JPS63125564A - Polyester composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. which does not have fluorescence observed by the naked eye under black light and is suitable for use in the field of sanitary materials having good hue, by incorporating a specified amount of rutile type TiO2 to reduce the fluorescence intensity against ultraviolet light having a specified wavelength to a specified value or below. CONSTITUTION:In a fiber-forming polyester obtd. by polycondensing a bi functional arom. dicarboxylic acid or its ester-forming derivative (e.g., terephthalic acid, dimethyl terephthalate, etc.) with a 2-10C aliph. or alicyclic glycol (e.g., ethylene glycol, cyclohexane-1,4-dimethylol, etc.), 0.3-2.5wt% rutile type TiO2 is incorporated in said polyester and the fluorescent intensity against ultraviolet light having a wavelength of 360nm is adjusted to 1.0 or below. Rutil type TiO2 has a high ability to absorb ultraviolet light so that when the fluorescence intensity at 630nm has the above value, the fluorescence under black light of the resulting polyester fiber cannot be observed by the naked eye and the compsn. is suitable for use in the field of sanitary materials such as sanitary napkin, paper diaper, etc.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a polyester composition, and more specifically,
This invention relates to a polyester composition suitable for use in art materials such as sanitary napkins and disposable diapers.

(Prior Art) Generally, polyester, especially polyethylene terephthalate, has excellent mechanical, physical, and chemical properties, so it is used for clothing, industrial fibers, and r! It is widely used in various fields such as i-air tape, other general-use films, and molded products for various drinking water bottles.

In recent years, polyester like this has been used for sanitary napkins.

It is also being widely used for art supplies such as disposable diapers.

Since the polyester fibers used in these applications are required to have a temperature of 0 degrees, polyester mixed with a fluorescent brightener is sometimes used.

However, some fluorescent brighteners are harmful to the human body, so it is important that polyester fibers used for art materials do not contain fluorescent brighteners and are mainly irradiated with ultraviolet light around 3f30nm. It is required that fluorescence under a near-ultraviolet fluorescent lamp (hereinafter sometimes referred to as a black light) is not visible to the naked eye.

Therefore, the present inventors investigated the presence or absence of fluorescence under black light for polyester fibers used for timber cutting applications, and found that even with polyester fibers that did not contain a fluorescent whitening agent, fluorescence was visible to the naked eye. It was recognized as such.

For this reason, the present inventors have conducted various studies on polyesters with extremely low fluorescence in order to produce polyester fibers in which fluorescence is not visible to the naked eye under a black light.

First, after changing various conditions in the polyester manufacturing process, we found that the lower the polycondensation reaction temperature, the lower the fluorescence of the resulting polyester.However, the lower the polycondensation reaction temperature, the lower the polyester productivity. There was a natural limit because of the decrease in

In addition, as a polyester with little fluorescence, JP-A-60-12
The polyester containing zinc oxide proposed in Publication No. 0744 was investigated.

It is true that zinc oxide-containing polyester has extremely low fluorescence, but if zinc oxide is added during the polyester manufacturing process, the hue of the resulting polyester may be extremely reduced, and such polyester is not suitable for use in tube materials. It could not be used for

(Objective of the Invention) The object of the present invention is to provide a polyester composition suitable for use as a tubular material that exhibits no visible fluorescence under a black light when molded into LA fibers and exhibits a good hue. There is a particular thing.

(Structure) As a result of studies to achieve the purpose of publication, the present inventors found that rutile titanium dioxide has higher ultraviolet absorption than anatase titanium dioxide, which is generally used as a matting agent for textiles. The obtained polyester am
The present invention was achieved by discovering that no fluorescence is visible to the naked eye under black light.

That is, the present invention provides at least one difunctional aromatic dicarboxylic acid or an ester-forming derivative thereof and at least one aliphatic or ring glycol having 2 to 10 carbon atoms.
In the 1ift-forming polyester obtained by polycondensation reaction with seeds, the polyester contains 0.3 to 2.5% by weight of rutile titanium dioxide, and has a fluorescence intensity of 360 rv ultraviolet light. This is a polyester composition characterized in that it has a molecular weight of 1.0 or less.

The fluorescence intensity of 36On1ll in the present invention against ultraviolet rays was measured by the following method using a Hitachi fluorescence spectrometer (MPF-2A type).

(1) Molding the obtained polyester into a plate shape 3
Irradiate with 600m ultraviolet rays and measure the fluorescence spectrum.

Next, the area of the measurement chart paper between the 380 to 600 rill fluorescence intensity curve and the baseline (A+
).

(1) Using an aluminum plate as a standard, (1) similarly measure the area of the part sandwiched between the 380-600 nm fluorescence intensity curve of the chart paper and the baseline (A2).
seek.

@ (+) Using A+ and Az obtained in (1), calculate the fluorescence intensity using the following formula.

Fluorescence intensity - AI/A2 In addition, the fiber-forming polyester targeted by the present invention mainly includes terephthalic acid or dimethyl terephthanate, ethylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexane-1,4-dimethylol, and the like. It is a polyester obtained by polycondensation reaction of
It may be replaced with β-oxyethoxybenzoic acid, p-oxybenzoic acid, diphenyldicarboxylic acid, naphthalenedicarboxylic acid, diphenylsulfonedicarboxylic acid, etc.

In the polyester of the present invention, rutile titanium dioxide is contained in the polyester in an amount of 0.3 to 2.5% by weight,
In addition, the fluorescence intensity against 360 n1ll ultraviolet rays is 1.
It needs to be 0 or less.

Here, if the amount of rutile type titanium dioxide is less than 0.3% by weight, the effect of suppressing the fluorescence intensity of polyester is insufficient, whereas the amount of rutile type titanium dioxide is 2.5% by weight.
If it exceeds this value, the fluorescent intensity suppressing effect of the polyester reaches saturation, and the hue of the polyester actually decreases.

In addition, the fluorescence intensity against 360 nm ultraviolet light is 1.0.
If it exceeds 20%, fluorescence of the obtained polyester fiber becomes visible to the naked eye under a black light.

In this way, the content of rutile titanium dioxide.

For the first time, a polyester composition having a fluorescence intensity within the range specified by the present invention can be used for art materials.

In the present invention, it is preferred that the average particle size of the rutile titanium dioxide added to the polyester be 1 μm or less, particularly preferably 0.5 μm or less, as measured by centrifugal sedimentation, since coarse particles in the polyester can be reduced and molded. This is preferable because the properties are improved.

Further, as long as the rutile type titanium dioxide is within the range specified by the present invention, anatase type titanium dioxide may be used in combination.

The method for obtaining such a polyester of the present invention will be explained by taking polyethylene terephthalate as an example. Polyethylene terephthalate is usually produced by transesterifying dimethyl terephthalate and ethylene glycol or by esterifying terephthalic acid and ethylene glycol to produce bis(β-hydroxyethyl) terephthalate and/or its low polymer. It can be obtained by producing a polycondensate and then subjecting it to a polycondensation reaction while heating under reduced pressure.

Generally, the temperature immediately before the completion of the polycondensation reaction (hereinafter sometimes referred to as PN-Tf) is the highest temperature.

The higher the temperature of the PN-Tf, the stronger the fluorescence intensity of the resulting polyethylene terephthalate (hereinafter sometimes referred to as PET) against 360 rv ultraviolet rays. is PN-Tf 2
The temperature is preferably 75°C or lower.

Rutile titanium dioxide may be added before the completion of the polycondensation reaction or during melt molding, but it is preferable to add it before the completion of the polycondensation reaction, especially for esters. The method of adding after the exchange reaction and before the polycondensation reaction is preferable because the dispersibility of the rutile type titanium dioxide particles becomes better. Such rutile-type titanium dioxide may be added in powder form, but it is preferably added after being dispersed in ethylene glycol.

In this way, when adding rutile-type titanium dioxide dispersed in ethylene glycol, in order to reduce the coarse particles of titanium particles, the rutile-type titanium dioxide and ethylene glycol are dispersed with a homogenizer, and further with a decanter. - or settling of coarse particles is preferred in order to improve the moldability of the resulting polyester.

The polycondensation reaction conditions when such rutile titanium dioxide is added can be the usual conditions except that the PN-Tf mentioned above is kept at 275°C or less. It is preferable to use for improving moldability.

Additionally, optional additives that do not emit fluorescence, such as colorants, matting agents, R-forming inhibitors, ether bond inhibitors, dye-mixing agents, and flame retardants, may be added as necessary.

Antistatic agents and the like may also be used.

(Function) According to the polyester composition of the present invention, the obtained Ill
Although the detailed reason why fluorescence under black light is not visible to the naked eye is still unclear, it is thought to be as follows.

When pyrolyzed products (degraded products) of polyester are irradiated with ultraviolet light, they emit fluorescence, so if a relatively large amount of such degraded products are present in polyester fibers, the fluorescence under a black light will be invisible to the naked eye. This is considered acceptable.

In contrast, the polyester composition of the present invention has very little polymer deterioration present in the polyester, and even if polymer deterioration is generated during melt spinning etc., ultraviolet rays can be absorbed by the rutile type titanium dioxide. Therefore, the fluorescence of the obtained polyester fiber cannot be seen with the naked eye under a black light.

Moreover, unlike zinc oxide, which has ultraviolet absorbing ability, rutile titanium dioxide does not deteriorate the hue of polyester even when added during the polyester manufacturing process.

(Effects of the Invention) The polyester composition of the present invention can be suitably used for art materials such as sanitary napkins and disposable diapers.

(Example) Next, the present invention will be explained in further detail with reference to Examples.

Parts in the examples are parts by weight, and [η] is the intrinsic viscosity determined from the value measured at 30° C. in orthochlorophenol solvent. The L value and b value representing hue are values measured using a Hunter type color difference meter.

The larger the L value, the higher the white discoloration, and the lower the b value, the lower the yellowness, that is, the better the hue.

The moldability was evaluated as follows. Using a spinneret with 30 spinnerets with a diameter of 0.3 mtn, a throughput of 80
g/win, discharge temperature 285℃, winding speed 1200m
The height of foreign matter around the outside of the spinneret was measured during melt spinning for 7 days at /mi spun, and the lower the height, the better the moldability.

Example 1 970 parts of dimethyl terephthalate, 6 parts of ethylene glycol
40 parts and 0.1 manganese acetate as transesterification catalyst
Two parts were charged into a reactor equipped with a stirrer, a rectification column, and a methanol distillation condenser, and heated from 140°C to 230°C, allowing transesterification to occur while distilling methanol produced as a result of the reaction out of the system. Ta. Three hours after the start of the reaction, the internal temperature reached 230°C, and 320 parts of methanol was distilled out. Here, 0611 parts of trimethyl phosphate (0.08 mol% based on dimethyl terephthalate) as a stabilizer and 2.9 parts of rutile titanium dioxide with an average particle size of 0.40 μm.
(0.3% by weight based on the polyester) and further added 0.39 parts of antimony trioxide as a polycondensation catalyst.

The reaction mixture was transferred to a reactor equipped with a stirrer and a glycol distillation condenser, and the temperature was gradually raised from 230°C to 275°C, while the pressure was lowered from normal pressure to a high vacuum of IMH (J) for polycondensation reaction. A polymer with [η] 0.640 was obtained in a total polycondensation reaction time of 3 hours.The fluorescence intensity of this polymer was 0.9, and the hue was L value 71.9.b value 4.
．． It was 0. Further, the height of the spinneret foreign matter was 28μ. Moreover, when the obtained fibers were observed under a black light, no fluorescence could be observed with the naked eye.

Examples 2-4. Comparative Examples 1 to 5 The type and amount of titanium dioxide added was the same as in Example 1, except that the type of type 1 condensation catalyst and the polycondensation reaction temperature (PN-Tf > were changed as shown in Table 1). The quality of the obtained polyester and the height of spinneret foreign matter are also shown in Table 1.

The method for preparing the titanium catalyst used in Example 5 in Table 1 is shown below. The amount used is 0.010 mol% as titanium metal based on dimethyl terephthalate.
Met.

[Titanium catalyst manufactured by Y4] 2.5 parts of ethylene glycol and 0.0 parts of trimellitic anhydride.
After dissolving 8 parts of tetrabutyl titanate, 0.7 parts of tetrabutyl titanate (
(1 part 2 mol) was added dropwise to trimellitic anhydride, and the mixture was kept at 80° C. under normal pressure in air to react and ripen for 60 minutes. Thereafter, the mixture was cooled to room temperature, 15 parts of acetone was added, and the precipitate was filtered using No. 5 filter paper and dried at 100° C. for 2 hours. The titanium content of 1q precipitate is 11.5
It was the highest percentage.

As is clear from Table 1, Example 2 in which the content of rutile titanium dioxide and the fluorescence intensity are within the range specified by the present invention.
The polyester compositions No. 6 to 6 have good hues, and no fluorescence is visible to the naked eye under a black light even in the form of fibers.

On the other hand, the polyester compositions of Comparative Examples 1 and 2 have a fluorescence intensity exceeding 1.0, Comparative Example 4 has a low rutile titanium dioxide content, or Comparative Example 5 has a rutile titanium dioxide content. Since we used anatase titanium dioxide instead, when molded into fibers, fluorescence became visible to the naked eye under black light.

Furthermore, in Comparative Example 3, the content of rutile titanium dioxide was too large, so the hue of the polyester composition deteriorated.

Comparative Example 6 Instead of rutile titanium dioxide, average particle size 0.59μ
Example 1 was carried out in the same manner as in Example 1, except that 4.9 parts of zinc oxide of m was used. The obtained polyester has [η] = 0
．． 629. Fluorescence intensity is 0.42, hue is L value 67.4.
The b value was 11.2. The height of the spinneret foreign matter was 19μ.

Further, even when molded into fibers, no fluorescence was observed with the naked eye under a black light, but the hue was significantly deteriorated.

Claims (2)

[Claims] (1) Fiber formation obtained by polycondensation reaction of at least one bifunctional aromatic dicarboxylic acid or its ester-forming derivative and at least one aliphatic or alicyclic glycol having 2 to 10 carbon atoms. A polyester composition characterized in that the polyester contains 0.3 to 2.5% by weight of rutile titanium dioxide, and has a fluorescence intensity of 1.0 or less against ultraviolet light at 360 nm. . (2) The polyester composition according to claim (1), wherein the average particle size of titanium dioxide is 1 μm or less as measured by centrifugal sedimentation.