A high-density, halogen-free, flame-retardant PP sheet and flame-retardant file boxes, folders, and other office plastic products.

Abstract

This invention discloses a high-density, char-forming, halogen-free flame-retardant PP sheet and flame-retardant file boxes, folders, and other office plastic products, belonging to the field of polymer flame-retardant materials technology. This invention employs a unique high-density phase halogen-free composite flame-retardant system, interface anchoring compatibility technology, and self-lubricating cross-linking toughening technology, achieving UL94 V-0 high-efficiency flame retardancy with low additive dosage. It is halogen-free, low-smoke, environmentally friendly, and safe, while also possessing advantages such as high flexural strength, high stiffness, non-deformation, and no powdering. It completely solves the drawbacks of traditional flame-retardant PP materials, such as easy cracking, melting and dripping, poor processability, and ease of imitation. The technical approach of this invention is completely different from existing patents, exhibiting outstanding inventiveness, high difficulty in imitation, and strong patent authorization stability. It is suitable for office stationery products such as file boxes, folders, and document books, and can be widely used in archives, libraries, government agencies, and other places, possessing extremely high industrial production value and core patent protection value.

Description

Technical Field

[0001] This invention belongs to the technical field of polymer flame retardant materials and office stationery products. Specifically, it relates to a high-density, low-addition, high-toughness halogen-free flame retardant PP composite material, flame retardant PP sheets, and flame retardant file boxes, folders and other office stationery products made therefrom. These products are particularly suitable for places with high requirements for fire safety, environmental protection, low smoke, folding resistance and durability, such as archive storage, government offices, libraries and archives. Background Technology

[0003] Polypropylene (PP) is widely used in office stationery products such as file boxes, folders, document holders, and file racks due to its lightweight, good toughness, easy processing, and moderate cost. However, ordinary PP material has a low limiting oxygen index and is extremely flammable. The combustion process is accompanied by severe melting and dripping, which can easily cause the flame to spread rapidly, posing a significant fire safety hazard and failing to meet the fire safety requirements of archives and centralized office areas.

[0004] Most existing flame-retardant PP materials use halogen-containing flame-retardant systems. While they offer some flame-retardant effect, they release large amounts of toxic and corrosive hydrogen halide gases and dense black smoke during combustion, polluting the environment and harming human health, thus failing to meet modern environmental protection and safety standards. Conventional halogen-free flame-retardant polypropylene materials generally suffer from defects such as excessively high levels of flame retardants, significantly reduced material toughness, brittleness, poor flexural strength, insufficient molding stability, and a loose, easily detached char structure. When made into file boxes and folders, they are prone to deformation and breakage, failing to meet the needs of long-term repeated use.

[0005] Currently, in the market and in publicly available patents, halogen-free flame-retardant PP systems mostly adopt conventional ternary compound systems of ammonium polyphosphate, pentaerythritol, and melamine polyphosphate. This type of technology is already a publicly available and common technology, but it has problems such as low flame retardant efficiency, poor mechanical properties, no technical barriers, and easy imitation, making it impossible to form core technology protection and product competitiveness.

[0006] Therefore, developing a flame-retardant PP sheet and office stationery products that are highly innovative, highly flame-retardant, halogen-free and low-smoke, highly flexurally resistant, highly stiff, difficult to imitate, and completely avoid existing patented technology routes has become an urgent technical problem to be solved in this field. Summary of the Invention

[0008] This invention addresses the shortcomings and deficiencies of existing technologies by providing a high-density, charred, halogen-free flame-retardant PP sheet and flame-retardant file boxes, folders, and office plastic products. Through a unique dense-phase charring system, interface anchoring compatibility technology, and self-lubricating cross-linking toughening technology, it achieves UL94 V-0 high-efficiency flame retardancy with low flame retardant addition, while significantly improving the sheet's flexural strength, stiffness, and processing stability.

[0009] The technical solution adopted in this invention is as follows: (a) Raw material ratio (parts by weight) 1. Homopolymer polypropylene (melt index 8~15g / 10min): 100 parts 2. High-density phase halogen-free composite flame retardant: 22-28 parts 3. Interface anchoring compatibilizer: 3.0~5.0 parts 4. Self-lubricating crosslinking agent: 0.4~0.8 parts 5. Organo-montmorillonite modified PTFE nano anti-dripping agent: 0.3~0.6 parts 6. Compound antioxidant: 0.3~0.5 parts 7. Needle-shaped wollastonite whisker filler: 4-7 parts 8. High-efficiency lubricant: 0.3~0.5 parts (ii) Best Practice Implementation Ratio 1. Homopolymer polypropylene: 100 parts 2. High-density phase halogen-free composite flame retardant: 25 parts 3. Interface anchoring compatibilizer: 4 parts 4. Self-lubricating crosslinking agent: 0.6 parts 5. Organo-montmorillonite modified PTFE nano anti-dripping agent: 0.5 parts 6. Antioxidant 1010 / Antioxidant 168 (1:1): 0.4 parts 7. Needle-shaped wollastonite whiskers: 5 parts 8. Zinc stearate lubricant: 0.4 parts (III) Core Innovation Components 1. High-density phase halogen-free composite flame retardant It is composed of dense-phase ammonium polyphosphate, melamine cyanurate, and modified carbon six-membered ring polyol in a weight ratio of 4:2:1. It forms a dense and continuous carbon layer at high temperature, which does not fall off and has excellent heat insulation and smoke suppression effects.

[0010] 2. Interface anchoring compatibilizer By using epoxy-grafted PP and silane coupling agent for composite modification, a strong interfacial bond between the flame retardant and the matrix is ​​achieved, which greatly improves the flexural strength and mechanical strength, unlike conventional MAH-g-PP.

[0011] 3. Self-lubricating crosslinking agent It uses hyperbranched siloxane polymers, which have the triple effects of toughening, carbonization and self-lubrication, improving processing fluidity and surface gloss of products.

[0012] 4. Nano-anti-dripping agent The PTFE modified with organomontmorillonite has a significantly better anti-dripping effect than conventional PTFE, with a lower addition amount and stronger flame retardant stability.

[0013] (iv) Preparation method 1. Weigh each raw material according to the formula, put them into a high-speed mixer for intensive mixing and pre-dispersion, temperature 80~100℃, mixing time 5min; 2. Add the pre-dispersed mixture to a twin-screw extruder at a temperature range of 175~205℃, perform melt reaction extrusion, and then water-cool and pelletize. 3. Flame retardant particles are added to the sheet extruder at a temperature of 190~215℃. After extrusion, three-roll calendering, cooling and shaping, and traction cutting, a high-density char-forming halogen-free flame retardant PP sheet is obtained. 4. Flame-retardant PP sheets are die-cut, creasing, folding, and bound to produce flame-retardant file boxes, folders, document books, and other office stationery plastic products.

[0014] (v) Product performance 1. Flame retardant rating: UL94 V-0 (1.0mm / 1.6mm) 2. Limiting oxygen index: ≥30% 3. Bending resistance: ≥500 cycles without breaking. 4. Halogen-free, low-smoke, non-toxic, and no corrosive gas release. 5. The board has high stiffness, high flatness, does not deform, and does not shed powder. 6. Excellent processing fluidity, suitable for mass automated production. (vi) Beneficial effects 1. Completely avoids existing patents; the technical approach is original. 2. Low flame retardant content, excellent mechanical properties, solving the problems of brittleness, cracking, bending, and deformation of traditional materials; 3. The char is dense and does not fall off, has strong flame retardant stability, no melting dripping, and a higher safety level; 4. The scope of protection covers the formula, particles, plates, products, and preparation methods, providing full-chain patent protection. Detailed Implementation

[0015] Example 1 (Best Example, for File Boxes) Raw material ratio: 100 parts homopolymer polypropylene, 25 parts high-density phase halogen-free composite flame retardant, 4 parts interface anchoring compatibilizer, 0.6 parts self-lubricating crosslinking agent, 0.5 parts organomontmorillonite modified PTFE nano anti-dripping agent, 0.4 parts composite antioxidant, 5 parts needle-like wollastonite whiskers, and 0.4 parts lubricant.

[0016] Preparation process: Pre-dispersion → twin-screw extrusion granulation → sheet extrusion → die cutting and creasing → production of flame-retardant file boxes.

[0017] Performance results: UL94 V-0, LOI=30%, folding resistance ≥500 times, halogen-free and low smoke, excellent mechanical properties.

[0018] Example 2 (High toughness, for folders only) Raw material ratio: 100 parts polypropylene, 23 parts high-density phase flame retardant, 4.5 parts interface anchoring compatibilizer, 0.6 parts self-lubricating crosslinking agent, 0.4 parts nano anti-dripping agent, 0.4 parts composite antioxidant, 4.5 parts wollastonite whiskers, and 0.4 parts lubricant.

[0019] Performance results: It is more durable and suitable for thin folders and document books.

[0020] Example 3 (High flame retardancy, for archives only) Raw material ratio: 100 parts polypropylene, 28 parts high-density phase flame retardant, 4 parts interface anchoring compatibilizer, 0.7 parts self-lubricating crosslinking agent, 0.6 parts nano anti-dripping agent, 0.5 parts composite antioxidant, 6 parts wollastonite whiskers, and 0.5 parts lubricant.

[0021] Performance results: It has stronger flame retardant stability and is suitable for use in high-density filing cabinets and fireproof archives.

Claims

1. A composite material, characterized in that, Included by weight: 100 parts homopolymer polypropylene; 22-28 parts of high-density phase halogen-free composite flame retardant; 3.0~5.0 parts of interface anchoring compatibilizer; 0.4~0.8 parts of self-lubricating crosslinking agent; 0.3-0.6 parts of organomontmorillonite-modified PTFE nano anti-dripping agent; 0.3-0.5 parts of compound antioxidant; 4-7 parts of needle-shaped wollastonite whisker filler; 0.3 to 0.5 parts of high-efficiency lubricant.

2. The composite material according to claim 1, characterized in that, The high-density phase halogen-free composite flame retardant is composed of dense-phase ammonium polyphosphate, melamine cyanurate, and modified carbon six-membered ring polyol in a weight ratio of 4:2:

1.

3. The composite material according to claim 1, characterized in that, The interface anchoring compatibilizer is a composite modified material of epoxy-grafted PP and silane coupling agent.

4. The composite material according to claim 1, characterized in that, The self-lubricating crosslinking agent is a hyperbranched siloxane polymer.

5. The composite material according to claim 1, characterized in that, The composite antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a 1:1 ratio.

6. A high-density, char-forming, halogen-free flame-retardant PP sheet, characterized in that, The composite material described in any one of claims 1 to 5 is obtained by mixing, pre-dispersing, twin-screw extrusion granulation, and sheet extrusion molding.

7. A flame-retardant file box and folder office plastic product, characterized in that, It is made from the halogen-free flame-retardant PP sheet described in claim 6 through die-cutting, creasing, folding and binding.

8. A method for preparing the high-density, char-forming, halogen-free flame-retardant PP composite material according to claim 1, characterized in that, Includes the following steps: (1) Add each component to a high-speed mixer according to the proportion, and knead and pre-disperse at 80~100℃ for 5 minutes; (2) Add the mixture to a twin-screw extruder, melt and extrude at 175~205℃, and then water-cool and pelletize; (3) The particles are extruded, calendered and shaped by a sheet extruder at 190~215℃ to obtain flame-retardant PP sheets.