PHOSPHAZENE COMPOUND CONTAINING ESTER GROUP, PREPARATION METHOD AND USE THEREOF

Abstract

The present invention relates to a phosphazene compound containing an ester group having a structure of formula (I). The present invention grafts ester groups to phosphazene compounds and makes terminal grafted hydroxyl and carboxyl groups reacted with polymer matrix, producing an improvement of flame retardancy and a reduction of dielectric constant at the same time when the phosphazene compound is introduced into polymer matrix. Since N and P atoms are directly bonded into the polymer matrix by a reaction rather than addition and combination means in the prior art, there is no reduced mechanical properties of the matrix due to the addition of flame retardants.

Claims

1. A phosphazene compound-containing ester group, comprising a structure of formula (I): ##STR00013## in formula (I), Y, Z.sub.1 and Z.sub.2 are inert nucleophilic groups; M is any one of phosphazene compounds or a combination of at least two of them; R′.sub.1 is —X—R′.sub.3—; R′.sub.2 is —X—R′.sub.4—; R′.sub.3 and R′.sub.4 are organic groups having two broken bonds; X is oxygen atom, nitrogen atom or sulfur atom; a is an integer greater than or equal to 1; b is an integer greater than or equal to 0; c is an integer greater than or equal to 0; d is an integer greater than or equal to 0; the sum of b and a is two times of the number of phosphorus atoms in M; the sum of c+2 is two times of the number of phosphorus atoms in M; the sum of d+2 is two times of the number of phosphorus atoms in M; m is an integer less than or equal to 10.

2. The phosphazene compound: containing ester group of claim 1, comprising a structure of formula (II): ##STR00014## in formula (II), Z.sub.1 and Z.sub.2 are inert nucleophilic groups; M is any one of phosphazene compounds, or a combination of at least two of them; R′.sub.1 is —X—R′.sub.3—; R′.sub.2 is —X—R′.sub.4—; R′.sub.3 and R′.sub.4 are organic groups having two broken bonds; X is oxygen atom, nitrogen atom or sulfur atom; c is an integer greater than or equal to 0; d is an integer greater than or equal to 0; the sum of c+2 is two times of the number of phosphorus atoms in M; the sum of d+2 is two times of the number of phosphorus atoms in M; m is an integer greater than 0 and less than or equal to 10.

3. The phosphazene compound-containing ester group of claim 2, wherein Z.sub.1 and Z.sub.2 are independently selected from any one of ##STR00015## or a combination of at least two of them; R.sub.14, R.sub.13, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.15, R.sub.11 and R.sub.12 are independently any one of substituted or unsubstituted linear alkyl or branched alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylthio group, substituted or unsubstituted cycloalkoxy, substituted or unsubstituted arylalkoxy, substituted or unsubstituted alkylaryloxy, substituted or unsubstituted carbonate group, substituted or unsubstituted sulfonate group, substituted or unsubstituted phosphonate group, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl.

4. The phosphazene compound-containing ester group of claim 2, wherein M is selected from cyclic phosphazene having a structure of formula (III), or linear phosphazene having a structure of formula (IV); ##STR00016## in formula (III) or formula (IV), n.sub.1 and n.sub.2 are independently selected from integers of 3-10.

5. The phosphazene compound: containing ester group of claim 2, wherein M is selected from any one of cyclotriphosphazene group M.sub.1, cyclotetraphosphazene group M.sub.2, or non-cyclic polyphosphazene group M.sub.3, or a combination of at least two of them.

6. The phosphazene compound: containing ester group of claim 2, wherein R′.sub.3 is selected from substituted or unsubstituted hydrocarbylene.

7. The phosphazene compound-containing ester group of claim 2, wherein R′.sub.3 is selected from substituted or unsubstituted linear alkylene, substituted or unsubstituted branched alkylene, substituted or unsubstituted arylene.

8. The phosphazene compound-containing ester group of claim 2, wherein R′.sub.3 is C.sub.1-C.sub.30 substituted or unsubstituted linear alkylene, C.sub.1-C.sub.30 substituted or unsubstituted branched alkylene, and C.sub.6-C.sub.30 substituted or unsubstituted arylene.

9. The phosphazene compound-containing ester group of claim 2, wherein R′.sub.3 is phenylene, methylphenylene, dimethylphenylene, ethylphenylene, ##STR00017## methylene, ethylene, propylene, n-butylene, or isopropylene.

10. The phosphazene compound: containing ester group of claim 2, wherein that the phosphazene compound containing ester group comprises any one of the phosphazene compounds having the following structures, or a mixture of at least two of them: ##STR00018## ##STR00019## wherein m is an integer greater than 0 and less than or equal to 10.

11. A method for preparing the phosphazene compound-containing ester group of claim 2, comprising the following steps: (1) carrying out a nucleophilic reaction of phosphazene chloride ##STR00020## with an inert nucleophile, thereby replacing partial chlorine atoms on M by inert nucleophilic groups, with two remaining chlorine atoms on the phosphazene chloride being not replaced; (2) dividing the product obtained in step (1) into two equal parts in mole, with one part being reacted with H—X—R′.sub.3—OH to relapce the remaining chlorine atoms on phosphazene matrix by —R′.sub.1—OH, and the other part being reacted with H—X—R′.sub.4—COOH to replace the remaining chlorine atoms on phosphazene matrix by —R′.sub.2—COOH; and (3) carrying out esterification reaction of the phosphazene compound having hydroxyl groups with the phosphazene compound having carboxyl groups obtained in step (2), thereby obtaining a phosphazene compound containing ester group; wherein M, X, R′.sub.1, R′.sub.2, R′.sub.3 and R′.sub.4 have scopes as defined in claim 2.

12. A prepreg, prepared by impregnating a substrate with an resin composition comprising the phosphazene compound-containing ester group of claim 2 or coating an resin composition comprising the phosphazene compound containing ester group of claim 2 onto a substrate.

13. The prepreg of claim 12, wherein the substrate is a glass fiber substrate, a polyester substrate, a polyimide substrate, a ceramic substrate or a carbon fiber substrate.

Description

EMBODIMENTS

[0038] In order to facilitate the understanding of the present invention, examples are listed as follows. Those skilled in the art should appreciate that the embodiments are only used to understand the present invention and shall not be deemed as limitations to the present invention.

[0039] In order to describe the structure and method expediently, specific positions of substituents in the phosphazene compounds obtained by the examples of the present invention are not marked, and this means that the substituents can be at any position. In addition, the number of substituents in the structure of the compound described in each example only an illustration of the product prepared by the method, and the number of substituents is the average value of the substituents in the product and does not mean that the product is a compound just having one specific structure.

Example 1

[0040] A phosphazene compound containing ester group, having the following structure:

##STR00009##

wherein cyclotriphosphazene is substituted by four phenoxyl groups on average, and m is 3.

[0041] The preparation method thereof is as follow:

(1) 1 mol of hexachlorocyclotriphosphazene, 200 ml of acetone, 4 mol of sodium phenate were added to a 3-neck glass reactor having a volume of 2000 ml and equipped with a stirring apparatus. While stirring, nitrogen was fed therein, and the reactor was heated to 60° C. 20% sodium hydroxide solution was dripped therein taking 60 min to make pH neutral, and then the mixture was held at 60° C., stirred and reacted for 15 hours;
(2) The product of step (1) was divided into two equal parts;
One part was reacted with 2 mol of methylene glycol. While stirring, nitrogen was fed therein, and the reactor was heated to 40° C. 20% sodium hydroxide solution was dripped therein taking 30 min to make pH neutral, and then the mixture was held at 40° C., stirred and reacted for 15 hours. Then a phosphazene compound containing hydroxymethyloxyl group was obtained;
The other part was reacted with 2 mol of 2-glycolic acid. While stirring, nitrogen was fed therein, and the reactor was heated to 40° C. 20% sodium hydroxide solution was dripped therein taking 30 min to make pH neutral, and then the mixture was held at 40° C., stirred and reacted for 15 hours. Then a phosphazene compound containing carboxyethyloxyl group was obtained;
(3) An esterification reaction of the phosphazene compound containing hydroxymethyloxyl group and the phosphazene compound containing carboxyethyloxyl group obtained in step (2) was carried out, so as to obtain a phosphazene compound containing ester group.

[0042] After reaction, the inorganic constituents and water in the system were removed by physical method; and the solvent in the system was removed by distillation; and thereby a phosphazene compound containing ester group was obtained.

[0043] The obtained phosphazene compound containing ester group was characterized by nuclear magnetic resonance hydrogen spectrum, and the results are as follows:

[0044] .sup.1H NMR (CDCl.sub.3, 500 MHz):6.7-6.8, 7.0-7.15, 6.8-6.9 (hydrogen on benzene ring), 5.75-5.80 (hydrogen on O—C—O), 6.30-6.35 (hydrogen on O—C—O—C═O), 4.45-4.55 (hydrogen on O═C—C—O), 11.0 (hydrogen on carboxyl group), 2.0 (hydrogen on hydroxyl group).

[0045] Characteristic peak positions in infrared spectroscopy: characteristic absorption peak of P═N in phosphazene skeleton, 1217 cm.sup.−1; P—N in phosphazene skeleton, 874 cm.sup.−1; absorption peak of P—O—C, 1035 cm.sup.−1; skeleton vibration of benzene ring, 1500˜1600 cm.sup.−1; absorption peak of ester group, 1200-1300 cm.sup.−1.

[0046] An epoxy resin composition is prepared by adding 100 g of the above phosphazene compound containing ester group as a coupling curing agent to 100 g of o-cresol novolac epoxy resin with an epoxide equivalent of 200 g/eq and 0.1 g of 2-methylimidazole as a curing accelerator. A copper-clad laminate sample meeting the national, UL and other standards is prepared using the epoxy resin composition according to generally used copper-clad laminate production process. The copper-clad laminate is named as copper-clad laminate a and the properties thereof are measured and the results are shown in table 1.

Example 2

[0047] A phosphazene compound containing ester group, having the following structure:

##STR00010##

wherein cyclotriphosphazene is substituted by four methoxyl groups on average, and m is 2.

[0048] The preparation method thereof is as follow:

(1) 1 mol of hexachlorocyclotriphosphazene, 200 ml of acetone, 4 mol of sodium methoxide were added to a 3-neck glass reactor having a volume of 2000 ml and equipped with a stirring apparatus. While stirring, nitrogen was fed therein, and the reactor was heated to 60° C. 20% sodium hydroxide solution was dripped therein taking 60 min to make pH neutral, and then the mixture was held at 60° C., stirred and reacted for 15 hours;
(2) The product of step (1) was divided into two equal parts;
One part was reacted with 2 mol of methylene glycol. While stirring, nitrogen was fed therein, and the reactor was heated to 40° C. 20% sodium hydroxide solution was dripped therein taking 30 min to make pH neutral, and then the mixture was held at 40° C., stirred and reacted for 15 hours. Then a phosphazene compound containing hydroxymethyloxyl group was obtained;
The other part was reacted with 2 mol of 2-glycolic acid. While stirring, nitrogen was fed therein, and the reactor was heated to 40° C. 20% sodium hydroxide solution was dripped therein taking 30 min to make pH neutral, and then the mixture was held at 40° C., stirred and reacted for 15 hours. Then a phosphazene compound containing carboxyethyloxyl group was obtained;
(3) An esterification reaction of the phosphazene compound containing hydroxymethyloxyl group and the phosphazene compound containing carboxyethyloxyl group obtained in step (2) was carried out, so as to obtain a phosphazene compound containing ester group.

[0049] The obtained phosphazene compound containing ester group was characterized by nuclear magnetic resonance hydrogen spectrum, and the results are as follows:

[0050] .sup.1H NMR (CDCl.sub.3, 500 MHz): 5.75-5.80 (hydrogen on O—C—O), 6.30-6.35 (hydrogen on O—C—O—C═O), 4.45-4.55 (hydrogen on O═C—C—O), 11.0 (hydrogen on carboxyl group), 2.0 (hydrogen on hydroxyl group), 3.35 (hydrogen on methyl group).

[0051] Characteristic peak positions in infrared spectroscopy: characteristic absorption peak of P═N in phosphazene skeleton, 1217 cm.sup.−1; P—N in phosphazene skeleton, 874 cm.sup.−1; absorption peak of P—O—C, 1035 cm.sup.−1; stretching vibration of C—H in hydrocarbyl group, 2850-3000 cm.sup.−1; stretching vibration of C═O, 1680-1630 cm.sup.−1; absorption peak of ester group, 1200-1300 cm.sup.−1.

[0052] An epoxy resin composition is prepared by adding 100 g of the above phosphazene compound containing ester group as a coupling curing agent to 100 g of o-cresol novolac epoxy resin with an epoxide equivalent of 200 g/eq and 0.1 g of 2-methylimidazole as a curing accelerator. A copper-clad laminate sample meeting the national, UL and other standards is prepared using the epoxy resin composition according to generally used copper-clad laminate production process. The copper-clad laminate is named as copper-clad laminate b and the properties thereof are measured and the results are shown in table 1.

Example 3

[0053] A phosphazene compound containing ester group, having the following structure:

##STR00011##

wherein cyclotriphosphazene is substituted by four methoxyl groups on average, and m is 10.

[0054] The preparation method thereof is as follow:

(1) 1 mol of hexachlorocyclotriphosphazene, 200 ml of acetone, 4 mol of sodium methoxide were added to a 3-neck glass reactor having a volume of 2000 ml and equipped with a stirring apparatus. While stirring, nitrogen was fed therein, and the reactor was heated to 60° C. 20% sodium hydroxide solution was dripped therein taking 60 min to make pH neutral, and then the mixture was held at 60° C., stirred and reacted for 15 hours;
(2) The product of step (1) was divided into two equal parts;
One part was reacted with 2 mol of resorcin. While stirring, nitrogen was fed therein, and the reactor was heated to 60° C. 20% sodium hydroxide solution was dripped therein taking 30 min to make pH neutral, and then the mixture was held at 60° C., stirred and reacted for 15 hours. Then a phosphazene compound containing hydroxyphenyloxyl group was obtained;
The other part was reacted with 2 mol of m-hydroxybenzoic acid. While stirring, nitrogen was fed therein, and the reactor was heated to 60° C. 20% sodium hydroxide solution was dripped therein taking 30 min to make pH neutral, and then the mixture was held at 60° C., stirred and reacted for 15 hours. Then a phosphazene compound containing carboxyl group was obtained;
(3) An esterification reaction of the phosphazene compound containing hydroxyphenyloxyl group and the phosphazene compound containing carboxyl group obtained in step (2) was carried out, so as to obtain a phosphazene compound containing ester group.

[0055] The obtained phosphazene compound containing ester group was characterized by nuclear magnetic resonance hydrogen spectrum, and the results are as follows:

[0056] .sup.1H NMR (CDCl.sub.3, 500 MHz): 6.15-6.25, 6.90-7.05 (hydrogen on HO—O—Ar—O—P), 7.65-7.75, 7.20-7.50 (hydrogen on O—Ar—C═O), 3.39 (hydrogen on methyl group), 6.6-6.8, 7.1-7.7 (hydrogen on Ar—O—C(═O)—Ar).

[0057] Characteristic peak positions in infrared spectroscopy: characteristic absorption peak of P═N in phosphazene skeleton, 1217 cm.sup.−1; P—N in phosphazene skeleton, 874 cm.sup.−1; absorption peak of P—O—C, 1035 cm.sup.−1; stretching vibration of C—H in hydrocarbyl group, 2850-3000 cm.sup.−1; stretching vibration of C═O, 1680-1630 cm.sup.−1; absorption peak of ester group, 1200-1300 cm.sup.−1.

[0058] An epoxy resin composition is prepared by adding 100 g of the above phosphazene compound containing ester group as a coupling curing agent to 100 g of o-cresol novolac epoxy resin with an epoxide equivalent of 200 g/eq and 0.1 g of 2-methylimidazole as a curing accelerator. A copper-clad laminate sample meeting the national, UL and other standards is prepared using the epoxy resin composition according to generally used copper-clad laminate production process. The copper-clad laminate is named as copper-clad laminate c and the properties thereof are measured and the results are shown in table 1.

Comparative Example 1

[0059] 200 g of o-cresol novolac epoxy resin having an epoxide equivalent of 200 g/eq was added to 105 g of linear phenolic resin curing agent having a phenolic hydroxyl equivalent of 105 g/eq, 70 g of hexaphenoxycyclotriphosphazene as a flame retardant and 0.2 g of 2-methylimidazol, and the mixture was dissolved into solution using an appropriate amount of butanone. A copper-clad laminate d with a resin content of 50% was prepared by using standard glass cloths according to a generally used production process. The properties of copper-clad laminate d are shown in table 1.

Comparative Example 2

[0060] 200 g of o-cresol novolac epoxy resin having an epoxide equivalent of 200 g/eq was added to 220 g of a resin compound having a structure of formula (1), 70 g of hexaphenoxycyclotriphosphazene having an ester equivalent of 220 g/eq as a flame retardant and 0.2 g of pyridine, and the mixture was dissolved into solution using an appropriate amount of butanone. A copper-clad laminate e with a resin content of 50% was prepared by using standard glass cloths according to a generally used production process. The properties of copper-clad laminate e are shown in table 1.

##STR00012##

[0061] The test results of products of examples and comparative examples are shown in table 1 below.

TABLE-US-00001 TABLE 1 Comparison of properties of the above copper clad laminates Copper-clad Copper-clad Copper-clad Copper-clad Copper-clad Test Items laminate a laminate b laminate c laminate d laminate e Tg (DSC) (° C.) 156 157 154 145 135 T-peeling 1.85 1.85 1.88 1.74 1.69 strength (kg/mm.sup.2) Peeling 1.64 1.65 1.70 1.55 0.82 strength (kg/mm.sup.2) Saturated 0.33 0.31 0.31 0.22 0.60 water absorption (%) Thermal 395 396 395 356 392 decomposition temperature (° C.) Bending 11.8 12.2 12.3 10.0 10.9 strength (kg/mm.sup.2) Combustibility V-0 V-0 V-0 V-0 V-1 (UL-94) Dielectric 3.20 3.18 3.22 3.00 3.70 constant (1 GHz) Dielectric loss 0.0050 0.0052 0.0055 0.0040 0.014 (1 GHz)

[0062] Test methods for the above characteristics are as follows:

(1) Water Absorption

[0063] A 100 mm×100 mm×1.6 mm sample was placed in an oven at 105° C. to dry for 1 h, and was weighted after cooling and then was steamed under a vapor pressure of 105 kPa for 120 min, and finally was dried and weighted, and then the water absorption thereof was calculated.

(2) Glass Transition Temperature Tg

[0064] A sample with a width of about 8-12 mm and a length of 60 mm was prepared and the glass transition temperature Tg thereof was measured on NETZSCH DMA Q800 by setting the measurement mode as bending mode and the scanning temperature as from room temperature to 200° C., and by reading the corresponding temperature at which the loss tangent value was maximum.

(3) Bending Strength

[0065] A 25.4 mm×63.5 mm sample was prepared, and the thickness thereof was measured using a vernier caliper, and the bending strength thereof was measured on universal material testing machine by adjusting the test mode as bending test mode, the space as 15.9 mm, and the test speed as 0.51 mm/min. An average value of three parallel tests was taken, and the test temperature was room temperature and 180° C. respectively.

(4) Peeling Strength

[0066] The copper-clad laminate was cut into a 100 mm×3 mm test piece. The peeling strength of copper foil and resin was measured by stripping the copper foil and delaminating it at a speed of 50.8 mm/min using peeling resistance testing device. A larger value represents a better adhesive force between resin and copper foil.

(5) Combustibility

[0067] The combustibility was tested according to standard ANSL UL94-1985.

(6) Dielectric Constant and Dielectric Loss

[0068] Dielectric constant and dielectric loss was tested according to standard ASTM D150.

[0069] The applicant states that, the present invention describes the detailed technological equipment and process by the aforesaid examples, but the present invention is not limited to the aforesaid detailed technological equipment and process. That is to say, it does not mean that the present invention cannot be fulfilled unless relying on the aforesaid detailed technological equipment and process. Those skilled in the art shall know that, any modification to the present invention, any equivalent replacement of each raw material of the product of the present invention and the addition of auxiliary ingredient, the selection of specific embodiment and the like all fall into the protection scope and the disclosure scope of the present invention.