JPS6219524B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to copolymerized polyester binder fibers that are effective as adhesive materials, particularly adhesive materials for nonwoven fabrics. In recent years, in the nonwoven fabric field, energy saving,
From the viewpoint of pollution prevention, various types of fibrous binders have been developed to replace the conventional emulsion type binders, and are gradually being accepted in the market. For example, sheath/core type polyolefin fibers in which the sheath component is made of polyethylene or copolymerized polyethylene and the core component is made of polypropylene (for example, ES fibers and EA fibers manufactured by Chitsuso Co., Ltd.),
There are polyvinyl alcohol fibers that melt at 80°C (for example, Kuraray Vinylon VPB series manufactured by Kuraray Co., Ltd.). However, when used in fiber aggregates consisting mainly of polyolefin fibers, these fibers exhibit an effect as a binder, but their binder effect is very small for other synthetic fibers such as rayon, polyester, and nylon. Therefore, it is necessary to use 30% or more, which has the disadvantage that the properties of the main fiber aggregate are impaired. Since these fibers do not melt in the absence of water, they are mostly used as binders for paper making, and when the main fiber aggregate is vinylon, rayon, or pulp, they exhibit a fairly large binder effect.
In the case of polyester, nylon, acrylic, etc., the binder effect is very small, so a fairly large amount must be used. Therefore, there are drawbacks such as a very hard texture. The inventors of the present invention, as a result of intensive studies in order to eliminate such drawbacks, found that polyester, which had been conventionally used as a sizing agent for fibers or an adhesive coating agent for fibers and films by dispersing it in water, contained diethylene glycol and an ester-forming bifunctional compound. A water-dispersible polyester obtained by copolymerizing a sulfonic acid metal salt compound having a group (for example, Japanese Patent Publication No. 47-40873), or a polyester copolymerized with a sulfonic acid metal salt compound having polyethylene glycol and an ester-forming bifunctional group. By focusing on polymerized water-dispersible polyesters (for example, Japanese Patent Application Laid-Open No. 121336/1983), we have developed a method for making fibers from specific water-dispersible copolyesters that have not been previously known to be made into fibers. They succeeded in obtaining a new binder fiber made of copolyester that has a wide range of applications and can be used in a small amount. That is, the present invention involves spinning a polyester comprising at least one dicarboxylic acid and/or its ester-forming derivative, a glycol, and an ester-forming alkali metal sulfonic acid salt compound, and then cutting the polyester without stretching and/or heat treatment. The polyester has a compound having the formula H(-OCH ₂ CH ₂ )- _o OH (wherein n is an integer of 2 to 13) with respect to its total glycol component. This is a binder fiber for nonwoven fabric characterized by being copolymerized with 50 mol%. The dicarboxylic acid component used in the present invention may be an aliphatic, alicyclic or aromatic acid. For example, oxalic acid, malonic acid, Dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, azelaic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanecarboxylic acid,
1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5
Examples include naphthalenedicarboxylic acid, biphenyldicarboxylic acid, diphenic acid, diglycolic acid, thiodipropionic acid, and ester-forming derivatives thereof. There is no problem in using two or more of these. In addition, examples of glycol components include ethylene glycol, 1,2-propanediol, 1,
3-propanediol, 1,4-butanediol, 2,4-dimethyl-2ethylhexane, 1,
3-diol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol,
1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 2,2,4-
Trimethyl-1,6-hexanediol, 1,2
-Cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, p-xylylene glycol, etc. is used. Among these, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like are preferred, and two or more of these may be used. Examples of ester-forming sulfonic acid alkali metal salt compounds include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, sulfo-p-xylylene glycol, 2- Sulfo-1,
Examples include alkali metal salts such as 4-bis(hydroxyethoxy)benzene and ester-forming derivatives thereof. The amount of the ester-forming sulfonic acid alkali metal salt compound to be used is not particularly limited, but it is preferably 0.5 mol % or more based on the dicarboxylic acid component. The polyoxyethylene glycol component used in the present invention has the formula H (-OCH ₂ CH ₂ )- _o OH [n in the formula is 2
~13 integers], such as dioxyethylene glycol, trioxyethylene glycol, tetraoxyethylene glycol,
Examples include pentaoxyethylene glycol. In particular, it is easy to make fibers by melt spinning,
Fibers are less likely to stick together and are easy to handle.
In terms of good heat resistance, the formula H(-OCH ₂ CH ₂ ) _-o
It is preferable that n in OH is an integer within the range of 2 to 5. In addition, the amount of polyoxyethylene glycol represented by the formula H(-OCH ₂ CH ₂ )- _o OH (n is an integer of 2 to 13, preferably 2 to 5) is based on the total glycol components constituting the polyester. It is necessary that it be 5 to 50 mol%. If the polyoxyethylene glycol content is less than 5 mol%, the adhesive strength will decrease and the performance as a binder will be poor; if it exceeds 50 mol%, the resulting fibers will tend to stick together and have poor handling properties. Moreover, the heat resistance is also inferior. In particular, when the amount of polyoxyethylene glycol added is 5 mol % or more and less than 20 mol %, it is easy to form fibers by melt spinning, and the binder fiber has excellent adhesive strength, handleability, and heat resistance. . In order to produce the copolymerized polyester used in the binder fiber of the present invention, any general method such as a polymerization method using transesterification or a direct polymerization method can be applied as is. For example, predetermined amounts of dicarboxylic acid alkyl ester, glycol, and sulfonic acid alkali metal salt dialkyl ester are heated in the presence of a transesterification catalyst, the transesterification reaction is carried out while the methanol produced is distilled off, and then the polymerization catalyst and stabilizer are , a method in which a predetermined amount of polyoxyethylene glycol is added, and then ethylene glycol is distilled off under high temperature and high vacuum to perform polycondensation. A dicarboxylic acid, a glycol, and an ester-forming sulfonic acid alkali metal salt compound are heated without a catalyst or in the presence of an esterification catalyst, and esterified while distilling off the water produced under normal pressure or under pressure, and then esterified with polyoxyethylene. The most commonly employed method is to add glycol and perform polycondensation. It is preferable to add the ester-forming alkali metal sulfonic acid salt compound and polyoxyethylene glycol before transesterification or esterification, but they may be added after transesterification or esterification. Moreover, the method of adding these compounds may be a glycol solution, flakes, or powder. The copolymerized polyester obtained as described above can be made into fibers by any method such as melt spinning, wet spinning, or dry spinning, but it is easy to operate and saves energy, and does not require complicated solvent recovery. Otherwise, it is most preferable to use the melt spinning method because of its high productivity. When melt-spinning the copolyester used in the present invention, the intrinsic viscosity of the copolyester must be adjusted to ensure stable spinning.
It is preferable to set it to 0.25 or more. In the present invention, it is important to cut the undrawn yarn obtained by spinning in this manner into short fibers to a predetermined fiber length without stretching and/or heat treatment. Here, when the undrawn yarn is subjected to drawing and/or heat treatment, the melting point of the short fibers obtained becomes higher than that of the undrawn yarn, making it unsuitable as a binder fiber. There are no particular limitations on the single fibers and fiber length of the binder fibers, but when used as a binder for ordinary papermaking, it is preferable that the single fiber fineness is 0.5 denier to 15 denier and the fiber length is 1 mm to 20 mm. The copolymerized polyester binder fibers thus obtained are easily swollen or dispersed in water, particularly in water at relatively high temperatures, and therefore are very suitable as binder fibers for papermaking. The binder fiber of the present invention not only has a binder effect on fiber aggregates mainly made of polyester, but also has a great binder effect on fiber aggregates such as rayon, vinylon, nylon, and acrylic, and addition of a small amount is sufficient. That is surprising. Although the binder fiber of the present invention can be applied to dry nonwoven fabrics, spunbond fabrics, etc., it exhibits a greater binder effect when used in the presence of a certain amount of water. The present invention will be specifically explained below with reference to Examples. Example 1 Comparative Examples 1-2 92.2 parts of dimethyl terephthalate, 7.4 parts of dimethyl 5-sodium sulfoisophthalate, 57.4 parts of ethylene glycol, dioxyethylene glycol
After mixing 8.0 parts of zinc acetate and 0.13 parts of zinc acetate and performing a transesterification reaction while distilling off methanol at 140 to 200°C, 0.098 parts of trimethyl phosphate and 0.146 parts of antimony trioxide were added and the mixture was heated at 250°C and 0.20 mmHg. After polymerization, the intrinsic viscosity calculated from the viscosity measured in an orthochlorophenol solution at 35°C was 0.55, and the 5-
A polyethylene terephthalate polymer was obtained in which 5 mol% of sodium dimethyl sulfoisophthalate and 15 mol% of dioxyethylene glycol were copolymerized. This polymer was made into chips of approximately 4 mm x 4 mm x 2 mm, and dried at 60°C for 4 hours under reduced pressure (2 mmHg).
The dried chips were melted at 250°C, discharged through a spinneret with 36 holes, and wound at a speed of 500 m/min to obtain an undrawn yarn with a single filament fineness of 5 denier, which was wound into a length of approximately 5 mm. It was cut into This fiber had no stickiness at all and was very easy to handle. This binder fiber has a single yarn fineness without crimping.
20% by weight mixed with 0.6 denier, 5mm fiber length polyethylene terephthalate staple fiber, fiber concentration 0.03
It was dispersed in water to give a weight percentage of 50 g/m ² by hand using a square sheet machine manufactured by Kumagai Riki Kogyo Co., Ltd. Next, this polyester paper was dried in a dryer controlled at 120°C (manufactured by Kumagai Riki Kogyo Co., Ltd.).
The sample was supplied in a wet state to a KRK type rotary dryer), and was simultaneously dried and heat treated, and the tensile strength, tensile elongation, and breaking length were measured in accordance with JIS P-8113, and the texture was also evaluated. On the other hand, for comparison, commercially available binder fibers, Kuraray Vinylon VPB101, single yarn fineness 1.3 denier, fiber length 4 mm, and Chitsuso EA
A fiber having a single yarn fineness of 3 denier and a fiber length of 5 mm was tested under the same conditions as in Example 1, and the results are shown in Table 1 together with the results of Example 1.

[Table] It is clear from this table that the binder fiber of the present invention has an extremely excellent binder effect and can provide a product with a good texture. Example 2 87.3 parts of dimethyl terephthalate, 14.8 parts of dimethyl 5-sodium sulfoisophthalate, 57.4 parts of ethylene glycol, 14.6 parts of tetraoxyethylene glycol, and 0.13 parts of zinc acetate were mixed and heated to 140 to 200°C.
After carrying out the transesterification reaction while distilling methanol off, 0.098 parts of trimethyl phosphate and 0.146 parts of antimony trioxide were added and polymerized, and the intrinsic viscosity calculated from the viscosity measured in an orthochlorophenol solution at 35°C was 0.61. Thus, a polyethylene terephthalate polymer was obtained in which 10 mol% of dimethyl 5-sodium sulfoisophthalate and 15 mol% of tetraoxyethylene glycol were copolymerized. This polymer was made into chips in the same manner as in Example 1,
After drying, it is melted at 255°C, discharged through a spinneret with 36 holes, and wound at a speed of 600 m/min to obtain an undrawn yarn with a single filament fineness of 6 denier, approximately 5 mm.
Cut to length. This fiber showed no stickiness at all and was very easy to handle. 10% by weight of this binder fiber was mixed with non-crimped polyethylene terephthalate staple fibers with a fineness of 0.6 denier and a fiber length of 5 mm to make paper under the same conditions as in Example 1. As a result of the tensile Strong 1.25
Kg/15mm (rupture length 1.67Km) and tensile elongation 11.2%. Also, the texture of this paper was very soft. Examples 3 to 6, Comparative Examples 3 to 4 Regarding the polymer composition of Example 1, polymers were prepared in the same manner as in Example 1 by changing the amount of dioxyethylene glycol added, and the results were evaluated in the same manner as in Example 2. Shown in the table.

[Table] As can be seen from Table 2, when the amount of dioxyethylene glycol added is less than 5 mol%, the binder performance becomes poor. On the other hand, if the copolymerization amount of polyoxyethylene glycol exceeds 50 mol %, there will be more adhesion between the fibers during winding and the thermal stability will be poor. In particular, when the copolymerization amount of dioxyethylene glycol is 5 mol % or more and less than 20 mol %, there is little adhesion between the fibers, the thermal stability is good, and spinning can be performed in a stable state.

Claims (1)

[Scope of Claims] 1 A polyester comprising at least one dicarboxylic acid and/or its ester-forming derivative, a glycol, and an ester-forming sulfonic acid alkali metal salt compound is spun, and then without stretching and/or heat treatment. The polyester is a short fiber obtained by cutting, and the polyester contains a compound represented by the formula H(-OCH ₂ CH ₂ )- _o OH (where n is an integer from 2 to 13) with respect to all its constituent glycol components. A binder fiber for nonwoven fabrics characterized by being copolymerized in an amount of 5 to 50 mol%. 2 Formula H (-OCH ₂ CH ₂ )- _o OH (where n is 2 to 13
2. The binder fiber for nonwoven fabric according to claim 1, wherein 5 mol% or more and less than 20 mol% of the compound represented by (an integer of ) is copolymerized. 3 n in formula H(-OCH ₂ CH ₂ )- _o OH is 2 to 5
The binder fiber for nonwoven fabric according to claim 1 or 2, which is an integer of .