A halogen-free flame-retardant polypropylene material and preparation method thereof

Abstract

The present invention discloses a halogen-free flame-retardant polypropylene material and a preparation method thereof. The halogen-free flame-retardant polypropylene material is made of the following raw materials in parts by weight: 45-84 parts of polypropylene, 10-25 parts of modified ammonium polyphosphate, 5-20 parts of macromolecular carbonizing agent, 0-5 parts of flame retardant synergist, 0.5-1 parts of antioxidant, 0.5-2 parts of lubricating dispersant, and 0-2 parts of other additives; wherein the modified ammonium polyphosphate is ammonium polyphosphate modified by hyperbranched resin and calcium stearate; the degree of polymerization of the ammonium polyphosphate is 2000-3000. The present invention improves the degree of polymerization of ammonium polyphosphate, uses a hyperbranched resin to modify and activate it, greatly reduces its water solubility, and increases the thermal decomposition temperature; uses a macromolecular carbonizing agent to withstand high temperature and high humidity environments without precipitation; uses a hyperbranched dispersant to greatly reduce the black spots of the product, and finally obtains a halogen-free flame-retardant polypropylene material with no precipitation, few black spots, and a high oxygen index.

Description

Technical Field

[0001] The invention belongs to the field of halogen-free flame-retardant polypropylene materials, and particularly relates to a halogen-free flame-retardant polypropylene material with no precipitation, few black spots and high oxygen index and a preparation method thereof. Background Art

[0002] Among flame-retardant polypropylene materials, halogen-free expanded polypropylene materials are widely used because of their high flame retardant efficiency, low smoke generation during combustion, and no production of toxic and corrosive hydrogen halide gas to cause secondary harm. In recent years, in particular, the price of halogen-containing flame retardants has skyrocketed, and the price advantage of halogen-free flame retardants has become more significant, and the use of halogen-free flame retardant polypropylene materials has become more frequent. Compared with piperazine-based expanded halogen-free flame retardants, ammonium polyphosphate-based expanded halogen-free flame retardants have a more obvious price advantage, and their usage is far greater than that of piperazine-based expanded halogen-free flame retardants.

[0003] However, ammonium polyphosphate-based intumescent halogen-free flame retardants also have disadvantages: first, ammonium polyphosphate is hygroscopic, not resistant to high temperature and high humidity, and is easy to precipitate; second, ammonium polyphosphate has poor compatibility with polypropylene resin, which affects the mechanical properties of the composite material and is also easy to precipitate; third, ammonium polyphosphate has poor heat resistance and will decompose in the conventional polypropylene processing temperature range of 200-220°C, resulting in flame retardancy failure and a large number of black spots. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems existing in the prior art and to provide a halogen-free flame-retardant polypropylene material with no precipitation, few black spots and high oxygen index and a preparation method thereof.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a halogen-free flame-retardant polypropylene material, which is made of the following raw materials in parts by weight:

[0007]

[0008] The modified ammonium polyphosphate is prepared by modifying ammonium polyphosphate using hyperbranched resin and calcium stearate; the degree of polymerization of the ammonium polyphosphate is 2000-3000.

[0009] In a specific embodiment, the halogen-free flame-retardant polypropylene material is made of the following raw materials in parts by weight:

[0010]

[0011] The polypropylene is either homopolypropylene or copolymer polypropylene or a combination of the two; the melt index of the polypropylene is in the range of 3-60 g / 10 min, preferably 3-30 g / 10 min.

[0012] The present invention uses ammonium polyphosphate with a degree of polymerization of 2000-3000, preferably 2000-2500, such as 2000, 2100, 2200, 2300, 2400, 2500, but not limited thereto. The inventors found that ammonium polyphosphate with this degree of polymerization range is not easy to precipitate in the flame retardant polypropylene material system.

[0013] In a specific embodiment, the method for modifying ammonium polyphosphate using a hyperbranched resin and calcium stearate comprises: mixing the ammonium polyphosphate with the hyperbranched resin and calcium stearate in a mass ratio of (65-90):(5-20):(5-15) to obtain modified ammonium polyphosphate. The mixing reaction can be carried out in a high-speed mixer, the speed of which can be 800-1200 r / min, and the mixing reaction time is 1-3 min.

[0014] In a specific embodiment, the hyperbranched resin is a hydroxyl-terminated hyperbranched polyester or a carboxyl-terminated hyperbranched polyester, and its molecular weight range is 4800-12000 g / mol. For example, H104 or C104 from Wuhan Hyperbranched Resin Technology Co., Ltd. can be used.

[0015] In a specific embodiment, the macromolecular carbon former is a triazine carbon former with a molecular weight of 5000-50000 g / mol and a thermal decomposition temperature of greater than 270° C. For example, it may be XCT30 produced by Guangzhou Edenda Chemical Co., Ltd.

[0016] In a specific embodiment, the flame retardant synergist is selected from one or a combination of melamine cyanurate (MCA), zinc borate, nano zinc oxide, etc.

[0017] In a specific embodiment, the antioxidant is a combination of a hindered phenol primary antioxidant and a phosphite auxiliary antioxidant in a ratio of (3-5): (5-7), for example, 2: 1. The hindered phenol primary antioxidant may be one or more of 1010, 1076, 1098, and the phosphite auxiliary antioxidant may be one or more of 168, 626, 9228.

[0018] In a specific embodiment, the lubricating dispersant is a combination of one or more of a hyperbranched resin dispersant, ethylene bisstearamide (EBS), silicone, and a calcium stearate lubricant; preferably a hyperbranched resin dispersant, and the hyperbranched resin dispersant can be Hyper C100 or C180 of Wuhan Hyperbranched Resin Technology Co., Ltd.

[0019] In a specific embodiment, the other auxiliary agents include one or more of silane coupling agents, weathering agents, and masterbatches.

[0020] The silane coupling agent can be selected from one or a combination of amino silane coupling agents, vinyl silane coupling agents, and epoxy silane coupling agents, for example, the silane coupling agent KH560.

[0021] The weathering agent may be selected from one or more of ultraviolet absorbers and light stabilizers, for example, it may be UV-3808PP5.

[0022] In one embodiment, the other additives include 0.1-0.4 parts of a silane coupling agent, 0.1-0.4 parts of a weathering agent, and 0.8-1.2 parts of a masterbatch.

[0023] In a second aspect, the present invention provides a method for preparing the above-mentioned halogen-free flame-retardant polypropylene material, comprising the following steps:

[0024] (1) The modified ammonium polyphosphate, macromolecular carbonizing agent, flame retardant synergist, antioxidant, lubricating dispersant and other additives are mixed uniformly according to a certain proportion, and then polypropylene is added according to a certain proportion and mixed uniformly;

[0025] (2) The mixed material obtained in step (1) is extruded in a twin-screw extruder, stretched into strips, blown dry, and pelletized to obtain the product.

[0026] In a specific embodiment, in step (1), the mixing time is 1-5 min.

[0027] In a specific embodiment, in step (2), the aspect ratio of the twin-screw extruder is 36:1-40:1; the extrusion speed is 300-500 r / min, and the extrusion temperature is 160-190°C.

[0028] The present invention has the following beneficial effects:

[0029] 1. The present invention uses ammonium polyphosphate with a degree of polymerization exceeding 2000 and modifies it with a hyperbranched resin. After the modified ammonium polyphosphate is added to the polypropylene resin, it does not precipitate under a high temperature and high humidity environment, and the heat resistance is greatly improved, and the black spots generated by thermal decomposition are greatly reduced.

[0030] 2. The present invention uses a macromolecular triazine carbonizing agent, which is matched with a hyperbranched resin dispersion lubricant and a high-polymerization degree ammonium polyphosphate modified by a hyperbranched resin, which greatly improves the heat resistance of the polypropylene material and greatly reduces the black spots generated by thermal decomposition; and increases the compatibility of the flame retardant with the polypropylene substrate, and improves the effect of the flame retardant on the performance of the flame-retardant polypropylene material. The halogen-free flame-retardant polypropylene material of the present invention can achieve the effect of no precipitation in the precipitation test at 60°C and 95% humidity for 168 hours, rarely having black spots during processing, and an oxygen index greater than 33. DETAILED DESCRIPTION

[0031] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it more clearly and easily according to the contents of the specification, the specific implementation methods of the present invention are listed below.

[0032] It should be noted that the following examples are provided for illustrative purposes only and do not constitute a limitation on the scope of the present invention. Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are all conventional raw materials, reagents, methods in the art.

[0033] The present invention is further explained below with reference to specific embodiments, which are merely illustrative and exemplary and are not restrictive.

[0034] Material:

[0035] Polypropylene resin: purchased from Guangzhou Petrochemical, model PP K8009, melt index 9g / 10min.

[0036] Ammonium polyphosphate (APP): the degrees of polymerization are 1200, 2200, and 2300 respectively.

[0037] Hyperbranched resin used for activating ammonium polyphosphate: purchased from Wuhan Hyperbranched Resin Technology Co., Ltd., model C104, molecular weight 12000g / 10min; model H104, molecular weight 4500-5300g / 10min.

[0038] Macromolecular triazine carbon-forming agent: purchased from Guangzhou Edenda Chemical Co., Ltd., model number is XCT30.

[0039] Triazine carbon former: purchased from Guangdong Shunde Tongcheng New Material Technology Co., Ltd., model KN380.

[0040] Hyperbranched resin dispersant: purchased from Wuhan Hyperbranched Resin Technology Co., Ltd., model number is Hyper C100.

[0041] Melamine cyanurate (MCA, ≤10 μm), calcium stearate (325 mesh), nano-active zinc oxide (50-500 nm), EBS (325 mesh), silane coupling agent KH560, antioxidants 1010, 168, weathering agent UV-3808PP5, and W4800 masterbatch are all commercially available.

[0042] Modified ammonium polyphosphate: homemade;

[0043] The preparation method of the modified ammonium polyphosphate in Examples 1, 2 and 3 is as follows: ammonium polyphosphate, hyperbranched resin and calcium stearate are modified in a high mixer at a mass ratio of 80:10:10 for 2 minutes at 1000 r / min to obtain the modified ammonium polyphosphate. The degree of polymerization of the ammonium polyphosphate used in Example 1 is 2200, and the hyperbranched resin is C104; the degree of polymerization of the ammonium polyphosphate used in Example 2 is 2300, and the hyperbranched resin is C104; the degree of polymerization of the ammonium polyphosphate used in Example 3 is 2300, and the hyperbranched resin is H104.

[0044] The degree of polymerization of ammonium polyphosphate used in the preparation of modified ammonium polyphosphate in Comparative Example 1 is 1200, and the rest of the method is the same as that in Example 1. The preparation method of modified ammonium polyphosphate in Comparative Example 2 is: ammonium polyphosphate with a degree of polymerization of 2300 and calcium stearate are modified in a high mixer at 1000r / min for 2min according to a mass ratio of 80:20 to obtain modified ammonium polyphosphate. The preparation method of modified ammonium polyphosphate in Comparative Example 3 is the same as that in Example 3.

[0045] Test standard:

[0046] Density: Determined in accordance with GB / T 1033.1-2008.

[0047] Oxygen index: measured in accordance with GB / T 2406.2-2009.

[0048] 70℃ water boiling for 168h precipitation test: put the sample into a constant temperature 70℃ water bath, change the water every 24h, keep it for 168h, take out the sample and dry it at 80℃ for 24h, and cool it to room temperature. Visually observe whether there is precipitation under D65 light source. For the injection molding conditions of the sample, see the statistical method of black spot rate.

[0049] 60℃95% humidity 168h precipitation test: Place the sample in a constant temperature box set at 60℃ and 95% humidity for 168h, take it out and cool it to room temperature. Visually observe whether precipitation occurs under D65 light source.

[0050] Black spot rate: The black spot rate of 100 120mm*100mm flat plate samples continuously injected was counted: Black spot rate = number of flat plates with black spots / 100*100%.

[0051] Examples 1 to 3, Comparative Examples 1 to 3

[0052] The raw material composition of the halogen-free flame-retardant polypropylene material in each embodiment and comparative example is shown in Table 1, and the preparation method thereof comprises the following steps:

[0053] According to Table 1, the raw materials of halogen-free flame-retardant polypropylene material were mixed evenly, extruded in a twin-screw extruder with a ratio of 36:1, the screw speed was 420r / min, and the extrusion temperature was set to 160-180℃. After extrusion, strip drawing, drying, pelletizing, and mixing evenly, 120mm*100mm flat plates and 80mm*10mm*4mm strips were injection molded at a temperature of 180-190℃. The flat plates were tested for precipitation and black spot rate, and the strips were tested for density and oxygen index.

[0054] The test results are shown in Table 2.

[0055] Table 1. Raw material composition of halogen-free flame-retardant polypropylene materials in various embodiments and comparative examples (in parts by weight)

[0056]

[0057] Table 2. Test results of various indicators of halogen-free flame-retardant polypropylene materials of various embodiments and comparative examples

[0058] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 density 1.04 1.03 1.03 1.04 1.03 1.03 Oxygen Index 33 35 33 33 31 30 70℃ boiling water for 168h precipitation test PASS PASS PASS PASS PASS PASS 60℃95% humidity 168h precipitation test No precipitation No precipitation No precipitation Separation No precipitation Separation Black spot rate 6％ 2％ 3％ 31％ 17％ 33％

[0059] Result analysis: It can be seen from the above table that, by comparing Example 1 with Comparative Example 1, the degree of polymerization of ammonium polyphosphate is increased, the flame-retardant polypropylene material can pass the precipitation test at 65°C, 95% humidity for 168h, and the black spot rate is also greatly reduced. Comparing Example 2 with Comparative Example 2, the modified ammonium polyphosphate, macromolecular triazine carbon-forming agent, supramolecular resin dispersant and polypropylene resin system have better compatibility, and the flame-retardant polypropylene material obtained has better flame retardant effect, higher oxygen index, and greatly reduced black spots. Comparing Example 3 with Comparative Example 3, the use of macromolecular triazine carbon-forming agent can pass the precipitation test at 65°C, 95% humidity for 168h, and the flame retardant effect is better, the oxygen index is higher, and the black spots are greatly reduced.

[0060] The above specific implementations are all preferred embodiments of the present invention, and are not intended to limit the protection scope of this law. For those skilled in the art, several changes and improvements can be made without departing from the principles of the present invention, and these changes and improvements should also be considered as the protection scope of the present invention.

Claims

1. A halogen-free flame-retardant polypropylene material, made from the following raw materials in parts by weight: in, The modified ammonium polyphosphate is prepared by modifying ammonium polyphosphate with hyperbranched resin and calcium stearate; the degree of polymerization of the ammonium polyphosphate is 2000-3000; the hyperbranched resin is a hydroxyl-terminated hyperbranched polyester or a carboxyl-terminated hyperbranched polyester, and the molecular weight range is 4800-12000 g / mol; The preparation method of the modified ammonium polyphosphate comprises: mixing the ammonium polyphosphate with a hyperbranched resin and calcium stearate in a mass ratio of (65-90):(5-20):(5-15) to obtain the modified ammonium polyphosphate; the mixing reaction is carried out in a high-speed mixer at a rotation speed of 800-1200 r / min and the mixing reaction time is 1-3 min; The macromolecular carbon former is a triazine carbon former with a molecular weight range of 5000-50000 g / mol and a thermal decomposition temperature greater than 270°C; The flame retardant synergist is selected from one or a combination of melamine cyanurate, zinc borate, and nano zinc oxide; The lubricating dispersant is a hyperbranched resin dispersant.

2. The halogen-free flame-retardant polypropylene material according to claim 1, characterized in that: The halogen-free flame-retardant polypropylene material is made of the following raw materials in parts by weight:

3. The halogen-free flame-retardant polypropylene material according to claim 1 or 2, characterized in that: The polypropylene is either homopolymer polypropylene or copolymer polypropylene, or a combination of the two.

4. The halogen-free flame-retardant polypropylene material according to claim 1 or 2, characterized in that: The melt index of the polypropylene is in the range of 3-60 g / 10 min.

5. The halogen-free flame-retardant polypropylene material according to claim 4, characterized in that: The melt index of the polypropylene is in the range of 3-30 g / 10 min.

6. The halogen-free flame-retardant polypropylene material according to claim 1 or 2, characterized in that: The antioxidant is a combination of a hindered phenol main antioxidant and a phosphite auxiliary antioxidant in a ratio of (3-5): (5-7); The hindered phenol primary antioxidant is one or more of 1010, 1076, and 1098; The phosphite auxiliary antioxidant is one or more of 168, 626, and 9228.

7. The halogen-free flame-retardant polypropylene material according to claim 1 or 2, characterized in that: The other auxiliary agents include one or more of silane coupling agents, weathering agents, and color masterbatches; the weathering agent is selected from one or more of ultraviolet absorbers and light stabilizers.

8. The halogen-free flame-retardant polypropylene material according to claim 7, characterized in that: The silane coupling agent is selected from one or a combination of amino silane coupling agents, vinyl silane coupling agents, and epoxy silane coupling agents.

9. The halogen-free flame-retardant polypropylene material according to claim 8, characterized in that: The silane coupling agent is silane coupling agent KH560.

10. The halogen-free flame-retardant polypropylene material according to claim 7, characterized in that: The weathering agent is UV-3808PP5.

11. The halogen-free flame-retardant polypropylene material according to claim 7, characterized in that: The other auxiliary agents include 0.1-0.4 parts of silane coupling agent, 0.1-0.4 parts of weathering agent and 0.8-1.2 parts of masterbatch.

12. The method for preparing the halogen-free flame-retardant polypropylene material according to any one of claims 1 to 11, characterized in that: The preparation method comprises the following steps: (1) The modified ammonium polyphosphate, macromolecular carbonizing agent, flame retardant synergist, antioxidant, lubricating dispersant and other additives are mixed uniformly according to a certain proportion, and then polypropylene is added according to a certain proportion and mixed uniformly; (2) The mixed material obtained in step (1) is extruded in a twin-screw extruder, stretched into strips, blown dry, and pelletized to obtain the product.

13. The preparation method according to claim 12, characterized in that: In step (1), the mixing time is 1-5 min.

14. The preparation method according to claim 12, characterized in that: In step (2), the aspect ratio of the twin-screw extruder is 36:1-40:1; the extrusion speed is 300-500 r / min, and the extrusion temperature is 160-190°C.

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