JPH0456859B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polybutylene terephthalate (hereinafter abbreviated as PBT) polyester having excellent light resistance.

PBT-based polyester has traditionally been used as an engineering plastic, but due to its excellent elongation recovery properties, it is also attracting attention for use in clothing. However, when this is used for clothing, the light fastness of the dyed product is not sufficient, especially when a fluorescent dye, especially a white fluorescent dye, is used.The light fastness is extremely insufficient. It is something.

In other words, PBT-based polyester has photochemical properties that allow it to absorb light in the ultraviolet wavelength range of around 314 nm, and transfer this absorbed light energy to wavelengths of 300 to 450 nm.
It emits light and exhibits fluorescence. In other words, even if the same light is irradiated, it will apparently correspond to the irradiation of light with high light intensity in the wavelength range of 300 to 450 nm. On the other hand, many dyes have a wave wavelength of 300 to 450 nm.
When PBT-based polyester is dyed with such a dye, the dye molecules are excited to a higher level and the color is more vivid, but its light fastness is reduced. Main peak position of fluorescence of polyester-based polyester
When a white dye (fluorescent brightener) with a main absorption peak near 370 nm is used, its light fastness deteriorates significantly, and when evaluated according to JIS L-0842, it is grade 1, in fact , it becomes difficult to recognize the product value.

Therefore, as a result of intensive research in order to improve this serious drawback, the present inventors found that by adding an appropriate amount of cobalt compound or (and) phosphorus compound, PBT
We discovered that it is extremely effective to select a catalyst when synthesizing polyester and to adjust the intrinsic viscosity [η] of the polyester to an appropriate range,
This led to the present invention.

That is, PBT polyester, cobalt (Co) compound is converted to cobalt metal, and
It has been found that the light fastness of dyed polyester products is significantly improved by adding it in an amount within the range of 50 ppm, and in addition to the cobalt compound, the phosphorus compound is added in an amount of 5 to 50 ppm in terms of phosphorus atoms.
The effect is further increased by using the titanium compound in an amount within the range of 50 ppm.
≦[M]/[Ti]≦0.7…Equation (3) (however, [M],
[Ti] contains alkali metals and/or alkali metals in the proportions specified by the alkali metals and/or alkali metals contained in the compound (representing the chemical equivalent of the titanium atom); The amount added is converted to titanium atoms and is 15~
By setting the amount within the range of 150 ppm, the light fastness is further increased, and by setting the intrinsic viscosity [η] of the polyester to 0.5 to 1.0, further effects are exhibited.

Polyester as used in the present invention means that 80% or more of its constituent units are butylene terephthalate residues.
It is a PBT-based polyester, and may be modified, for example, by copolymerization. Examples of modifiers include 5-sulfoisophthalic acid sodium salt or its derivatives as the acid component, isophthalic acid or its derivatives, aliphatic dibasic acids such as adipic acid and sebacic acid, and their derivatives, and ethylene glycol as the diol component. , propylene glycol, neopentyl glycol, hexamethylene diol, condensates thereof, polymethylene glycols, etc., but are not limited to these.

Note that the present invention aims to improve the light resistance of PBT, which is inferior to polyethylene terephthalate (PET), and even if the present invention is applied to PET, no substantial effect will be obtained. this is,
This is presumed to be due to the special circumstances that PBT, unlike PET, has specific light absorption and light emission characteristics as described above.

As the cobalt compound used in the present invention,
Organic acid salts of cobalt such as cobalt formate and cobalt acetate are preferable from the viewpoint of their solubility, but they are not necessarily limited thereto.

Examples of the phosphorus compound used in the present invention include phosphorous acid, orthophosphoric acid, or esters thereof, such as triphenyl phosphite, tri-n-butyl phosphite, trimethyl phosphate, and tri-n-butyl phosphate. However, it is not limited to these.

The titanium compound used as a synthesis catalyst for the PBT polyester used in the present invention includes, but is not limited to, potassium titanium tartrate, potassium titanium oxalate, sodium titanium tartrate, sodium titanium oxalate, and mixtures thereof. It is not something that will be done.

The amount of the cobalt compound added in the present invention is within the range of 5 to 50 ppm in terms of cobalt atoms. If the amount added is less than 5 ppm, the effect will not be recognized, and if it is added more than 50 ppm, the effect will not only be saturated, but also the polymer itself will turn blue-black, which will actually reduce its value.

Next, the amount of the phosphorus compound added is within the range of 5 to 50 ppm in terms of phosphorus atoms. If the amount added is less than 5 ppm, the effect will not be recognized, and if it is added more than 50 ppm, the effect will not only be saturated, but also cause gelation of the polymer or 1,4-butane depending on the type of compound. This results in harmful effects such as promotion of conversion of diol to tetrahydrofuran.

These cobalt compounds and phosphorus compounds may be added at the same time or separately, and may be added at any time from the start of the synthesis reaction to the spinning process, but from before the start of the synthesis reaction. Easy to add into raw materials.

The amount of the titanium compound added as a synthesis catalyst according to the present invention is 15 to 15% in terms of titanium atoms.
An amount within the range of 150 ppm, preferably an amount within the range of 20 to 70 ppm. If the amount added is less than 15ppm,
If the reaction does not proceed sufficiently and the desired polymer cannot be obtained, on the other hand, if more than 150 ppm is added, the synthesis reaction will certainly proceed rapidly, but it will also promote the decomposition reaction, which is undesirable as it will lead to coloration of the polymer. Not only is this poor, but the light fastness, which is the objective of the present invention, is significantly impaired.

The content of the alkali metal and/or alkali metal in the titanium compound is preferably within the range defined by formula (1). If the chemical equivalent ratio is smaller than 0.1, the effect will not be sufficient, and if it is larger than 0.7, the activity as a catalyst will decrease.

The intrinsic viscosity [η] of the PBT polyester in the present invention is preferably in the range of 0.5 to 1.0. [η] is
If it is less than 0.5, the light fastness will certainly be sufficient, but the processability will be insufficient. On the contrary [η]
If it exceeds 1.0, the molecules become unstable due to the high molecular weight, resulting in a decrease in light fastness and a decrease in the physical properties of the yarn when it is made into fibers. The intrinsic viscosity [η] referred to in the present invention is a value at 30° C. determined by a conventional method using an Ubbelohde viscometer using a 50/50 weight mixture of phenol/tetrachloroethane as a solvent.

Although the reason for the effect of the cobalt compound on light fastness in the present invention has not been scientifically clarified, it is assumed that this is because it absorbs and weakens the fluorescence emitted by the PBT polyester. It is thought that there is. Regarding the effect of phosphorus compounds, due to the effect of the outer shell electron orbit of the phosphorus atom, even if the dye etc. is partially decomposed by light energy and radicals are generated, further decomposition and deterioration progresses to capture this radical. It is presumed that this prevents the Regarding the effect of the titanium compound according to the present invention, it is generally said that the action of the titanium compound as a synthesis catalyst is as a titanate ester, thereby functioning as an esterification, transesterification, and polymerization catalyst. Therefore, unless the dye molecules are neutralized by atoms such as alkali metals and alkali metals, they will be excited by light even at low temperatures and in a solid state. Since it is weak, it is presumed that the light fastness is reduced accordingly. Therefore, it is presumed that titanium compounds containing alkali metals and/or alkali metals are effective in improving light fastness.

Although the effects of each compound in the present invention have been speculated above, it goes without saying that the present invention is not limited thereto.

The present invention will be explained below with reference to Examples.

Example 1 Dimethyl terephthalate (hereinafter abbreviated as DMT)
88.2Kg, 1,4-butanediol (hereinafter abbreviated as BD) 49.2Kg, tetraisobutyl titanate 70.98
g, and 12.7 g of cobalt acetate (hereinafter abbreviated as CoAc) were charged into a reaction vessel, and the transesterification reaction was carried out at 180° C. until no methanol was distilled out. Subsequently, the pressure was gradually reduced while increasing the temperature to 260°C, and finally a polymerization reaction was carried out at 1.0 mmHg or less to obtain a polymer with an intrinsic viscosity [η] of 0.82 and chips with good whiteness. This chip was spun using a conventional small spinning machine for polyester, and then stretched to about twice its original size to form a drawn yarn of 75 denier and 36 filaments.

This was made into a knitted fabric, and white dye (Uvitex ERN,
(manufactured by Ciba Geigy) was stained with 2% owf, and this
When the light fastness was measured according to JIS L-0482, it was grade 3, which was a good result.

Example 2 A polymer was obtained in the same manner as in Example 1 except that 5.29 g of phosphorous acid was charged into a reaction vessel together with other raw materials before the start of the reaction, and the polymer was made into fibers, dyed, and the light fastness was measured, and it was found to be JIS grade 4. In comparison with the case of Example 1, even better results were obtained.

Comparative Example 1 88.2 kg of DMT, 49.2 kg of BD, and 70.98 g of tetraisobutyl titanate were charged into a reaction vessel, and a polymer was obtained in the same manner as in Example 1. The polymer was made into fibers, dyed, and the light fastness was measured, and it was found to be JIS grade 1. In fact, it was difficult to recognize the commercial value.

Example 3 The light fastness was measured in the same manner as in Example 1 except that 73.94 g of potassium titanium oxalate was used as a catalyst instead of tetraisobutyl titanate, and it was JIS grade 2 to 3, which was better than Comparative Example 1. Got the results.

Example 4 The light fastness was measured in the same manner as in Example 2, except that 73.94 g of potassium titanium oxalate was used as a catalyst instead of tetraisobutyl titanate, and it was JIS grade 4 to 5, which was a good result.

Comparative Example 2 88.2 kg of DMT, 49.2 kg of BD, 150 g of potassium titanium oxalate, 60 g of CoAc, and 177 g of phosphorous acid were charged into a reaction vessel, and the intrinsic viscosity [η] was prepared in the same manner as in Example 1.
I obtained a chip of 1.15, but the color tone was blue-black with a hint of brown and was defective. Furthermore, it was made into fibers and dyed in the same manner as in Example 1, and its light fastness was measured, but it was poor at JIS grade 1-2. It should be noted that after dyeing, the color had already turned brown and dull, making it difficult to appreciate its commercial value.

Reference comparative example DMT101.0Kg and ethylene glycol
A reaction vessel was charged with 71.0 kg and 40 g of zinc acetate as a transesterification catalyst, and the transesterification reaction was carried out at 200°C until no methanol was distilled out. At this point, 26.6 g of phosphoric acid and 35.0 g of antimony oxide were added, and the temperature was further raised to 260°C to complete the reaction.
Furthermore, the pressure is gradually reduced while increasing the temperature to 290℃, and finally the polymerization reaction is carried out at 1 mmHg or less, and the intrinsic viscosity is
A PET chip of 0.70 was obtained. This is called Chip A.

Similarly, cobalt-containing PET chips (intrinsic viscosity 0.71) were obtained in the same manner except that 12.7 g of cobalt acetate was added to the raw material during the transesterification reaction. This is called Chip B.

The chips A and B were each spun and then stretched 3.5 times to obtain drawn polyester yarns A and B of 75 denier/36 filaments.

These drawn yarns A and B were dyed in the same manner as in Example 1, and the light fastness was measured.
Both B grades were grade 4-5, and no difference was observed between the two.

Claims (1)

[Claims] 1. A polyester in which 80% or more of the constituent units of the polyester are butylene terephthalate residues, and a cobalt (Co) compound is contained within the range of 5 to 50 ppm in terms of cobalt atoms. A polyester composition with improved light resistance. 2 A polyester in which 80% or more of the constituent units of the polyester are butylene terephthalate residues, and the amount of cobalt (Co) compounds is within the range of 5 to 50 ppm calculated as cobalt atoms, and the amount of phosphorus (P) compounds is within the range of 5 to 50 ppm in terms of cobalt atoms. A polyester composition with improved light resistance, characterized in that it is contained in an amount within the range of 5 to 50 ppm in terms of phosphorus atoms. 3 A polyester in which 80% or more of the constituent units of the polyester are butylene terephthalate residues, containing a cobalt (Co) compound in an amount within the range of 5 to 50 ppm in terms of cobalt atoms, and further containing the following ( 1) Improvement in light resistance characterized by containing a titanium (Ti) compound containing an alkali metal and an alkali metal defined by the formula in an amount within the range of 15 to 150 ppm in terms of titanium atoms. polyester composition. 0.1≦[M]/[Ti]≦0.7 …Equation (1) (However, [M] and [Ti] are the chemical equivalents of the alkali metal and/or alkali metal and titanium atoms contained in the compound, respectively. 4 A polyester in which 80% or more of the constituent units of the polyester are butylene terephthalate residues, the amount of cobalt (Co) compound is within the range of 5 to 50 ppm calculated as cobalt atoms, and the amount of phosphorus (P) The amount of the compound is within the range of 5 to 50 ppm in terms of phosphorus atoms, and the titanium (Ti) compound containing the alkali metal and alkali metal defined by the following formula (1) is 15 ppm in terms of titanium atoms. ~
A polyester composition with improved light resistance, characterized in that it is contained in an amount within the range of 150 ppm. 0.1≦[M]/[Ti]≦0.7 …Equation (1) (However, [M] and [Ti] are the chemical equivalents of the alkali metal and/or alkali metal and titanium atoms contained in the compound, respectively. ).