make knitted fabrics,
A 18 powder alkali treatment was performed with a 0.5% caustic soda aqueous solution at boiling temperature. The water absorption rate of this fabric is as shown in Table 1. Comparative Example 1 Almost the same procedure as in Example 1 was used, except that instead of using w parts of the sodium alkyl sulfonate mixture in Example 1, 6.5 parts of the mixture of sodium alkyl sulfonates and 8 parts of polyethylene glycol were used. A multifilament of 74 denier/36 filaments was obtained.

Knitted fabric using this filament, 0.5
% caustic soda aqueous solution at boiling temperature for 120 minutes. The water absorption rate of this fabric is as shown in Table 1. In addition, electron microscope (300mm) photographs of the cross section and side surface of the constituent fibers of the stockinette fabric are shown in Figures 3 and 4.
It is a diagram. Comparative Example 2 The water absorption rate of the stockinette fabric obtained in Example 1 without alkali treatment is as shown in Table 1.

Comparative Example 3 The water absorption rate of the stockinette fabric obtained in Example 2 without alkali treatment is as shown in Table 1.

Comparative Example 4 The water absorption rate of the stockinette fabric obtained in Example 3 without alkali treatment is as shown in Table 1.

Claims (1)

[Scope of Claims] 1 Mainly consisting of a repeating unit represented by the following general formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ ・・・・・・[I] (n is an integer from 2 to 6) A polyester molded article made of a polyester, wherein the molded article has micropores uniformly and at least partially communicating with each other,
The micropores have the following general formula [II] RSO_3M...[II] [R is an alkyl group having 3 to 30 carbon atoms or 7 to 7 carbon atoms]
40 is an aryl group or an alkylaryl group, M represents an alkali metal or an alkaline earth metal. A polyester molded product having micropores formed by removing at least a portion of the organic sulfonic acid metal salt from a polyester molded product blended with the organic sulfonic acid metal salt represented by ] by treatment with an aqueous solution of an alkaline compound. thing. 2. The polyester molded article according to claim 1, wherein the micropores have a diameter of 0.001 to 5 μm. 3 Claim 1 or 2 in which the molded product is a fiber
The polyester molded article described in Section 1. 4. The polyester molded product according to claim 3, wherein the micropores are arranged uniformly in the fiber cross section and in the fiber axis direction. 5 The total cross-sectional area of micropores is 0.01 to 50% of the fiber cross-sectional area
The polyester molded article according to claim 3 or 4.