TW201905031A - Flame retardant polyester and method for manufacturing the same - Google Patents

Abstract

A flame retardant polyester and a method for manufacturing the same are provided. The flame retardant polyester is represented by general formula (3) or general formula (4): In general formula (3) and general formula (4), n is an integer of 1 to 3; X represents a molar fraction of phosphorus-containing polyester and 0 < X < 0.5; R1 represents a substituted or unsubstituted C1-C10 alkyl group; is a 1,4-phenylene, 1,3-phenylene, 2,6-naphthylene or 2,7-naphthylene.

Description

Flame retardant polyester and manufacturing method thereof

The present invention relates to a polyester and a process for the preparation thereof, and in particular to a flame retardant polyester and a process for the preparation thereof.

Polyester has good mechanical and chemical properties and is therefore an important plastic material widely used in related industries such as fiber, woven fabric, non-woven fabric and film. In recent years, the requirements for the flame resistance characteristics of synthetic fibers have been increasingly emphasized, and in particular, polyester polymers which are widely used in industries related to the people's livelihood. Therefore, how to make polyester have flame resistance characteristics is an important research topic.

In order to achieve a flame retardant effect on the polyester polymer, the following method is generally used. (1) A flame retardant is added in a blending manner. This method is simple but has problems of poor compatibility and migration of the flame retardant, which in turn causes a decrease in the flame retardancy of the polyester polymer. (2) Subsequent processing with finished products. After the fabric is finished, it is treated with a flame retardant on the surface. However, this method causes a decrease in flame retardancy after the number of washings is increased. Therefore, the development of flame retardant polyesters having high heat resistance and good flame retardant properties is currently an urgent need.

The present invention provides a flame retardant polyester having a high glass transition temperature and good flame retardant properties.

The invention provides a preparation method of a flame retardant polyester, which can realize a flame retardant polyester with high glass transition temperature and good flame retardant property.

The flame retardant polyester of the present invention can be represented by the following formula (3) or formula (4): (3) (4) In the general formulae (3) and (4), n is an integer of 1 to 3; X is a molar fraction of the phosphorus-containing polyester, and 0 < X <0.5; R ₁ is substituted or Unsubstituted C1~C6 alkyl; It is a 1,4-phenylene group, a 1,3-phenylene group, a 2,6-anthranyl group or a 2,7-anthranyl group.

The method of producing a flame retardant polyester of the present invention comprises the following steps. A phosphorus compound is provided, which is represented by the following general formula (1): (1) In the formula (1), R ₁ is a substituted or unsubstituted C1 to C6 alkyl group. The phosphorus compound is mixed with the base polymer to form a blend in which the molar ratio of the phosphorus compound to the base polymer is 1:0.05 to 0.5. The base polymer in the blend is melted to form a melting blend. The catalyst is added to the molten blend and subjected to a polycondensation reaction under vacuum.

In an embodiment of the invention, the above-mentioned base polymer is, for example, a recycled polyester.

In an embodiment of the invention, the raw material polymer is, for example, a polyester represented by the formula (2-1), a polyester represented by the formula (2-2), or a combination thereof. (2-1) (2-2) In the formula (2-1) and the formula (2-2), Ar is 1,4-phenylene, 1,3-phenylene, 2,6-anthranyl or 2 , 7-strandyl; n is an integer from 2 to 6; m is an integer from 30 to 300.

In one embodiment of the present invention, the above-mentioned base polymer is, for example, a polyester represented by the formula (2-1-1), a polyester represented by the formula (2-1-2), and a formula ( a polyester represented by 2-2-1), a polyester represented by the general formula (2-2-1), or a combination thereof, (2-1-1) (2-1-2) (2-2-1) (2-2-2) In the formula (2-1-1) to the formula (2-2-2), n is an integer of 2 to 6; m is an integer of 30 to 300.

In an embodiment of the invention, the base polymer in the blend is melted, for example, at 210 ° C to 280 ° C for 30 minutes to 180 minutes.

In an embodiment of the invention, the catalyst is, for example, a titanium catalyst.

In an embodiment of the invention, the titanium catalyst is, for example, Ti(OR) ₄ , wherein R is a C1 to C6 alkyl group.

In an embodiment of the invention, the content of the catalyst is, for example, from 0.1% by weight to 1.0% by weight based on the total weight of the base polymer.

In an embodiment of the invention, the above polycondensation reaction is carried out, for example, at 230 ° C to 280 ° C for 30 minutes to 180 minutes.

Based on the above, the phosphorus-based compound of the present invention undergoes a polycondensation reaction with a base polymer to form a flame-retardant polyester having a bonding type phosphorus element. Moreover, the phosphorus element in the flame retardant polyester does not migrate to the surface, so the flame retardant polyester prepared has a high glass transition temperature and good flame retardant properties.

The above described features and advantages of the invention will be apparent from the following description.

In the present specification, the range represented by "a value to another value" is a schematic representation that avoids enumerating all the values in the range in the specification. Therefore, the recitation of a particular range of values is intended to include any value in the range of values and the range of values defined by any value in the range of values, as in the specification. The scope is the same.

The invention is further illustrated by the following examples, which are intended to be illustrative only and not to limit the scope of the invention.

One embodiment of the present invention provides a method of preparing a flame retardant polyester comprising the following steps. First, a phosphorus compound is provided. In the present embodiment, the phosphorus-based compound is represented by the following general formula (1): (1) In the formula (1), R ₁ is a substituted or unsubstituted C1 to C6 alkyl group.

In one embodiment, the above R ₁ is methyl

Next, the phosphorus compound is mixed with the base polymer to form a blend. In the present embodiment, the base polymer is, for example, a recycled polyester. In one embodiment, the recycled polyester is a polyester that has been reworked after removal of the impurities and/or cleaning process.

In one embodiment, the base polymer is, for example, a polyester represented by the general formula (2-1), a polyester represented by the general formula (2-2), or a combination thereof. (2-1) (2-2) In the formula (2-1) and the formula (2-2), Ar is 1,4-phenylene, 1,3-phenylene, 2,6-anthranyl or 2 , 7-strandyl; n is an integer from 2 to 6; m is an integer from 30 to 300.

In one embodiment, the base polymer includes a polyester represented by the formula (2-1-1), a polyester represented by the formula (2-1-2), and a formula (2-2-1) a polyester represented by the formula, a polyester represented by the formula (2-2-1), or a combination thereof, (2-1-1) (2-1-2) (2-2-1) (2-2-2) In the formula (2-1-1) to the formula (2-2-2), n is an integer of 2 to 6; m is an integer of 30 to 300.

In one embodiment, the base polymer is, for example, polyethylene (polyethylene terephthalate), polybutylene terephthalate (PBT), poly Poly(trimethylene terephthalate) (PTT) or a combination thereof.

In the present embodiment, the molar ratio of the phosphorus-based compound to the base polymer is 1:0.05 to 0.5. In one embodiment, the molar ratio of the phosphorus compound to the base polymer is 1:0.05 to 0.2.

The base polymer in the blend is then melted to form a melting blend. In the present embodiment, in the process of melting the base polymer in the blend, the base polymer in the blend and the phosphorus compound undergo an alcoholysis reaction.

In one embodiment, the melting of the base polymer in the blend is carried out, for example, at 210 ° C to 280 ° C. In another embodiment, the melting of the base polymer in the blend is carried out, for example, at 240 ° C to 270 ° C. In one embodiment, the base polymer is heated, for example, under a nitrogen atmosphere. In one embodiment, the reaction time is, for example, from 30 minutes to 180 minutes. In another embodiment, the reaction time is, for example, from 30 minutes to 120 minutes. In one embodiment, the alcoholysis reaction can be carried out under vacuum conditions. In the present embodiment, since the raw material polymer is melted before the condensation reaction is carried out, it contributes to uniform mixing and reaction.

Thereafter, a catalyst is added to the molten blend and subjected to a polycondensation reaction in a vacuum atmosphere to obtain a flame retardant polyester. Specifically, the hydroxyl group of the phosphorus compound is first subjected to a transesterification reaction with the base polymer, followed by a condensation reaction, whereby the phosphorus element is introduced into the formed polyester.

In the present embodiment, the catalyst is, for example, a titanium catalyst. In one embodiment, the titanium catalyst is, for example, Ti(OR) ₄ , wherein R is a C1 to C6 alkyl group. The amount of catalyst used in the present invention depends on the amount of the base polymer. In one embodiment, the catalyst is present in an amount of from 0.1% by weight to 1.0% by weight based on the total weight of the base polymer. In another embodiment, the catalyst is present in an amount of 0.5% by weight based on the total weight of the base polymer. The content of the catalyst is within the above range, and the transesterification reaction and the condensation reaction can be effectively promoted.

In one embodiment, the polycondensation reaction is carried out, for example, at 230 ° C to 280 ° C. In another embodiment, the polycondensation reaction is carried out, for example, at 240 ° C to 270 ° C. In one embodiment, the time of the polycondensation reaction is, for example, from 30 minutes to 180 minutes. In another embodiment, the time of the polycondensation reaction is, for example, a reaction of from 30 minutes to 120 minutes. In one embodiment, the polycondensation reaction can be carried out under vacuum conditions.

In the present embodiment, the bonding type phosphorus element is formed by a chemical reaction method and the phosphorus element is introduced into the flame retardant polyester formed, so that the phosphorus element in the flame retardant polyester does not migrate to the surface, and is recovered by the polymerization. The flame retardant polyester prepared by the ester has a high glass transition temperature and flame retardant properties.

In the present embodiment, the flame retardant polyester prepared can be represented by the following formula (3) or formula (4): (3) (4) In the general formulae (3) and (4), n is an integer of 1 to 3; X is a molar fraction of the phosphorus-containing polyester, and 0 < X <0.5; R ₁ is substituted or Unsubstituted C1~C6 alkyl; It is a 1,4-phenylene group, a 1,3-phenylene group, a 2,6-anthranyl group or a 2,7-anthranyl group.

Next, the characteristics of the flame-retardant polyester produced by the method for producing a flame-retardant polyester of the present invention will be described by way of experimental examples. However, the materials, the methods of use, and the like shown in the following experimental examples can be appropriately changed without departing from the spirit of the invention. Therefore, the scope of the present invention should not be construed as limited by the experimental examples shown below. [ Synthesis of Phosphorus Compounds ]

Synthesis Example 1: Synthesis of Phosphorus Compound (1)

[Reaction Flow Chart 1]

Compound (a-1) (10 g, 23.3 mmol), ethylene carbonate (4.522 g, 51.26 mmol), potassium carbonate (0.013 g, 0.0932 mmol) and N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, NMP) (100 mL) was placed in a 250 mL three-neck reactor and stirred at 120 ° C for 6 hours under nitrogen. After the completion of the reaction, the product in the three-necked reactor was cooled to room temperature, and saturated brine was added thereto to precipitate. Thereafter, the precipitate was suction-filtered and dried in a vacuum oven at 60 ° C to obtain a white solid phosphorus compound (1) (yield: about 72%). [ Preparation of flame retardant polyester ]

The flame retardant polyester of the present invention can be formed, for example, by the steps shown below.

The reaction steps described above are for illustrative purposes only, and the present invention is not limited thereto, and may be prepared according to the change of the flame retardant polyester formed by selecting a suitable raw material polymer, a phosphorus compound, and reaction conditions, and the reaction preparation method may be based on the field. The well-known techniques change.

Example 1

Preparation of flame retardant polyester 1

The phosphorus compound (1) and PET were fed at a molar ratio of 0.05, placed in a separate reactor, stirred, purged with nitrogen, and heated to 250 °C. The reaction was stirred under a vacuum for 0.5 hour, and then Titanium (IV) butoxide (0.5% by mass of PET) was added and the temperature was raised to 280 ° C, and the reaction was stirred for 1 hour under vacuum, after the reaction. The temperature was lowered to room temperature to obtain a flame retardant polyester 1 of a dark red solid.

Example 2

Preparation of flame retardant polyester 2

The flame-retardant polyester 2 was prepared in a manner similar to that of Example 1, except that the molar ratio of the phosphorus-based compound (1) to PET in Example 2 was 0.1.

Example 3

Preparation of flame retardant polyester 3

The flame-retardant polyester 3 was prepared in a manner similar to that of Example 1, except that the molar ratio of the phosphorus-based compound (1) to PET in Example 3 was 0.15.

Example 4

Preparation of flame retardant polyester 4

The flame-retardant polyester 4 was prepared in a manner similar to that of Example 1, except that the molar ratio of the phosphorus-based compound (1) to PET in Example 4 was 0.2.

Figure 1 is a ¹ H NMR (400 MHz) spectrum of PET and flame retardant polyester 1 ~ flame retardant polyester 4 in CDCl ₃ /CF ₃ COOH solution, and the integrated area conforms to its structure. As shown in Fig. 1, a characteristic peak of a methyl group was formed at 1.8 ppm, and other peaks were formed in the range of 6.6 to 8.0 ppm. Therefore, it was found that the phosphorus compound (1) was surely copolymerized with PET. The copolymerization structure of the flame-retardant polyester 1 to the flame-retardant polyester 4 is as follows, wherein X represents the molar fraction of the phosphorus-containing polyester. Specifically, in the flame-retardant polyester 1 to the flame-retardant polyester 4, X is 0.05, 0.1, 0.15, and 0.2, respectively.

Example 5

Preparation of flame retardant polyester 5

The phosphorus compound (1) and PBT were fed at a molar ratio of 0.05, placed in a separate reactor, stirred, passed through a nitrogen gas, and heated to 210 °C. The reaction was stirred under a vacuum for 0.5 hour, and then Titanium (IV) butoxide (0.5% by mass of PET) was added and the temperature was raised to 230 ° C, and the reaction was stirred for 1 hour under vacuum, after the reaction. The temperature was lowered to room temperature to obtain a flame retardant polyester 5 having a dark red solid.

Example 6

Preparation of flame retardant polyester 6

The flame-retardant polyester 6 was prepared in a manner similar to that of Example 5 except that the molar ratio of the phosphorus-based compound (1) to PBT in Example 6 was 0.1.

Example 7

Preparation of flame retardant polyester 7

The flame-retardant polyester 7 was prepared in a manner similar to that of Example 5 except that the molar ratio of the phosphorus-based compound (1) to PBT in Example 7 was 0.15.

Example 8

Preparation of flame retardant polyester 8

The flame-retardant polyester 8 was prepared in a manner similar to that of Example 5 except that the molar ratio of the phosphorus-based compound (1) to PBT in Example 8 was 0.2.

2 is a ¹ H NMR (400 MHz) spectrum of PBT and flame retardant polyester 5~ flame retardant polyester 8 in CDCl ₃ /CF ₃ COOH solution, and the integrated area conforms to its structure. As shown in Fig. 2, a characteristic peak of a methyl group was formed at 1.8 ppm, and other peaks were formed in the range of 6.6 to 8.0 ppm. Therefore, it was found that the phosphorus compound (1) and PBT were surely copolymerized. The copolymerization structure of the flame retardant polyester 5 to the flame retardant polyester 8 is as follows, wherein X represents the molar fraction of the phosphorus-containing polyester. Specifically, in the flame-retardant polyester 5 to the flame-retardant polyester 8, X is 0.05, 0.1, 0.15, and 0.2, respectively. [ Evaluation of thermal properties and flame retardant properties of flame retardant polyester ]

The prepared flame retardant polyester 1 to flame retardant polyester 8 was melted into a bulk on a mold and its thermal properties were evaluated by the following methods. Further, the flame retardancy of the flame-retardant polyester 1 to the flame-retardant polyester 8 was measured using the UL-94 test method. The results are listed in Table 1.

(1) Glass transition temperature (Tg)

The glass transition temperature of the sample was measured using thermo-mechanical analysis (TMA). The thermomechanical analysis was carried out under the conditions of measuring the glass transition temperature of the sample using a Dynamic Mechanical Analyzer (DMA) (Model: Perkin-Elmer Pyris Diamond) at a heating rate of 5 ° C/min.

(2) 5% thermogravimetric loss temperature (T _d5% ) and coke residual rate

Thermo-gravimetric analysis (TGA) was used to measure the sample's 5% thermogravimetric loss temperature and Char yield. The thermogravimetric analysis was carried out under the condition that the weight change of the sample was measured using a thermogravimetric analyzer (Model: Thermo Cahn Versa Therm) under a nitrogen atmosphere at a heating rate of 20 ° C / min. The 5% thermogravimetric loss temperature refers to a temperature at which the weight loss of the sample reaches 5%, and the higher the 5% thermogravimetric loss temperature, the better the thermal stability of the sample. The coke residual ratio refers to the residual weight ratio of the sample at a heating temperature of 800 ° C, wherein the higher the residual weight ratio, the better the thermal stability of the sample.

Figure 3 is a dynamic mechanical analysis of PET and flame retardant polyester 1~ flame retardant polyester 4. Figure 4 is a dynamic mechanical analysis of PBT and flame retardant polyester 5~ flame retardant polyester 8. The glass transition temperature (Tg) of PET, PBT and flame retardant polyester 1 to flame retardant polyester 8 can be known from the temperature corresponding to the damping (tan δ) peak.

[Table 1]

Referring to FIG. 3, FIG. 4 and Table 1, it can be seen that as the introduction ratio of the phosphorus-based compound (1) increases, the glass transition temperature of the prepared flame-retardant polyester tends to increase due to the phosphorus compound ( The introduction of the large phosphorus-containing group in 1) makes the structure asymmetrical, thus restricting the rotation of the molecular chain, thereby increasing the glass transition temperature of the flame-retardant polyester. In addition, as can be seen from FIG. 3 and FIG. 4, as the introduction ratio of the phosphorus-based compound (1) increases, the height of the damping (tan δ) peak also increases, which is due to the phosphorus compound (1). The large phosphorus-containing groups cause the spacing between the arrays to be indistinct as pure PET and PBT-like, thus causing a height increase in the damping (tan δ) peak.

Further, as apparent from Table 1, as the introduction ratio of the phosphorus-based compound (1) increases, the coke residual ratio of the prepared flame-retardant polyester is greatly increased because the phosphorus-containing polymer is burned in the air. A coke layer with a high phosphorus content is formed with oxygen to block the conduction of air and heat, thereby protecting the internal polymer, and thus has a high coke residual rate.

Further, as the introduction ratio of the phosphorus-based compound (1) increases, the flame retardant properties of the prepared flame-retardant polyester also increase. For example, a flame retardant polyester (ie, flame retardant polyester 1) prepared by using a phosphorus compound (1) and a PET molar ratio of 0.05 (the flame retardant polyester 1) has a phosphorus content (P%) of 0.72% and is in UL. -94 V-01 rating in flame retardant test. A flame retardant polyester (ie, flame retardant polyester 7) prepared by using a phosphorus compound (1) and a PBT molar ratio of 0.15, has a phosphorus content (P%) of 1.65% and is flame retardant in UL-94. The test can reach V-0 level.

As described above, after the phosphorus-based compound of the present invention undergoes a polycondensation reaction with a base polymer, a flame-retardant polyester having a bonding type phosphorus element is formed. Moreover, the phosphorus element in the flame retardant polyester does not migrate to the surface, so the flame retardant polyester prepared has a high glass transition temperature and good flame retardant properties.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

no

Figure 1 is a ¹ H NMR (400 MHz) spectrum of PET and flame retardant polyester 1 ~ flame retardant polyester 4 in CDCl ₃ /CF ₃ COOH solution. 2 is a ¹ H NMR (400 MHz) spectrum of PBT and flame retardant polyester 5 to flame retardant polyester 8 in a CDCl ₃ /CF ₃ COOH solution. 3 is a dynamic mechanical analysis (DMA) diagram of PET and flame retardant polyester 1 to flame retardant polyester 4. Figure 4 is a dynamic mechanical analysis of PBT and flame retardant polyester 5~ flame retardant polyester 8.

Claims (10)

A flame retardant polyester represented by the following general formula (3) or formula (4): (3) (4) In the general formulae (3) and (4), n is an integer of 1 to 3; X is the molar fraction of the phosphorus-containing polyester, and 0 < X <0.5; R ₁ is substituted or Unsubstituted C1~C6 alkyl; It is a 1,4-phenylene group, a 1,3-phenylene group, a 2,6-anthranyl group or a 2,7-anthranyl group. A method of preparing a flame-retardant polyester, comprising: providing a phosphorus-based compound represented by the following general formula (1): (1) In the formula (1), R ₁ is a substituted or unsubstituted C1 to C6 alkyl group; the phosphorus compound is mixed with a base polymer to form a blend, wherein The molar ratio of the phosphorus compound to the base polymer is 1:0.05 to 0.5, the raw material polymer in the blend is melted to form a molten blend; and the catalyst is added thereto. The polycondensation reaction is carried out in a molten blend under vacuum. A method of producing a flame retardant polyester according to claim 2, wherein the base polymer is a recycled polyester. The method for producing a flame-retardant polyester according to claim 2, wherein the base polymer comprises a polyester represented by the formula (2-1), and a polyester represented by the formula (2-2) Or a combination thereof, (2-1) (2-2) In the formula (2-1) and the formula (2-2), Ar is 1,4-phenylene, 1,3-phenylene, 2,6-anthranyl or 2 , 7-strandyl; n is an integer from 2 to 6; m is an integer from 30 to 300. The method for producing a flame-retardant polyester according to claim 2, wherein the base polymer comprises a polyester represented by the formula (2-1-1), and the formula (2-1-2) The polyester represented by the formula, the polyester represented by the formula (2-2-1), the polyester represented by the formula (2-2-1), or a combination thereof, (2-1-1) (2-1-2) (2-2-1) (2-2-2) In the formula (2-1-1) to the formula (2-2-2), n is an integer of 2 to 6; m is an integer of 30 to 300. A method of producing a flame-retardant polyester according to claim 2, wherein the melting of the base polymer in the blend is carried out at 210 ° C to 280 ° C for 30 minutes to 180 minutes. A method of producing a flame retardant polyester according to claim 2, wherein the catalyst is a titanium catalyst. The method for producing a flame-retardant polyester according to claim 7, wherein the titanium catalyst is Ti(OR) ₄ , wherein R is a C1 to C6 alkyl group. The method for producing a flame-retardant polyester according to claim 2, wherein the catalyst is contained in an amount of from 0.1% by weight to 1.0% by weight based on the total of the base polymer. The method for producing a flame-retardant polyester according to claim 2, wherein the polycondensation reaction is carried out at 230 ° C to 280 ° C for 30 minutes to 180 minutes.