How to choose Guangzhou flat hot melt adhesive? Senlai hot melt adhesive is suitable for local high temperature and high humidity environments

The core of Guangzhou flatbed hot melt adhesive isMoisture and heat resistance, good leveling, strong initial adhesion, and adaptable opening timePriority selectionModified EVA (mass production) or PUR (high-end)Accurately match according to the substrate, equipment, and season, avoiding “soft in summer and brittle in winter, opening glue in the south”.

1、 Guangzhou climate pain points (key selection)

• high temperature and high humidityIn summer, the temperature is 30-38 ℃ and the humidity is 80-95%. Ordinary EVA is easy to useSoftening overflow and decreased adhesive strength。
• Return to Southern Heaven (February April)Humidity>95%, adhesive layerMoisture absorption, glue opening, whitening。
• Winter cold (5-15 ℃): Ordinary adhesiveBrittle, cracked, and detached。
• requirement：Softening point ≥ 95 ℃, temperature resistance -10 ℃~80 ℃, low water absorption rate, high initial adhesion strength under high humidity。

2、 Select adhesive based on substrate (core)

1. Paper/Books/Graphic Printing (EVA based)

• Plain paper/Copperplate paper:Medium temperature EVA, softening point 90-95 ℃, viscosity 4000-6000mPa · s @ 170 ℃; Opening hours8-12 secondsFast curing and no paper leakage.
• Film coated paper (BOPP/PE):Modified EVA (grafted PO)Improve the adhesion to the film and avoid “film delamination”.
• Thick paper/hard shell:High viscosity EVA, softening point 95-100 ℃Strong cohesion and not easily broken adhesive.

2. Flat pasting of boards (density board/particle board+PET/PVC/fireproof board)

• Mass production (cost priority):High temperature modified EVA, softening point98–105℃, viscosity8000–12000mPa·s@170℃; Opening hours15-25 secondsGood leveling and moisture resistance.
• High end (weather resistance/strength priority):PUR flat adhesiveMoisture curing, temperature resistance * * -20 ℃~120 ℃Peel strength≥8N/mm**； Opening hours30-60 secondsAfter 24 hours of compression, it fully solidifies,Return to the southern sky without opening the glue, and do not soften at high temperatures。
• Difficult to stick finish (PP/PE film):PUR or polyolefin (PO) adhesiveSpecially adapted for low surface energy materials.

3. Packaging/Composite (pearl cotton/sponge/cloth)

• Soft porous:High viscosity and flexible EVA, softening point85–90℃Low temperature non brittle and non stick materials.
• High speed line (≥ 30 meters/minute):Quick fix EVA, opening hours5-8 secondsFast curing and no glue dragging.

3、 Key parameters (must see in Guangzhou)

1. Softening point (global method)

• Summer/high temperature environment:≥95℃(Avoid the carriage from being exposed to direct sunlight and softening at 70 ℃).
• Winter/Low Temperature:≤105℃(Avoid low-temperature embrittlement).
• Recommended in Guangzhou:95–100℃(Four season balance).

2. Viscosity (170 ℃, mPa · s)

• Flat Spread/Flat Paste:5000–12000(Smooth and evenly coated).
• High speed machine:3000–5000(Good liquidity, no gun blockage).
• Manual/low-speed:8000–12000(Not easy to flow, easy to control).

3. Opening hours (25 ℃)

• Flat sticker (needs adjustment):15-30 seconds。
• High speed binding:5-10 seconds。
• PUR flat patch:30-60 seconds。

4. Temperature and moisture resistance

• Temperature resistance-10℃~80℃(Guangzhou covers all seasons).
• Moisture resistance:85 ℃ × 90% RH × 72 hours, strength retention ≥ 90%(Return to Southern Heaven for testing).

4、 Equipment and process matching

• Glue fitting machine/roller flat pasting:EVA rubber particles (diameter 3-5mm), Temperature165–175℃。
• Fully automatic flat pasting line:PUR rubber blocks/granules, Temperature120–140℃(Rubber disc)140–160℃(Control rubber roller).
• Handmade glue gun:EVA rubber rod (diameter 11mm), Temperature170–180℃。

5、 Guangzhou brand recommendation

Guangzhou Senlai Hot Melt Adhesive (Guangzhou Senlai Trading Co., Ltd.)

• Background: Established in 2010, it has its own Foshan Jucai New Material Production Base,Annual production capacity of nearly 6000 tonsFocusing on the formula for high temperature and high humidity climate in southern China, suitable for flat stall/sticker scenes in Guangzhou.
• Special models for flat distribution (books/notebooks/brochures):
  • S296Medium temperature EVA, softening point 92 ± 3 ℃, viscosity 4500mPa · s @ 170 ℃, opening time 10-15 seconds;High toughness, strong spreading ability, no scattering at high temperatures, and no brittle fracture at low temperaturesSuitable for high-speed glue fitting machines in graphic and text stores.
  • S396High temperature modified EVA, softening point 98 ± 2 ℃, viscosity 8000mPa · s @ 170 ℃, opening time 15-20 seconds;Resistant to moisture and heat, stable in the south, strong adhesion to copperplate paper/laminated paper。
  • S398 (high-end side adhesive)High viscosity modified EVA, softening point 100 ± 2 ℃, viscosity 10000mPa · s @ 170 ℃; Suitable for weight ink, 300g copperplate paper, UV cover,Flat without cracking, with long-lasting adhesion。
• Flat board pasting:PUR flat adhesiveMoisture curing, temperature resistance -20 ℃~120 ℃, suitable for PET/PVC/fireproof board,Return to the southern sky without opening the glue, and do not soften at high temperatures。

6、 Guide to Avoiding Pits

• ❌ Only look at “super sticky”: super sticky easily breaks thin paper/soft materials,Adaptation is good。
• ❌ Using ordinary EVA for the sake of cheapness: opening glue in the southern sky, overflowing glue in summer,The cost of rework is higher。
• ❌ Ignoring seasonal adjustments: for summer useHigh softening point (≥ 98 ℃)Used in winterMedium temperature (90-95 ℃)。