Chloroprene rubber (CR) is a synthetic rubber obtained by polymerization of chloroprene. It is widely used because of its excellent aging resistance, oil resistance, corrosion resistance and other properties. Polychloroprene Rubber CR2442 vulcanized rubber has good physical properties and can be used in many occasions (Such as chloroprene rubber adhesive). However, since the process of CR2442 in internal mixing, open mixing and vulcanization is not easy to master, the physical properties of the prepared vulcanized rubber are sometimes poor, which affects its production and application.

1. The influence of process parameters on the preparation of mixed rubber and vulcanized rubber

1.1 Internal mixer mixing process

CR2442 has high requirements for the mixing process. When preparing CR2442 mixed rubber, the initial temperature, mixing time and rotor speed of the internal mixer have a great influence on the discharge temperature. The discharge temperature is an important parameter for measuring the mixing process. The optimal discharge temperature of CR2442 is 110℃. The order of adding various materials during the mixing process is also important. The correct way to add materials to CR2442 during the mixing process is: add CR2442 and small materials at the same time → add carbon black → add white carbon black and operating oil in sequence.

1.2 Mixing process of open mill

After the mixed rubber prepared by the internal mixer is cooled, the vulcanization system is added on the open mill. The vulcanization system includes vulcanizing agent and accelerator. The correct way to add is to add accelerator first and then vulcanizing agent. When adding the vulcanization system to the mixed rubber on the open mill, it is generally required that there is accumulated rubber on the roller. With the shearing and extrusion of the open mill, the roller temperature will increase significantly. When the temperature of the rubber is too high, the rubber should be cut, pulled out and cooled, and then the rubber should be mixed after it is completely cooled.

1.3 Vulcanization process

After adding the vulcanization system on the open mill, the rubber is cooled and placed for 16~24h before vulcanization. Since the CR2442 mixed rubber is easy to crystallize at low temperatures, it is generally necessary to perform indirect heating treatment in an oven. The vulcanization time of CR2442 was set to 30, 40, 50, 60, 70 and 80 minutes respectively. After many tests, it was found that the tensile strength and elongation at break of the vulcanized rubber were the largest when the vulcanization time was 60 minutes. Therefore, the optimal vulcanization time of CR2442 was determined to be 60 minutes.

1.4 Bonding operation

In the process of bonding the mixed rubber and brass, the rubber is first cut into sheets with the same length and width as the mold. After the mold is preheated, the cut film is placed in the mold cavity. Since the mold is heated, placing it too slowly will cause early vulcanization of the rubber, reduce the fluidity of the rubber, make the bonding insufficient, and then reduce the bonding force. Therefore, the scorch time should be controlled to be much longer than the placement time of the film.

2. Influence of vulcanization system, reinforcement system and bonding system

Vulcanization system: When CR2442 uses only zinc oxide and magnesium oxide for vulcanization, the resulting rubber's physical properties are worse compared to when zinc oxide, magnesium oxide, sulfur, and accelerator DM are used as a system.

Reinforcement system: The reinforcement system of CR2442 is often based on carbon black and supplemented by white carbon black.

Bonding system: Rubber as a single material can no longer meet the needs of society, and it is often necessary to bond rubber to metal to expand its scope of use. CR2442 is usually bonded to metal using a resorcinol-methylene-white carbon black-cobalt salt bonding system.

3. Conclusion

When mixing, it's important to think about temperature, how long you mix, and how fast the rotor spins. Also, when you add the vulcanization system using the open mill, pay attention to the order you add things. The heat from the rollers can really change things.For vulcanization and bonding, if you make sure the scorch time is longer than it takes to place the sample, you can get better quality vulcanized rubber and better bonding with other types of materials. The CR2442 discharge temperature matters too. It's a good idea to add white carbon black as a reinforcement in CR2442. This helps control how fast vulcanization and bonding happen.

Website: www.elephchem.com

Whatsapp: (+)86 13851435272

E-mail: admin@elephchem.com

Chloroprene rubber adhesive is the largest and most widely used variety among rubber adhesives. It can be sorted into a few groups, like resin modified, filler, grafted, and latex types. Grafted chloroprene rubber adhesive, which is made mostly of chloroprene rubber and a grafted modifier, is known as easy to their usage, strong bonds, high initial adhesion, and many uses. As early as the 1950s, the shoemaking industry began to use chloroprene rubber adhesive. As shoemaking materials and styles change, standard chloroprene rubber adhesive may not be strong enough. This can cause the upper and sole of shoes, or composite soles, to separate. This issue harms shoe quality and limits growth in the adhesive shoe business. To solve this problem, we used a variety of graftable chloroprene rubbers at home and abroad as graft bodies and used MMA to study their grafting modification.

1 Grafting mechanism

2 Experimental part

2.1 Raw materials and polymerization formula

2.2 Polymerization Procedure

Add CR to the solvent. Heat the solution to 50 °C and stir until the CR is completely dissolved. Raise the temperature to 80°C, and slowly add the MMA solution that contains BPO while stirring. Maintain the temperature and continue stirring until the viscosity reaches a suitable level (about 40 minutes). Immediately add hydroquinone to stop the reaction. Keep warm for 4 to 6 hours. After the reaction is complete, cool down to 40°C; add thickening resin, vulcanizing agent, antioxidant and filler, and finally keep warm for 2 to 3 hours, cool down to room temperature, and obtain the product. A small amount of toluene can be added to adjust the viscosity. The obtained graft copolymer (CR-MMA) is a brown-yellow transparent viscous liquid. The viscosity measures between 1000 and 1500 mPa·s. Solid content ranges from 15% to 25%, and the strength registers at 34 N/cm².

2.3 Product analysis

2.3.1 Determination of adhesive viscosity

The viscosity value (mPa·s) was tested in a 25℃ constant temperature water bath using a rotary viscometer (Shanghai Optical Factory, NDI-1 type).

2.3.2 Determination of adhesive solid content

The film after vacuum drying and constant weight of the adhesive was wrapped with filter paper and placed in a fat extractor. It was extracted with acetone in a 65℃ constant temperature water bath for 48 hours (to remove PMMA homopolymer in copolymerization). The solid content (W%) was calculated according to the following formula:

W %=W₂ / W₁×100%

Wherein, W₁ is the mass of the grafted adhesive, and W₂ is the mass of the film after vacuum drying and constant weight.

2.3.3 Determination of peel strength of artificial leather/artificial leather (PVC/PVC) bonded by adhesive

The soft PVC sheet was wiped with acetone or butanone to remove the oil stains on the surface. The entire process was in accordance with GB7126-86.

3 Results and discussion

3.1 Solvent selection

The solvent used in chloroprene rubber adhesive is very important. It affects the solubility of chloroprene rubber, the initial viscosity of the adhesive, stability, permeability to the adherend, bonding strength, flammability and toxicity, etc. Therefore, the selection of solvents should take into account many factors.

Commonly used solvents include toluene, ethyl acetate, butanone, acetone, n-hexane, cyclohexane, solvent gasoline, etc. The test confirmed that when the solvent cannot dissolve chloroprene rubber alone, two or three solvents can be mixed in appropriate proportions to have good solubility, viscosity and low toxicity.

3.2 Effect of CR type and concentration on the performance of grafted products

Different types of chloroprene rubber (CR) show differences in how quickly they form crystals and how deep their colors are. These factors can change how well the grafted materials initially stick together and how they look. Tests show that using Denka A120 Chloroprene rubber and Chloroprene Rubber SN-244X to graft chloroprene rubber results in good initial adhesion and color. The amount of CR does not change peel strength much, but it does affect how well copolymerization works. When the CR concentration is too high, that is, the viscosity is high, MMA is difficult to diffuse and has a strong tendency to self-polymerize. Maintaining the appropriate CR concentration is necessary; if it's too low, the MMA volume will be too small, which slows down the grafting copolymerization. CR concentration works best between 11% and 12%.

3.3 Effect of reaction time on the performance of grafted products

Generally speaking, the longer the reaction time, the higher the grafting rate and viscosity value. At the beginning, the initial and final adhesion strengths increase with the extension of reaction time and the increase of viscosity. Extended reaction times coupled with high viscosity can actually reduce both initial and final adhesion. Experiments suggest reaction times should ideally fall between 3.0 and 5.0 hours.

3.4 Effect of reaction temperature on grafting reaction

When the reaction temperature is lower than 70℃, the reaction is slow, which is due to the slow decomposition of BPO. Because BPO decomposes quickly above 90℃, leading to a rapid increase in viscosity and poorer processing, we set the reaction temperature between 80°C and 90℃.

4 Conclusion

Our initial tests included scaled-up experiments and pilot production runs, which successfully yielded acceptable products. They were supplied to many leather shoe factories and achieved satisfactory results. The quality met the various standards required for shoemaking.

CR-MMA grafted adhesive shows better peel strength on PVC artificial leather compared to regular CR adhesive used for boots.The addition of a small quantity of isocyanate (5-10%) can serve as a temporary curing agent. The -NCO group in the isocyanate then reacts with active hydrogen in the rubber, creating an amide bond. This reaction strengthens the rubber's internal structure, improving the overall bond strength.

Website: www.elephchem.com

Whatsapp: (+)86 13851435272

E-mail: admin@elephchem.com

Chloroprene rubber (CR)  is one of the commonly used rubber varieties. The strength of vulcanized rubber without carbon black reinforcement can reach 28MPa, and the relative elongation is about 800%. It has the characteristics of oil resistance, flame resistance, oxidation resistance and ozone resistance. It is soluble in benzene and chloroform. It swells slightly but does not dissolve in mineral oil and vegetable oil.

1. Progress in CR Technology Abroad

• Monomer Production

DuPont in the U.S. came up with a liquid method to make chloroprene from butadiene. This is safer than the gas method that was first used. It can produce higher yield products at a lower cost, improve safety, and reduce maintenance costs. In 1992, the company upgraded its monomer production line, moving from a single-loop control system to a computerized distributed control system. 

• Post-processing technology

Recent progress in CR post-processing tech is apparent in the developments related to spiral extrusion dehydration and drying. Chloroprene latex and coagulant go into a screw extruder that has a specific design. The coagulated latex removes most of the water in the dehydration section of the extruder by the back pressure. The success of this process has created conditions for the industrial production of CR and asphalt and CR and short fibers, thereby increasing the operational flexibility and being able to handle CR varieties with poor freezing film-forming and tape-forming properties. In 1992, DuPont launched a series of elastomer masterbatches including CR with Kevlar (polyarylamide) short fibers as reinforcement materials, proving that this process has begun to be used in the production of blended products.

• Development of new varieties

There are hundreds of foreign brands. Companies in the United States and Japan have developed many high-performance special CR based on a series of mature brands. In order to improve the thermal stability of CR, Bayer has developed copolymers of chloroprene (CD) with carboxylic acid amide, carboxylic acid anhydride and (or) carboxylic acid monomers. These new CR also have better spraying and brushing characteristics. Denka Corporation of Japan has also improved traditional products and launched a new generation of CR (Denka chloroprene rubber). For example, the DCR 20 series. Tosoh Corporation of Japan is also developing special shock-absorbing CR, and has produced CR latexes with high softening temperature, good normal temperature and high temperature adhesive properties, high water resistance and stability (SKYPRENE Chloroprene Rubber).  

2. Progress in domestic CR technology

In 1958, Changshou Chemical Plant in Sichuan, my country built a device for producing CR by acetylene. The main CR production in China does not control the conversion rate, and many places use manual operations, which is basically a workshop-style production status. Besides the earlier producers of CR glue like Chongqing Changshou Chemical Co., Ltd., Shanxi Synthetic Rubber Company, Jiangsu Lianshui Chemical General Plant, and Tianjin Donghai Adhesives Company, Shandong Laizhou Kangbaili Glue Industry Co., Ltd. developed in October 2003 a new CR glue. They carefully chose and mixed the composite solvent. 

3. Suggestions for the development of domestic CR industry

• Strengthen technology development

For domestic carbon black firms, boosting investment in science and tech, along with adopting and assimilating advanced foreign tech, is key. These actions should lower consumption and costs, and it should raise acetylene use from 57% to over 70% quickly.

• Strengthen the development of new varieties

To maintain the Mooney viscosity in current products, we will create new types. The focus will be on making functional latex, like carboxyl and copolymer latex. Our goal is to bring high Mooney, non-sulfur regulated WHV to industrial production.

• Increase market share

In the next few years, the market of CR in my country will be saturated, and relevant manufacturers can consider developing overseas markets. At present, the development trend of CR in the world is that the European and American markets are shrinking, while China, Eastern Europe, Russia and Southeast Asia are in the rising stage. CR can not only contend with imported goods locally, but can also progressively expand sales to North America, Eastern Europe, Russia, East Asia, and Southeast Asia.

Website: www.elephchem.com

Whatsapp: (+)86 13851435272

E-mail: admin@elephchem.com

Polyether Ether Ketone (PEEK) is a high-performance engineering thermoplastic known for its exceptional resistance to high temperatures, chemicals, and mechanical stress. It offers outstanding thermal stability with a continuous use temperature of up to 250°C, along with excellent chemical resistance against a wide range of aggressive substances.

PEEK exhibits high mechanical strength and rigidity, maintaining dimensional stability and reliability even under extreme conditions. As a result, it is widely used across aerospace, medical devices, automotive, and electronics industries. In addition, its low coefficient of friction and superior wear resistance make it ideal for manufacturing precision components that require high durability and long-term performance.

Overview of PEEK Material

Definition and Chemical Structure

Polyetheretherketone (PEEK) is a high-performance specialty engineering plastic that belongs to the family of semi-crystalline aromatic polymers. Its chemical structure consists of repeating ether and ketone linkages arranged alternately, with benzene rings embedded in the molecular chain. This unique configuration endows PEEK with outstanding comprehensive properties. The molecular formula of PEEK is:

The presence of benzene rings contributes to its excellent thermal and chemical stability, while the ether and ketone groups provide flexibility and mechanical strength.


Development History
The development of PEEK materials can be traced back to the 1970s. In 1978, the British company Imperial Chemical Industries (ICI) first synthesized PEEK and commercialized it in 1982. Initially, PEEK was primarily used in the aerospace industry due to its excellent high-temperature resistance, corrosion resistance, and high mechanical strength. It served as a lightweight alternative to traditional metal materials, effectively reducing the weight of aircraft. With continuous technological advancements and decreasing production costs, the application of PEEK has gradually expanded into various fields such as automotive, electronics, medical, and machinery.

Processability of PEEK Material
Injection Molding
PEEK exhibits excellent injection molding properties, allowing efficient production of complex and high-precision components for a wide range of industries.

Processing Temperature Range:
PEEK typically requires an injection molding temperature between 360°C and 400°C. This high processing range ensures thorough melting and flow of the material while preventing thermal degradation.

Flowability:
PEEK has good melt flow properties, with a melt flow rate (MFR) ranging from 0.5 to 2.0 g/10min. This allows it to effectively fill intricate mold cavities and produce thin-walled, fine-structured parts.

Shrinkage Rate:
PEEK exhibits low shrinkage during injection molding—generally between 0.5% and 0.8%. This results in minimal dimensional changes upon cooling and ensures high dimensional accuracy, which is especially important for aerospace and electronic components.

Mold Requirements:
Due to its high processing temperature, molds used for PEEK need to be made from high-strength, heat-resistant steels, such as H13 or SKD61, and should be equipped with efficient cooling systems to optimize cycle times. Proper mold design can reduce the molding cycle by over 20%.

Application Example:
In the automotive industry, PEEK is injection molded to produce engine sensor housings. Its high strength and thermal stability ensure reliable operation under high-temperature, high-load conditions.

Extrusion Molding
PEEK extrusion molding is primarily used for manufacturing continuous products such as pipes, sheets, and films, offering high productivity and consistency.

Processing Temperature:
The typical extrusion temperature for PEEK ranges from 340°C to 380°C, ensuring good melt flow and formability during processing.

Extrusion Speed:
PEEK can be extruded at relatively high speeds. For instance, PEEK tubing can be produced at speeds of up to 10 meters per minute, supporting large-scale production.

Product Performance:
Extruded PEEK pipes and sheets offer excellent mechanical strength and chemical resistance. For example, PEEK tubing can achieve tensile strengths up to 120 MPa and is capable of transporting corrosive media such as strong acids and alkalis.

Application Example:
In the electronics industry, PEEK films are used as insulation layers due to their outstanding electrical insulation and thermal resistance. In flexible circuit boards, PEEK films can operate at temperatures up to 200°C while maintaining excellent dielectric properties.

Die Design:
The design of extrusion dies is crucial to the quality and performance of PEEK products. For example, tubing dies must precisely control the dimensions and gap between the die and mandrel to ensure uniform wall thickness and dimensional accuracy.

Other Processing Methods
Beyond injection and extrusion molding, PEEK can be processed using several other methods to meet diverse application needs.

Machining:
PEEK offers good machinability and can be turned, milled, drilled, and shaped into high-precision parts. In the aerospace sector, for instance, PEEK is used to produce engine blades with dimensional tolerances of ±0.01 mm through precision machining.

3D Printing:
With advancements in additive manufacturing, PEEK is increasingly used in 3D printing to produce complex or customized components. Typical printing temperatures range from 380°C to 420°C, and the printed parts exhibit excellent mechanical and thermal properties.

Welding:
PEEK can be joined using ultrasonic or thermal welding methods. In electronics housings, PEEK parts welded by ultrasound can achieve joint strengths exceeding 80% of the base material’s strength.

Coating:
PEEK can also be applied as a coating material using spraying or dip-coating methods, offering heat resistance, corrosion resistance, and wear protection. For example, PEEK coatings on metal mechanical components significantly improve their wear resistance and extend service life.

Application Fields of PEEK Material
Aerospace Industry
PEEK plays an irreplaceable role in the aerospace sector due to its outstanding combination of properties.

Lightweight and High Performance:
With a density of only 1.3 g/cm³—significantly lower than traditional metals—PEEK offers comparable strength and stiffness. For example, in aircraft engine blades, using PEEK can reduce weight by up to 30% without compromising structural integrity. This contributes to improved fuel efficiency and reduced operational costs.

High Temperature and Thermal Stability:
Aerospace components demand superior heat resistance. PEEK has a glass transition temperature of 143°C and a melting point of 343°C. It retains excellent mechanical properties and dimensional stability under high temperatures. In engine components, PEEK can operate continuously at 200°C for 1,000 hours with less than 5% performance degradation.

Chemical Resistance and Hydrolysis Resistance:
Aircraft are exposed to various chemicals and moisture during flight. PEEK's excellent chemical resistance and hydrolytic stability make it ideal for such environments. After 1,000 hours of immersion in hot water, PEEK retains up to 80% of its tensile strength, making it suitable for hydraulic and fuel system components.

Application Example:
In the Boeing 787, PEEK is widely used in engine blades, wing skins, and fuselage components. It is estimated that PEEK accounts for about 20% of the material composition in the Boeing 787, significantly enhancing performance and safety.

Medical Devices
PEEK is increasingly used in the medical field due to its biocompatibility and resistance to degradation.

Biocompatibility:
PEEK is well tolerated by human tissues, with no irritation or toxicity. It holds a cytotoxicity rating of Class 1, indicating excellent compatibility with body tissues and minimal risk of inflammation or adverse reactions.

Corrosion Resistance:
Medical devices often come into contact with bodily fluids and chemicals. PEEK maintains excellent chemical stability—after immersion in 10% hydrochloric acid and sodium hydroxide solutions for 1,000 hours, mass change remains below 0.5%.

Mechanical Strength:
PEEK’s high tensile strength (over 100 MPa) and flexural modulus (up to 3.5 GPa) allow it to withstand internal mechanical loads in the body, making it ideal for implants such as artificial joints.

Application Example:
PEEK is widely used to manufacture artificial joints, spinal implants, and dental implants. Global usage of PEEK in medical implants exceeds 1,000 tons annually and is growing steadily. For instance, artificial hip joints made from PEEK demonstrate excellent clinical performance and a service life of over 20 years.

Automotive Industry
PEEK is extensively applied in automotive manufacturing thanks to its strength, heat resistance, and wear performance.

High Temperature and Thermal Stability:
Engine and transmission components operate in high-temperature environments. PEEK’s high Tg and melting point ensure reliable performance under such conditions (as detailed earlier).

Wear Resistance and Mechanical Strength:
PEEK demonstrates excellent wear resistance under high-load, high-frequency friction. For example, in transmission gears, the wear of PEEK parts is only 1/10 that of traditional metals.

Lightweight and Fuel Efficiency:
Reducing vehicle weight improves fuel economy and lowers emissions. PEEK helps achieve this goal by replacing metal components while maintaining mechanical performance.

Application Example:
PEEK is used in engine components, transmission gears, and sensor housings. A well-known automaker uses PEEK to mold engine sensor housings that can operate reliably for over 10 years under high heat and stress. It is also applied in braking systems—PEEK brake discs and pads offer excellent durability and performance due to their heat and wear resistance.

Introduction
Polyphenylene Sulfide (PPS) is a semi-crystalline thermoplastic engineering polymer composed of alternating benzene rings and sulfur atoms in its molecular backbone, with the structural formula -[Ph-S]n- (Ph representing a phenyl ring). This unique combination of rigidity and stability has earned PPS the nickname “Plastic Gold.”

PPS Long Glass Fiber Reinforced

Four Core Properties of PPS
1. High Temperature Resistance
Heat Deflection Temperature (HDT):

≥260°C (unreinforced), with a continuous use temperature of up to 220°C.

Thermal Aging Resistance:

Maintains 80% or more of its mechanical strength even after 1,000 hours of exposure at 200°C.


2. Chemical Stability
Corrosion Resistance:

PPS resists acids, bases, and organic solvents (e.g., gasoline, ethanol). It corrodes only slowly in strong oxidizing media such as concentrated sulfuric or nitric acid.

Hydrolysis Resistance:

PPS exhibits excellent stability in high-temperature and high-pressure steam environments, making it ideal for extreme conditions such as deep-sea applications or chemically aggressive industrial environments.


3. Mechanical Performance
High Rigidity:

Pure PPS has a flexural modulus of about 3.8 GPa. When reinforced with glass fiber (e.g., PPS GF40), it can reach 12–15 GPa—comparable to aluminum alloys.

Wear Resistance:

With a low coefficient of friction (0.02–0.03), PPS significantly extends the lifespan of moving components like gears and bearings—by more than 30%.


4. Flame Retardancy & Electrical Properties
Flame Rating:

UL94 V-0 at 1.5 mm thickness, without the need for additional flame retardants.

Dielectric Strength:

18–22 kV/mm, making it an excellent insulator for high-frequency electronic components.

Modification Directions and Processing Techniques
Modification Technologies

Extensive Applications of PPS Across Various Fields
1. Electronics and Electrical Industry
Semiconductor Packaging:

With high heat resistance (>260℃), PPS provides excellent protection for chips against damage caused by soldering thermal stress, such as in CPU packaging housings.

High-Frequency Connectors:

Featuring low moisture absorption (<0.05%), PPS ensures signal stability even in humid environments, making it ideal for use in 5G base stations and smartphones.


2. Automotive Industry
Engine Components:

PPS can withstand high temperatures up to 220℃ and is suitable for use in turbocharger housings, fuel injectors, and other segments. It can replace metals and reduce component weight by up to 40%.

Electrification Trend:

With inherent flame-retardant properties under high-voltage conditions, PPS is applicable in electric vehicle charging station insulators, battery module brackets, and other components requiring high flame resistance.


3. Aerospace
Lightweight Structural Components:

PPS has a density of 1.34 g/cm³, offering up to 50% weight reduction compared to standard aluminum alloys. It is suitable for lightweight applications such as aircraft interior brackets and satellite radomes.

Radiation Resistance:

Due to its ability to resist cosmic rays and extreme temperature fluctuations, PPS can be used as a substrate material for spacecraft circuit boards.


4. Environmental Protection and Chemical Industry
Corrosion-Resistant Piping:

In chemical pipelines transporting concentrated hydrochloric acid and organic solvents, PPS pipes offer a service life twice that of stainless steel.

For more information on PPS long glass fiber and long carbon fiber reinforced materials, please contact our technical experts. We are committed to providing professional support and customized material solutions to meet the specific demands of your application.

Aluminum Nitride (AlN) crystallizes in a hexagonal structure, typically appearing bluish-white in pure form but often gray or off-white in practice. As a high-performance advanced ceramic material, AlN boasts exceptional thermal conductivity, reliable electrical insulation, low dielectric constant and loss, non-toxicity, and a thermal expansion coefficient that matches silicon. These outstanding properties make it an ideal choice for next-generation high-integration semiconductor substrates and electronic packaging materials. Below is a brief introduction to the preparation of AlN.

Synthesis of AlN Powder

AlN powder serves as the foundational raw material for ceramic products. Its purity, particle size, oxygen content, and impurity levels significantly impact the thermal conductivity, sintering process, and forming techniques of the final product, ultimately determining its performance. Key methods for synthesizing AlN powder include:

1. Direct Nitridation Method
   Aluminum powder reacts with nitrogen gas at high temperatures (800°C–1200°C) to form AlN powder.

2. Carbothermal Reduction Method
   A mixture of alumina (Al₂O₃) and carbon powders undergoes reduction and nitridation in a flowing nitrogen atmosphere at elevated temperatures (1400°C–1800°C) to produce AlN powder.

3. Self-Propagating High-Temperature Synthesis (SHS)
   This method leverages the highly exothermic reaction between aluminum powder and nitrogen. Once ignited, the reaction sustains itself, rapidly synthesizing AlN.

4. Chemical Vapor Deposition (CVD)
   Volatile aluminum compounds react with nitrogen or ammonia gas, depositing AlN powder from the vapor phase. Depending on the aluminum source, CVD can be classified into inorganic (e.g., aluminum halides) and organic (e.g., alkyl aluminum) methods.

This advanced material is revolutionizing electronics with its superior properties—choose AlN for high-performance, reliable solutions in semiconductor and packaging applications!

Xiamen Juci Technology Co., Ltd. uses the carbothermal reduction method to prepare aluminum nitride powder. The synthesized powder has high purity, stable performance, fine and uniform particle size, and can be used to prepare high-grade powder.Xiamen Juci Technology, as a leading supplier of aluminum nitride powder in China, is committed to providing high-purity and high-grade aluminum nitride thermal management materials both at home and abroad.

Media Contact:
Xiamen Juci Technology Co., Ltd.

Phone: +86 592 7080230
Email: miki_huang@chinajuci.com

Website: www.jucialnglobal.com

Chloroprene rubber (CR) is an important variety of synthetic rubber. It stands up well to light, aging, flexing, acids, bases, ozone, flames, heat, and oil. It also has good physical and electrical properties. Its comprehensive performance is unmatched by natural rubber and other synthetic rubbers. It is widely used in defense, transportation, construction, light industry and military industry. Chloroprene rubber has several uses. It's a key element in making auto parts, machinery, industrial items, and adhesives. You'll also find it in construction materials, coated fabrics, and wire and cable insulation. By itself, chloroprene rubber is used to create rubber harness clips and shock absorbers for cars and farm equipment. Initially, chloroprene rubber from Japan's DENKA and Japan's Toyo Soda was used. Later, due to the increase in raw material prices and the restrictions of the procurement cycle, a series of research and development work on the replacement of imported chloroprene rubber with domestic chloroprene rubber was carried out. Finally, the replacement goal was successfully achieved, and some process and formula problems of domestic chloroprene rubber in the use process were solved.

1. Neoprene rubber model

Imported neoprene rubber model: Denka M120 Chloroprene Rubber, a product of Japan DENKA, light-colored blocks; B-10, a product of Japan Toyo Soda, light-colored blocks. Domestic neoprene rubber model: CR3221, a product of Chongqing Changshou Chemical Co., Ltd. Polychloroprene Rubber CR3221 is a chloroprene polymer with sulfur and diisopropyl xanthate disulfide as mixed regulators, with a low crystallization rate, a relative density of 1.23, beige or brown blocks, and a non-polluting type.

2. Production process performance comparison

Imported neoprene handles better during production. For example, the raw rubber pieces do not stick together, even after baking, which makes them easy to measure. The process is smooth; it does not stick to the roller, so removing it is simple. The semi-finished film is stiff and holds its shape well.

Domestic neoprene does not perform as well. The rubber pieces tend to stick, especially after baking. The rubber also sticks to the roller, which makes removal hard, and the semi-finished film sticks easily and loses its shape.

Despite these things, domestic neoprene has some benefits. It mixes powder faster and with less effort in both internal and open mixers. Rubber from Japan is harder to mix. In the open mixer, M-120 can even fall off the roller at first. The internal mixer requires more effort and time, especially in the winter. Domestic mixed rubber still works well after being stored for a long time. Rubber from Japan, especially M-120, gets hard and loses its flexibility after two to four weeks.

Tests show that production methods that work for imported neoprene do not work well for domestic neoprene. The original method needs some changes. If not, it will be hard to make it work for production, even when the physical and mechanical qualities meet the standards.

3.  Conclusion

Compared with Japanese chloroprene rubber, domestic chloroprene rubber CR3221 has lower Mooney viscosity and greater viscosity, which is more favorable for mixing and powder consumption, and can significantly reduce the operation time, but the processability is poor and the operation is difficult. If the temperature is not well controlled, the operation is improper or the rubber is over-mixed, it may cause the roller to stick or even fail to unload normally. By selecting the correct process conditions and methods and adjusting the formula appropriately, it can fully meet the production needs.

Website: www.elephchem.com

Whatsapp: (+)86 13851435272

E-mail: admin@elephchem.com

Chloroprene adhesive is popular in the shoemaking industry because it bonds materials very well. Among them, grafted chloroprene adhesive is the most widely used. As shoe materials develop towards lighter colors, the color requirements for adhesives are becoming more and more stringent. Right now, SN24 adhesive starts out light, but it yellows pretty fast after sitting around for a while, especially if it's in the sun. After being prepared into chloroprene adhesive, there is a yellowing problem, which leads to two problems: first, it affects the appearance of shoes. For light-colored shoes such as sports shoes and travel shoes, the problem is more prominent; second, the darkening of color is a manifestation of polymer aging, which leads to the deterioration of the bonding performance of the adhesive. Therefore, in order to improve the appearance of footwear and ensure that it does not turn yellow during wearing, a yellowing-resistant adhesive should be used.

1. Experimental materials

Chloroprene rubber latex: Chloroprene Rubber SN-242, Sana Synthetic Rubber Co., Ltd.; toluene, methyl methacrylate, butanone, BPO, SKYPRENE G-40S; Denka A90 Chloroprene rubber

2. Performance test results

2.1 Comparison of glue solutions

The different types of dry glue obtained by the drum were dissolved in toluene to obtain the glue solution comparison chart in Figure 1, and the comparison chart of different types of glue solutions after heating is shown in Figure 2.

As can be seen from Figure 1, the color of the glue solution in this experiment is not much different from the color of the same type of glue solution at home and abroad. After adding BPO and MMA and shaking well, the color will change.After being tested, SN242A became yellow. Domestic rubber samples No. 2 and No. 3 also turned yellow. The other samples got a bit darker, but our test rubber was still lighter than domestic rubber No. 4. Its color was close to that of samples No. 7 and No. 8.After 20 minutes in a 90℃ oven, rubber samples No. 1, 2, 3, and 5 turned yellow. Samples No. 4, 6, 7, and 8 got lighter. After an hour, the colors changed in the same way, but everything was darker than it was at 20 minutes.As you can see in Figures 1 and 2, when this test rubber was dissolved in toluene and heated with an initiator, it looked a little whiter than similar domestic glues. It looked about the same as similar foreign glues.

2.2 Grafting comparison

According to the grafting formula, 0.1 parts of BPO and 50 parts of methyl methacrylate were added, and different types of chloroprene rubber were grafted. The viscosity of the solution before and after grafting was measured, as shown in Table 4. The comparison between the experimental glue and the domestic glue after grafting is shown in Figure 3.

Figure 3 presents a comparison between our experimental glue and a domestic glue following grafting.When exposed to free radicals, the unsaturated double bonds on the chloroprene rubber backbone transform the MMA monomer into a monomer free radical. This then grafts and copolymerizes with CR through a chain transfer reaction, creating a complex graft copolymer. This process leads to asymmetry and polarity in the adhesive structure, improving adhesion.

Based on the data in Table 5, our experimental glue shows a high grafting rate, nearly 100%. This solves the issue of low grafting rates seen with SN242, which stem from residual terminators. Plus, it eliminates the problem of red glue forming during the grafting process. Figure 3 is a comparison chart of the grafted glue solution after being placed in the sun for several days. The color of the experimental glue solution is much lighter than that of SN242.

2.3 GPC comparison

According to Figure 4 and Table 5, the relative molecular weight and relative molecular weight distribution of the experimental glue are not much different from those of foreign glue. The average relative molecular weight is around 350,000, and the relative molecular weight distribution is below 2.3, which is larger than the relative molecular weight of domestic grafted glue, and the relative molecular weight distribution is narrow, and the regularity of the molecular chain is higher.

2.4 DSC comparison

Based on the data in Figure 5 and Table 5, the experimental glue's glass transition temperature is similar to both domestic and foreign glues. The experimental glue's crystallization temperature, which is higher than the domestic glue, is nearly the same as the foreign glue.

3 Conclusion

The chloroprene rubber adhesive developed in this paper has excellent yellowing resistance and stable grafting performance. Through DSC and GPC analysis, grafted chloroprene rubber with uniform relative molecular weight and high regularity was obtained, and its performance is comparable to that of the same type of foreign rubber.

Website: www.elephchem.com

Whatsapp: (+)86 13851435272

E-mail: admin@elephchem.com

Aluminum Nitride (AlN) performance critically depends on purity, particularly the content of oxygen (O), carbon (C), and metal impurities (Fe, Na, etc.).

Oxygen impurities → Form Al₂O₃ or AlON phases, significantly reducing thermal conductivity (every 1% increase in oxygen decreases thermal conductivity by 10-20 W/(m·K)).

Metal impurities → Degrade carrier mobility in semiconductor devices, reducing performance.

Carbon impurities → Generate Al₄C₃ at high temperatures, causing material embrittlement.

Currently, commercial AlN powder typically has a purity of 99.5%-99.9% (oxygen content >0.5%), while high-end applications (e.g., semiconductor substrates) require oxygen content <0.1%, even <100ppm.

How to Achieve High-Purity Aluminum Nitride?

1. AlN Powder Purification Techniques

①Surface Modification (H₃PO₄ Treatment)

Phosphoric acid (H₃PO₄) forms a protective layer on AlN, inhibiting hydrolysis (reducing Al₂O₃ formation).

Advantage: Simple operation, suitable for industrial production.

Limitation: Cannot remove oxygen impurities inside the crystal lattice.

②High-Temperature Heat Treatment (2000-2200°C)

Heat treatment in a reducing atmosphere (H₂/N₂) to volatilize impurities.

Result: Oxygen content can be reduced to 220ppm, metal impurities <1ppm.

Challenge: Requires advanced equipment (tungsten crucible), AlN sublimation loss (~0.5-1%/h at 2200°C).

2. AlN Ceramic Purification Techniques

①NH₄F Sintering Additive

NH₄F decomposes into NH₃ & HF, reacting with Al₂O₃ to form volatile byproducts (e.g., AlF₃), reducing oxygen content.

Advantage: No new impurities introduced, enhances ceramic purity.

②High-Temperature Annealing

Heat treatment at 1800-1900°C to volatilize grain boundary phases, optimize microstructure, and improve thermal conductivity.

Future Trends: Higher Purity, Lower Cost

Advanced Purification Methods: Plasma-assisted purification, solvent extraction, CVD (Chemical Vapor Deposition) for ultra-pure AlN films.

Scalable Production: Optimized high-temperature processes to reduce AlN loss and costs.

Composite Materials: AlN-Graphene, AlN-SiC hybrid thermal materials for enhanced performance.

Conclusion: Aluminum Nitride – The Core Material for Future Technology

With the rapid growth of 5G, electric vehicles (EVs), deep-UV LEDs, and aerospace technologies, the demand for high-purity AlN will surge. Through advanced purification and sintering techniques, AlN will play a pivotal role in:

① Semiconductor devices (GaN-on-AlN, power electronics)

② High-power RF & 5G base stations

③EV power modules & thermal management

④Deep-UV LED substrates (UVC disinfection)

⑤Aerospace & extreme-environment applications

About Xiamen Juci Technology

Xiamen Juci Technology Co., Ltd. is a high-tech enterprise specializing in the research and development, production and sales of high-performance aluminum nitride (AlN) ceramic materials. The company is committed to providing high thermal conductivity and high purity aluminum nitride ceramic solutions for fields such as 5G communication, semiconductor packaging, power electronics, new energy vehicles, and aerospace. We can provide AlN substrates, structural components and functional devices of different specifications according to customer requirements.

Media Contact:
Xiamen Juci Technology Co., Ltd.

Phone: +86 592 7080230
Email: miki_huang@chinajuci.com

Website: www.jucialnglobal.com

Project Background

In high-performance bicycle design, the brake lever is not only a key control component but also directly impacts riding safety and handling precision.

Traditional materials often fail to balance lightweight and strength, whereas long fiber reinforced thermoplastics offer outstanding rigidity, impact resistance, and fatigue durability, making them ideal alternatives to metals or short-fiber plastics.

Materials such as PA66 with long carbon fiber or TPU with long glass fiber can significantly enhance structural performance while improving molding efficiency and surface quality—perfectly aligning with modern demands for safety, lightweight design, and aesthetics.

Customer's Project

The products shown above are two types of bicycle brake levers, respectively manufactured using PA66 filled with 40% long carbon fiber (without color masterbatch) and polyether-based TPU filled with 50% long glass fiber (with black color masterbatch).

Each material offers unique advantages, allowing customers to choose the most suitable option based on their specific performance requirements.

Material 1: TPU-LGF50-BLK
Material:

Polyether-based TPU filled with 50% long glass fiber (with black color masterbatch)

Key Features:
1. Finished in a deep matte black tone, this version delivers a sleek, modern look with a smoother surface texture.

2. Offers a slightly flexible feel for enhanced grip comfort, while still maintaining significant structural integrity thanks to the high glass fiber content.

Performance Highlights:
1. Exceptional impact resistance and abrasion resistance

2. Improved surface comfort, ideal for frequent contact or high-vibration environments

3. Perfect for applications where tactile feel, flexibility, and weather resistance are key considerations

Click the material image to see details

Material 2: PA66-LCF40-NAT
Material:

PA66 filled with 40% long carbon fiber (no color masterbatch)

Key Features:
1. This brake lever features a natural finish that highlights the carbon fiber texture, clearly visible on the surface.

2. The unique grain of the long carbon fibers offers a premium look and feel, echoing the aesthetics of carbon fiber parts in professional cycling equipment.

Performance Highlights:
1. Excellent rigidity and strength, ideal for high-load applications

2. Superior heat resistance and dimensional stability

3. Best suited for riders or product designs that demand lightweight structural strength and a carbon-tech appearance

Click the material image to see details

Advantages

Lightweight Metal Replacement
1. Both PA66-LCF40-NAT and TPU-LGF50-BLK offer significant weight reduction compared to traditional aluminum alloy or steel brake levers.

2. PA66-LCF40-NAT provides high stiffness at low density, reducing overall component weight without sacrificing mechanical strength.

3. This lightweight solution helps improve riding efficiency and handling agility, especially in competitive or endurance cycling.

Integrated Cost Efficiency
1. Long fiber thermoplastics allow one-step injection molding, eliminating the need for secondary assembly or metal machining.

2. This streamlines production and reduces tooling complexity.

3. Compared with aluminum or engineering plastics, the total cost is significantly optimized.

Durability in Harsh Conditions
1. These materials are designed to perform reliably under outdoor and high-vibration environments, such as mountain biking or long-distance rides.

2. PA66 offers superior resistance to fatigue, heat, and moisture.

3. TPU brings added flexibility, shock absorption, and grip comfort, ideal for frequent user contact.

Design Flexibility & Customization
1. LFT-G supports custom formulations tailored to customer needs:

2. Color options (natural carbon fiber texture, matte black, etc.)

3. Surface finish customization (visible fiber pattern vs. smooth touch)

4. Optional UV or chemical resistance for extended product lifespan

Typical Application Scenarios
High-performance road or mountain bike brake levers

E-bike brake systems requiring vibration damping and rigid control

Ergonomic brake components for urban commuter bikes

Lightweight replacement of metal brake handles in mid- to high-end bicycles

Learn More
If you're exploring material solutions for bicycle components that require a balance of strength, durability, and processing efficiency, our formulations offer reliable, well-tested options.

We welcome you to get in touch for further technical details, sample requests, or to discuss specific application needs.