High-glass-fiber-content, high-weather-resistance and high-flame-retardance unidirectional prepreg tape and preparation method thereof

Abstract

The invention belongs to the field of high-performance polypropylene functional materials, and particularly relates to a high-glass-fiber-content, high-weather-resistance and high-flame-retardance unidirectional prepreg tape and a preparation method thereof. The unidirectional prepreg tape with high glass fiber content, high weather resistance and high flame retardance provided by the invention is prepared from the following raw materials in parts by mass: 40 to 70 parts of glass fiber, 15 to 30 parts of halogen-free flame retardant, 5 to 40 parts of polypropylene matrix, 0.1 to 1 part of light stabilizer, 0.1 to 1 part of UV absorbent, 0.5 to 1 part of antioxidant, 2 to 5 parts of compatilizer, 0.1 to 1 part of filler, 0.1 to 0.5 part of silane coupling agent and 0.1 to 0.5 part of dispersing agent. The product is excellent in flame retardant effect, the tensile strength retention rate is larger than or equal to 70% after 2000-hour ultraviolet accelerated aging, the tensile strength of the unidirectional belt is larger than or equal to 800 MPa, and the unidirectional belt has excellent mechanical performance, weather resistance and flame retardance and is suitable for the high-end application fields of automobiles, photovoltaics and the like.

Description

Technical Field

[0001] This invention belongs to the field of high-performance polypropylene functional materials, specifically relating to a high-glass fiber content, high-weather-resistant, and high-flame-retardant unidirectional prepreg tape and its preparation method. Background Technology

[0002] With the rapid development of industries such as automobiles and photovoltaics, the performance requirements for materials are becoming increasingly stringent, especially in terms of weather resistance, flame retardancy, mechanical properties, and environmental friendliness. While traditional polypropylene (PP) materials have good corrosion resistance and chemical additive resistance, they have certain limitations in terms of mechanical properties, flame retardancy, and weather resistance, making it difficult to meet the needs of some harsh environments.

[0003] The limiting oxygen index (LOI) of polypropylene (PP) is approximately 17.0%, classifying it as a flammable material. During combustion, it produces a large amount of flaming dripping and releases significant heat. To improve the performance of PP materials, the industry typically uses glass fiber reinforcement. While adding glass fiber significantly suppresses dripping, the "wick effect" of glass fiber results in a prolonged combustion period and high heat release. In demanding applications, flame-retardant treatment is essential. In recent years, some bromine-antimony flame-retardant systems have been found to produce toxic fumes upon combustion, leading to their prohibition under relevant domestic and international laws and regulations. Examples include bromine-based flame retardants such as decabromodiphenyl ether. A key technical challenge is how to ensure high glass fiber content while simultaneously achieving flame retardancy, weather resistance, and safety and environmental performance. While some related products exist on the market, most suffer from substandard flame retardancy, insufficient weather resistance, or poor mechanical properties, failing to simultaneously meet the requirements of high strength, high flame retardancy, high weather resistance, and environmental friendliness. For example, some products cannot achieve the V0 level of flame retardancy with high glass fiber content, or have a low tensile strength retention rate in UV accelerated aging tests, failing to meet the 10-year outdoor weathering requirements; some products, while performing well in one aspect, have significant defects in other aspects, failing to comprehensively meet the full performance requirements of materials in industries such as automotive and photovoltaics.

[0004] Therefore, there is an urgent need to develop a polypropylene with high glass fiber content, high flame retardancy, high weather resistance, and excellent mechanical properties to fill the market gap and meet the growing demand for high-end applications. Summary of the Invention

[0005] To address the aforementioned technical problems, the first aspect of this invention provides a high-glass fiber content, high-weather-resistance, and high-flame-retardant unidirectional prepreg tape. The raw materials used in its preparation, by weight, include: 40-70 parts glass fiber, 15-30 parts halogen-free flame retardant, 5-40 parts polypropylene matrix, 0.1-1 parts light stabilizer, 0.1-1 parts UV absorber, 0.5-1 parts antioxidant, 2-5 parts compatibilizer, 0.1-1 parts filler, 0.1-0.5 parts silane coupling agent, and 0.1-0.5 parts dispersant.

[0006] As an implementable example, the glass fiber includes continuous glass fiber or glass fiber of fixed length.

[0007] Furthermore, the continuous glass fiber includes alkali-free continuous glass fiber, with grades including but not limited to ER-1200-162D, which can be purchased from Taishan Glass Fiber Co., Ltd.

[0008] As an example of an implementable approach, the halogen-free flame retardant includes ultrafine red phosphorus powder halogen-free flame retardant, with grades including but not limited to REDNIC 15460N3, which is available from Nantong Yite Chemical Co., Ltd.

[0009] As an implementable example, the melt index of the polypropylene matrix is ​​60-70 g / 10 min (230℃ / 2.16 kg).

[0010] Furthermore, the polypropylene matrix is ​​designated as LA640T and is available from Dongming Hengchang Chemical Co., Ltd.

[0011] This invention utilizes LA640T polypropylene with a high melt flow index, which maintains excellent flowability even with high continuous glass fiber content filling. This allows the resin to fully wet the monofilaments, reducing porosity. With the synergistic effect of halogen-free flame retardants, a 1mm thick product can achieve a UL94 V0 flame retardancy rating. Simultaneously, the high flowability of LA640T allows for processing under lower temperature and shear conditions, reducing glass fiber breakage and resin degradation. This ensures a uniaxial tensile strength ≥800MPa and significantly reduces energy consumption. Furthermore, a higher melt flow index in polypropylene facilitates the migration of compatibilizers to the glass fiber surface, constructing a uniform and dense interfacial layer. This significantly improves interlaminar shear strength and UV and humid heat resistance, achieving a tensile strength retention rate ≥70% after 2000h aging. This approach balances high flame retardancy, high weather resistance, and high-efficiency production.

[0012] As an example of implementation, the raw materials for the light stabilizer include hindered amine light stabilizers and polypropylene.

[0013] Furthermore, the light stabilizer is designated UV-801PP5 and is available from Fujian Disheng Technology Co., Ltd.

[0014] In this invention, the UV-801PP5 light stabilizer is selected to play a triple role of "free radical capture, surface protection, and synergistic enhancement" in high glass fiber and high flame retardant polypropylene systems. The hindered amine functional groups of UV-801PP5 light stabilizer continuously capture ultraviolet-induced polymer free radicals, blocking the photo-oxidation chain reaction, so that the tensile strength retention rate of polypropylene in high glass fiber content systems is ≥70% after 2000h of ultraviolet aging; at the same time, the high molecular weight stearate skeleton has both lubrication and low volatility, inhibiting chalking, loss of gloss and yellowing, and maintaining long-term appearance; in addition, the masterbatch morphology of UV-801PP5 light stabilizer has good compatibility with polypropylene matrix, no blooming migration, and is easy to accurately and uniformly disperse in twin-screw extrusion, thus taking into account the advantages of weather resistance, processing and cost.

[0015] As an example of implementation, the UV absorber includes one or more of benzotriazole UV absorbers, triazine UV absorbers, and hindered amine UV absorbers.

[0016] Furthermore, the benzotriazole UV absorbers include one or more of the following: UV-P absorber, UV-1130 absorber, UV-234 absorber, UV-328 absorber, UV-326 absorber, UV-384 absorber, UV-171 absorber, UV-900 absorber, UV-571 absorber, and UV-928 absorber.

[0017] Furthermore, the triazine UV absorbers include one or more of the following: UV-400 absorber, UV-477 absorber, UV-405 absorber, and UV-479 absorber.

[0018] Furthermore, the hindered amine UV absorbers include one or more of the following: UV-770 absorber, UV-292 absorber, UV-123 absorber, UV-144 absorber, and UV-152 absorber.

[0019] Furthermore, the UV absorber is a UV-P absorber.

[0020] This invention does not further limit the selection of antioxidants; any additive that can improve the product's resistance to yellowing is acceptable, including but not limited to B225M antioxidant.

[0021] As an feasible example, the compatibilizer includes a maleic anhydride-grafted compatibilizer.

[0022] Furthermore, the maleic anhydride graft compatibilizer is branded CMG5001 and is available from Ningbo Nengzhiguang New Materials Co., Ltd.

[0023] The maleic anhydride graft compatibilizer is selected in this invention mainly because the maleic anhydride groups chemically bond with the silane coupling agent on the surface of the continuous glass fiber, while anchoring the non-polar polypropylene segments to the resin matrix to form a strong and tough interface layer, which significantly improves the interlaminar shear strength and uniaxial tensile strength of the product.

[0024] As an implementable example, the filler comprises at least one of zinc borate, nano-hydrotalcite, aluminum hydroxide, magnesium hydroxide, zinc stannate, montmorillonite, wollastonite, calcium carbonate, dolomite, and fumed silica.

[0025] Furthermore, the filler comprises zinc borate and nano-hydrotalcite, with a mass ratio of zinc borate to nano-hydrotalcite of (1-2):(6-10).

[0026] Furthermore, the zinc borate has a particle size of 3-7 μm and is graded HT-207; the nano-hydrotalcite has a particle size of 0.5-1 μm and is graded AC-207.

[0027] In this invention, zinc borate HT-207 is compounded with nano-hydrotalcite AC-207 to form a "layered-ceramic" synergistic barrier in a high glass fiber content, high flame retardant PP system: zinc borate decomposes upon heating and absorbs heat to generate a glassy coating layer, providing initial flame retardancy and smoke suppression; nano-hydrotalcite loses water to generate porous Mg-Al oxide, which interweaves with the glass layer to form a dense carbon layer, preventing heat and oxygen penetration and inhibiting dripping and carbon layer cracking caused by the "wick effect" of glass fiber, significantly reducing smoke density and odor, while taking into account cost, mechanical properties and environmental protection requirements.

[0028] As an example of implementation, the dispersant is a hyperbranched dispersant.

[0029] Furthermore, the hyperbranching dispersant is designated HyPer C100 and is available from Wuhan Hyperbranching Resin Technology Co., Ltd.

[0030] This invention uses the hyperbranched dispersant HyPer C100 to uniformly disperse nano-hydrotalcite, zinc borate, and continuous glass fibers through the "anchor-chain" coating mechanism of three-dimensional branched segments. This reduces melt viscosity, decreases glass fiber breakage, and reduces resin degradation. At the same time, it eliminates defects such as floating fibers and agglomeration, ensuring a unidirectional tape tensile strength ≥800MPa. A 1mm thickness can achieve UL94 V0 flame retardancy, and the strength retention rate is ≥70% after 2000h of UV aging, without the problem of conventional lubricant precipitation.

[0031] As an implementable example, the silane coupling agent includes N-(2-aminoethyl)-3-aminopropyltrimethoxysilane coupling agent.

[0032] A second aspect of this invention provides a method for preparing a high-glass fiber content, high-weather-resistant, and high-flame-retardant unidirectional prepreg tape, comprising:

[0033] A mixture of halogen-free flame retardant, polypropylene matrix, light stabilizer, UV absorber, antioxidant, compatibilizer, filler, silane coupling agent and dispersant is applied to the surface of glass fiber to obtain a high glass fiber content, high weather resistance and high flame retardant unidirectional prepreg tape.

[0034] Furthermore, the preparation method of the high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape includes:

[0035] S1. Mix the halogen-free flame retardant, polypropylene matrix, light stabilizer, UV absorber, antioxidant, compatibilizer, filler, silane coupling agent and dispersant, put them into a mixer and mix for 5 minutes. After mixing evenly, take it out to obtain the mixture.

[0036] S2. Using a twin-screw extruder, the uniformly mixed material is blended and granulated. The temperature of zone 1 of the extruder barrel is set to 180℃, the temperature of zones 2-5 is 190℃, and the temperature of zone 1 of the die head is 180℃. After the mixed material is blended and melt-extruded by the twin-screw extruder, it is cooled by water, dried by a blower, pelletized by a pelletizing device, and vibrated by a screen to obtain prepreg with a diameter of about 3mm, uniform particle size and similar size.

[0037] S3. Feed the prepreg into a twin-screw extruder and use a strip preparation process of "double-sided coating die + rotary impregnation roller + cooling roller". The extruder is a single-screw extruder. The temperature of the extruder barrel zones 1-9 is set to 190℃, the temperature of the connecting zone is set to 200℃, the temperature of the double-sided coating die and impregnation roller is set to 220℃, and the temperature of the cooling roller is set to 60℃. The granulated prepreg is extruded through the screw extruder, and the molten resin is evenly coated on the surface of the continuous glass fiber. Then, the resin and glass fiber are further melt-impregnated by the impregnation roller, so that the resin can be fully combined with each glass fiber as much as possible. After that, the resin and glass fiber are cooled and shaped by the steel roller, and the resin and glass fiber are cooled and solidified to obtain a high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape (thickness 0.2-0.5mm is acceptable).

[0038] Beneficial effects

[0039] (i) Under the premise of ensuring high glass fiber content, the high glass fiber content, high weather resistance and high flame retardant unidirectional prepreg tape prepared by the present invention achieves halogen-free and environmentally friendly high flame retardant effect, and can reach UL94V0 level with a thickness of 1.0mm, meeting the stringent flame retardant requirements.

[0040] (II) By adding light stabilizers, UV absorbers and other additives, the tensile strength retention rate is still ≥70% after 2000 hours of accelerated UV aging test, which is equivalent to 10 years of outdoor service life and has long-term weather resistance stability.

[0041] (III) The product of this invention has a high glass fiber content, which can be combined with the optimized impregnation process to make the unidirectional tape tensile strength ≥800MPa and the 1.0mm laminate tensile strength ≥300MPa, possessing excellent mechanical properties such as high rigidity and high strength.

[0042] (iv) This invention significantly enhances the interfacial bonding force between resin and glass fiber through the synergistic effect of maleic anhydride graft compatibilizer, silane coupling agent and hyperbranched dispersant, ensuring uniform and stable material properties.

[0043] (V) The high glass fiber content, high weather resistance and high flame retardant unidirectional prepreg tape prepared by this invention has the advantages of polypropylene resin itself, such as corrosion resistance and chemical resistance. It can be widely used in fields with high requirements for weather resistance, strength and environmental protection, such as automobiles and photovoltaics, and has broad market prospects. Detailed Implementation

[0044] Example 1

[0045] The first aspect of this example provides a high-glass fiber content, high-weather-resistant, and high-flame-retardant unidirectional prepreg tape. The raw materials for its preparation, by weight, are: 60 parts glass fiber, 28 parts halogen-free flame retardant, 6 parts polypropylene matrix, 0.5 parts antioxidant, 3.5 parts compatibilizer, 0.5 parts light stabilizer, 0.3 parts UV absorber, 0.5 parts filler, 0.2 parts silane coupling agent, and 0.2 parts dispersant.

[0046] The glass fiber is alkali-free continuous glass fiber, grade ER-1200-162D, purchased from Taishan Glass Fiber Co., Ltd.

[0047] The halogen-free flame retardant is an ultrafine red phosphorus powder halogen-free flame retardant, brand name REDNIC 15460N3, purchased from Nantong Yite Chemical Co., Ltd.

[0048] The polypropylene matrix is ​​grade LA640T and was purchased from Dongming Hengchang Chemical Co., Ltd.

[0049] The antioxidant mentioned is B225M antioxidant, purchased from Suqian Lianhong New Materials Co., Ltd.

[0050] The compatibilizer is a maleic anhydride graft compatibilizer, brand name CMG5001, purchased from Ningbo Nengzhiguang New Materials Co., Ltd.

[0051] The light stabilizer is brand name UV-801PP5, purchased from Fujian Disheng Technology Co., Ltd.

[0052] The UV absorber is designated as UV-P absorber and was purchased from Fujian Disheng Technology Co., Ltd.

[0053] The filler is nano-hydrotalcite and zinc borate, with a mass ratio of nano-hydrotalcite to zinc borate of 1:3. The nano-hydrotalcite is grade AC-207 and was purchased from Chenghe Technology Co., Ltd.; the zinc borate is grade HT-207 and was purchased from Shandong Taixing New Material Co., Ltd.

[0054] The silane coupling agent is N-(2-aminoethyl)-3-aminopropyltrimethoxysilane coupling agent, brand name JH-A112, purchased from Hubei Jianghan New Material Co., Ltd.

[0055] The dispersant is a hyperbranched dispersant, brand name HyPer C100, purchased from Wuhan Hyperbranched Resin Technology Co., Ltd.

[0056] The second aspect of this example provides a method for preparing a unidirectional prepreg tape with high glass fiber content, high weather resistance, and high flame retardancy. The specific steps are as follows:

[0057] S1. Mix the halogen-free flame retardant, polypropylene matrix, light stabilizer, UV absorber, antioxidant, compatibilizer, filler, silane coupling agent and dispersant, put them into a mixer and mix for 5 minutes. After mixing evenly, take it out to obtain the mixture.

[0058] S2. Using a twin-screw extruder, the uniformly mixed material is blended and granulated. The temperature of zone 1 of the extruder barrel is set to 180℃, the temperature of zones 2-5 is 190℃, and the temperature of zone 1 of the die head is 180℃. After the mixed material is blended and melt-extruded by the twin-screw extruder, it is cooled by water, dried by a blower, pelletized by a pelletizing device, and vibrated by a screen to obtain prepreg with a diameter of about 3mm, uniform particle size and similar size.

[0059] S3. The prepreg is fed into a twin-screw extruder, using a strip preparation process of "double-sided coating die + rotary impregnation roller + cooling roller". The extruder is a single-screw extruder. The temperature of the extruder barrel zones 1-9 is set to 190℃, the temperature of the connecting zone is set to 200℃, the temperature of the double-sided coating die and impregnation roller is set to 220℃, and the temperature of the cooling roller is set to 60℃. The granulated prepreg is extruded through the screw extruder, and the molten resin is evenly coated on the surface of the continuous glass fiber. Then, the resin and continuous glass fiber are further melt-impregnated by the impregnation roller, so that the resin can be fully combined with each continuous glass fiber as much as possible. After cooling, the resin and continuous glass fiber are squeezed and cooled by the steel roller to solidify, thus obtaining a high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape.

[0060] Comparative Example 1

[0061] The first aspect of this example provides a unidirectional prepreg tape with high glass fiber content, high weather resistance, and high flame retardancy. The raw materials for its preparation, by mass parts, are: 45 parts glass fiber, 18 parts halogen-free flame retardant, 33 parts polypropylene matrix, 0.5 parts antioxidant, and 3.5 parts compatibilizer.

[0062] The halogen-free flame retardant is brand name RBFR-420 and was purchased from Dujiangyan Longbang Technology Co., Ltd.; the other raw material information is the same as in Example 1.

[0063] The second aspect of this example provides a method for preparing a unidirectional prepreg tape with high glass fiber content, high weather resistance, and high flame retardancy. The specific steps are as follows:

[0064] S1. Mix the halogen-free flame retardant, polypropylene matrix, and antioxidant in a mixer for 5 minutes. After mixing evenly, remove the mixture to obtain the final product.

[0065] S2. Using a twin-screw extruder, the uniformly mixed material is blended and granulated. The temperature of zone 1 of the extruder barrel is set to 180℃, the temperature of zones 2-5 is 190℃, and the temperature of zone 1 of the die head is 180℃. After the mixed material is blended and melt-extruded by the twin-screw extruder, it is cooled by water, dried by a blower, pelletized by a pelletizing device, and vibrated by a screen to obtain prepreg with a diameter of about 3mm, uniform particle size and similar size.

[0066] S3. The prepreg is fed into a twin-screw extruder, using a strip preparation process of "double-sided coating die + rotary impregnation roller + cooling roller". The extruder is a single-screw extruder. The temperature of the extruder barrel zones 1-9 is set to 190℃, the temperature of the connecting zone is set to 200℃, the temperature of the double-sided coating die and impregnation roller is set to 220℃, and the temperature of the cooling roller is set to 60℃. The granulated prepreg is extruded through the screw extruder, and the molten resin is evenly coated on the surface of the continuous glass fiber. Then, the resin and continuous glass fiber are further melt-impregnated by the impregnation roller, so that the resin can be fully combined with each continuous glass fiber as much as possible. After cooling, the resin and continuous glass fiber are squeezed and cooled by the steel roller to solidify, thus obtaining a high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape.

[0067] Comparative Example 2

[0068] This example provides a high-glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape. The raw materials used in its preparation, by weight, are: 45 parts glass fiber, 18 parts halogen-free flame retardant, 33 parts polypropylene matrix, 0.5 parts antioxidant, and 3.5 parts compatibilizer.

[0069] The information on raw materials in this example is the same as in Example 1. The difference between this example and Comparative Example 1 is that the halogen-free flame retardant in this example is an ultrafine red phosphorus powder halogen-free flame retardant, brand name REDNIC 15460N3, purchased from Nantong Yite Chemical Co., Ltd.

[0070] In this example, the preparation method of the high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape is the same as that of Comparative Example 1.

[0071] Comparative Example 3

[0072] This example provides a high-glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape. The raw materials used in its preparation, by weight, are: 50 parts glass fiber, 18 parts halogen-free flame retardant, 28 parts polypropylene matrix, 0.5 parts antioxidant, and 3.5 parts compatibilizer.

[0073] The information about the raw materials in this example is the same as in Example 1.

[0074] In this example, the preparation method of the high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape is the same as that of Comparative Example 1.

[0075] Comparative Example 4

[0076] This example provides a high-glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape. The raw materials used in its preparation, by weight, are: 60 parts glass fiber, 18 parts halogen-free flame retardant, 18 parts polypropylene matrix, 0.5 parts antioxidant, and 3.5 parts compatibilizer.

[0077] The information about the raw materials in this example is the same as in Example 1.

[0078] In this example, the preparation method of the high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape is the same as that of Comparative Example 1.

[0079] Comparative Example 5

[0080] This example provides a high-glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape. The raw materials used in its preparation, by weight, are: 60 parts glass fiber, 25 parts halogen-free flame retardant, 11 parts polypropylene matrix, 0.5 parts antioxidant, and 3.5 parts compatibilizer.

[0081] The information about the raw materials in this example is the same as in Example 1.

[0082] In this example, the preparation method of the high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape is the same as that of Comparative Example 1.

[0083] Comparative Example 6

[0084] The first aspect of this example provides a unidirectional prepreg tape with high glass fiber content, high weather resistance, and high flame retardancy. The raw materials for its preparation are, by mass parts: 60 parts glass fiber, 25 parts halogen-free flame retardant, 10.6 parts polypropylene matrix, 0.5 parts antioxidant, 3.5 parts compatibilizer, 0.2 parts light stabilizer, and 0.2 parts UV absorber.

[0085] The information about the raw materials in this example is the same as in Example 1.

[0086] The second aspect of this example provides a method for preparing a unidirectional prepreg tape with high glass fiber content, high weather resistance, and high flame retardancy. The specific steps are as follows:

[0087] S1. Mix the halogen-free flame retardant, polypropylene matrix, light stabilizer, UV absorber, antioxidant, and compatibilizer in a mixer for 5 minutes. After mixing evenly, remove the mixture to obtain the final product.

[0088] S2. Using a twin-screw extruder, the uniformly mixed material is blended and granulated. The temperature of zone 1 of the extruder barrel is set to 180℃, the temperature of zones 2-5 is 190℃, and the temperature of zone 1 of the die head is 180℃. After the mixed material is blended and melt-extruded by the twin-screw extruder, it is cooled by water, dried by a blower, pelletized by a pelletizing device, and vibrated by a screen to obtain prepreg with a diameter of about 3mm, uniform particle size and similar size.

[0089] S3. The prepreg is fed into a twin-screw extruder, using a strip preparation process of "double-sided coating die + rotary impregnation roller + cooling roller". The extruder is a single-screw extruder. The temperature of the extruder barrel zones 1-9 is set to 190℃, the temperature of the connecting zone is set to 200℃, the temperature of the double-sided coating die and impregnation roller is set to 220℃, and the temperature of the cooling roller is set to 60℃. The granulated prepreg is extruded through the screw extruder, and the molten resin is evenly coated on the surface of the continuous glass fiber. Then, the resin and continuous glass fiber are further melt-impregnated by the impregnation roller, so that the resin can be fully combined with each continuous glass fiber as much as possible. After cooling, the resin and continuous glass fiber are squeezed and cooled by the steel roller to solidify, thus obtaining a high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape.

[0090] Comparative Example 7

[0091] This example provides a high-glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape. The raw materials used in its preparation, by weight, are: 60 parts glass fiber, 25 parts halogen-free flame retardant, 10.4 parts polypropylene matrix, 0.5 parts antioxidant, 3.5 parts compatibilizer, 0.4 parts light stabilizer, and 0.2 parts UV absorber.

[0092] The information about the raw materials in this example is the same as in Example 1.

[0093] In this example, the preparation method of the high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape is the same as that of Comparative Example 6.

[0094] Comparative Example 8

[0095] This example provides a high-glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape. The raw materials used in its preparation, by weight, are: 60 parts glass fiber, 25 parts halogen-free flame retardant, 10.2 parts polypropylene matrix, 0.5 parts antioxidant, 3.5 parts compatibilizer, 0.5 parts light stabilizer, and 0.3 parts UV absorber.

[0096] The information about the raw materials in this example is the same as in Example 1.

[0097] In this example, the preparation method of the high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape is the same as that of Comparative Example 6.

[0098] Comparative Example 9

[0099] This example provides a high-glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape. The raw materials used in its preparation, by weight, are: 60 parts glass fiber, 30 parts halogen-free flame retardant, 5.2 parts polypropylene matrix, 0.5 parts antioxidant, 3.5 parts compatibilizer, 0.5 parts light stabilizer, and 0.3 parts UV absorber.

[0100] The information about the raw materials in this example is the same as in Example 1.

[0101] In this example, the preparation method of the high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape is the same as that of Comparative Example 6.

[0102] Comparative Example 10

[0103] The first aspect of this example provides a high-glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape. The raw materials for its preparation, by mass parts, are: 60 parts glass fiber, 30 parts halogen-free flame retardant, 3.2 parts polypropylene matrix, 0.5 parts antioxidant, 3.5 parts compatibilizer, 0.5 parts light stabilizer, 0.3 parts UV absorber, and 2 parts filler.

[0104] In this example, the fillers are nano-hydrotalcite and zinc borate, with a mass ratio of 1:1. The nano-hydrotalcite is grade AC-207 and was purchased from Chenghe Technology Co., Ltd.; the zinc borate is grade HT-207 and was purchased from Shandong Taixing New Material Co., Ltd.; the other raw material information is the same as in Example 1.

[0105] The second aspect of this example provides a method for preparing a unidirectional prepreg tape with high glass fiber content, high weather resistance, and high flame retardancy. The specific steps are as follows:

[0106] S1. Mix the halogen-free flame retardant, polypropylene matrix, light stabilizer, UV absorber, antioxidant, compatibilizer, and filler in a mixer and mix for 5 minutes. After mixing evenly, remove the mixture to obtain the final product.

[0107] S2. Using a twin-screw extruder, the uniformly mixed material is blended and granulated. The temperature of zone 1 of the extruder barrel is set to 180℃, the temperature of zones 2-5 is 190℃, and the temperature of zone 1 of the die head is 180℃. After the mixed material is blended and melt-extruded by the twin-screw extruder, it is cooled by water, dried by a blower, pelletized by a pelletizing device, and vibrated by a screen to obtain prepreg with a diameter of about 3mm, uniform particle size and similar size.

[0108] S3. The prepreg is fed into a twin-screw extruder, using a strip preparation process of "double-sided coating die + rotary impregnation roller + cooling roller". The extruder is a single-screw extruder. The temperature of the extruder barrel zones 1-9 is set to 190℃, the temperature of the connecting zone is set to 200℃, the temperature of the double-sided coating die and impregnation roller is set to 220℃, and the temperature of the cooling roller is set to 60℃. The granulated prepreg is extruded through the screw extruder, and the molten resin is evenly coated on the surface of the continuous glass fiber. Then, the resin and continuous glass fiber are further melt-impregnated by the impregnation roller, so that the resin can be fully combined with each continuous glass fiber as much as possible. After cooling, the resin and continuous glass fiber are squeezed and cooled by the steel roller to solidify, thus obtaining a high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape.

[0109] Comparative Example 11

[0110] This example provides a high-glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape. The raw materials used in its preparation, by weight, are: 60 parts glass fiber, 28 parts halogen-free flame retardant, 6.2 parts polypropylene matrix, 0.5 parts antioxidant, 3.5 parts compatibilizer, 0.5 parts light stabilizer, 0.3 parts UV absorber, and 1 part filler.

[0111] In this example, the fillers are nano-hydrotalcite and zinc borate, with a mass ratio of 1:1. The nano-hydrotalcite is grade AC-207 and was purchased from Chenghe Technology Co., Ltd.; the zinc borate is grade HT-207 and was purchased from Shandong Taixing New Material Co., Ltd.; the other raw material information is the same as in Example 1.

[0112] In this example, the preparation method of the high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape is the same as that of Comparative Example 10.

[0113] Comparative Example 12

[0114] This example provides a high-glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape. The raw materials used in its preparation, by weight, are: 60 parts glass fiber, 28 parts halogen-free flame retardant, 6.4 parts polypropylene matrix, 0.5 parts antioxidant, 3.5 parts compatibilizer, 0.5 parts light stabilizer, 0.3 parts UV absorber, and 0.8 parts filler.

[0115] In this example, the fillers are nano-hydrotalcite and zinc borate, with a mass ratio of 1:3. The nano-hydrotalcite is grade AC-207 and was purchased from Chenghe Technology Co., Ltd.; the zinc borate is grade HT-207 and was purchased from Shandong Taixing New Material Co., Ltd.; the other raw material information is the same as in Example 1.

[0116] In this example, the preparation method of the high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape is the same as that of Comparative Example 10.

[0117] Performance Evaluation

[0118] 1. Ultraviolet radiation accelerates aging:

[0119] Samples of the products from Example 1 and Comparative Examples 1-12 were prepared and subjected to accelerated UV aging tests according to ASTM G154.

[0120] UV radiation simulation: test cycle 2000+ hours (≈10 years outdoor), tensile strength retention rate of qualified materials ≥70%.

[0121] 2. Flame retardant properties:

[0122] Samples of the products from Example 1 and Comparative Examples 1-12 were prepared and subjected to vertical burning tests according to UL 94 standards:

[0123] Spline size: 13mm×125mm; thickness options include 1mm, 2.0mm, 3.2mm, etc.

[0124] The flame retardant performance of the product must reach V0 level (1mm).

[0125] 3. Tensile properties:

[0126] Samples of the products from Example 1 and Comparative Examples 1-12 were prepared and tested according to ISO 527:

[0127] Spline dimensions: 13mm × 125mm; thickness: 0.25mm.

[0128] The unidirectional tensile strength of the belt is required to be ≥800MPa; the tensile strength of the 1.0mm laminate is required to be ≥300MPa.

[0129] The experimental results are shown in Table 1:

[0130] Table 1

[0131]

[0132]

[0133] The experimental results above show that the unidirectional prepreg tape with high glass fiber content, high weather resistance and high flame retardancy prepared by the present invention has a unidirectional tensile strength greater than 800MPa, and can reach UL94 (1.0mm) V0 level. Moreover, the tensile strength retention rate after UV accelerated aging is more than 70%, which means that after 10 years of outdoor use, the product still has high mechanical properties and excellent actual use effect.

Claims

1. A unidirectional prepreg tape with high glass fiber content, high weather resistance, and high flame retardancy, characterized in that, The raw materials, by mass, include 40-70 parts glass fiber, 15-30 parts halogen-free flame retardant, 5-40 parts polypropylene matrix, 0.1-1 parts light stabilizer, 0.1-1 parts UV absorber, 0.5-1 parts antioxidant, 2-5 parts compatibilizer, 0.1-1 parts filler, 0.1-0.5 parts silane coupling agent, and 0.1-0.5 parts dispersant.

2. The high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape according to claim 1, characterized in that, The glass fibers include continuous glass fibers or glass fibers of fixed length.

3. The high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape according to claim 1, characterized in that, The melt index of the polypropylene matrix is ​​60-70 g / 10 min.

4. The high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape according to claim 1, characterized in that, The UV absorber includes one or more of benzotriazole UV absorbers, triazine UV absorbers, or hindered amine UV absorbers.

5. The high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape according to claim 4, characterized in that, The benzotriazole UV absorbers include one or more of the following: UV-P absorber, UV-1130 absorber, UV-234 absorber, UV-328 absorber, UV-326 absorber, UV-384 absorber, UV-171 absorber, UV-900 absorber, UV-571 absorber, or UV-928 absorber.

6. The high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape according to any one of claims 1-5, characterized in that, The compatibilizer includes maleic anhydride-grafted compatibilizer.

7. The high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape according to claim 1, characterized in that, The filler comprises at least one of zinc borate, nano-hydrotalcite, aluminum hydroxide, magnesium hydroxide, zinc stannate, montmorillonite, wollastonite, calcium carbonate, dolomite, and fumed silica.

8. The high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape according to claim 7, characterized in that, The filler comprises zinc borate and nano-hydrotalcite, with a mass ratio of zinc borate to nano-hydrotalcite of (1-2):(6-10).

9. The high glass fiber content, high weather resistance, and high flame retardant unidirectional prepreg tape according to claim 1, characterized in that, The dispersant is a hyperbranched dispersant.

10. A method for preparing a high-glass fiber content, high-weather-resistant, and high-flame-retardant unidirectional prepreg tape according to any one of claims 1-9, characterized in that, include: A mixture of halogen-free flame retardant, polypropylene matrix, light stabilizer, UV absorber, antioxidant, compatibilizer, filler, silane coupling agent and dispersant is applied to the surface of glass fiber to obtain a high glass fiber content, high weather resistance and high flame retardant unidirectional prepreg tape.

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