JPS6021185B2 - Flame retardant polyester composition - Google Patents

Description

[Detailed description of the invention] FIELD OF THE INVENTION This invention relates to flame retardant polyester compositions.

More specifically, the present invention relates to a flame-retardant polyester composition in which a specific phosphorus compound and a non-reactive bromine compound are mixed at a specific mixing ratio. Polyester, particularly polyethylene terephthalate, has excellent mechanical properties and is therefore widely used in fibers, films, and the like. However, said polyesters have the disadvantage of being inherently flammable.

One way to make polyester flammable is to
A method of adding and mixing a bromine compound to a thermoplastic polyester is known.

However, in this method, a large amount of a bromine compound must be added and mixed in order to impart flame retardancy, which has the disadvantage that the inherent physical properties of the polyester are deteriorated.

In order to eliminate these drawbacks, a method has been proposed in which the addition and mixing ratio of the bromine compound is reduced and the lack of flame retardancy is compensated for by the combined use of a phosphorus compound.

In JP-A-50-73948, a specific bromine compound is added to a thermoplastic polyester so that the bromine content in the polyester composition is 3 to 3% by weight, and a phosphorus compound is added to the polyester composition so that the phosphorus content is 3 to 3% by weight. A method is disclosed in which a flame-retardant polyester is obtained by adding and blending it in an amount of 0.1 to 1.5% by weight.

The bromine compounds used in this invention are limited to bis(dibromohydroxyphenyl)sulfone derivatives, and the specification states that if the bromine content is 3% by weight or less, a polyester that exhibits sufficient flame retardancy cannot be obtained. It is stated that. However, the processability of flame-retardant POIJ ester
In order to have completely satisfactory coloration and light resistance in practical terms, it is desirable that the bromine content in the flame-retardant polyester be less than 3% by weight.

Therefore, the present inventors have found that a wide range of bromine compounds can be used, and even if the bromine content is 2.0% by weight or less, flame retardancy can be imparted to thermoplastic polyester through a synergistic effect with the bromine compound. After searching for a moisturizing phosphorus compound, we discovered that a phosphorus compound with a bisphenol S structure is most suitable for this purpose, and that an excellent flame-retardant polyester composition can be obtained by mixing such phosphorus compounds in a specific proportion. We have arrived at the present invention.

That is, the present invention combines a thermoplastic polyester with a non-reactive aromatic bromine compound and the following general formula [where R is 1 carbon atom]
-3 alkyl group or C6-8 aryl group.

n is 0 or 1.

m represents the average degree of polymerization and is a number of 3100. ] A polyester composition prepared by adding and blending a phosphorus compound having a repeating structural unit represented by {1}, wherein the bromine atom in the compound {1} is present in the composition in an amount of 0.5 to 2. The phosphorus atoms of the compound (2) are 0.1 to 1.5 weight % in the composition, and the ratio of the number of phosphorus atoms to the number of bromine atoms in the composition is 0.17 to 4.7.
This is a highly flame-retardant polyester composition.

The flame retardant polyester composition of the present invention has a bromine content of 3.
It exhibits the same level of flame retardancy as the flame retardant polyester described in the above-mentioned known literature, which has a content of 0% by weight or more, and is much superior in light resistance, degree of coloring, etc.

The thermoplastic polyester in the present invention is selected from polyesters containing alkylene terephthalate units as a main component, such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate, and mixtures thereof.

The bromine compound used in the present invention may be any non-reactive aromatic bromine compound, but it must be stable at around 250 qo, which is the melting temperature of the polyester, and have relatively good compatibility with the polyester. Preferably, it is a compound.

Examples of such bromine compounds include compounds in which hydrogen in an aromatic ring is substituted with bromine or an alkyl bromide group, such as hexabromobenzene, bentabromobenzene, dibromomethylbenzene, difuromodiphenyl, octapromodiphenyl, and octabromobenzene. Bromine compounds such as bromodiphenyl ether, decabromodiphenyl ether, etc., 2
, 2-pis(4-hydroxy-3,5-dibromophenyl)propane [hereinafter abbreviated as TBA.

]Bis(4-hydroxy-3,5-dipromophenyl)
Examples of low molecular weight compounds include ether compounds derived from brominated pisphetol such as sulfones, and further examples of high molecular weight retardants include brominated polystyrene brominated phenyl acrylate polymers and compounds derived from TBA-dihaloethane. Examples include bromine polyether, polycarbonate derived from TBA, and combined bromine polyether obtained by ring-opening from 3,3-bisbromomethyloxetane.

In the present invention, preferred bromine compounds to be used are those having a thermal decomposition onset temperature of 2450°C or higher measured under a nitrogen stream, such as hexabromobenzene, octapromodiphenyl ether, 2,2-pis(4-hydroxy-3, These include ether compounds derived from 5-dibromophenylpropane.

The phosphorus compound used in the present invention is represented by the following general formula.

[In the formula, R is an alkyl group having 1 to 3 carbon atoms or an alkyl group having 6 to 3 carbon atoms.
8 aryl group, n is 0 or 1.

m represents a number average molecular weight and is a number from 3 to 100. ] R is preferably a phenyl, tolyl, methyl, ethyl or propyl group.

m is a number from 3 to 10, preferably from 5 to 80.

is less than 3, the thermal stability of the phosphorus compound itself is insufficient and 1
If m exceeds 100, it will be difficult to synthesize the phosphorus compound and mold the resulting polyester composition.
There is no need to exceed. The terminal group of the phosphorus compound varies depending on its synthesis method, but any group does not pose an obstacle to achieving the object of the present invention. These phosphorus compounds are obtained by polycondensation of monosubstituted phosphoric acid or phosphoranic acid and their ester-forming conductors with bis(4-hydroxyphenyl)sulfone and its ester-forming derivatives by a known method. The above-mentioned bromine compound and phosphorus compound may be blended into the thermoplastic polyester by any method. For example, a method of adding polyester to the molten state from the end of the polymerization reaction to immediately after completion, a method of dry blending polyester chips and a heat retardant, melting and mixing, and a method of mixing polyester and a heat retardant immediately before molding and molding. I can give you methods.

The above-mentioned bromine compound and phosphorus compound are added and blended in the following amounts. That is, the bromine compound is
Bromine content in the polyester composition is 0.5% by weight or more; 2. % by weight or less, preferably 0.55-1.9% by weight, more preferably 0.6-1. Used in an amount of $% by weight.

If it is less than 0.5% by weight, the flame retardant effect will not be sufficient even if a phosphorus compound is used in combination. If the amount is greater than 2% by weight, the light resistance of the resulting polyester composition will decrease, and physical properties such as coloring will decrease.

The phosphorus compound has a phosphorus content in the polyester composition,
0.1-1.5% by weight, preferably 0.15-1.3% by weight, more preferably 0.2-1. a% by weight.

If it is less than 0.1% by weight, the effect of incorporating the phosphorus compound will not be observed, and if it exceeds 1.5% by weight, the mechanical properties of the product obtained by molding the resulting polyester composition will deteriorate, which is not preferable.

Furthermore, in the present invention, the ratio of the number of phosphorus atoms to the number of bromine atoms (P/Br) in the polyester composition is 0.17 to 4.7,
Preferably it should be in the range 0.30-4.5.

Outside the above range, the phase effect of phosphorus and bromine on flame retardancy is not significant and the object of the present invention cannot be achieved.

In the present invention, pigments, stabilizers, antistatic agents,
Various modifiers such as plasticizers can be added, and inorganic elutriation combustion aids such as antimony compounds, shelving compounds, zinc compounds, etc. may be added to further increase flame retardancy.

The flame-retardant polyester composition of the present invention not only has excellent flame retardancy, but also has excellent processability, light resistance, and mechanical properties comparable to that of a polyester homopolymer that does not contain a flame-retardant component. Since it is not colored, it can be used for various molded products such as fibers and films.

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

Various data in Examples were measured by the following methods. '1} Intrinsic viscosity Measured at 35°C using orthochlorophenol as a solvent.

■ The flame retardant oxygen index is based on JISK7201, and the flammability classification test is based on Underwriters Laboratories Suject UL.
Measured according to Kazuhiro.

Examples 1 to 14, Comparative Examples 1 to 13 Polyethylene terephthalate (intrinsic viscosity 0.67 or less, abbreviated as PET), polybutylene terephthalate (intrinsic viscosity 1.2 u or less, abbreviated as PBT), polyethylene-2,6 naphthalene dicarboxylate (abbreviated as PEN with an intrinsic viscosity of 0.625 or less), etc., are dry blended with the flame retardants listed below at various blending ratios,
It was melt extruded and made into chips.

Each test piece is injection molded from this chip,
An elutriation test was conducted and the results are shown in Table 1. Compounding agent Phosphorus compound form Table 1 However, the results of the flame retardancy test of polyester itself are shown in Table 2.
It is as shown in the table.

As shown in Table 2 and Table 1, in the examples that satisfy the essential conditions of the present invention, the flame retardance is extremely good, and there is no deterioration in physical properties or coloring.

In addition, in Example 9, by using the phosphorus compound {1), the amount of added bromine compound (d) used in JP-A-50-73948 was reduced to 1.0% by weight of Br content. Also, a good flame-retardant polyester composition can be obtained. As shown in Comparative Examples 1 to 13, flame retardance is insufficient outside the range of the present invention, or even if the flame retardance is satisfied, the physical properties are significantly deteriorated.

Furthermore, as shown in Comparative Example 7, when the content of Br is high, the light resistance decreases, and in Comparative Example 8, even if the content of P and Br is within the range of the present invention, the phosphorus compound is It is shown that flame retardancy decreases when the values are different.

Example 15 Polymerization was carried out at 275°C using dimethyl terephthalate and ethylene glycol using titanium tetrabutoxide as a catalyst, and when the intrinsic viscosity reached 0.65, the pressure of the system was reduced and nitrogen was introduced to return it to normal pressure. , 1.2 as phosphorus for the polyethylene terephthalate produced.
The compound of '1} above was added to 1% by weight, and bromine was added to 1. Each of the above-mentioned compounds (C) was added to the above-mentioned melted polyethylene terephthalate so as to give a weight percent of 10% by weight, and the mixture was stirred at the same temperature for 10 minutes, and then taken out as chips.

After drying, the chips were drawn into paper yarn using a conventional method to produce 75-denier 24-filament long fibers, which were used to make stockinette wire and tested by the coil method according to the JISLIO91D method. The number of ignitions is 5.
7 times, indicating good flame retardancy. Further, when this knitted fabric and a knitted fabric made in the same manner from only polyethylene terephthalate were tested using a can weatherometer, no difference was found between the two. The colors of both stockinette stripes were completely indistinguishable, and there were almost no dye spots.

Claims (1)

[Claims] 1 Thermoplastic polyester contains (1) a non-reactive aromatic bromine compound and (2) the following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, R has 1 to 3 carbon atoms] or an aryl group having 6 to 8 carbon atoms. n is 0 or 1. m represents the average degree of polymerization and is a number from 3 to 100. A polyester composition prepared by adding and blending a phosphorus compound having a repeating structural unit represented by ) The phosphorus atom of the compound is 0.1 to 1.5% by weight in the composition,
and the ratio of the number of phosphorus atoms to the number of bromine atoms in the composition is 0.17.
A highly flame-retardant polyester composition blended so as to have a polyester content of 4.7.