Low-corrosion fire-resistant thermoplastic resin composition

Abstract

A low-corrosion fire-resistant thermoplastic resin composition comprising a thermoplastic resin, a phosphinic acid salt flame retardant, a reinforced glass fiber, and a rare earth metal salt corrosion inhibitor. The resin composition improves the corrosion resistance and mechanical performance of the metal to a great extent while maintaining the high flame resistance.

Claims

1. A low-corrosion flame-resistant thermoplastic resin composition consisting of a thermoplastic resin, a phosphinic acid salt, a reinforced glass fiber, a rare earth metal salt, and optionally, an auxiliary flame retardant, wherein the phosphinic acid salt is selected from the group consisting of an ammonium salt, an amine salt, an alkali metal salt, an alkali-earth metal salt, an aluminum salt, a zinc salt, and ferric salt, and the phosphinic acid salt is a hypophosphite, a bis-hypophosphite, a polymer of the phosphinic acid salt, or a polymer of the bis-hypophosphite; the rare earth metal salt is a phosphinic acid rare earth metal salt having a formula (1) or (2): ##STR00006## R.sup.1 and R.sup.2 are each independently selected from a linear or branched C.sub.1-C.sub.8 alkyl or a phenyl; n is 3; R.sup.3 is selected from any of the linear or branched C.sub.1-C.sub.10 alkylidene, arylidene, alkyl arylidene, or aryl alkylene; and M is a rare earth metal, and the auxiliary flame retardant is selected from the group consisting of a melamine polyphosphate, ammonium polyphosphate, melamine ammonium phosphate, melamine ammonium polyphosphate, melamine ammonium pyrophosphate, a reaction product of melamine and phosphoric acid, and a mixture thereof.

2. The low-corrosion flame-resistant thermoplastic resin composition as stated in claim 1, wherein the rare earth metal is La or Ce.

3. The low-corrosion flame-resistant thermoplastic resin composition as stated in claim 1, wherein R.sup.1 and R.sup.2 are ethyl.

4. The low-corrosion flame-resistant thermoplastic resin composition as stated in claim 1, wherein the phosphinic acid salt has a structure as in formula (3): ##STR00007## wherein either R.sup.1′ or R.sup.2′ is a hydrogen, and the other is a C.sub.1-C.sub.8 alkyl; or both of R.sup.1′ and R.sup.2′ are C.sub.1-C.sub.8 alkyl; T is selected from the group consisting of (C.sub.1-C.sub.4 alkyl).sub.4N, (C.sub.1-C.sub.4 alkyl).sub.3NH, (C.sub.2-C.sub.4 alkyl OH).sub.4N, (C.sub.2-C.sub.4 alkyl OH).sub.3NH, (C.sub.2-C.sub.4 alkyl OH).sub.2N(CH.sub.3).sub.2, (C.sub.2-C.sub.4 alkyl OH).sub.2NHCH.sub.3, (C.sub.6H.sub.5).sub.4N, (C.sub.6H.sub.5).sub.3NH, (C.sub.6H.sub.5CH.sub.3).sub.4N, (C.sub.6H.sub.5CH.sub.3).sub.3NH, NH.sub.4, melamine, guanidine, alkali metal, alkali-earth metal ions, aluminum ion, zinc ion, and ferric ion; and y is an integer of 1 to 4.

5. The low-corrosion flame-resistant thermoplastic resin composition as stated in claim 1, wherein the phosphinic acid salt is diethyl phosphinic acid aluminum salt.

6. The low-corrosion flame-resistant thermoplastic resin composition as stated in claim 1, wherein the thermoplastic resin is a polyester resin, a polyamide resin, or a mixture thereof.

7. The low-corrosion flame-resistant thermoplastic resin composition as stated in claim 1, wherein the thermoplastic resin is 50˜85% weight percentage of the composition, the phosphinic acid salt is 10˜20% weight percentage of the composition, the reinforced glass fiber is up to ˜30% weight percentage of the composition, and the rare earth metal salt is 1.5˜10% weight percentage of the composition, and the total weight percentage of the thermoplastic resin, the phosphinic acid salt, the reinforced glass fiber, and the rare earth metal salt equals to 100%.

Description

EXAMPLES

(1) The present invention is described in detail in combination with the examples of implementation. However, it is understood that the following examples of implementation are only the illustration to the implementation mode of the present invention, but not the limitation to the scope of the present invention.

Example 1. Preparation of Flame-Retardant Thermoplastic Resin and Resin Composition

(2) The components of the flame retardant and the polymer particles are mixed with the additive, and added into the double-screw extruder at the temperature of 230˜260° C. (To make reinforced flame-retardant PBT, i.e., GRPBT) or 260˜280° C. (To make the reinforced flame-retardant PA66, i.e. GRPA66). Extract the homogenized polymer extrudate, cool down in the water bath, and then pelletize to obtain the flame-retardant thermoplastic resin composition. The sources of the raw materials are shown in Table 1. The preparation methods for the diethyl phosphinic acid lanthanum salt and the diethyl phosphinic acid lanthanum salt dimer are shown as follows. The other raw materials shall be available in the market except for the specially specified.

(3) D-1

(4) Synthesis of diethyl phosphinic acid lanthanum salt: Add 101.8 g of diethyl phosphinic acid sodium salt and 400 g of the water solution into the reactor, rise the temperature to 90° C. while stirring, and then start to add drop by drop 248.5 g of the water solution containing 57.4 g of lanthanum chloride in one hour, and then preserve the heat for one hour; at the end of the reaction, filter, clean, dry, and crush, in order to obtain 106.5 g of the diethyl phosphate lanthanum (theoretical value of 117.8 g).

(5) D-2

(6) Synthesis of diethyl phosphinic acid lanthanum salt dimer: Add 91.3 g of diethyl phosphinic acid sodium salt dimer and 400 g of water solution into the reactor. The structural formula of the diethyl phosphinic acid sodium salt dimer is shown in general formula (2), and both R.sub.1 and R.sub.2 are ethyl; rise the temperature to 90° C. while stirring, and then start to add drop by drop 248.5 g of the water solution containing 57.4 g of lanthanum chloride in one hour, and then preserve the heat for one hour; at the end of the reaction, filter, clean, dry, and crush, in order to obtain 95.5 g of the diethyl sodium hypophosphite dimer (theoretical value of 107.3 g).

Example 2. UL-94 Test

(7) After the full drying, process the molded composition in the injection molding machine at the melt temperature of 240˜270° C. (GRPBT) or 260˜290° C. (GRPA66) to obtain the test sample. With regard to the test sample generated from each mixture, the test sample in the thickness of 1.6 mm shall be used to measure the burning level under UL94 “Test for Flammability of Plastic Materials for Parts in Devices and Appliances” (“Test for Flammability of Plastic Materials for Parts in Devices and Appliances”, the standard for plastic combustibility issued by USA Underwriters Laboratories Corporation) (Underwriters Laboratories). The following burning levels are given under UL-94:

(8) V0: Afterflame time for each individual specimen t.sub.1 or t.sub.2 is no more than 10 seconds, the total afterflame time for any condition set is no more than 50 seconds, no fire drops, the specimen is not burned up completely, afterflame plus afterglow time for each individual specimen after second flame application is no more than 30 seconds.

(9) V-1: Afterflame time for each individual specimen t.sub.1 or t.sub.2 is no more than 30 seconds, the total afterflame time for any condition set is no more than 250 seconds, afterflame plus afterglow time for each individual specimen after second flame application is no more than 60 seconds. other standard as V-0.

(10) V-2: The cotton indicator is fire dropped and ignited. The other standards shall be the same as those for V-1.

(11) Unclassifiable (n.d.): Failing to meet the requirements for burning level of V-2.

Example 3. Metal Corrosion Test

(12) 1) Copper strip corrosion test:

(13) Add the particles or molded product containing approximately 10 g of the resin composition into the glass petri dish with a cover and in the diameter of 60 mm, and place the watch glass in the diameter of 25 mm onto the particles or molded product, place the copper plate in the length of 10 mm, width of 20 mm, and thickness of 1 mm onto the watch glass, and then place the above glass cover, so as to make the sample; put such sample into the heat ageing chamber at the temperature of 270° C. and stay for 3 hours; after cooling the sample down to the room temperature, visually observe the corrosion to the copper plate in the sample. Specially, since the copper plate will become green because the corrosion of such plate produces the verdigris in aerugo, it shall be judged as corrosive if the change of the color into green is observed.

(14) 2) Steel Corrosion Test

(15) The test device shall be composed of two test samples made of Q235 steel and arranged in pairs so as to form the rectangular channel slit in the length of 12 mm, width of 16 mm, and height of 0.4 mm for the polymer melt. The polymer melt is fed through such silt by the extruder, so as to produce the highly local shearing stress and shearing rate in the silt. The abrasion shall be described by measuring the weight of the test sample with the analysis balance at the accuracy of 1 mg.

(16) The weight of the test sample shall be measured before and after the corrosion test of the polymer with the material throughput of 11 kg. The sample shall be taken out from the nozzle and the adhered polymer shall be cleaned off in two steps. The hot polymer is removed by wiping with the soft textile (cotton). The following cleaning step shall be implemented by heating the test sample in the mixture of dichlorobenzene and phenol at ratio of 1:1 at the temperature of 60° C. for 25 minutes. The remaining polymer shall be removed by wiping with the soft cotton cloth.

(17) The performance of notched izod impact strength shall be measured according to DIN EN ISO180. This reference number refers to the standardized high strain rate test for the value of the energy absorbed during the process of fracture. Such absorbed energy is the measurement of the toughness of the given material. The low izod impact strength of the composition containing the same contents of polymer, reinforced glass fiber, and flame retardant indicates the partial decomposition of the polymer matrix.

(18) TABLE-US-00001 TABLE 1 (A) Thermoplastic resin Poly ethylene terephthalate (In GE307 abbreviation PBT2) Nylon 66(PA66) BASFA3 (B) Hypophosphite Diethyl aluminum hypophosphite OP1240 (C) Glass fiber HP3786 (3.2 MM) Taiwan Company Bicheng (D) Rare earth metal salt See synthesis (E) Nitrogen compound Melamine pyrophosphate MPP CibaM200 (F) Flexibilizer Ethylene/butene/maleic anhydride MH-5020 copolymer (G) Antioxidant Irganox1010/168 = 1:1
Please see Table 2 for the components, and the results of the corrosion test and notched izod impact strength test of the composition in the examples of implementation.

(19) TABLE-US-00002 TABLE 2 Examples of Implementation 1 2 3 4 5 6 7 8 9 (A) Thermoplastic PBT 49.8 49.8 49.8 49.8 49.8 49.8 49.8 resin PA66 52 52 (B) Hypophosphite OP1240 13 12 11.5 11 11 10 12 12 10 (C) Glass fiber 30 30 30 30 30 30 30 30 30 (D) Rare earth metal D-1 1 1.5 2 3 2 salt D-2 2 1 (E) Nitrogen Melapur 200/70 5 5 5 5 5 5 5 6 6 compound (F) Flexibilizer 2 2 2 2 2 2 2 (G) Antioxidant 1010/168 = 1/1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Corrosion (Visual Copper strip Yes Micro No No No No Yes Yes No observation) Q235 Yes Micro No No No No Yes Yes No UL-94 (1.6 mm) VO VO VO VO VO VO VO VO VO Notch impact 8.3 9 9.5 8.7 9.1 8.7 8.5 strength (KJ/M2)