JPH043446B2 - - 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, an attempt was made to copolymerize polyoxyethylene glycol into polyester fibers to make the polymer itself hydrophilic and to prevent oil stains.In order to obtain a sufficient level of stain resistance, the amount of copolymerization was reduced to 10%. It was found that it is necessary to make the amount more than 20% 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. Further, in order to maintain light fastness, the copolymerization amount of polyoxyethylene glycol was set to 10% or less, particularly 5% by weight or less, but sufficient stain resistance 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 ends of the main chain acts specifically, polyester fibers with It has been found that this fiber exhibits significantly improved stain resistance and washing durability compared to fibers made of oxyethylene glycol or polyester in which polyoxyethylene glycol, which is insoluble in polyester, is mixed into polyester. The present invention was completed as a result of further studies based on this knowledge. That is, the present invention provides the following general formula (1) R ¹ O(R ² O)-n (1) (wherein R ¹ is a monovalent organic group without active hydrogen,
^R2 is an alkylene group, n is an integer from 20 to 140)
A fiber made of modified polyester copolymerized with 0.5 to 10% by weight of a polyoxyalkylene glycol component represented by
50~100Å, crystal size on (010) plane 65~170A
This relates to an antifouling polyester fiber having a birefringence of 0.15 or more, an elongation of 40% or less, and a strength of 4 g/de 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. -1,4-dimethanol, neopentyl glycol, bisphenol A, bisphenol S
Examples include aliphatic, alicyclic, and aromatic diol compounds such as, polyoxyalkylene glycol with both ends unblocked, and the like. 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 a polyoxyalkylene endblocked at one end represented by the following general formula (1) R ¹ O(R ² O)-n...(1) It is necessary that the glycol be copolymerized. 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 fiber. 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 as if polyoxyalkylene glycol was mixed with polyester, and high antifouling properties would not be obtained. do not have. 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. According to 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 a decrease in the degree of polymerization and discoloration. It is often preferable to use these in combination. 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. The spun fibers are drawn to have an elongation of 40% or less and a strength of 4 g/de or more in order to exhibit sufficient fiber performance, and are heat treated if necessary.
In particular, the birefringence should be increased to 0.15 or more by stretching. When the birefringence does not reach 0.15,
It is difficult for the crystal size in the (010) plane, which will be described later, to reach a preferable value, and it is difficult to obtain sufficient antifouling properties and durability. The upper limit does not need to be particularly limited, but if it is too high, the spinning properties will deteriorate, so it is preferably 0.18 or less. The fiber of the present invention has the above properties and has a special fiber structure, that is, the crystal size in the (100) plane is
Must be within the range of 50-100 Å. If even one of these ranges is exceeded, sufficient antifouling properties and durability cannot be exhibited. The following method is effective for obtaining such a fiber structure. That is, it can be obtained by strongly heat-treating a yarn obtained from the modified polyester using a conventional spinning method. The spinning speed of polyester is usually about 1000 m/min, and a stretching step is generally added to ensure its mechanical properties. However,
When this method is applied to the above-mentioned modified polyester, the above-mentioned fiber structure cannot be achieved as it is, and further sufficient heat treatment is required. For example, in the case of polyethylene terephthalate, crystallization begins at temperatures above 160°C and becomes noticeable at temperatures above 175°C.
Therefore, a method is employed in which the yarn or fabric is heat treated at a temperature exceeding 175°C, preferably at a temperature of 180°C or higher, and more preferably at a temperature exceeding 190°C. Furthermore, if the heat treatment temperature is too high, the fiber properties will deteriorate, so it is preferably 240°C or lower, particularly preferably 220°C or lower. The heat treatment of the fabric can also be carried out simultaneously with heating for smoothing out wrinkles using an iron. In the case of yarn, the above preferred fiber structure can be obtained by heat-treating it on a drawing roller or a heat plate at a temperature exceeding 175°C, more preferably at a temperature exceeding 190°C, over a sufficient period of time. . Furthermore, a more preferable fiber structure can be obtained when heat treatment is combined with heat treatment in a fixed length or relaxed state. The heat treatment time varies depending on the treatment temperature, and when the treatment temperature is T (°C) and the treatment time is t (seconds), the following formula is used: 1000/(T-175) ² <t<30000/(T-175) ² . It is preferable to set the value within a range that satisfies the above. 1000/(T
-175) If the time is less than ² , it is difficult to form the above-mentioned fibrous structure,
30000/(T-175) When the time is longer than ² , the fiber properties begin to deteriorate. Particularly preferred is
3000/(T-175) ² or less time. In the present invention, it is easy to adhere a hydrophilic resin film to the surface of the polyester fiber obtained in this way, and thereby the antifouling performance can be further improved. The hydrophilic resin used here is not particularly limited as long as it can form a film exhibiting hydrophilic properties, but when combined with the modified polyester fiber, it has a unique antifouling performance and washing durability. A film made of a polyether resin is particularly preferable because it has the effect of increasing the overall performance. [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 absorbed 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 portion of polyester has short intermolecular distances and is compact, so it is impossible for oily components to penetrate between the crystal lattices of several angstroms.
On the other hand, in the amorphous part and the gap between crystal micelles,
The molecular density of polyester is low, and combined 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 copolymers, has been studied. For example, "surface"
Vol. 22, No. 6, p. 297 (1984) and “Industrial Materials” Vol. 33
As stated in No. 12, page 46, research has been actively conducted on the application of these polymers to polymer activators and polymer surface improvement. Block copolymerization of hydrophilic polyoxyalkylene glycol and lipophilic polyester ether, that is, one end has an active hydrogen group,
Polyoxyalkylene glycol (PAG) whose other end is capped with a group that does not have active hydrogen
When copolymerized with polyester (PE),
A large amount of PAG-PE-PAG or PAG-PE molecules
It becomes the form that exists in 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-resistant properties even after repeated washing. No darkening occurs. Therefore, the soil-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 model RAD-A manufactured by Rigaku Denki, the sample was fixed on a fiber sample stage and set vertically on the goniometer mount.
Measure diffraction from diffraction angle 2θ = 10° to 40°. The lowest points of diffraction in the meridian direction are connected with a straight line, and based on this, the half width B of the diffraction peaks of the (100) plane and (010) plane is determined. (100) plane and (010)
The crystal size of the plane is determined by the following formula. Crystal size D=Aλ/(√-)×cosθ A is the correction coefficient, b is the correction angle λ is the wavelength of (Refer to supervision) (2) Contamination treatment Pour 300 c.c. of washing liquid with the following composition into the pot of the Colorpet dyeing tester (manufactured by Nippon Senzo Kikai), and soak the 10 cm x 13 cm fabric held in the 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 colorimeter was determined, and the degree of contamination was calculated as follows. Contamination level (ΔL*) = L* before contamination - L after treatment
* Examples 1 to 4 and Comparative Examples 1 to 6 100 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 resulting methanol 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 the polymerization was then further continued for 30 minutes. The obtained polymer was made into chips according to a conventional method. The chips were dried using a conventional method, and a spinneret with 24 circular spinning holes with a hole diameter of 0.3 mm was used.
Melt spinning is carried out at 285°C, and then drawing heat treatment is performed using a heated roller at 84°C and a slit heater at 180°C at a draw ratio that makes the elongation of the final drawn yarn 30%, resulting in 50 denier/24 filaments. A drawn yarn was obtained. A circular fabric was knitted using the obtained polyester filament yarn of 50 denier/24 filaments.
After scouring by conventional method and heat treatment at 170℃ to eliminate scouring wrinkles, Mikawhite is used as a fluorescent dye.
In a treatment bath containing 2% owf of ATN (manufactured by Mitsubishi Kasei Corporation)
A fluorescently stained product was obtained by staining at 130°C for 30 minutes. Next, heat treatment was performed using an iron at the temperature and time shown in the table. The fiber properties are shown in Table 2. The obtained sample was subjected to contamination treatment, and the degree of contamination ΔL* was determined. A passing degree of contamination is 30 or less, preferably 20 or less.

【table】

[Table] Example 5 and Comparative Examples 7 and 8 Polymers of Example 2 and Comparative Examples 2 and 3 were used with a pore size of 0.28.
Using a spinneret with 1,008 circular spinning holes of 1,000 mm in diameter, an amount of 530 g/min was discharged at 290° C., and the material was wound at 1,000 m/min while applying an oil agent. The 165 spun undrawn yarns were simultaneously fed to a drawing machine and heated to 70°C.
Stretched in warm water at 90°C at stretching ratios of 3.74 times and 1.15 times, then heat treated with a set roller at 225°C,
Furthermore, a spinning oil was applied (speed 100 m/min). Next, it was crimped using a 30mm width push-in crimper, and subjected to dry heat treatment at 90°C in a continuous drying process.
It was fed to a cutter and cut into a length of 38 mm to obtain a staple fiber. The fiber properties are shown in Table 3. 65% of this staple fiber was mixed with 35% of cotton, and a spun yarn with an English cotton count of No. 33 was obtained using a regular spinning machine. The number of twists at this time was 17.8 pieces/inch. This is used to weave plain woven fabric, and after desizing, scouring, and heat treatment are carried out using conventional methods, fluorescent dye Mikawhite is used.
In a treatment bath containing 2% owf of ATN (manufactured by Mitsubishi Kasei Corporation)
A fluorescently stained product was obtained by staining at 130°C for 30 minutes. This was subjected to contamination treatment to determine the degree of contamination. The passing line is 10% or less.

[Table] Comparative Example 7 is an example in which PEG was copolymerized within the main chain of polyethylene terephthal, and although the crystal growth was small and the degree of orientation Δn was high, the specific gravity was low.
It has a more tense amorphous part than these, indicating that a two-component phase separation structure has not been formed, and the contamination degree is also 18.3.
It was expensive. In Comparative Example 8, the contamination rate was high probably because the PEG component whose both ends were blocked with inert hydrogen was extracted into water. On the other hand, in Example 5, PEG having active hydrogen at only one end was copolymerized with polyethylene terephthalate end,
The heat treatment was sufficient, the crystal size grew large, the phase separation of the two components was sufficient, and the contamination rate was kept low.

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 has the following general formula (1) R ¹ O(R ² O)-n ...(1) (in the formula, R ¹ is a monovalent organic group without active hydrogen,
^R2 is an alkylene group, n is an integer from 20 to 140)
A fiber made of modified polyester obtained by copolymerizing 0.5 to 10% by weight of a polyoxyalkylene glycol component represented by
50-100 Å, crystal size on (010) plane 65-170 Å
A stain-resistant polyester fiber having a birefringence of 0.15 or more, an elongation of 40% or less, and a strength of 4 g/de or more.