Tech Blog

Influential Factors on Melamine Moulding Compounds

Melamine moulding compounds are widely used in electronics, household utensils, and automotive parts due to their excellent heat resistance, flame retardancy, and electrical insulation. Incorporating bamboo powder into MF resin can reduce costs and improve sustainability, but the final product performance depends on four critical factors: bamboo powder ratio, drying time, NaOH concentration, and moulding powder fineness.

This article details the impact of each factor and practical optimization strategies for material researchers and manufacturers.

Background of Melamine Moulding Compounds with Bamboo Powder

Melamine moulding compounds are prepared by mixing MF resin with cellulose fillers, curing agents, and release agents, followed by drying, crushing, and hot-pressing. Bamboo powder is an ideal filler due to its low cost, wide availability, and renewable properties. It enhances the mechanical strength of the composite while reducing reliance on synthetic materials.

The performance of bamboo-reinforced MF moulding compounds is determined by the interaction between the filler and resin matrix. Key performance indicators include bending strength, impact strength, fluidity, mould shrinkage rate, boiling water resistance, and water absorption. This study tests these indicators under varying conditions to identify the optimal formulation.

Experimental Setup

Raw Materials & Equipment

Raw Materials: MF resin, industrial bamboo powder, analytical-grade NaOH, curing agents, and release agents.
Equipment: Drying oven, high-speed crusher, universal testing machine, plastic impact tester, constant temperature water tank, and hot press.

Preparation Process

Treat bamboo powder with 5%, 10%, or 15% NaOH solutions for 2h, rinse with water, and dry at 70℃ for 30h.
Mix treated bamboo powder with MF resin at different ratios (40%, 50%, 60%).
Dry the wet mixture at 70℃ for 4h, 6h, or 8h to control the moisture content (2%–5%).
Crush and sieve the mixture into 60-mesh, 80-mesh, or 100-mesh moulding powder.
Hot-press the powder at 150℃ and 32MPa (60s/mm) to form test specimens.

Performance Testing Standards

Bending strength: GB 9341
Impact strength: GB 1043
Water absorption/boiling water resistance/mould shrinkage/fluidity: GB 13454-92

Key Influential Factors on Melamine Moulding Compounds

Bamboo Powder Ratio: Balancing Strength & Fluidity

Bamboo powder acts as a reinforcing filler, but excessive content reduces moulding fluidity. Test results are shown in Table.

Bamboo Powder Ratio (%)	Bending Strength (MPa)	Impact Strength (kJ/m²)	Fluidity (mm)
40	52.31	1.7156	131
50	66.87	1.7532	122
60	72.53	1.9588	108

50% Ratio is Optimal: At 40%, strength is low; at 60%, fluidity drops sharply, making hot-pressing and mould filling difficult. The 50% ratio achieves a balance between high mechanical strength and sufficient fluidity for smooth moulding.

Drying Time: Controlling Moisture & Volatiles

Drying time affects the moisture content and volatile matter of the mixture, which in turn impacts mould shrinkage and product quality.

Drying Time (h)	Moisture Content (%)	Volatile Matter (%)	Mould Shrinkage Rate (%)
4	7.73	7.1	1.05
6	3.75	3.5	0.83
8	2.37	3.3	0.71

6h Drying is Ideal: Short drying time (4h) leads to high moisture and volatiles, causing bubbles during hot-pressing. A long drying time (8h) reduces moisture levels too much, weakening resin curing strength and extending production cycles. The 6h drying time controls moisture content at 3.75%, minimizing defects and ensuring efficient production.

NaOH Concentration:

NaOH treatment removes impurities (pectin, lignin) from bamboo powder, improving its compatibility with MF resin and enhancing composite performance.

NaOH Concentration (%)	Bending Strength (MPa)	Boiling Water Resistance	Mould Shrinkage Rate (%)
0	60.22	No blistering, no fading	0.87
5	66.23	Slight blistering	0.93
10	68.36	Slight blistering	0.63
15	70.56	Slight blistering	1.25

10% Concentration is Optimal: NaOH treatment improves bending strength by modifying the surface properties of bamboo powder. At 15%, the shrinkage rate increases significantly, causing product deformation. The 10% concentration provides high strength and low shrinkage, with acceptable boiling-water resistance.

Moulding Powder Fineness

Powder fineness affects the uniformity of the resin-filler mixture and the final product’s surface quality (Table 4).

Moulding Powder Fineness (mesh)	Bending Strength (MPa)	Mould Shrinkage Rate (%)	Appearance
60	68.22	0.98	Rough, dull
80	73.23	0.91	Smooth, dull
100	77.36	0.71	Smooth, glossy

100-Mesh Powder is Optimal: Finer powder mixes more uniformly with resin, enhancing bending strength and reducing shrinkage. The 100-mesh powder produces specimens with a smooth, glossy surface, meeting high-quality product requirements.

Optimal Formulation & Practical Applications

Optimal Formulation Summary

Factor	Optimal Parameter
Bamboo Powder Ratio	50%
Drying Time	6h (70℃)
NaOH Concentration	10%
Moulding Powder Fineness	100 mesh

Application Value

Cost Reduction: Bamboo powder is cheaper than synthetic fillers, lowering production costs while improving sustainability.
Performance Improvement: The optimal formulation meets GB 13454-92 standards, suitable for manufacturing electrical fittings, household utensils, and automotive components.
Resource Utilization: Converts industrial bamboo waste into high-value materials, reducing environmental pollution.

conclusion

The performance of bamboo-reinforced MF resin moulding compounds is highly dependent on four key factors: bamboo powder ratio, drying time, NaOH concentration, and moulding powder fineness. The optimal formulation (50% bamboo powder, 6h drying, 10% NaOH, 100-mesh powder) produces composites with excellent mechanical strength, fluidity, and water resistance. This study provides a practical guide for manufacturers to produce high-quality, cost-effective, and sustainable MF moulding compounds, promoting the application of bamboo resources in the material industry.

Tech Blog

Influential Factors on Melamine Moulding Compounds

Background of Melamine Moulding Compounds with Bamboo Powder