What is In-Mold Labeling (IML): Guide for Phone Case Suppliers

What is In-Mold Labeling (IML): Guide for Phone Case Suppliers

As a phone case buyer/wholesaler in Europe or the USA, some of you may have faced common pain points with traditional labeling: silk-screened designs scratch off, adhesive stickers peel, and non-recyclable materials fail EU REACH or US CPSIA standards. IML (In-Mold Labeling) solves these issues by fusing labels into phone cases during manufacturing—creating a permanent, durable finish.

This guide breaks down IML for your business, utilizing industry-proven insights to help you determine if it’s the right fit for your needs.

What is In-Mold Labeling(Tailored for Phone Cases)

IML (In-Mold Labeling) is a manufacturing technique where pre-printed labels (plastic films like PP or PET) are placed inside a mold before molten plastic is injected. As the plastic cools and solidifies, the label bonds seamlessly with the phone case—no glue, no post-production labeling, and no visible edges.
For phone cases, this means:
  • A smooth finish that fits curved surfaces (e.g., iPhone/Samsung rounded edges) without peeling.
  • Alignment with industry trends: 32% of durable phone cases in Europe and the USA used IML in 2024, per market data, with an 18% annual growth rate.

Why the IML Process Works for Your Phone Case Business

The IML process addresses three core needs, backed by industry research:

1. Unmatched Durability

Traditional labels fail fast—silk-screening scratches after 1,500 uses, stickers peel in 3–6 months. IML phone cases resist wear:
  • They pass 5,000 scratch tests (meeting ASTM standards) and withstand moisture (humid climates) and temperature swings (-20°C to 60°C), reducing returns from your retailers.

2. Customization for Shelf Appeal

IML supports high-resolution (300DPI) full-color printing—perfect for logos, IP designs, or gradients. Unlike stickers, it adapts to curved/slim phone cases without wrinkling or edge blur, helping your products stand out in crowded EU/USA markets.

3. EU/USA Compliance

IML labels use the same material as the phone case (e.g., PP label + PP case), making the product 100% recyclable. This avoids customs delays from non-compliant glue-based stickers, as it meets EU REACH, US CPSIA, and WEEE standards.

4. Cost Efficiency for Bulk Orders

IML combines molding and labeling into one step, cutting labor and equipment costs. It also has a lower defect rate (0.5% vs. 3% for manual stickers), reducing waste for bulk B2B orders.

How does In-Mold Labeling Work: Step-by-Step 

Here’s how IML phone cases are made, per established manufacturing practices:

1. Label Preparation: Pre-print PP/PET films with UV-curable ink (fade-resistant) and cut to match phone case designs.

phone case Label Preparation

2. Mold Setup: Secure labels inside a precision mold (±0.05mm accuracy) using static or clamps to avoid shifting.

3. Injection & Fusion: Inject molten plastic (PP, PC, or TPU—all compliant) at 180–220°C. The plastic fuses with the label as it cools.

in mold labeling injection molding

4.Cooling & Quality Check: Cool for 10–15 seconds, then test for label alignment, adhesion (tape test), and scratch resistance before packaging.

Quality inspection of IMLIMD phone cases

IML vs. Traditional Labeling

FactorIML ProcessSilk-ScreeningAdhesive Stickers
Durability5,000 scratch tests; no peeling1,500 scratch tests; fades fast500 scratch tests; peels in 3–6 months
CustomizationFull-color 300DPI; fits curves1–2 colors; edge blur on curvesFull-color but low precision; wrinkling
EU/USA Compliance100% recyclable; REACH/CPSIA certifiedRisk of heavy metals in inkPVC glue fails recycling standards
Unit Cost (10k+ units)$0.8–$1.2$0.9–$1.4$0.7–$1.1 (3% defect rate)
Production Cycle7–10 days (including sampling)10–14 days8–12 days (plus labeling time)

What is the Difference between IML and lMD?

You may have heard of IMD (In-Mold Decoration)—a broader category of in-mold techniques that includes IML. While both integrate decoration into the molding process, their core differences matter for your B2B phone case business:
DimensionIML (In-Mold Labeling)IMD (In-Mold Decoration)
Core DefinitionA pre-printed label film is fused to the product surface during molding, becoming part of the case.A decorative ink layer or film is transferred/embedded into the product during molding (subtypes: IMR, IMF).
Decoration Layer LocationThe label sits on the outer surface of the phone case (direct contact with hands/objects).Decorative layer is often embedded under a clear plastic topcoat (protected from wear).
Key MaterialsPP/PET label films (matched to case material for recyclability).Ink layers, PET base films, or clear protective films (e.g., PC for scratch resistance).
Customization FlexibilityIdeal for high-resolution graphics, logos, and textured finishes (e.g., matte / glossy).Excels at complex effects: 3D textures, metallic sheens, or “touch-sensitive” decorative layers.
Durability for Phone CasesHigh—label is fused to the surface, resisting scratches (5,000+ tests) and fading.Higher for embedded designs (IMR/IMF): decorative layer is protected by topcoat, but outer films can still wear.
Cost (Bulk Orders)Lower upfront cost—pre-printed labels are simpler to produce.Higher upfront cost—requires custom ink/film setups, but competitive for large volumes.
Phone Case Use CasesEveryday protective cases, brand-logo focused designs, budget-friendly B2B lines.Premium cases (e.g., luxury brands), cases with 3D textures, or designs needing long-term UV resistance.

Quick Takeaway for phone case brands:

If you prioritize affordability, recyclability, and straightforward branding (e.g., retailer private labels), IML is the better fit. If you’re selling premium phone cases with complex textures or metallic effects (targeting high-end EU/USA markets), IMD may align—but expect higher initial tooling costs. Both meet REACH/CPSIA standards (no extra glue), so compliance isn’t a differentiator.

How to Choose an IML Phone Case Supplier 

Prioritize these industry-aligned factors to avoid quality or compliance issues:
  1. IML Expertise: Choose suppliers with experience in 3C accessories (not just generic IML) to handle phone case precision.
  2. Compliance Docs: Ask for REACH, CPSIA, and CE certificates—non-negotiable for EU/USA imports.
  3. Sampling Support: Look for free samples (3–5 day turnaround) to test design fit and durability before bulk orders.
  4. Quality Control: Ensure suppliers run alignment, adhesion, and scratch tests—critical for consistent B2B quality.

Our IML Phone Case  Services 

YG offers IML/IMD phone cases to your business, grounded in proven manufacturing standards:
  • Process Options: Focus on injection molding IML (most suitable for phone cases), compatible with PP, PC, and TPU materials.
  • Compliance Support: Provide REACH, CPSIA, and CE documentation for every order to simplify customs clearance.
  • Customization: Support high-resolution (300DPI) designs for curved/slim phone cases, with design optimization for IML compatibility.
  • Sampling & Quality: Offer small-batch sampling (to test market demand) and 3-step quality checks (alignment, adhesion, scratch resistance) for bulk orders.

FAQ: IML Phone Case Questions 

Can I add anti-counterfeit features to IML phone cases?

Yes—IML labels can include hidden QR codes or holographic elements, as supported by industry IML capabilities.

Are IML phone cases recyclable?

Yes—label and case materials are identical, making them EU WEEE and US EPR compliant for standard plastic recycling.

What’s the minimum order quantity (MOQ) for IML phone cases?

We offer flexible MOQs, starting with small batches to help you test EU/USA market demand—common for B2B IML production.

Ready to Explore IML for Your Phone Case Business?

The EU/USA market demands durable, compliant, and eye-catching phone cases—and IML delivers. We’ll help you navigate every step: from sampling to bulk production, with compliance docs and quality checks built in.
Take action:
  • Submit your IML phone case request (share target model, design, and quantity) for a free quote.
  • Get a sample within 3–5 days to test fit and durability.
Contact us now→
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