JPH043447B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to stain-resistant polyester fibers, and more particularly to stain-resistant polyester fibers that have improved restaining properties during washing. [Prior Art] Polyester fibers have traditionally been used in many fields because they have many excellent properties such as good dimensional stability, strength, and resistance to wrinkles. However, these excellent properties Compared to hydrophilic fibers such as cotton, due to the hydrophobic nature of polyester, polyester fibers have problems such as oil stains that adhere more easily and are difficult to remove, and stains that tend to re-adhere during washing. . This restaining property has always been a problem ever since polyester fibers were put into practical use, and many methods have been proposed to solve this problem. For example, a method of immersing a polyester molded product in a solution or dispersion of a copolymer of polyoxyethylene glycol and a polyester resin (see Japanese Patent Publication No. 1983-2512), hydrophilic properties such as dimethacrylate of polyoxyethylene glycol, etc. A method in which vinyl compounds are subjected to steam treatment after padding or spraying (see Japanese Patent Publication No. 51-2559), or a method in which low-temperature plasma treatment with oxygen-containing gas ('
Polymer' August 1978 issue, pages 904-912), etc. are known. However, all of these methods have been proposed as finishing treatments for polyester fiber products, and they have problems in terms of processing, such as being complicated to operate, requiring special equipment, or having poor processing reproducibility. Furthermore, there is a problem that the initial effect gradually disappears as the number of washings increases for clothes that are washed frequently, such as underwear and white coats. There was a strong desire for the emergence of polyester fibers (which do not darken when washed). On the other hand, it is known that polyoxyethylene glycol is copolymerized to make polyester fibers easier to dye. Therefore, we attempted to copolymerize polyoxyethylene glycol into polyester fibers to make the polymer itself hydrophilic and prevent it from staining with oil.We found that in order to obtain a sufficient level of stain resistance, the copolymerization amount was 10% by weight. %, preferably 20% by weight or more. However, when such a large amount of polyoxyethylene glycol is copolymerized, the mechanical properties of the resulting fiber are impaired, the shrinkage rate increases, and the light fastness deteriorates, making it unusable for practical use, especially for linen supplies. It could not be used for cotton blends. In addition, in order to maintain light fastness, the amount of polyoxyethylene glycol copolymerized is 10% by weight or less, especially 5% by weight.
With the following conditions, sufficient antifouling properties could not be obtained. [Object of the Invention] The present inventor aims to provide a polyester fiber that is particularly resistant to darkening caused by washing, and has excellent durability and antifouling properties. [Structure of the Invention] In order to achieve the above object, the present inventors have
After extensive research, it was discovered that by controlling the distribution of hydrophilic groups within the fibers, excellent antifouling properties can be achieved. In other words, as a result of intensive studies on the copolymerization method of polyoxyethylene glycol, which is a hydrophilic polymer, a specially selected structure consisting of a modified polyester in which one end-blocked polyoxyethylene glycol was copolymerized at the end of the main chain was developed. Possibly because polyoxyethylene glycol copolymerized at the end of the main chain acts specifically, polyester fibers with It has been found that this method exhibits significantly improved stain resistance and washing durability compared to fibers made of polyoxyethylene glycol or polyester insoluble in polyester mixed with polyoxyethylene glycol. The present invention was completed as a result of further studies based on this knowledge. That is, the present invention provides at least a portion of the terminal end of a polyester having ethylene terephthalate as a main constituent unit, with the following general formula R ¹ O (R ² O) - _o (wherein R ¹ is a monovalent compound having no active hydrogen). organic group,
^R2 is an alkylene group, n is an integer from 20 to 140)
A fiber made of a modified polyester copolymerized with 0.5 to 10% by weight of a polyoxyalkylene glycol component expressed by the following formula (1) and a crystal size in 100 planes [(100)A] (Å): (2) (100)A≧(1.7×10 ³ )×Δn−110 …(1) (100)A≧50 …(2) (In the formula, Δn is the birefringence index of the product fiber). The present invention relates to stain-resistant polyester fibers having an elongation of 100% or less and a strength of 3 g/de or more. Furthermore, the present invention provides a polyester having ethylene terephthalate as its main constituent unit, at least in part at its terminal end, with the following general formula R ¹ O(R ² O) - _o (wherein R ¹ is a monovalent compound having no active hydrogen). organic group,
^R2 is an alkylene group, n is an integer from 20 to 140)
Modified polyester copolymerized with 0.5 to 10% by weight of polyoxyalkylene glycol component represented by
The present invention relates to a method for producing stain-resistant polyester fiber, which is characterized by melt spinning at a take-up speed of 4500 m/min or more. The polyester referred to in the present invention refers to a polyester containing terephthalic acid as the main acid component and ethylene glycol as the main glycol component.
In such a polyester, a portion of its acid component terephthalic acid may be replaced with another difunctional carboxylic acid. Such other carboxylic acids include, for example, isophthalic acid, 5-sodium sulfoisophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, β-oxyethoxybenzoic acid, and p-oxybenzoic acid. Examples include difunctional aromatic carboxylic acids, difunctional aliphatic carboxylic acids such as sebacic acid, adipic acid, and oxalic acid, and difunctional alicyclic carboxylic acids such as 1,4-cyclohexanedicarboxylic acid. Further, a part of the ethylene glycol component may be replaced with other glycol components, such as trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, etc., and other diol compounds such as cyclohexane. Examples thereof include aliphatic, alicyclic, and aromatic diol compounds such as -1,4-dimethanol, neopentyl glycol, bisphenol A, and bisphenol S, and polyoxyalkylene glycols having both ends capped. Such polyesters can be produced by any method. For example, regarding polyethylene terephthalate, terephthalic acid and ethylene glycol may be directly esterified, a lower alkyl ester of terephthalic acid such as dimethyl terephthalate and ethylene glycol may be transesterified, or terephthalic acid and ethylene glycol may be 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 polycondensation reaction until the desired degree of polymerization is achieved. It is easily produced by the second stage reaction. In the present invention, at least one end of the polymer chain of the polyester is copolymerized with a polyoxyalkylene glycol having one end blocked and represented by the following general formula R ¹ O (R ² O) - _o . is necessary. In this formula, R ¹ is a monovalent organic group having no active hydrogen, preferably a hydrocarbon group, and particularly preferably an alkyl group, a cycloalkyl group, an aryl group, or an alkylaryl group. R ² is an alkylene group, preferably an alkylene group having 2 to 4 carbon atoms. Specific examples include ethylene group, propylene group, and tetramethylene group. It may also be a mixture of two or more types, for example a copolymer having an ethylene group and a propylene group. Further, n indicates an average degree of polymerization, and is in the range of 20 to 140. n is 20
When attempting to copolymerize polyoxyalkylene glycol of less than
A high copolymerization rate is required, and in such a case, the ends of the polyester are blocked, making it impossible to sufficiently increase the degree of polymerization of the polyester itself, and thus making it impossible to ensure the mechanical properties of the resulting fibers.
On the other hand, if n is larger than 140, the reaction between polyoxyalkylene glycol and polyester will not proceed sufficiently, resulting in the same result where polyoxyalkylene glycol is mixed with polyester, and high stain resistance cannot be obtained. . In particular, a preferable average degree of polymerization exists in a very limited range of 30 to 80. Preferred specific examples of such single end-blocked polyoxyalkylene glycols include polyoxyethylene glycol monomethyl ether, polyoxyethylene glycol monophenyl ether, polyoxyethylene glycol monooctylphenyl ether, polyoxyethylene glycol monononyl phenyl ether, Polyoxyethylene glycol monocetyl ether, polyoxypropylene glycol monophenyl ether, polyoxypropylene glycol monononyl phenyl ether, polyoxytetramethylene glycol monomethyl ether, polyoxyethylene glycol/
Examples include monomethyl ether of polyoxypropylene glycol copolymer and ester-forming derivatives thereof. In order to copolymerize the above single end-capped polyoxyalkylene glycol at the end of a polyester chain,
At any stage before the synthesis of the polyester described above is completed, for example, before the start of the first stage reaction, during the reaction,
After completion of the reaction, it may be added at any stage, such as during the second stage reaction, and the production reaction may be completed after the addition. In this case, if the amount used is too small, the antifouling performance and washing durability of the final polyester resin will be insufficient, and on the other hand, if it is too large, the degree of polymerization of the polyester will be too low during the polycondensation reaction process. Since the level reaches a plateau, the yarn physical properties such as strength of the polyester fiber finally obtained deteriorate. Furthermore, if a large amount of polyoxyalkylene glycol is contained, the light resistance of the resulting fiber will deteriorate, so it is preferable to keep the amount of copolymerization as small as possible. In the present invention, the copolymerized amount of polyoxyalkylene glycol should be in the range of 0.5 to 10% by weight, preferably in the range of 2 to 5% by weight, based on the polyester. As described above, in the present invention, since the amount of copolymerization of polyoxyalkylene glycol can be suppressed to a small amount, the obtained fiber can also maintain sufficient light resistance. If necessary, stabilizers, matting agents, antioxidants, flame retardants, antistatic agents, fluorescent brighteners, catalysts, color inhibitors, heat resistant agents, colorants, inorganic particles, etc. may be used in combination. good. In particular, when polyoxyalkylene glycol is left at high temperatures such as under melt-spinning conditions, it is easily oxidized and can cause problems such as decreased polymerization and discoloration. It is often preferable to use them together. Furthermore, if an ionic antistatic agent is used in combination with the modified polyester of the present invention, fibers with excellent antistatic properties can be obtained, further expanding the field of use thereof. The degree of polymerization of the modified polyester thus obtained is preferably 0.58 or more in terms of intrinsic viscosity, particularly preferably 0.6 or more, in order to exhibit sufficient fiber properties. Such modified polyester is made into fibers by melt spinning. Here, the fiber to be spun may be a solid fiber without a hollow portion or a hollow fiber having a hollow portion. Further, the outer shape and the shape of the hollow portion in the cross section of the fiber to be spun may be circular or irregular. When performing melt spinning, in order to obtain the fiber structure specified in the present invention, the take-up speed, that is, the spinning speed must be set at 4500.
A preferred method is to use a high speed of at least m/min. By spinning at a very high speed of 4500 m/min or more, large deformation stress acts during the spinning process, causing oriented crystallization of the polymer during spinning. As a process of developing fiber structure in high-speed spinning, an increase in orientation due to large spinning tension and accompanying crystallization have been observed. It is possible to obtain fibers having a large crystal size, and the fiber structure specified in the present invention can be easily obtained. Crystallization during spinning occurs at a spinning speed of approximately 3,500 m/min or higher, but this is not sufficient to ensure fiber mechanical properties and maintain stain resistance at a sufficient level.
A speed of 4500 m/min is required, preferably 5000 m/min or more, more preferably 5500 m/min or more. In addition to high speed spinning, it is also a preferred method to increase the cooling of the discharged yarn to increase the spinning tension.
For this reason, it is also a preferable method to make the yarn irregularly shaped or hollow. It is effective to further heat-treat the yarn thus obtained. For example, in the case of polyethylene terephthalate, crystallization begins at temperatures above 160°C, but becomes noticeable at temperatures above 175°C.
Therefore, temperatures above 175°C, more preferably
A method is employed in which the yarn or fabric is heat treated at a temperature exceeding 190°C. The heat treatment of the fabric can also be carried out simultaneously with heating for smoothing out wrinkles using an iron. In that case, the temperature exceeds 175°C, more preferably 190°C, on a stretching roller or heating plate.
A preferable fiber structure can be obtained by heat treatment at a temperature exceeding .degree. C. for a sufficient period of time. Furthermore, when the above heat treatment is combined with heat treatment in a fixed length or relaxed state, a more preferable fiber structure can be obtained. [Effect] The reason why the modified polyester fiber obtained in this way has a superior level of stain resistance compared to conventional materials is not fully understood, but it is thought to be due to the following mechanism. It is estimated that It is well known that polyester is lipophilic (hydrophobic). Therefore, it has an affinity for oil-based stains and is easily adsorbed into the fibers, and even when washed (i.e., the stains are removed with water), the oil-based components are not pushed out of the fibers, causing stains and even dark spots. It will remain in the fibers. However, oil-based stains are not uniformly adsorbed onto fibers. For example, the crystalline parts of polyester have short intermolecular distances and are compact, so it is impossible for oily components to penetrate between the crystal lattices of several angstroms. On the other hand, in the amorphous parts and the gaps between crystal micelles, the density of polyester molecules is low, and together with the lipophilic nature of polyester, oily components can easily penetrate between the fibers. Therefore, we have come to the conclusion that the key to preventing oily components from penetrating into the fibers is to make the gaps between these amorphous parts and crystalline micelles hydrophilic as efficiently as possible. Therefore, we have repeatedly investigated the presence of polyoxyalkylene glycol, a hydrophilic component, in polyester. First, polyoxyalkylene glycol whose both ends were blocked with a group not having active hydrogen was mixed with polyester and its antifouling effect was confirmed, and it was found to have antifouling properties. However, after repeated wearing and washing, its performance deteriorated rapidly, and it became clear that there was a problem with its durability.
In order to clarify the mechanism, washing water,
Furthermore, when polyoxyethylene glycol was analyzed in high-pressure boiling water, it was found that polyoxyalkylene glycol was easily extracted by water. On the other hand, when polyoxyethylene glycol having a group having active hydrogen at both ends is blended into polyester, copolymerization easily occurs, and even if the above-mentioned yarn spinning method is adopted, it is difficult to obtain a preferable fiber structure. It was also inferior in stain resistance. The reason for the poor stain resistance is presumed to be that polyoxyalkylene glycol was copolymerized completely randomly into polyester, and therefore polyoxyalkylene glycol could not be effectively collected in the amorphous portion. Recently, the use of polymers whose constituent components are bipolarly blocked, such as block copolymers and graft polymers, has been studied. For example, “surface”
Vol. 22, No. 6, p. 297 (1984) and “Industrial Materials” Vol. 33, 12
As stated on page 46 of the issue, research has been actively conducted to apply these polymers to polymer activators and polymer surface modification.
Block copolymerization of hydrophilic polyoxyalkylene glycol and lipophilic polyester;
In other words, when polyoxyalkylene glycol (PAG), which has one end with a group having active hydrogen and the other end is blocked with a group without active hydrogen, and polyester (PE) are copolymerized, PAG-PE
- PAG or PAG-PE molecules are present in a large amount of PE. This shows that PAG molecules tend to aggregate in PAG, so they tend to localize in the two regions of the polymer, one with a lot of polyoxyalkylene glycol and the other with a lot of polyester (polymer activator micelle structure). This can also be determined from the polymer properties shown in the following table.

〔Effect of the invention〕

The modified polyester fiber of the present invention exhibits its characteristics particularly when used in frequently washed clothing such as underwear and white coats, and retains its stain-resistance properties no matter how many times it is washed. No darkening occurs. Therefore, the stain-resistant modified polyester fiber of the present invention is particularly useful in the linen supply field. Furthermore, the modified polyester fiber of the present invention can be used for blending, inter-knitting, inter-weaving, etc. with natural fibers such as cotton and wool, recycled fibers such as rayon and acetate, and synthetic fibers other than the polyester fiber of the present invention. be done. [Example] The present invention will be further explained with reference to Examples below. Parts and % in Examples indicate parts by weight and % by weight, respectively. The intrinsic viscosity [η] of the polymer was determined from the value measured in an orthochlorophenol solution at 35°C, and the softening point (SP) was measured by the penetration method. In the examples, the fiber structure, contamination treatment, and contamination rate were determined using the following methods. (1) Crystal size Using an X-ray diffractometer RAD-A manufactured by Rigaku Corporation, the sample is fixed on a fiber sample stage and set vertically on the goniometer mount.
Measure diffraction from diffraction angle 2θ = 10° to 40°. Connect the lowest points of diffraction in the meridian direction with a straight line, and use this as a base to find the half width B of the diffraction peak of the (100) plane. Find the crystal size of the (100) plane using the following formula. Crystal size D=Aλ/[(√-)×cosθ] A is the correction coefficient, b is the correction angle λ is the wavelength of the X-ray, and 1.5481A is used. B: Half width (X-ray Crystallography, published by Maruzen Co., Ltd.) (Refer to Isamu Nita's supervision) (2) Stain treatment Pour 300 c.c. of washing liquid with the following composition into the pot of Colorpet dyeing tester (manufactured by Nippon Sensei Kikai), and soak a 10 cm x 13 cm fabric sandwiched in a holder in this pot. The mixture was stirred at 50°C for 100 minutes. Artificial dirt liquid 1% ●Motor oil (Dia Queen Motor Oil M
-2 manufactured by Mitsubishi Motors Corporation) 99.335% by weight ● B heavy oil 0.634% by weight ● Carbon black 0.031% by weight is used. Sodium alkylbenzenesulfonate 0.02% Sodium sulfate 0.03% Sodium tripolyphosphate 0.02% After being lightly washed with water, the sample was sandwiched between filter papers to remove excess contaminated liquid. Next, wash the contaminated sample in a home washing machine on gentle conditions and add 2g/ml of Marcel soap.
Washed for 10 minutes in 40°C hot water. after that,
Air dried. These staining and washing treatments constituted one cycle, and this cycle was repeated eight times. Next, the degree of contamination of the fabric was determined by the following method. (3) How to determine the degree of contamination Macbeth MS−2020 (Instrumental Color
Systems Limited) and CIE using the conventional method.
L* of the color system was determined, and the degree of contamination was calculated as follows. Contamination level (ΔL*) = L* before contamination - L after treatment
* Examples 1 to 5 and Comparative Examples 1 to 8 100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, 0.06 part of calcium acetate monohydrate (0.066 mol% relative to dimethyl terephthalate), and cobalt acetate tetrahydrate as a coloring agent. 0.009 parts of salt (0.007 mol% based on dimethyl terephthalate) was charged into a transesterification tank, and the mixture was heated under a nitrogen gas atmosphere for 4 hours.
The temperature was raised from 140°C to 220°C, and the methanol produced was distilled out of the system while transesterification was carried out.
After the transesterification reaction was completed, 0.058 part of trimethyl phosphate (0.080 mol % based on dimethyl terephthalate) was added as a stabilizer. Then, 10 minutes later, 0.04 part of antimony trioxide (0.027 mol % based on dimethyl terephthalate) was added, and at the same time, the temperature was raised to 240°C while expelling excess ethylene glycol, and the mixture was transferred to a polymerization vessel. After adding the polyoxyethylene glycol listed in Table 2 in the amount listed in Table 2 to the polymerization reactor, the pressure was reduced from 760 mmHg to 1 mmHg over 1 hour, and at the same time the temperature was raised from 240°C to 280°C over 1 hour and 30 minutes. After further polymerization for 2 hours at a polymerization temperature of 280° C. under reduced pressure of 1 mmHg or less, 0.4 part of Irganox 1010 (manufactured by Ciba Geigy) as an antioxidant was added under vacuum, and then polymerization was continued for another 30 minutes. The obtained polymer was made into chips according to a conventional method. High-speed spinning was performed using this chip. Pore diameter
Using a spinneret with 24 circular spinning holes of 0.28 mm, the polymer was wound at a temperature of 290 DEG C. and at the spinning speed shown in Table 2. Furthermore, the obtained high-speed spun yarn was run on a heat plate to heat set it. The heat treatment temperature is
The temperature was 190°C and the time was 2 seconds. Circular knitting was performed using the obtained polyester filament yarn to obtain a knit product. After further scouring and heat treatment using conventional methods, 2% Mika White ATN (manufactured by Mitsubishi Kasei) was added as a fluorescent dye.
Fluorescent dyed products were obtained by dyeing in a treatment bath containing owf at 130°C for 30 minutes, and the staining rate was determined by carrying out the staining treatment described above. The passing line is ΔL*=30 or less, preferably 20 or less.

[Table] In Comparative Examples 1 and 2, after spinning, the fibers were stretched 3.1 times. High antifouling properties were shown in Practical Examples 1 to 5 in which M-PEG copolymerized polyethylene terephthalate was spun at high speed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the crystal size in the (100) plane and the birefringence Δn of the stain-resistant polyester fiber, and the shaded area indicates the crystal size of the stain-resistant polyester fiber of the present invention. It shows.

Claims (1)

[Scope of Claims] 1 At least a part of the terminal end of a polyester having ethylene terephthalate as a main constituent unit is formed by the following general formula R ¹ O(R ² O)− _o (wherein R ¹ is a group having no active hydrogen) valent organic group,
^R2 is an alkylene group, n is an integer from 20 to 140)
A fiber made of a modified polyester copolymerized with 0.5 to 10% by weight of a polyoxyalkylene glycol component expressed by the following formula (1): ) and (2) (100) A≧(1.7×10 ³ )×Δn−110 ...(1) (100) A≧50 ...(2) (In the formula, Δn is the birefringence index of the product fiber) A stain-resistant polyester fiber that satisfies the following, has an elongation of 100% or less, and a strength of 3 g/de or more. 2. At least a part of the terminal end of the polyester having ethylene terephthalate as a main constituent unit has the following general formula R ¹ O (R ² O) - _o (wherein R ¹ is a monovalent organic group having no active hydrogen,
^R2 is an alkylene group, n is an integer from 20 to 140)
Modified polyester copolymerized with 0.5 to 10% by weight of polyoxyalkylene glycol component represented by
A method for producing stain-resistant polyester fiber, which comprises melt spinning at a take-up speed of 4500 m/min or more.