阅读说明：本技术 一种高性能高灼热丝聚甲醛组合物及其制备方法与应用 (High-performance high glow wire polyformaldehyde composition and preparation method and application thereof ) 是由 曹绍强 黄险波 叶南飚 陈锋 付学俊 丁超 于 2020-11-05 设计创作，主要内容包括：本发明公开了一种高性能高灼热丝聚甲醛组合物,其包括如下重量份的组分：POM树脂32～70份、玻璃纤维10～25份、有机硅包覆型聚磷酸铵25～40份、季戊四醇1～7份、润滑剂0.5～2份、主抗氧剂0.1～0.5份和辅抗氧剂0.1～0.3份；所述有机硅包覆型聚磷酸铵的pH值为6.5～8.5,所述玻璃纤维为无碱短切玻璃纤维。本发明加入了有机硅包覆型聚磷酸铵与季戊四醇配合使用,有效提高了POM组合物的灼热丝可燃性指数,并减小了聚磷酸铵对POM的劣化作用,本发明还加入了反应型的无碱短切玻璃纤维来增强POM的力学性能,最终获得高灼热丝可燃性指数和力学性能较优的POM组合物,扩大了POM的应用领域。(The invention discloses a high-performance high glow wire polyformaldehyde composition which comprises the following components in parts by weight: 32-70 parts of POM resin, 10-25 parts of glass fiber, 25-40 parts of organic silicon coated ammonium polyphosphate, 1-7 parts of pentaerythritol, 0.5-2 parts of lubricant, 0.1-0.5 part of main antioxidant and 0.1-0.3 part of auxiliary antioxidant; the pH value of the organic silicon coated ammonium polyphosphate is 6.5-8.5, and the glass fiber is alkali-free chopped glass fiber. According to the invention, the organic silicon coated ammonium polyphosphate is added to be matched with pentaerythritol for use, so that the glowing filament flammability index of the POM composition is effectively improved, the deterioration of the POM by the ammonium polyphosphate is reduced, the reaction type alkali-free chopped glass fiber is added to enhance the mechanical property of the POM, the POM composition with high glowing filament flammability index and excellent mechanical property is finally obtained, and the application field of the POM is expanded.)

1. The high-performance high-glow-wire polyformaldehyde composition is characterized by comprising the following components in parts by weight: 32-70 parts of POM resin, 10-25 parts of glass fiber, 25-40 parts of organic silicon coated ammonium polyphosphate, 1-7 parts of pentaerythritol, 0.5-2 parts of lubricant, 0.1-0.5 part of main antioxidant and 0.1-0.3 part of auxiliary antioxidant; the pH value of the organic silicon coated ammonium polyphosphate is 6.5-8.5, and the glass fiber is alkali-free chopped glass fiber.

2. The high performance high glow wire polyoxymethylene composition of claim 1, wherein the weight ratio of said POM resin to said silicone coated ammonium polyphosphate is 0.85 to 2.

3. The high performance high glow wire polyoxymethylene composition of claim 1, wherein said alkali-free chopped glass fiber has a diameter of 10 to 15um and a length of 3 to 4.5 mm.

4. The high performance high glow wire polyoxymethylene composition of claim 1, wherein said POM resin has a melt index of 1 to 50g/10min at 190 ℃ under a 2.16kg test; the density is 1.38 to 1.43g/cm³。

5. The high performance high glow wire polyoxymethylene composition of claim 1, wherein said silicone-coated ammonium polyphosphate has a phosphorus content of 29.5% to 30% and a nitrogen content of 13% to 15%.

6. The high performance high glow wire polyoxymethylene composition of claim 1, wherein said lubricant is selected from at least one of the group consisting of erucamide, TAF, EBS B50 amide lubricants.

7. The high performance high glow wire polyoxymethylene composition of claim 1, wherein said primary antioxidant is a hindered phenolic antioxidant.

8. The high performance high glow wire polyoxymethylene composition of claim 1, wherein said secondary antioxidant is at least one selected from the group consisting of phosphite antioxidants and thioether antioxidants.

9. The method for preparing a high performance high glow-wire polyoxymethylene composition according to any of claims 1 to 8, comprising the steps of:

(1) adding the POM resin, the organic silicon coated ammonium polyphosphate, the pentaerythritol, the lubricant, the main antioxidant and the auxiliary antioxidant into a high-speed mixer together, and mixing for 2-5 min to obtain a premix;

(2) adding the premix into a double-screw extruder from a main feeding port, adding the glass fiber into the double-screw extruder from a side feeding port, and performing melt extrusion, cooling and granulation at 160-200 ℃ to obtain the polyformaldehyde composition.

10. Use of the high performance high glow-wire polyoxymethylene composition according to any of claims 1 to 8 in a low voltage electrical appliance.

Technical Field

The invention belongs to the technical field of engineering plastics, and particularly relates to a high-performance high-glow-wire polyformaldehyde composition as well as a preparation method and application thereof.

Background

Polyoxymethylene (POM) is an engineering plastic with excellent properties, hardness, strength and rigidity similar to metals, good self-lubricity, good fatigue resistance, and elasticity in a wide temperature and humidity range, and also has good chemical resistance. At present, POM is replacing some markets traditionally occupied by metal, such as replacing many parts made of zinc, brass, aluminum and steel, at a lower cost than many other engineering plastics, and has been widely used in the fields of electronics, electricity, machinery, instruments, daily light industry, automobiles, building materials, agriculture and the like.

However, POM resins have a low oxygen index (14.9%), resulting in very easy burning and melt dripping; meanwhile, the glowing filament flammability index of the POM resin is low, the GWFI 2.0mm is only 600 ℃, and the situation with higher requirements on the GWFI cannot be met. For example, products such as double-end connecting pins, mounting cards and the like in low-voltage electrical appliances require high glow wires, require 650 ℃ for GWFI 2.0mm, and simultaneously require good mechanical properties, and have the impact strength of 6.5KJ/m²The tensile strength is 25MPa or more. In addition, since the POM resin is a polymer with high crystallinity and has poor compatibility with other additives, the mechanical properties, especially toughness, of the material are significantly reduced by adding a large amount of the flame retardant. Furthermore, POM resins are sensitive to acids and bases, which are present during processingIn the case of POM which is severely degraded, conventional flame retardants are not suitable for addition to POM.

Therefore, how to obtain a POM material with high glow wire and good mechanical properties at the same time has become a technical problem which needs to be solved urgently at present.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a high-performance high-glow-wire polyformaldehyde composition as well as a preparation method and application thereof.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a high-performance high glow wire polyformaldehyde composition comprises the following components in parts by weight: 32-70 parts of POM resin, 10-25 parts of glass fiber, 25-40 parts of organic silicon coated ammonium polyphosphate, 1-7 parts of pentaerythritol, 0.5-2 parts of lubricant, 0.1-0.5 part of main antioxidant and 0.1-0.3 part of auxiliary antioxidant; the pH value of the organic silicon coated ammonium polyphosphate is 6.5-8.5.

In the organic silicon coated ammonium polyphosphate, the deterioration of the POM mechanical property by the ammonium polyphosphate can be effectively reduced by the coating action of silicon. Moreover, the pH value of the organic silicon coated ammonium polyphosphate is 6.5-8.5, is neutral or neutral, and has small degradation effect on POM. Meanwhile, the composition of the organic silicon coated ammonium polyphosphate contains phosphorus and nitrogen components, can play a role of an acid source and a gas source at the same time, is matched with pentaerythritol for use, and can effectively improve the glow wire flammability index of the POM composition.

Preferably, the weight ratio of the POM resin to the organic silicon coated ammonium polyphosphate is 0.85-2. According to the proportion, the glowing filament flammability index of the composition is effectively improved, the GWFI 2.0mm can reach 650 ℃, and the composition has excellent mechanical properties.

Preferably, in the high-performance high-glow-wire polyformaldehyde composition, the weight part of pentaerythritol is 1-5 parts. According to researches, when the pentaerythritol is added to the formula, the formed carbon layer structure is weak, even incomplete or incapable of being formed. When the amount of pentaerythritol added is less than 1 part by weight, the glow wire flammability index of the polyoxymethylene composition cannot be effectively increased. When the addition amount of pentaerythritol is 1 part by weight or more, the glow wire flammability index of the polyoxymethylene composition is effectively increased, and the GWFI of the polyoxymethylene composition is kept more stable as the addition amount of pentaerythritol is increased; however, as the amount of pentaerythritol added increases, the mechanical properties of the polyoxymethylene composition tend to decrease. When the addition amount of the pentaerythritol is 1-5 parts by weight, the mechanical property of the polyformaldehyde composition is reduced to a small extent, the raw material consumption is small, and the cost is low. When the addition amount of the pentaerythritol exceeds 5 parts by weight, the mechanical property of the polyformaldehyde composition is greatly reduced, the consumption of raw materials is large, and the cost is high. Therefore, in comprehensive consideration, the preferable adding amount of the pentaerythritol in the formula of the invention is 1-5 parts by weight, and the polyformaldehyde composition has better comprehensive performance and lower cost.

Preferably, the melt index of the POM resin under the test condition of 190 ℃ and 2.16kg is 1-50 g/10 min; the density is 1.38 to 1.43g/cm³。

Preferably, the glass fiber is alkali-free chopped glass fiber (i.e. E glass fiber), the diameter is 10-15 um, and the length is 3-4.5 mm. The reaction type alkali-free chopped glass fiber can effectively enhance the mechanical property of the POM composition.

Preferably, the phosphorus content of the organosilicon coated ammonium polyphosphate is 29.5-30%, and the nitrogen content is 13-15%.

Preferably, the lubricant is selected from at least one of erucamide, TAF (modified ethylene bis fatty acid amide), EBS B50(N, N' -ethylene bis stearamide) amide type lubricants.

Preferably, the primary antioxidant is a hindered phenolic antioxidant, such as: basf IRGANOX 245, bis [3- (1, 1-dimethylethyl) -4-hydroxy-5-methylpropanoic acid ] tripeleneglycol, and the like.

Preferably, the auxiliary antioxidant is at least one selected from phosphite antioxidants (such as tris (2, 4-di-tert-butylphenyl) phosphite) and thioether antioxidants (such as pentaerythritol tetrakis (3-laurylthiopropionate)).

The high-performance high glow wire polyformaldehyde composition is suitable for low-voltage electrical appliances and can meet the requirementsThe GWFI 2.0mm required by a low-voltage electrical appliance product reaches 650 ℃, and the impact strength is 6.5KJ/m²As described above, the tensile strength is required to be 25MPa or more.

The invention also provides a preparation method of the high-performance high glow wire polyformaldehyde composition, which comprises the following steps:

(1) adding the POM resin, the organic silicon coated ammonium polyphosphate, the pentaerythritol, the lubricant, the main antioxidant and the auxiliary antioxidant into a high-speed mixer together, and mixing for 2-5 min to obtain a premix;

(2) adding the premix into a double-screw extruder from a main feeding port, adding the glass fiber into the double-screw extruder from a side feeding port, and performing melt extrusion, cooling and granulation at 160-200 ℃ to obtain the polyformaldehyde composition.

Wherein, the temperature of each screw cylinder from the charging opening to the machine head of the double-screw extruder is respectively as follows: 150-170 ℃, 160-180 ℃, 170-190 ℃, 180-200 ℃ and 180-200 ℃, the screw rotation speed is 250-400 r/min, the feeding amount is 50-200 kg/h, and the vacuum degree is-0.1-0 MPa.

Compared with the prior art, the invention has the beneficial effects that: in the POM composition, the organic silicon coated ammonium polyphosphate is added to be matched with pentaerythritol for use, so that the glow wire flammability index of the POM composition is effectively improved, and the organic silicon coated ammonium polyphosphate does not have obvious degradation effect on the mechanical property of the POM and also does not have obvious degradation effect on the POM. In addition, the alkali-free chopped glass fiber is added to enhance the mechanical property of the POM composition, so that the toughness and rigidity of the material are obviously improved. The POM composition has better mechanical property and high glow wire flammability index, and is suitable for low-voltage electrical appliance products with high glow wire and high mechanical property requirements, such as: double-end connecting pin, installation card.

Detailed Description

The technical solutions of the present invention will be further described with reference to the following embodiments, and it should be apparent that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the organic silicon coated ammonium polyphosphate, the phosphorus content is determined according to GB/T10512-.

The raw materials in the examples and comparative examples were obtained commercially from the following sources:

the organic silicon coated ammonium polyphosphate with the model of XS-APP II 200 is purchased from Zhejiang Asahson non-halogen smoke-eliminating flame retardant, and has 29.5-30 percent of phosphorus, 13-15 percent of nitrogen and 6.5-8.5 of pH value;

the ammonium polyphosphate with the model of APP101 is purchased from Shouguangdong chemical industry Co., Ltd, the pH value is 7.5-9.0 (alkaline), the phosphorus content is 27-29%, and the nitrogen content is 14-15%;

the ammonium polyphosphate with the model of APP102 is purchased from Shouguangdong chemical Limited, the pH value is 5.5-7.0 (acidity), the phosphorus content is 31-32%, and the nitrogen content is more than or equal to 18%;

alkali-free chopped glass fibers, model glass fiber FT785, available from Owens Corning Hong kong, were 10.5um in diameter and 3.0mm in length;

glass fiber HMG436S-10-6.0 glass fiber is purchased from Taishan glass fiber Co., Ltd, and has a diameter of 10um and a length of 6.0 mm;

pentaerythritol: the purity is more than or equal to 99 percent, and the product is purchased from Jiangsu Ruiyang chemical industry Co., Ltd;

POM resin is available from Yunnan Tiantianhua GmbH, model number POM M270, and has a melt index of 27g/10min (190 deg.C/2.16 kg) and a density of 1.4g/cm³；

The lubricant is erucamide available from sitaflavic chemical (Sichuan) Inc. type: crodamide ER-CH-MB- (SI), chemical name: (cis) -13-eicosadienoamide;

the main antioxidant is bis [3- (1, 1-dimethylethyl) -4-hydroxy-5-methylpropanoic ] triethylene glycol which is purchased from Authening trade company, Inc. of Guangzhou, and has the model of IRGANOX 245;

the auxiliary antioxidant is tris (2, 4-di-tert-butylphenyl) phosphite available from Yuansheng chemical Co., Ltd, Fushan City, and is SONOX 168.

Performance test standard:

glow wire GWFI: testing standard IEC60695, wherein the thickness of a sample plate is 2.0 mm;

tensile strength: the test standard ISO 527-2, the test speed is 10 mm/min;

notched impact strength: test standard ISO 180, pendulum energy 2.75J.

The formulations of the polyoxymethylene compositions of examples 1 to 10 and comparative examples 1 to 9 are shown in tables 1 and 2, and the preparation methods are as follows:

(1) adding POM resin, organic silicon coated ammonium polyphosphate (or ammonium polyphosphate), pentaerythritol, a lubricant, a main antioxidant and an auxiliary antioxidant into a high-speed mixer together, and mixing for 2-5 min to obtain a premix;

(2) adding the premix into a double-screw extruder from a main feeding port, adding the glass fiber into the double-screw extruder from a side feeding port, and performing melt extrusion, cooling and granulation at 160-200 ℃ to obtain the polyformaldehyde composition; wherein, the temperature of each screw cylinder from the charging opening to the machine head of the double-screw extruder is respectively as follows: 150-170 ℃, 160-180 ℃, 170-190 ℃, 180-200 ℃ and 180-200 ℃, the screw rotation speed is 250-400 r/min, the feeding amount is 50-200 kg/h, and the vacuum degree is-0.1-0 MPa.

TABLE 1

TABLE 2

Note: in the table, "-" indicates that the raw material was not added.

And (4) analyzing results:

as can be seen from examples 1 to 4 and comparative examples 8 to 9: in the formula of the invention, the ratio of the organic silicon coated ammonium polyphosphate to the POM resin influences the glowing filament flammability index and the mechanical property of the composition. An excessively small XS-APP II 200 proportion results in a composition with a GWFI of only 600 ℃ at 2.0mm, and an ineffective increase in the glow wire flammability index. When the XS-APP II 200 accounts for too much, the mechanical property of the composition is remarkably reduced, and the use requirement of low-voltage electrical appliance products cannot be met. When the weight ratio of the POM to the XS-APP II 200 is within the range of 0.85-2, the GWFI 2.0mm of the composition can reach 650 ℃, and the composition has excellent mechanical property and can meet the use requirements of low-voltage electrical appliance products.

As can be seen from examples 2, 7 to 10 and comparative examples 4 to 5: in the formula of the invention, when pentaerythritol is not added (namely, comparative example 4), the GWFI 2.0mm of the composition is only 600 ℃, and the glow wire flammability index can not be effectively improved; however, the mechanical properties of the composition are better, which shows that the mechanical properties of pentaerythritol are affected by the addition of pentaerythritol. When the addition amount of pentaerythritol is 1-7 parts by weight (namely, in the embodiment 2 and the embodiment 7-10), the GWFI 2.0mm of the composition reaches 650 ℃, the glow wire flammability index is obviously improved, the mechanical property of the composition is still good at the moment, and the use requirement of a low-voltage electrical appliance product can be met, wherein the mechanical properties of the embodiment 2 and the embodiment 7-9 are better. When pentaerythritol was added in an amount of 8 parts by weight (comparative example 5), the composition had poor mechanical properties and had a notched impact strength of only 6.3KJ/m²And the use requirements of low-voltage electrical appliance products cannot be met.

It can also be seen from example 2 and comparative examples 3 to 4 that: in the formula of the invention, only when effective amounts of pentaerythritol and organic silicon coated ammonium polyphosphate are added simultaneously, the GWFI of the composition with the thickness of 2.0mm can reach 650 ℃, and the glow wire flammability index can be effectively improved. In the formula of the invention, the glow wire flammability index of the POM composition can be effectively improved only by using the organic silicon coated ammonium polyphosphate and pentaerythritol.

As can be seen from comparative examples 1 to 2: when the organic silicon coated ammonium polyphosphate is replaced by acidic or alkaline ammonium polyphosphate, the glow wire flammability index of the composition is remarkably reduced, and the mechanical property of the composition is also remarkably reduced. The deterioration effect of uncoated ammonium polyphosphate on POM is large, and the POM is severely degraded due to the existence of acid and alkali, but the deterioration effect of the ammonium polyphosphate on the POM is remarkably reduced by the organic silicon coated type polyphosphoric acid, and the POM is not severely degraded.

As can be seen from examples 2, 5 to 6 and 6 to 7: in the formula of the invention, the mechanical property of the composition can be effectively enhanced by adding the reactive alkali-free chopped glass fiber, when the addition amount of the alkali-free chopped glass fiber reaches 20 parts by weight, the mechanical property of the composition reaches the optimum, and at the moment, if the addition amount of the alkali-free chopped glass fiber is continuously increased, the mechanical property of the composition tends to be reduced. When the alkali-free chopped glass fiber is added in the amount of the invention, the composition material meeting the use requirement of low-voltage electrical appliances can be obtained. When the alkali-free chopped glass fiber of the invention is replaced by other glass fiber (such as glass fiber HMG436S-10-6.0), the mechanical property of the composition cannot be effectively enhanced.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.