From Sticking to Release: A Practical Guide to Selecting Rubber High-Temperature Vulcanization, Hose Mandrel, and Extrus

1. Introduction: The Release Challenge Behind Every Rubber Hose

In the rubber production chain, release agents are often overlooked—until problems occur.

In tire plants, when the curing bladder sticks to the green tire, defects such as missing rubber or bladder tearing can occur. Replacing a bladder costs hundreds to thousands of dollars, and the downtime loss is several times the bladder cost itself. In hose factories using the mandrel method, after vulcanization, the hose cannot be easily stripped from the metal mandrel. Workers pry and pull forcefully, causing damage, deformation, and a high scrap rate. In extrusion, freshly extruded hose is hot and tacky. After coiling and storage for a few hours, the layers stick together. When separated, the surface tears and interlayer adhesion occurs, forcing downgrading or rework.

The root cause often points to the same link: improper selection or use of release agents. This article focuses on three product categories—high-temperature vulcanization release agents, hose mandrel release agents, and hose extrusion release agents—and provides systematic selection ideas and practical recommendations based on customer pain points, market data, and real cases.

2. Market Demand and Trends: Structural Changes in the Release Agent Industry

2.1 Global Market Size Data

In 2026, the global rubber release agent market is estimated at USD 4.78 billion, up 8.1% from USD 4.42 billion in 2025. China, as the world's largest rubber products producer, accounts for 32.5% of global release agent consumption, with a market size of USD 1.55 billion in 2026.

By product category, powder release agents still hold the largest share, with global demand of USD 2.23 billion in 2026, growing at 6.2%. However, liquid release agents, due to their advantages in precision rubber products, are growing at 9.8%, reaching USD 1.46 billion. Semi-solid release agents maintain stable growth in specialty rubber processing, with a market size of about USD 1.09 billion in 2026.

2.2 Accelerating Product Structure Upgrade

Global demand reached 1.824 million tons in 2026, a year-on-year increase of 7.3%. The Asia-Pacific region contributed 54.6% of demand, with China, India, and Southeast Asian countries growing at 8.1%, 10.3%, and 7.9% respectively due to tire capacity shifts and infrastructure demand.

The product structure is shifting toward eco-friendly, low-VOC solutions. Water-based system penetration rose from 41% in 2023 to 56% in 2026. This trend is driven by continuous updates to EU REACH regulations and China's carbon peak and neutrality goals, which are raising energy efficiency standards for rubber processing. In January 2026, the EU tightened the limit for polycyclic aromatic hydrocarbons in rubber additives from 50 ppm to 10 ppm, directly replacing about 12% of ordinary products in the European market.

2.3 Segmented Growth of Vulcanization Release Agents

Tire curing bladder release agents are a high-growth segment. In 2025, global sales of tire curing bladder release agents reached USD 187 million and are projected to reach USD 304 million by 2032, with a CAGR of 7.3%. This growth rate is significantly higher than the overall release agent market average, reflecting the urgent need in the tire industry to protect bladders, extend service life, and improve curing efficiency.

In terms of technology routes, global public patents related to rubber release agents reached 1,207 between 2025 and 2026, with China accounting for 48.3%. The main directions are nano-encapsulation, biodegradable carriers, and automated spraying devices.

3. In-Depth Analysis of Three Major Products

3.1 Rubber High-Temperature Vulcanization Release Agent: Core of Bladder Protection and Release Efficiency

3.1.1 Industry Term Definition

High-temperature vulcanization release agent refers to a chemical formulation applied to the surface of a tire curing bladder or the inner wall of a green tire. Under high-temperature curing conditions (110–230°C), it can crosslink on the bladder surface to form a protective film. Its core functions are to prevent sticking between the bladder and green tire, provide high-temperature lubrication, and extend bladder life.

Reactive release agent is the most technically advanced category. After application, it does not simply cover physically but chemically crosslinks with the bladder surface at curing temperature, forming a more adherent protective film. Permanent release agents can be applied once and used for hundreds of curing cycles, reducing overall production costs.

3.1.2 Core Customer Pain Points

The most troublesome issues in tire curing workshops are concentrated in three areas:

Pain Point 1: Short bladder life and frequent replacement. New bladders without release treatment repeatedly rub and stick against green tires in the high-temperature curing environment. The surface is prone to cracking and chemical corrosion. Test data show that using a high-quality release agent can increase bladder life by about 30%.

Pain Point 2: Poor release causing appearance defects. When the release agent is unevenly sprayed, the bladder sticks to the tire, causing chunking, missing rubber, and shoulder blistering, leading to early bladder damage.

Pain Point 3: Harsh working conditions during on-site application. Traditional methods require application next to the hot curing press, resulting in high labor intensity and safety risks.

3.1.3 Product Comparison Table

3.1.4 Operation Steps

Step 1: Clean the bladder surface. Before first use, remove dust and oil from the new bladder to ensure film adhesion.

Step 2: Pre-coating treatment. Apply the release agent evenly with a special glove. Over-application or missed spots will affect release. After coating, stretch the bladder several times, then close the mold and preheat for 20 minutes.

Step 3: Coat the green tire inner wall. Use a release agent glove to apply along the inner liner splice direction.

Step 4: Interval use. Generally, every 10th green tire is coated with release agent. Adjust frequency based on production conditions.

Step 5: Check coating quality. Ensure even and adequate coverage; avoid missed areas.

3.1.5 Quantitative Data

With release agent FBP-202, continuous release cycles can exceed 100 times with excellent release performance. Using a viscous treatment combined with glove application can enhance effectiveness and reduce usage, while facilitating continuous and automated production.

3.2 Hose Mandrel Release Agent: From "Prying and Pulling" to Smooth Stripping

3.2.1 Industry Term Definition

Hose mandrel release agent refers to a water-based release and lubrication product applied to the surface of a metal mandrel or fiber-reinforced plastic core. It provides lubrication before vulcanization and facilitates hose removal after vulcanization. Core requirements: good lubrication, easy release, no contamination of the product surface, and no interference with subsequent vulcanization bonding.

3.2.2 Core Customer Pain Points

Pain Point 1: Difficult stripping and high scrap rate. After vulcanization, the hose tightly grips the metal mandrel. Without effective release lubrication, stripping damages the hose and causes deformation.

Pain Point 2: Silicone residue affects downstream processes. Traditional silicone oil release agents have good release but leave silicone residue on the hose surface, forming an isolation layer that affects subsequent joint bonding, coating, and other processes, causing poor adhesion.

Pain Point 3: More difficult release for complex shapes. Corrugated and irregular cross-section hoses have complex mandrel shapes, greater release resistance, and higher requirements for lubricity and uniformity.

3.2.3 Selection Guide Table

3.2.4 Operation Steps

Step 1: Prepare the solution. The release agent can be used directly or diluted with water. The dilution ratio is generally controlled within 1:1.

Step 2: Clean the mandrel. Before use, clean the mandrel surface to remove dust, oil, and residual silicone-based release agents.

Step 3: Apply the release agent. Use dipping, brushing, or spraying to evenly coat the mandrel surface. Ensure uniform and adequate coverage.

Step 4: Mount and vulcanize. After coating, proceed with mounting. The lubricating film makes mounting smoother.

Step 5: Inspect after stripping. After vulcanization, check the hose inner surface for residue, tears, or deformation.

3.3 Rubber Hose Extrusion Release Agent: Integrated Cooling and Release

3.3.1 Industry Term Definition

Hose extrusion release agent refers to a water-based release product used in the cooling water trough after hose extrusion. It forms a release film on the hose outer surface while cooling, preventing interlayer sticking during coiling and storage.

3.3.2 Core Customer Pain Points

Pain Point 1: Semi-finished product sticking after extrusion. Freshly extruded hose is hot and tacky. After coiling and storage, layers stick together, causing surface tearing when separated.

Pain Point 2: Dust from traditional powder release agents. Talc and calcium powder create dust, worsening workshop conditions and affecting worker health. Powder release agents generally suffer from difficult dissolution, foaming, easy settling, and slow drying.

Pain Point 3: Foaming affects workshop cleanliness. When using spray equipment, silicone-free release agents tend to foam, affecting the workshop environment and spray uniformity.

Pain Point 4: Water-containing layer affects downstream processing. Traditional liquid release agents can leave a water-containing layer on the sheet surface. Residual liquid interferes with downstream extrusion and calendering, causing slipping, internal bubbles, and delamination.

3.3.3 Operation Steps

Step 1: Prepare the release solution. Dilute the release agent with water according to the hose compound and surface tackiness. SIP-30LT is recommended at 1:5; EFN-LJ25 is generally within 1:1.

Step 2: Fill the cooling trough. Pour the prepared solution into the immersion spray cooling trough at the end of the extrusion line, integrating cooling and release.

Step 3: Coat and dry. The extruded hose passes through the cooling trough and is evenly coated. Ensure sufficient drying time before coiling.

Step 4: Coil and store. After drying, the hose can be coiled and stored. The lubricating film prevents interlayer sticking.

4. Frequently Asked Questions (FAQ)

Q1: How much can a high-temperature vulcanization release agent extend bladder life?

A: Test data show that a high-quality release agent can increase bladder life by about 30%. Permanent products can be applied once and used for hundreds of curing cycles; some products achieve over 100 continuous release cycles. The exact improvement depends on bladder material, curing temperature, and operating conditions.